bionic (3) Plotchart.3tk.gz

Provided by: tklib_0.6-3_all bug

NAME

       Plotchart - Simple plotting and charting package

SYNOPSIS

       package require Tcl  ?8.5?

       package require Tk  ?8.5?

       package require Plotchart  ?2.1.0?

       ::Plotchart::createXYPlot w xaxis yaxis args

       ::Plotchart::createStripchart w xaxis yaxis

       ::Plotchart::createTXPlot w timeaxis xaxis

       ::Plotchart::createXLogYPlot w xaxis yaxis

       ::Plotchart::createLogXYPlot w xaxis yaxis

       ::Plotchart::createLogXLogYPlot w xaxis yaxis

       ::Plotchart::createPolarPlot w radius_data

       ::Plotchart::createWindrose w radius_data sectors

       ::Plotchart::createIsometricPlot w xaxis yaxis stepsize

       ::Plotchart::createHistogram w xaxis yaxis

       ::Plotchart::create3DPlot w xaxis yaxis zaxis

       ::Plotchart::create3DRibbonPlot w yaxis zaxis

       ::Plotchart::createPiechart w

       ::Plotchart::createSpiralPie w

       ::Plotchart::createRadialchart w names scale style

       ::Plotchart::createBarchart w xlabels yaxis noseries

       ::Plotchart::createHorizontalBarchart w xaxis ylabel noseries

       ::Plotchart::create3DBarchart w yaxis nobars

       ::Plotchart::create3DRibbonChart w names yaxis zaxis

       ::Plotchart::createBoxplot w xdata ydata orientation

       ::Plotchart::createTimechart w time_begin time_end args

       ::Plotchart::createGanttchart w time_begin time_end args

       ::Plotchart::createRightAxis w_or_plot yaxis

       ::Plotchart::createTableChart w columns ?widths?

       $anyplot title text position

       $anyplot subtitle text

       $anyplot canvas

       $anyplot saveplot filename args

       $anyplot xtext text

       $anyplot ytext text

       $anyplot vtext text

       $anyplot xsubtext text

       $anyplot ysubtext text

       $anyplot vsubtext text

       $anyplot xconfig -option value ...

       $anyplot yconfig -option value ...

       $anyplot background part colour_or_image dir ?brightness?

       $anyplot xticklines colour ?dash?

       $anyplot yticklines colour ?dash?

       $anyplot legend series text ?spacing?

       $anyplot removefromlegend series

       $anyplot legendconfig -option value ...

       $anyplot balloon x y text dir

       $anyplot balloonconfig args

       $anyplot plaintext x y text dir

       $anyplot plaintextconfig args

       $anyplot object itemtype series args

       $anyplot deletedata

       $xyplot plot series xcrd ycrd

       $xyplot plotlist series xlist ylist every

       $histogram plotcumulative series xcrd ycrd

       $xyplot trend series xcrd ycrd

       $xyplot rchart series xcrd ycrd

       $xyplot interval series xcrd ymin ymax ?ycentr?

       $xyplot box-and-whiskers series xcrd ycrd

       $xyplot vector series xcrd ycrd ucmp vcmp

       $xyplot vectorconfig series -option value ...

       $xyplot dot series xcrd ycrd value

       $xyplot dotconfig series -option value ...

       $xyplot contourlines xcrd ycrd values ?classes?

       $xyplot contourlinesfunctionvalues xvec yvec valuesmat ?classes?

       $xyplot contourfill xcrd ycrd values ?classes?

       $xyplot contourbox xcrd ycrd values ?classes?

       $xyplot colorMap colours

       $xyplot legendisolines values classes

       $xyplot legendshades values classes

       $xyplot grid xcrd ycrd

       $xyplot xband ymin ymax

       $xyplot yband xmin xmax

       $xyplot labeldot x y text orient

       $polarplot plot series radius angle

       $windrose plot data colour

       $plot3d plotfunc function

       $plot3d plotfuncont function contours

       $plot3d gridsize nxcells nycells

       $plot3d plotdata data

       $plot3d colours fill border

       $plot3d ribbon yzpairs

       $plot3d plot yzpairs

       $xyplot dataconfig series -option value ...

       $pie plot data

       $pie colours colour1 colour2 ...

       $pie explode segment

       $radial plot data colour thickness

       $pie colours colour1 colour2 ...

       $barchart plot series ydata colour ?dir? ?brightness?

       $barchart config -option value ...

       $barchart plot series xdata colour ?dir? ?brightness?

       $barchart config -option value ...

       $barchart plot label yvalue colour

       $barchart config -option value ...

       $ribbon line xypairs colour

       $ribbon area xypairs colour

       $boxplot plot series label values

       $timechart period text time_begin time_end colour

       $timechart milestone text time colour

       $timechart vertline text time

       $timechart hscroll scrollbar

       $timechart vscroll scrollbar

       $ganttchart task text time_begin time_end completed

       $ganttchart milestone text time colour

       $ganttchart vertline text time

       $ganttchart connect from to

       $ganttchart summary text args

       $ganttchart color keyword newcolor

       $ganttchart font keyword newfont

       $ganttchart hscroll scrollbar

       $ganttchart vscroll scrollbar

       $isoplot plot rectangle x1 y1 x2 y2 colour

       $isoplot plot filled-rectangle x1 y1 x2 y2 colour

       $isoplot plot circle xc yc radius colour

       $isoplot plot filled-circle xc yc radius colour

       $table row items

       $table separator

       $table formatcommand procname

       $table cellconfigure args

       ::Plotchart::viewPort w pxmin pymin pxmax pymax

       ::Plotchart::worldCoordinates w xmin ymin xmax ymax

       ::Plotchart::world3DCoordinates w xmin ymin zmin xmax ymax zmax

       ::Plotchart::coordsToPixel w x y

       ::Plotchart::coords3DToPixel w x y z

       ::Plotchart::polarCoordinates w radmax

       ::Plotchart::polarToPixel w rad phi

       ::Plotchart::pixelToCoords w x y

       ::Plotchart::pixelToIndex w x y

       ::Plotchart::determineScale xmin xmax inverted

       ::Plotchart::determineScaleFromList values inverted

       ::Plotchart::plotconfig charttype component property value

       ::Plotchart::plotstyle subcmd style args

       ::Plotchart::createTargetDiagram w limits scale

       $target plot series xvalues yvalues

       ::Plotchart::createPerformanceProfile w max

       $performance plot series_and_data_pairs

       ::Plotchart::plotmethod charttype methodname plotproc

       ::Plotchart::plotpack w dir args

       $anyplot bindplot event command args

       $anyplot bindlast series event command

_________________________________________________________________

DESCRIPTION

       Plotchart is a Tcl-only package that focuses on the easy creation of xy-plots, barcharts and other common
       types of graphical presentations.  The  emphasis  is  on  ease  of  use,  rather  than  flexibility.  The
       procedures  that  create  a  plot  use the entire canvas window, making the layout of the plot completely
       automatic.

       This results in the creation of an xy-plot in, say, ten lines of code:

                  package require Plotchart

                  canvas .c -background white -width 400 -height 200
                  pack   .c -fill both

                  #
                  # Create the plot with its x- and y-axes
                  #
                  set s [::Plotchart::createXYPlot .c {0.0 100.0 10.0} {0.0 100.0 20.0}]

                  foreach {x y} {0.0 32.0 10.0 50.0 25.0 60.0 78.0 11.0 } {
                      $s plot series1 $x $y
                  }

                  $s title "Data series"

       A drawback of the package might be that it does not do any data management. So if the canvas  that  holds
       the  plot  is  to be resized, the whole plot must be redrawn.  The advantage, though, is that it offers a
       number of plot and chart types:

       •      XY-plots like the one shown above with any number of data series.

       •      Stripcharts, a kind of XY-plots where the horizontal axis is adjusted automatically. The result is
              a kind of sliding window on the data series.

       •      Polar plots, where the coordinates are polar instead of cartesian.

       •      Histograms, for plotting statistical information.

       •      Isometric plots, where the scale of the coordinates in the two directions is always the same, i.e.
              a circle in world coordinates appears as a circle on the screen.

              You can zoom in and out, as well as pan with these plots (Note: this works best  if  no  axes  are
              drawn, the zooming and panning routines do not distinguish the axes), using the mouse buttons with
              the control key and the arrow keys with the control key.

       •      Piecharts, with automatic scaling to indicate the proportions.

       •      Barcharts, with either vertical or horizontal bars, stacked bars or bars side by side.

       •      Timecharts, where bars indicate a time period and milestones or other important  moments  in  time
              are represented by triangles.

       •      3D plots (both for displaying surfaces and 3D bars)

       With  version  1.5 a new command has been introduced: plotconfig, which can be used to configure the plot
       options for particular types of plots and charts (cf. CONFIGURATION OPTIONS) With version  1.8.3  several
       new features were introduced, which allow more interactivity (cf. INTERACTIVE USE)

PLOT CREATION COMMANDS

       You create the plot or chart with one single command and then fill the plot with data:

       ::Plotchart::createXYPlot w xaxis yaxis args
              Create a new xy-plot (configuration type: xyplot).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A  3-element  list  containing minimum, maximum and stepsize for the x-axis, in this order.
                     For an inverted axis, where the maximum  appears  on  the  left-hand  side,  use:  maximum,
                     minimum and a negative stepsize.

              list yaxis (in)
                     A  3-element  list  containing minimum, maximum and stepsize for the y-axis, in this order.
                     For an inverted axis, where the maximum appears at the bottom, use: maximum, minimum and  a
                     negative stepsize.

              list args (in)
                     Zero or more options that influence the appearance of the plot:

                     •      -xlabels {labels}: Custom labels for the x-axis. If the labels are numeric, they are
                            positioned according to the given scale, otherwise they are  positioned  with  equal
                            distance,  based  on  the number of labels. Note: this only works if the stepsize of
                            the xaxis argument is the empty string.

                     •      -ylabels {labels}: Similarly, custom labels for the y-axis.

                     •      -box {measures}: See ARRANGING MULTIPLE PLOTS IN A CANVAS-axesbox {measures}: See ARRANGING MULTIPLE PLOTS IN A CANVAS

       ::Plotchart::createStripchart w xaxis yaxis
              Create a new strip chart (configuration type: stripchart). The only difference  to  a  regular  XY
              plot  is  that  the  x-axis  will  be  automatically adjusted when the x-coordinate of a new point
              exceeds the maximum.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the x-axis,  in  this  order.
                     Note that an inverted x-axis is not supported for this type of plot.

              list yaxis (in)
                     A  3-element  list  containing minimum, maximum and stepsize for the y-axis, in this order.
                     For an inverted axis, where the maximum appears at the bottom, use: maximum, minimum and  a
                     negative stepsize.

       ::Plotchart::createTXPlot w timeaxis xaxis
              Create  a  new  time-x-plot  (configuration  type:  txplot).  The  horizontal  axis represents the
              date/time of the data and the vertical axis the values themselves.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list timeaxis (in)
                     A 3-element list containing the minimum and maximum date/time to be shown and the  stepsize
                     (in  days)  for  the  time-axis,  in  this  order.   Note that an inverted time-axis is not
                     supported.

              list xaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the vertical  axis,  in  this
                     order.   For  an  inverted  axis,  where  the  maximum appears at the bottom, use: maximum,
                     minimum and a negative stepsize.

       ::Plotchart::createXLogYPlot w xaxis yaxis
              Create a new xy-plot where the y-axis has a logarithmic scale (configuration type: xlogyplot).

              The data should be given as for a linear scale, as the  logarithmic  transformation  is  taken  of
              internally.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A  3-element  list  containing minimum, maximum and stepsize for the x-axis, in this order.
                     For an inverted axis, where the maximum  appears  on  the  left-hand  side,  use:  maximum,
                     minimum and a negative stepsize.

              list yaxis (in)
                     A  2-element  list containing minimum and maximum for the y-axis, in this order.  Note that
                     an inverted logarithmic axis is not supported.

       ::Plotchart::createLogXYPlot w xaxis yaxis
              Create a new xy-plot where the x-axis has a logarithmic scale (configuration type: logxyplot).

              The data should be given as for a linear scale, as the  logarithmic  transformation  is  taken  of
              internally.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A  2-element  list containing minimum and maximum for the x-axis, in this order.  Note that
                     an inverted logarithmic axis is not supported.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis,  in  this  order.
                     For  an  inverted  axis,  where  the  maximum  appears on the left-hand side, use: maximum,
                     minimum and a negative stepsize.

       ::Plotchart::createLogXLogYPlot w xaxis yaxis
              Create a new xy-plot where both the x-axis and the y-axis have a logarithmic scale  (configuration
              type: logxlogyplot).

              The  data  should  be  given  as for a linear scale, as the logarithmic transformation is taken of
              internally.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A 2-element list containing minimum and maximum for the x-axis, in this order.   Note  that
                     an inverted logarithmic axis is not supported.

              list yaxis (in)
                     A  2-element  list containing minimum and maximum for the y-axis, in this order.  Note that
                     an inverted logarithmic axis is not supported.

       ::Plotchart::createPolarPlot w radius_data
              Create a new polar plot (configuration type: polarplot).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list radius_data (in)
                     A 2-element list containing maximum radius and stepsize for the radial axis, in this order.

       ::Plotchart::createWindrose w radius_data sectors
              Create a new windrose diagram. The diagram will consist of concentric circles as  defined  by  the
              radius_data  argument  and  a  number  of sectors (given by the sectors argument). The sectors are
              drawn in the "nautical" convention, that is: the first is located  at  the  positive  y-axis,  the
              second is to the right and so on in a clockwise direction.

              widget w (in)
                     Name of the existing canvas widget to hold the diagram

              list radius_data (in)
                     A  2-element  list,  the  first element is the maximum radius, the second is the step to be
                     used for the circles.

              int sectors
                     Number of sectors to use (defaults to 16).

       ::Plotchart::createIsometricPlot w xaxis yaxis stepsize
              Create a new isometric plot, where the vertical and the horizontal coordinates are scaled so  that
              a circle will truly appear as a circle (configuration type: isometric).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A 2-element list containing minimum, and maximum for the x-axis, in this order.

              list yaxis (in)
                     A 2-element list containing minimum, and maximum for the y-axis, in this order.

              float|noaxes stepsize (in)
                     Either  the  stepsize  used  by  both axes or the keyword noaxes to signal the plot that it
                     should use the full area of the widget, to not draw any of the axes.

       ::Plotchart::createHistogram w xaxis yaxis
              Create a new histogram (configuration type: histogram).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

       ::Plotchart::create3DPlot w xaxis yaxis zaxis
              Create a new 3D plot.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

              list zaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the z-axis, in this order.

       ::Plotchart::create3DRibbonPlot w yaxis zaxis
              Create a new 3D ribbon plot. It is a simplification of the full 3D plot and allows for the drawing
              of a ribbon only (the x-axis is dropped).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

              list zaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the z-axis, in this order.

       ::Plotchart::createPiechart w
              Create a new piechart (configuration type: piechart).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

       ::Plotchart::createSpiralPie w
              Create  a  new "spiral pie" (configuration type: spiralpie), a variation on the ordinary piechart.
              The value is used to scale the radius, rather than the angle. By default the data are sorted.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

       ::Plotchart::createRadialchart w names scale style
              Create a new radial chart (the data are drawn as a line connecting  the  spokes  of  the  diagram)
              (configuration type: radialchart).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list names (in)
                     Names for the spokes.

              float scale (in)
                     Scale value to determine the position of the data along the spokes.

              string style (in)
                     Style of the chart (optional). One of:

                     •      lines - the default: draw the data as independent polylines.

                     •      cumulative - draw the data as polylines where the data are accumulated.

                     •      filled - draw the data as filled polygons where the data are accumulated

       ::Plotchart::createBarchart w xlabels yaxis noseries
              Create  a new barchart with vertical bars (configuration type: vertbars). The horizontal axis will
              display the labels contained in the argument xlabels. The  number  of  series  given  by  noseries
              determines both the width of the bars, and the way the series will be drawn.

              If  the  keyword  stacked  was  specified  the  series will be drawn stacked on top of each other.
              Otherwise each series that is drawn will be drawn shifted to the right.

              The number of series determines the width of the bars, so that there is space of  that  number  of
              bars.  If  you  use  a floating-point number, like 2.2, instead of an integer, like 2, a small gap
              between the sets of bars will be drawn - the width depends on the fractional part.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xlabels (in)
                     List of labels for the x-axis. Its length also determines the number of bars that  will  be
                     plotted per series.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

              int|stacked noseries (in)
                     The  number  of  data series that will be plotted. This has to be an integer number greater
                     than zero (if stacked is not used).

       ::Plotchart::createHorizontalBarchart w xaxis ylabel noseries
              Create a new barchart with horizontal bars (configuration type: horizbars). The vertical axis will
              display  the  labels  contained  in  the  argument ylabels. The number of series given by noseries
              determines both the width of the bars, and the way the series will be drawn.

              If the keyword stacked was specified the  series  will  be  drawn  stacked  from  left  to  right.
              Otherwise each series that is drawn will be drawn shifted upward.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the x-axis, in this order.

              list ylabels (in)
                     List  of  labels for the y-axis. Its length also determines the number of bars that will be
                     plotted per series.

              int|stacked noseries (in)
                     The number of data series that will be plotted. This has to be an  integer  number  greater
                     than zero (if stacked is not used).

       ::Plotchart::create3DBarchart w yaxis nobars
              Create a new barchart with 3D vertical bars (configuration type: 3dbars). The horizontal axis will
              display the labels per bar. The number of bars given by nobars determines  the  position  and  the
              width of the bars. The colours can be varied per bar. (This type of chart was inspired by the Wiki
              page on 3D bars by Richard Suchenwirth.)

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

              int nobars (in)
                     The number of bars that will be plotted.

       ::Plotchart::create3DRibbonChart w names yaxis zaxis
              Create a new "ribbon chart" (configuration type: 3dribbon). This is a chart where the data  series
              are  represented  as ribbons in a three-dimensional axis system. Along the x-axis (which is "into"
              the screen) the names are plotted, each representing a single series. The first plot command draws
              the furthest series, the second draws the series in front of that and so on.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              widget w (in)
                     Names of the series, plotted as labels along the x-axis

              list yaxis (in)
                     A   3-element  list  containing  minimum,  maximum  and  stepsize  for  the  y-axis  (drawn
                     horizontally!), in this order.

              list zaxis (in)
                     A  3-element  list  containing  minimum,  maximum  and  stepsize  for  the  z-axis   (drawn
                     vertically), in this order.

              int nobars (in)
                     The number of bars that will be plotted.

       ::Plotchart::createBoxplot w xdata ydata orientation
              Create  a  new  boxplot  with horizontal or vertical boxes (box-and-whiskers) (configuration type:
              boxplot). Depending on the orientation the x- or y-axis is drawn with labels. The boxes are  drawn
              based on the raw data (see the plot subcommand for this type of plot).

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list xdata (in)
                     This is either a 3-element list containing minimum, maximum and stepsize for the x-axis, in
                     this order (when orientation is horizontal), or a list  of  labels  for  the  x-axis  (when
                     orientation  is vertical). The length of the label list also determines the number of boxes
                     that can be plotted. The labels are also used in the plot subcommand.

              list ydata (in)
                     This is either a 3-element list containing minimum, maximum and stepsize for the y-axis, in
                     this  order  (when  orientation  is  vertical),  or  a  list of labels for the y-axis (when
                     orientation is horizontal). The length of the label list  also  determines  the  number  of
                     boxes that can be plotted. The labels are also used in the plot subcommand.

              string orientation (in)
                     If given, "horizontal" or "vertical" determines the orientation of the boxes. This optional
                     value (default: horizontal) also determines the  interpretation  of  the  xdata  and  ydata
                     arguments.

       ::Plotchart::createTimechart w time_begin time_end args
              Create  a  new  timechart  (configuration  type:  timechart).   The time axis (= x-axis) goes from
              time_begin to time_end, and the vertical spacing is determined by the number of items to plot.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              string time_begin (in)
                     The start time given in a form that is recognised  by  the  clock  scan  command  (e.g.  "1
                     january 2004").

              string time_end (in)
                     The  end time given in a form that is recognised by the clock scan command (e.g. "1 january
                     2004").

              arguments args (in)
                     The remaining arguments can be:

                     •      The expected/maximum number of items. This  determines  the  vertical  spacing.  (If
                            given, it must be the first argument after "time_end"

                     •      The  keyword  -barheight  and  the  number of pixels per bar. This is an alternative
                            method to determine the vertical spacing.

                     •      The keyword -ylabelwidth and the number of pixels to reserve for the labels  at  the
                            y-axis.

       ::Plotchart::createGanttchart w time_begin time_end args
              Create  a  new  Gantt  chart (configuration type: ganttchart).  The time axis (= x-axis) goes from
              time_begin to time_end, and the vertical spacing is determined by the number  of  items  to  plot.
              Via the specific commands you can then add tasks and connections between the tasks.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              string time_begin (in)
                     The  start  time  given  in  a  form  that is recognised by the clock scan command (e.g. "1
                     january 2004").

              string time_end (in)
                     The end time given in a form that is recognised by the clock scan command (e.g. "1  january
                     2004").

              arguments args (in)
                     The remaining arguments can be:

                     •      The  expected/maximum  number  of  items.  This determines the vertical spacing. (If
                            given this way, it must be the first argument after "time_end")

                     •      The expected/maximum width of the descriptive text (roughly in characters,  for  the
                            actual  space  reserved  for  the  text, it is assumed that a character is about ten
                            pixels wide). Defaults to 20. (If given this way, it must  be  the  second  argument
                            after "time_end").

                     •      The  keyword  -barheight  and  the  number of pixels per bar. This is an alternative
                            method to determine the vertical spacing.

                     •      The keyword -ylabelwidth and the number of pixels to reserve for the labels  at  the
                            y-axis.

       ::Plotchart::createRightAxis w_or_plot yaxis
              Create  a  plot  command  that will use a right axis instead of the left axis (configuration type:
              inherited from the existing plot). The canvas widget must already contain an ordinary plot, as the
              horizontal axis and other properties are reused. Preferably use the plot command, as with multiple
              plots in a canvas (also when redefining an existing plot!), the wrong geometry might be used.

              To plot data using the right axis, use this new command, to plot data using the left axis, use the
              original plot command.

              widget w_or_plot (in)
                     Name  of the existing canvas widget to hold the plot or preferably the plot command for the
                     plot with the left axis.

              list yaxis (in)
                     A 3-element list containing minimum, maximum and stepsize for the y-axis, in this order.

       ::Plotchart::createTableChart w columns ?widths?
              Create a command to draw a table. You can use a variety of commands to draw the actual rows of the
              table, but the number of columns is fixed.  (See TABLE CHARTS for an example)

              widget w (in)
                     Name of the canvas widget to hold the table.

              list columns (in)
                     The  headers  of  the columns in the table. The number of elements determines the number of
                     columns.

              list widths (in)
                     If given, either a single value, the width in pixels for all columns or for each column the
                     width  of  that  column. If not given, the table is spread out over the width of the canvas
                     (minus the margins).

PLOT METHODS

       Each of the creation commands explained in the last section returns the name of a new object command that
       can  be  used to manipulate the plot or chart. The subcommands available to a chart command depend on the
       type of the chart.

       General subcommands for all types of charts. \$anyplot is the command returned by the creation command:

       $anyplot title text position
              Specify the title of the whole chart.

              string text (in)
                     The text of the title to be drawn.

              string position (in)
                     The position of the title. The default position is "center", but you can alternatively  use
                     "left" or "right". You can use multiple titles with different positions.

       $anyplot subtitle text
              Specify the subtitle of the whole chart.

              string text (in)
                     The text of the subtitle to be drawn.

       $anyplot canvas
              Return  the  name  of the canvas (or the alias if you use more than one plot within a canvas). Use
              this value for the coordinate transformations.

       $anyplot saveplot filename args
              Draws the plot into a file, using PostScript.

              string filename (in)
                     Contain the path name of the file to write the plot to.

              list args (in)
                     If the standard PostScript output is used, the option -plotregion can be specifed  to  save
                     the  whole  plot  (value:  bbox)  regardless of what is visible in the window.  The default
                     (value: window) is to only plot the visible part of the plot.

                     Optionally you can specify the option -format "some picture format" to store the plot in  a
                     different  file  than a PostScript file. This, however, relies on the Img package to do the
                     actual job.

                     Note: Because the window holding the plot must be fully visible before Img can successfully
                     grab  it,  it  is  raised  first.   On some systems, for instance Linux with KDE, raising a
                     window is not done automatically, but instead you need to click on the window in  the  task
                     bar. Similar things happen on Windows XP.

                     There  seems  to be something wrong under some circumstances, so instead of waiting for the
                     visibility of the window, the procedure simply waits two seconds. It is not ideal,  but  it
                     seems to work better.

       $anyplot xtext text
              Specify the title of the (horizontal) x-axis, for those plots that have a straight x-axis.

              string text (in)
                     The text of the x-axis label to be drawn.

       $anyplot ytext text
              Specify the title of the (horizontal) y-axis, for those plots that have a straight y-axis.

              string text (in)
                     The text of the y-axis label to be drawn.

       $anyplot vtext text
              Draw  a  vertical  label to the y-axis. Note: this requires Tk 8.6 or later, for older versions it
              does nothing.

              string text (in)
                     Text to drawn to the y-axis

       $anyplot xsubtext text
              Specify the subtext of the (horizontal) x-axis, for those plots that have a straight x-axis.  This
              text is drawn below the primary text.

              Since  this  involves positioning the primary text and setting margins, you need to set the option
              "usesubtext" for the bottom axis via the plotstyle command. The relevant options are:  usesubtext,
              subtextcolor and subtextfont.

              string text (in)
                     The secondary text of the x-axis label to be drawn.

       $anyplot ysubtext text
              Specify  the  subtext  of the (vertical) y-axis, for those plots that have a straight y-axis. This
              text is drawn below the primary text, for both axes on the left and the right.

              Since this involves positioning the primary text and setting margins, you need to set  the  option
              "usesubtext"  for  the  left  or  right  axis via the plotstyle command. The relevant options are:
              usesubtext, subtextcolor and subtextfont.

              string text (in)
                     The secondary text of the y-axis label to be drawn.

       $anyplot vsubtext text
              Specify the subtext of the (vertical) y-axis, for those plots that have a  straight  y-axis.  This
              text is drawn to the right of the primary text, for both axes on the left and the right.

              Since  this  involves positioning the primary text and setting margins, you need to set the option
              "usesubtext" for the left or right axis via the  plotstyle  command.  The  relevant  options  are:
              usevsubtext,  vsubtextcolor  and  vsubtextfont.  (Note the "v" to distinguish this option from the
              text at the top of a vertical axis that is drawn via $anyplot ytext or $anyplot ysubtext.)

              string text (in)
                     The secondary (vertical) text of the y-axis label to be drawn.

       $anyplot xconfig -option value ...
              Set one or more configuration parameters for the x-axis.  The following options are supported:

              format fmt
                     The format for the numbers along the axis.

              ticklength length
                     The length of the tickmarks (in pixels).

              ticklines boolean
                     Whether to draw ticklines (true) or not (false).

              scale scale_data
                     New scale data for the axis, i.e. a 3-element list containing minimum, maximum and stepsize
                     for the axis, in this order.

                     Beware: Setting this option will clear all data from the plot.

       $anyplot yconfig -option value ...
              Set  one or more configuration parameters for the y-axis. This method accepts the same options and
              values as the method xconfig.

       $anyplot background part colour_or_image dir ?brightness?
              Set the background of a part of the plot

              string part
                     Which part of the plot: "axes" for the axes  area  and  "plot"  for  the  inner  part.  The
                     interpretation depends on the type of plot. Two further possibilities are:

                     •      image, in which case a predefined image is loaded into the background of the plot.

                     •      gradient,  in which case the background is coloured in different shades of the given
                            colour. The "dir" argument specifies the direction in which the colour gets whiter.

              string colour_or_image
                     Colour for that part or the name of the image if "part" is "image"

              string dir
                     The direction of the gradient. One of: top-down, bottom-up, left-right or right-left.

              string brightness
                     Indicates whether the colour should become brighter (bright) or darker (dark). Defaults  to
                     bright

       $anyplot xticklines colour ?dash?
              Draw vertical ticklines at each tick location

              string colour
                     Colour  of  the  lines.  Specifying  an  empty colour ("") removes them again.  Defaults to
                     "black"

              string dash
                     Optional argument to specify the dash pattern for the lines. Defaults to  "lines"  Possible
                     values:  lines,  dots1,  dots2,  dots3,  dots4,  dots5.   The  actual effect depends on the
                     platform.

       $anyplot yticklines colour ?dash?
              Draw horizontal ticklines at each tick location

              string colour
                     Colour of the lines. Specifying an empty colour ("") removes them again Defaults to "black"

              string dash
                     Optional argument to specify the dash pattern for the lines. Defaults to  "lines"  Possible
                     values:  lines,  dots1,  dots2,  dots3,  dots4,  dots5.   The  actual effect depends on the
                     platform.

       $anyplot legend series text ?spacing?
              Add an entry to the legend. The series determines which graphical symbol is to be used. (As a side
              effect the legend is actually drawn.)

              string series
                     Name  of  the  data  series. This determines the colour of the line and the symbol (if any)
                     that will be drawn.

              string text
                     Text to be drawn next to the line/symbol.

              integer spacing
                     Optional argument to specify the vertical spacing between the entries (in  pixels).   (Note
                     that this spacing will be reused later.)

       $anyplot removefromlegend series
              Remove an entry for a series from the legend and redraw it.

              string series
                     Name of the data series to be removed.

       $anyplot legendconfig -option value ...
              Set  one or more options for the legend. The legend is drawn as a rectangle with text and graphics
              inside.

              background colour
                     Set the colour of the background (the default colour is white).  Set to  the  empty  string
                     for a transparant legend.

              border colour
                     Set  the colour of the border (the default colour is black). Set to the empty string if you
                     do not want a border.

              canvas c
                     Draw the legend in a different canvas widget. This gives you the freedom  to  position  the
                     legend outside the actual plot.

              font font
                     Set the font used to draw the text next to the symbol.

              legendtype
                     Override  the  type of the legend, that is pre-defined for the current type of plot. May be
                     one of: rectangle or line.

              position corner
                     Set the position of the legend. May be one of: top-left, top-right, bottom-left or  bottom-
                     right. (Default value is top-right.)

       $anyplot balloon x y text dir
              Add  balloon  text  to the plot (except for 3D plots). The arrow will point to the given x- and y-
              coordinates. For xy-graphs and such, the  coordinates  are  directly  related  to  the  axes;  for
              vertical  barcharts  the  x-coordinate  is  measured as the number of bars minus 1 and similar for
              horizontal barcharts.

              float x
                     X-coordinate of the point that the arrow of the balloon will point to.

              float y
                     Y-coordinate of the point that the arrow of the balloon will point to.

              string text
                     Text to be drawn in the balloon.

              string dir
                     Direction of the arrow, one of: north, north-east,  east,  south-east,  south,  south-west,
                     west or north-west.

       $anyplot balloonconfig args
              Configure the balloon text for the plot. The new settings will be used for the next balloon text.

              font fontname
                     Font to be used for the text

              justify left|center|right
                     Way to justify multiline text

              textcolour colour
                     Colour for the text (synonym: textcolor)

              background colour
                     Background colour for the balloon

              outline colour
                     Colour of the outline of the balloon

              margin value
                     Margin around the text (in pixels)

              rimwidth value
                     Width of the outline of the balloon (in pixels)

              arrowsize value
                     Length factor for the arrow (in pixels)

       $anyplot plaintext x y text dir
              Add  plain  text  to the plot (except for 3D plots). The text is positioned at the given x- and y-
              coordinates. For xy-graphs and such, the  coordinates  are  directly  related  to  the  axes;  for
              vertical  barcharts  the  x-coordinate  is  measured as the number of bars minus 1 and similar for
              horizontal barcharts.

              float x
                     X-coordinate of the text position

              float y
                     Y-coordinate of the text position

              string text
                     Text to be drawn.

              string dir
                     Anchor for the text, one of: north, north-east, east, south-east, south,  south-west,  west
                     or north-west.

       $anyplot plaintextconfig args
              Configure the plain text annotation for the plot. The new settings will be used for the next plain
              text.

              font fontname
                     Font to be used for the text

              justify left|center|right
                     Way to justify multiline text

              textcolour colour
                     Colour for the text (synonym: textcolor)

       $anyplot object itemtype series args
              Draw a canvas item in the plot where the coordinates are scaled using the coordinate system of the
              plot. In addition to the standard canvas types, it also supports circles, dots and crosses.

              Note: Currently implemented for xy-plots, (vertical and horizontal) barcharts, and piecharts.

              Note:  To  add an entry in the legend for the object, you can use the dataconfig subcommand with a
              type "rectangle". This will cause a rectangle to be shown.

              string itemtype (in)
                     Name of a standard canvas item or "circle", "dot" or "cross"

              string series (in)
                     The data series it belongs to, used for setting the default drawing options

              list args (in)
                     List of coordinates and drawing options

       $anyplot deletedata
              Remove the lines, symbols and other graphical object associated with  the  actual  data  from  the
              plot.

              Note: Currently implemented for xy-plots only

              Note: The existing options for data series and the legend entry are kept as they were.

              Note: Currently there are side effects if the canvas contains more than one plot.

       Note:  The  commands  xconfig and yconfig are currently implemented only for XY-plots and only the option
       -format has any effect.

       For xy plots, stripcharts, histograms and time-x-plots:

       $xyplot plot series xcrd ycrd
              Add a data point to the plot.

              string series (in)
                     Name of the data series the new point belongs to.

              float xcrd (in)
                     X-coordinate of the new point. (For time-x plots this must be valid date/time that  can  be
                     read with the clock scan command).

              float ycrd (in)
                     Y-coordinate of the new point.

       For  xy  plots  there  is the additional command plotlist, which is useful for plotting a large amount of
       data:

       $xyplot plotlist series xlist ylist every
              Draw a series of data as a whole. If symbols are asked for, draw them  only  for  every  Nth  data
              point.

              string series (in)
                     Name of the data series the new point belongs to.

              float xlist (in)
                     List of X-coordinates for the data series.

              float ycrd (in)
                     List of Y-coordinates for the data series.

              int every (in)
                     Optional  argument stating how often a symbol (if any) should be drawn.  If left out, use a
                     simple heuristic: N = sqrt(number of data points).

       Note on histograms:

       For histograms the x-coordinate that is given is interpreted to be the x-coordinate of the right side  of
       the  bar  (or line segment). The first bar starts at the y-axis on the left. To completely fill the range
       of the x-axis, you should draw a bar at the maximum x-coordinate.

       For histograms you can also use the plotcumulative command:

       $histogram plotcumulative series xcrd ycrd

       The arguments mean exactly the same as for the plot command, but the data are accumulated to the previous
       values.

       For xy plots:

       $xyplot trend series xcrd ycrd
              Draw or update a trend line using the data given sofar.

              string series (in)
                     Name of the data series the trend line belongs to.

              float xcrd (in)
                     X-coordinate of the new data point

              float ycrd (in)
                     Y-coordinate of the new data point

       $xyplot rchart series xcrd ycrd
              Draw  data in the same way as the plot method, but with two lines added that indicate the expected
              range (+/- 3*standard deviation) of the data.

              string series (in)
                     Name of the data series the data point belongs to.

              float xcrd (in)
                     X-coordinate of the new data point

              float ycrd (in)
                     Y-coordinate of the new data point

       $xyplot interval series xcrd ymin ymax ?ycentr?
              Add a vertical error interval to the plot. The interval is drawn from ymin to ymax. If the  ycentr
              argument is given, a symbol is drawn at that position.

              string series (in)
                     Name of the data series the interval belongs to.

              float xcrd (in)
                     X-coordinate of the interval

              float ymin (in)
                     Minimum y-coordinate of the interval.

              float ymax (in)
                     Maximum y-coordinate of the interval.

              float ycentr (in)
                     Y-coordinate to draw the symbol at (optional)

       $xyplot box-and-whiskers series xcrd ycrd
              Draw  a  box  and  whiskers  in the plot. If the argument xcrd is a list of several values and the
              argument ycrd is a single value, a horizontal box is drawn with the quartiles determined from  the
              list of values contained in xcrd.

              If,  instead,  the  argument ycrd contains a list of several values and the argument xcrd a single
              value, then a vertical box is drawn and the quartiles are determined from  ycrd.  (There  must  be
              exactly one list of several values. Otherwise an error is reported.)

              The  option  -boxwidth  to  the  dataconfig  command  determines  the width (or height) of the box
              (default: 10 pixels).

              The option -whiskers to the dataconfig command determines whether the whiskers are  drawn  to  the
              extreme values (value: extremes), to 1.5 times the interquartile range (value: IQR or iqr), or not
              at all (value: none).  If the value is 'IQR' (uppercase), then also extreme values will  be  shown
              (from  1.5  to  3  times  the  IQR  as  dots,  above  3 times IQR as stars). If the value is 'iqr'
              (lowercase) no extreme values will be shown (default value: IQR).

              The option -whiskerwidth to the dataconfig command determines the thickness of the line that draws
              the whiskers (default: 1 pixel).

              The  option -mediancolour to the dataconfig command determines the colour of the line used to draw
              the median within the box (default: same as -colour).

              The option -medianwidth to the dataconfig command determines the thickness of the line that  draws
              the median within the box (default: 1 pixel).

              string series (in)
                     Name of the data series the box-and-whiskers belongs to.

              float xcrd (in)
                     X-coordinate of the box or a list of values.

              float ymin (in)
                     Y-coordinate of the box or a list of values.

       The  box  ends  at  the  1st  and 3rd quartile, while the whiskers by default are plotted to span 1.5 IQR
       (interquartile range) from the 1st and 3rd quartile.

       $xyplot vector series xcrd ycrd ucmp vcmp
              Draw a vector in the plot. The  vector  can  be  given  as  either  cartesian  coordinates  or  as
              length/angle,  where  the  angle  is  in  degrees and is interpreted according to the mathematical
              convention or the nautical.  (See the vectorconfig subcommand)

              string series (in)
                     Name of the series the vector belongs to. Determines the appearance and interpretation.

              float xcrd (in)
                     X-coordinate of the point where the arrow appears

              float ycrd (in)
                     Y-coordinate of the point where the arrow appears

              float ucmp (in)
                     X-component or the length of the vector

              float ycentr (in)
                     Y-component or the angle of the vector

       $xyplot vectorconfig series -option value ...
              ] Set the vector drawing options for a particular series

              string series (in)
                     Name of the series the vector belongs to.

              The options can be one of the following:

              colour The colour of the arrow (default: black; synonym: color)

              scale value
                     The scale factor used to convert the length of the arrow into a number of pixels  (default:
                     1.0)

              centred onoff
                     Logical  value  indicating that the xy-coordinates are to be used as the start of the arrow
                     or as the centre (default: 0; synonym: centered)

              type keyword
                     Interpretation of the vector components. Can be "cartesian" (default), in which case the x-
                     and  y-components are expected, "polar" (the angle 0 coincides with the positive x-axis, 90
                     coincides with the positive y-axis) or "nautical" (0 is "north" and 90 is "east").

       $xyplot dot series xcrd ycrd value
              Draw a dot in the plot. The size and colour is determined by the value and by the options set  for
              the series it belongs to.  (See the dotconfig subcommand)

              string series (in)
                     Name of the series the dot belongs to. Determines size and colour

              float xcrd (in)
                     X-coordinate of the point where the arrow appears

              float ycrd (in)
                     Y-coordinate of the point where the arrow appears

              float value (in)
                     Value determining size and colour

       $xyplot dotconfig series -option value ...
              ] Set the dot drawing options for a particular series

              string series (in)
                     Name of the series the dot belongs to.

              The options can be one of the following:

              colour The  colour  of  the  dot  if no scaling is used or the value exceeds the last limit of the
                     classes.

              scale value
                     The scale factor used to convert the value into the radius of the dot in  pixels  (default:
                     1.0)

              radius value
                     The  default  radius of the dots, used if there is no scaling by value (in pixels; default:
                     3)

              scalebyvalue onoff
                     Determines whether the dots all have the same size or a size depending on the  given  value
                     (default: on).

              outline onoff
                     Draw a black circle around the dot or not (default: on)

              classes list
                     Set the limits and the corresponding colours. For instance:

                         $xyplot series1 -classes {0 blue 1 green} -colour red

                     will  cause  a  blue  dot  to  be  drawn  for values smaller than 0, a green dot for values
                     larger/equal 0 but lower than 1 and a red dot for values larger/equal 1.

              3deffect onoff
                     Show a highlight in the dots, to mimick a 3D effect (default: off)

                     If there is no list of classes for the particular series, the dots are scaled by the value.

                     You can combine the colouring by value and the scaling  by  value  by  setting  a  list  of
                     classes and setting the scalebyvalue option on.

       $xyplot contourlines xcrd ycrd values ?classes?
              Draw  contour  lines  for  the  values given on the grid. The grid is defined by the xcrd and ycrd
              arguments. The xcrd argument (resp. ycrd) is expected to be a matrix, implemented  as  a  list  of
              lists  which gives the x-coordinates (resp. y-coordinates) of the grid cell corners.  The function
              values are given at these corners.  The number of rows in xvec (resp. yvec) is  ny  and  each  row
              contains  nx  values  so  that  the  total  number of values in xvec (resp. yvec) is nx * ny.  The
              classes determine which contour lines are drawn. If a value on one of the corners is missing,  the
              contour lines in that cell will not be drawn.

              Entries in the legend are drawn via the legendisolines subcommand.

              list xcrd (in)
                     List of lists, each value is an x-coordinate for a grid cell corner

              list ycrd (in)
                     List of lists, each value is an y-coordinate for a grid cell corner

              list values (in)
                     List of lists, each value is the value at a grid cell corner

              list classes (in)
                     List  of  class  values or a list of lists of two elements (each inner list the class value
                     and the colour to be used). If empty or missing, the classes are determined automatically.

                     Note: The class values must enclose the whole range of values.  Note: The xcrd argument  is
                     generally  made  of nypoints identical rows, while each row of ycrd is made with one single
                     value.

       $xyplot contourlinesfunctionvalues xvec yvec valuesmat ?classes?
              Draw contour lines for the values given on the grid. The grid is defined  by  the  xvec  and  yvec
              arguments. Here, xvec (resp. yvec) is a list of x-coordinates (resp. y-coordinates). The number of
              values in xvec (resp. yvec) is the number of points in the x-coordinate (resp. y-coordinate).  The
              function  values  are given at these corners. The classes determine which contour lines are drawn.
              If a value on one of the corners is missing, the contour lines in that cell will not be drawn.

              Entries in the legend are drawn via the legendisolines subcommand.

              list xcrd (in)
                     List of x-coordinates in increasing order.

              list ycrd (in)
                     List y-coordinates in increasing order.

              list valuesmat (in)
                     List of lists, each value is the value at a grid cell corner.  The total number  of  values
                     is valuesmat is nx * ny.

              list classes (in)
                     List  of  class  values or a list of lists of two elements (each inner list the class value
                     and the colour to be used). If empty or missing, the classes are determined automatically.

                     Note: The class values must enclose the whole range of values.

       $xyplot contourfill xcrd ycrd values ?classes?
              Draw filled contours for the values given on the grid. (The use of this method is identical to the
              "contourlines" method).

              Entries in the legend are drawn via the legendshades subcommand.

       $xyplot contourbox xcrd ycrd values ?classes?
              Draw  the  cells as filled quadrangles. The colour is determined from the average of the values on
              all four corners.

              Entries in the legend are drawn via the legendshades subcommand.

       $xyplot colorMap colours
              Set the colours to be used with the contour methods. The argument is either a predefined colourmap
              (grey/gray,  jet,  hot  or  cool)  or  a  list of colours. When selecting the colours for actually
              drawing the contours, the given colours will be interpolated (based on the HLS scheme).

              list colours (in)
                     List of colour names or colour values or one of the predefined maps:

                     •      grey or gray: gray colours from dark to light

                     •      jet: rainbow colours

                     •      hot: colours from yellow via red to darkred

                     •      cool: colours from cyan via blue to magenta

       $xyplot legendisolines values classes
              Add the contour classes to the legend as coloured lines. The text indicates the values.

              list values (in)
                     The list of values as used for the actual drawing. This argument is used only if  the  list
                     of classes is empty.

              list values (in)
                     The list of classes as used for the actual drawing.

       $xyplot legendshades values classes
              Add the contour classes to the legend as coloured rectangles. The text indicates the values.

              list values (in)
                     The  list  of values as used for the actual drawing. This argument is used only if the list
                     of classes is empty.

              list values (in)
                     The list of classes as used for the actual drawing.

       $xyplot grid xcrd ycrd
              Draw the grid cells as lines connecting the (valid) grid points.

              list xcrd (in)
                     List of lists, each value is an x-coordinate for a grid cell corner

              list ycrd (in)
                     List of lists, each value is an y-coordinate for a grid cell corner

       $xyplot xband ymin ymax
              Draw a light grey band in the plot, ranging over the full x-axis. This can be used to  indicate  a
              "typical" range for the data.

              float ymin (in)
                     Lower bound for the band

              float ymax (in)
                     Upper bound for the band

       $xyplot yband xmin xmax
              Draw  a  light grey band in the plot, ranging over the full y-axis. This can be used to indicate a
              "typical" range for the data.

              float xmin (in)
                     Lower bound for the band

              float xmax (in)
                     Upper bound for the band

       $xyplot labeldot x y text orient
              Draw a label and a symbol in the plot. The label will appear near the symbol. The  label  will  be
              drawn in grey, so as not to be too conspicuous.

              You  can  configure  the  appearance  of  the  symbol by using the data series name "labeldot": $w
              dataconfig labeldot -colour red -type symbol -symbol dot

              float x (in)
                     X-coordinate of the symbol to be drawn

              float y (in)
                     Y-coordinate of the symbol to be drawn

              string text (in)
                     Text for the label

              string orient (in)
                     Optional orientation (one of w, e, n, s) defining the position of the label with respect to
                     the symbol. It defaults to w (so the label appears left of the symbol).

       For polar plots:

       $polarplot plot series radius angle
              Add a data point to the polar plot.

              string series (in)
                     Name of the data series the new point belongs to.

              float radius (in)
                     Radial coordinate of the new point.

              float angle (in)
                     Angular coordinate of the new point (in degrees).

       For wind rose diagrams:

       $windrose plot data colour
              Draw  the  data  contained in the data argument. The data are added to the existing spokes towards
              the outer circle.

              list data (in)
                     List of data (the length should correspond to the number of sectors)

              string colour
                     Colour in which the new segments will be drawn

       For 3D plots:

       $plot3d plotfunc function
              Plot a function defined over two variables x and y.  The resolution is determined by the set  grid
              sizes (see the method gridsize for more information).

              string function (in)
                     Name  of  the  procedure that calculates the z-value for the given x and y coordinates. The
                     procedure has to accept two float arguments (x is first argument, y is second) and return a
                     floating-point value.

       $plot3d plotfuncont function contours
              Plot  a function defined over two variables x and y using the contour levels in contours to colour
              the surface.  The resolution is determined by the set grid sizes (see the method gridsize for more
              information).

              string function (in)
                     Name  of  the  procedure that calculates the z-value for the given x and y coordinates. The
                     procedure has to accept two float arguments (x is first argument, y is second) and return a
                     floating-point value.

              list contours (in)
                     List of values in ascending order that represent the contour levels (the boundaries between
                     the colours in the contour map).

       $plot3d gridsize nxcells nycells
              Set the grid size in the two directions. Together they determine how many polygons will  be  drawn
              for a function plot.

              int nxcells (in)
                     Number of grid cells in x direction. Has to be an integer number greater than zero.

              int nycells (in)
                     Number of grid cells in y direction. Has to be an integer number greater than zero.

       $plot3d plotdata data
              Plot a matrix of data.

              list data (in)
                     The  data  to  be  plotted. The data has to be provided as a nested list with 2 levels. The
                     outer list contains rows, drawn in y-direction, and each row is a list whose  elements  are
                     drawn in x-direction, for the columns. Example:

                         set data {
                         {1.0 2.0 3.0}
                         {4.0 5.0 6.0}
                         }

       $plot3d colours fill border
              Configure the colours to use for polygon borders and inner area.

              color fill (in)
                     The colour to use for filling the polygons.

              color border (in)
                     The colour to use for the border of the polygons.

       $plot3d ribbon yzpairs
              Plot a ribbon based on the pairs of yz-coordinates. The colours for the ribbon itself and the edge
              are taken from the colours option.

              list yzpairs (in)
                     List of pairs of yz-coordinates

       For 3D ribbon plots:

       $plot3d plot yzpairs
              Plot a ribbon based on the pairs of yz-coordinates. The colours for the ribbon itself and the edge
              are taken from the colours option.

              list yzpairs (in)
                     List of pairs of yz-coordinates

       For xy plots, stripcharts, histograms and polar plots:

       $xyplot dataconfig series -option value ...
              Set the value for one or more options regarding the drawing of data of a specific series.

              string series (in)
                     Name of the data series whose configuration we are changing.

       The following options are allowed:

              colour c

              color c
                     The colour to be used when drawing the data series.

              type enum
                     The drawing mode chosen for the series.  This can be one of line, symbol, or both.

              symbol enum
                     What kind of symbol to draw. The value of this option is ignored when the drawing mode line
                     was chosen. This can be one of  plus,  cross,  circle,  up  (triangle  pointing  up),  down
                     (triangle pointing down), dot (filled circle), upfilled or downfilled (filled triangles).

              radius integer
                     The  size  of  the  radius of the symbol. The total width of the symbol will be 2 times the
                     radius size. The default radius is 4.

              width integer
                     The width of the line (if drawn) or the width of the polygon outline (if -filled).

              filled enum
                     Whether to fill the area above or below the data line or not. Can be one of: no, up or down
                     (SPECIAL EFFECTS)

              fillcolour colour
                     Colour to use when filling the area associated with the data line.

              style enum
                     The style to be used for histograms:

                     •      filled: Fill the area under the data points with bars (default)

                     •      spike: Draw vertical lines from the y-axis (lower boundary) to the data point

                     •      symbol: Draw a symbol at the data point

                     •      plateau: Draw a horizontal line at the height of the data point

                     •      stair: Draw a continuous stair-like line connecting the data points

       For piecharts and spiral pies:

       $pie plot data
              Fill a piechart.

              list data (in)
                     A  list  of pairs (labels and values). The values determine the relative size of the circle
                     segments. The labels are drawn beside the circle.

       $pie colours colour1 colour2 ...
              Set the colours to be used.

              color colour1 (in)
                     The first colour.

              color colour2 (in)
                     The second colour, and so on.

       $pie explode segment
              Explode a segment (that is: move one segment out of the circle). If the segment  is  indicated  as
              "auto",  then you can click on a segment. This will be exploded instead of any previously exploded
              segment.

              int segment
                     The segment to be exploded or "auto" if you want to do this interactively.

       For radial charts:

       $radial plot data colour thickness
              Draw a new line in the radial chart

              list data (in)
                     A list of data (one for each spoke). The values determine the distance from the  centre  of
                     the line connecting the spokes.

              color colour (in)
                     The colour for the line.

              int thickness (in)
                     An optional argument for the thickness of the line.

       $pie colours colour1 colour2 ...
              Set the colours to be used.

              color colour1 (in)
                     The first colour.

              color colour2 (in)
                     The second colour, and so on.

       For vertical barcharts:

       $barchart plot series ydata colour ?dir? ?brightness?
              Add a data series to a barchart.

              string series (in)
                     Name of the series the values belong to.

              list ydata (in)
                     A list of values, one for each x-axis label.

              color colour (in)
                     The colour of the bars.

              string dir (in)
                     If given, "top-down" or "bottom-up", to indicate the direction in which the colour changes.
                     (If not given, a uniform colour is used).

              string brightness (in)
                     If given,  "bright"  or  "dark"  (defaulting  to  "bright").  The  colour  will  change  to
                     respectively white or black, depending on the direction.

       $barchart config -option value ...
              Set options for drawing the bars.

              showvalues boolean
                     Whether to show the values or not (above the bars)

              valuefont newfont
                     Name of the font to use for the values

              valuecolour colour
                     Colour for the values

              valueformat format
                     Format string to use for formatting the values

       For horizontal barcharts:

       $barchart plot series xdata colour ?dir? ?brightness?
              Add a data series to a barchart.

              string series (in)
                     Name of the series the values belong to.

              list xdata (in)
                     A list of values, one for each y-axis label.

              color colour (in)
                     The colour of the bars.

              string dir (in)
                     If  given,  "left-right"  or  "right-left",  to  indicate the direction in which the colour
                     changes.  (If not given, a uniform colour is used).

              string brightness (in)
                     If given,  "bright"  or  "dark"  (defaulting  to  "bright").  The  colour  will  change  to
                     respectively white or black, depending on the direction.

       $barchart config -option value ...
              Set options for drawing the bars.

              showvalues boolean
                     Whether to show the values or not (to the right of the bars)

              valuefont newfont
                     Name of the font to use for the values

              valuecolour colour
                     Colour for the values

              valueformat format
                     Format string to use for formatting the values

       For 3D barcharts:

       $barchart plot label yvalue colour
              Add the next bar to the barchart.

              string label (in)
                     The label to be shown below the column.

              float yvalue (in)
                     The value that determines the height of the column

              color colour (in)
                     The colour of the column.

       $barchart config -option value ...
              Set one or more configuration parameters. The following options are supported:

              usebackground boolean
                     Whether to draw walls to the left and to the back of the columns or not

              useticklines boolean
                     Whether to draw ticklines on the walls or not

              showvalues boolean
                     Whether to show the values or not

              labelfont newfont
                     Name of the font to use for labels

              labelcolour colour
                     Colour for the labels

              valuefont newfont
                     Name of the font to use for the values

              valuecolour colour
                     Colour for the values

       For 3D ribbon charts:

       $ribbon line xypairs colour
              Plot the given xy-pairs as a ribbon in the chart

              list xypairs (in)
                     The pairs of x/y values to be drawn (the series is drawn as a whole)

              color colour (in)
                     The colour of the ribbon.

       $ribbon area xypairs colour
              Plot  the given xy-pairs as a ribbon with a filled area in front. The effect is that of a box with
              the data as its upper surface.

              list xypairs (in)
                     The pairs of x/y values to be drawn (the series is drawn as a whole)

              color colour (in)
                     The colour of the ribbon/area.

       For boxplots:

       $boxplot plot series label values
              Add a box-and-whisker to the plot. The dataconfig command can be used to  customize  the  box-and-
              whisker (see the box-and-whiskers command for the xyplot for details).

              string series (in)
                     Name of the data series the box belongs to

              string label (in)
                     The label along the x- or y-axis to which the data belong

              list values (in)
                     List  of  raw  values,  the extent of the box and the whiskers will be determined from this
                     list.

       For timecharts:

       $timechart period text time_begin time_end colour
              Add a time period to the chart.

              string text (in)
                     The text describing the period.

              string time_begin (in)
                     Start time of the period.

              string time_end (in)
                     Stop time of the period.

              color colour (in)
                     The colour of the bar (defaults to black).

       $timechart milestone text time colour
              Add a milestone (represented as an point-down triangle) to the chart.

              string text (in)
                     The text describing the milestone.

              string time (in)
                     Time at which the milestone must be positioned.

              color colour (in)
                     The colour of the triangle (defaults to black).

       $timechart vertline text time
              Add a vertical line (to indicate the start of the month for instance) to the chart.

              string text (in)
                     The text appearing at the top (an abbreviation of the date/time for instance).

              string time (in)
                     Time at which the line must be positioned.

       $timechart hscroll scrollbar
              Connect a horizontal scrollbar to the chart. See also the section on scrolling.

              widget scrollbar (in)
                     The horizontal scrollbar that is to be connected to the chart

       $timechart vscroll scrollbar
              Connect a vertical scrollbar to the chart. See also the section on scrolling.

              widget scrollbar (in)
                     The vertical scrollbar that is to be connected to the chart

       For Gantt charts:

       $ganttchart task text time_begin time_end completed
              Add a task with its period and level of completion to the chart. Returns a list  of  canvas  items
              that can be used for further manipulations, like connecting two tasks.

              string text (in)
                     The text describing the task.

              string time_begin (in)
                     Start time of the task.

              string time_end (in)
                     Stop time of the task.

              float completed (in)
                     The percentage of the task that is completed.

       $ganttchart milestone text time colour
              Add a milestone (represented as an point-down triangle) to the chart.

              string text (in)
                     The text describing the milestone.

              string time (in)
                     Time at which the milestone must be positioned.

              color colour (in)
                     The colour of the triangle (defaults to black).

       $ganttchart vertline text time
              Add a vertical line (to indicate the start of the month for instance) to the chart.

              string text (in)
                     The text appearing at the top (an abbreviation of the date/time for instance).

              string time (in)
                     Time at which the line must be positioned.

       $ganttchart connect from to
              Add an arrow that connects the from task with the to task.

              list from (in)
                     The  list  of  items returned by the "task" command that represents the task from which the
                     arrow starts.

              string text (in)
                     The text summarising the tasks

              list args (in)
                     One or more tasks (the lists returned by the "task" command). They are shifted down to make
                     room for the summary.

              list to (in)
                     The  list  of  items  returned  by the "task" command that represents the task at which the
                     arrow ends.

       $ganttchart summary text args
              Add a summary item that spans all the tasks listed. The graphical representation is  a  thick  bar
              running from the leftmost task to the rightmost.

              Use this command before connecting the tasks, as the arrow would not be shifted down!

              string text (in)
                     The text summarising the tasks

              list args (in)
                     One or more tasks (the lists returned by the "task" command). They are shifted down to make
                     room for the summary.

       $ganttchart color keyword newcolor
              Set the colour of a part of the Gantt chart. These colours hold for all items of that type.

              string keyword (in)
                     The keyword indicates which part of the Gantt chart to change:

                     •      description - the colour of the descriptive text

                     •      completed - the colour of the filled bar representing the completed part of a task

                     •      left - the colour for the part that is not yet completed

                     •      odd - the background colour for the odd entries

                     •      even - the background colour for the even entries

                     •      summary - the colour for the summary text

                     •      summarybar - the colour for the bar for a summary

              string newcolor (in)
                     The new colour for the chosen items.

       $ganttchart font keyword newfont
              Set the font of a part of the Gantt chart. These fonts hold for all items of that type.

              string keyword (in)
                     The keyword indicates which part of the Gantt chart to change:

                     •      description - the font used for descriptive text

                     •      summary - the font used for summaries

                     •      scale - the font used for the time scale

              string newfont (in)
                     The new font for the chosen items.

       $ganttchart hscroll scrollbar
              Connect a horizontal scrollbar to the chart. See also the section on scrolling.

              widget scrollbar (in)
                     The horizontal scrollbar that is to be connected to the chart

       $ganttchart vscroll scrollbar
              Connect a vertical scrollbar to the chart. See also the section on scrolling.

              widget scrollbar (in)
                     The vertical scrollbar that is to be connected to the chart

       For isometric plots (to be extended):

       $isoplot plot rectangle x1 y1 x2 y2 colour
              Plot the outlines of a rectangle.

              float x1 (in)
                     Minimum x coordinate of the rectangle to be drawn.

              float y1 (in)
                     Minimum y coordinate of the rectangle.

              float x2 (in)
                     Maximum x coordinate of the rectangle to be drawn.

              float y2 (in)
                     Maximum y coordinate of the rectangle.

              color colour (in)
                     The colour of the rectangle.

       $isoplot plot filled-rectangle x1 y1 x2 y2 colour
              Plot a rectangle filled with the given colour.

              float x1 (in)
                     Minimum x coordinate of the rectangle to be drawn.

              float y1 (in)
                     Minimum y coordinate of the rectangle.

              float x2 (in)
                     Maximum x coordinate of the rectangle to be drawn.

              float y2 (in)
                     Maximum y coordinate of the rectangle.

              color colour (in)
                     The colour of the rectangle.

       $isoplot plot circle xc yc radius colour
              Plot the outline of a circle.

              float xc (in)
                     X coordinate of the circle's centre.

              float yc (in)
                     Y coordinate of the circle's centre.

              color colour (in)
                     The colour of the circle.

       $isoplot plot filled-circle xc yc radius colour
              Plot a circle filled with the given colour.

              float xc (in)
                     X coordinate of the circle's centre.

              float yc (in)
                     Y coordinate of the circle's centre.

              color colour (in)
                     The colour of the circle.

       For tables you can use the following subcommands:

       $table row items
              Draw a single row of items. The appearance of the items  can  be  controlled  explicitly  via  the
              format command.

              list items (in)
                     List of text items to be drawn, one per column

       $table separator
              Draw a horizontal line to separate two rows

       $table formatcommand procname
              Set  the  procedure  that  controls  the formatting of items. By default items are simply drawn as
              centered text.

              string procname (in)
                     Name of the procedure to be used. Its signature is:

                     proc procname {table widget row column value} {...}

                     Use the cellconfigure subcommand to set the attributes per cell.

       $table cellconfigure args
              Set the attributes for the next cell(s) to be drawn.

              list args (in)
                     Key-value pairs: -background sets the background  colour  of  the  cells,  -cell  sets  the
                     foreground  colour,  -font sets the text font, -anchor sets the position of the text within
                     the cell and -justify controls the layout of multiline text.

       There are a number of public procedures that may be useful in specific situations: Pro memorie.

COORDINATE TRANSFORMATIONS

       Besides the commands that deal with the plots and charts directly, there are a number  of  commands  that
       can be used to convert world coordinates to pixels and vice versa.  These include:

       ::Plotchart::viewPort w pxmin pymin pxmax pymax
              Set the viewport for window w. Should be used in cooperation with ::Plotchart::worldCoordinates.

              widget w (in)
                     Name of the window (canvas widget) in question.

              float pxmin (in)
                     Left-most pixel coordinate.

              float pymin (in)
                     Top-most  pixel  coordinate  (remember:  the vertical pixel coordinate starts with 0 at the
                     top!).

              float pxmax (in)
                     Right-most pixel coordinate.

              float pymax (in)
                     Bottom-most pixel coordinate.

       ::Plotchart::worldCoordinates w xmin ymin xmax ymax
              Set the extreme world coordinates for window w. The world coordinates need  not  be  in  ascending
              order (i.e. xmin can be larger than xmax, so that a reversal of the x-axis is achieved).

              widget w (in)
                     Name of the window (canvas widget) in question.

              float xmin (in)
                     X-coordinate to be mapped to left side of viewport.

              float ymin (in)
                     Y-coordinate to be mapped to bottom of viewport.

              float xmax (in)
                     X-coordinate to be mapped to right side of viewport.

              float ymax (in)
                     Y-coordinate to be mapped to top side of viewport.

       ::Plotchart::world3DCoordinates w xmin ymin zmin xmax ymax zmax
              Set  the  extreme three-dimensional world coordinates for window w. The world coordinates need not
              be in ascending order (i.e. xmin can be larger than xmax, so that a  reversal  of  the  x-axis  is
              achieved).

              widget w (in)
                     Name of the window (canvas widget) in question.

              float xmin (in)
                     X-coordinate to be mapped to front side of the 3D viewport.

              float ymin (in)
                     Y-coordinate to be mapped to left side of the viewport.

              float zmin (in)
                     Z-coordinate to be mapped to bottom of viewport.

              float xmax (in)
                     X-coordinate to be mapped to back side of viewport.

              float ymax (in)
                     Y-coordinate to be mapped to right side of viewport.

              float zmax (in)
                     Z-coordinate to be mapped to top side of viewport.

       ::Plotchart::coordsToPixel w x y
              Return a list of pixel coordinates valid for the given window.

              widget w (in)
                     Name of the canvas alias (as returned by [\$anyplot canvas]) in question.

              float x (in)
                     X-coordinate to be mapped.

              float y (in)
                     Y-coordinate to be mapped.

       ::Plotchart::coords3DToPixel w x y z
              Return a list of pixel coordinates valid for the given window.

              widget w (in)
                     Name of the canvas alias (as returned by [\$anyplot canvas]) in question.

              float x (in)
                     X-coordinate to be mapped.

              float y (in)
                     Y-coordinate to be mapped.

              float y (in)
                     Z-coordinate to be mapped.

       ::Plotchart::polarCoordinates w radmax
              Set  the  extreme  polar coordinates for window w. The angle always runs from 0 to 360 degrees and
              the radius starts at 0. Hence you only need to give the maximum radius.  Note: If the viewport  is
              not  square,  this  procedure  will not adjust the extremes, so that would result in an elliptical
              plot. The creation routine for a polar plot always determines a square viewport.

              widget w (in)
                     Name of the canvas alias (as returned by [\$anyplot canvas]) in question.

              float radmax (in)
                     Maximum radius.

       ::Plotchart::polarToPixel w rad phi
              Wrapper for a call to ::Plotchart::coordsToPixel, which assumes the world coordinates and viewport
              are  set  appropriately.  Converts  polar coordinates to pixel coordinates.  Note: To be useful it
              should be accompanied by a matching ::Plotchart::worldCoordinates procedure. This is automatically
              taken care of in the creation routine for polar plots.

              widget w (in)
                     Name of the canvas alias (as returned by [\$anyplot canvas]) in question.

              float rad (in)
                     Radius of the point.

              float phi (in)
                     Angle to the positive x-axis.

       ::Plotchart::pixelToCoords w x y
              Return a list of world coordinates valid for the given window.

              widget w (in)
                     Name of the canvas alias (as returned by [\$anyplot canvas]) in question.

              float x (in)
                     X-pixel to be mapped.

              float y (in)
                     Y-pixel to be mapped.

       ::Plotchart::pixelToIndex w x y
              Return the index of the pie segment containing the pixel coordinates (x,y)

              widget w (in)
                     Name  of  the  canvas  alias  (as  returned  by  [\$anyplot canvas]) in question, holding a
                     piechart.

              float x (in)
                     X-pixel to be mapped.

              float y (in)
                     Y-pixel to be mapped.

       Furthermore there is a routine to determine "pretty" numbers for use with an axis:

       ::Plotchart::determineScale xmin xmax inverted
              Determine "pretty" numbers from the given range and return a list containing the minimum,  maximum
              and stepsize that can be used for a (linear) axis.

              float xmin (in)
                     Rough minimum value for the scaling

              float xmax (in)
                     Rough maximum value for the scaling.

              boolean inverted (in)
                     Optional  argument:  if  1, then the returned list produces an inverted axis. Defaults to 0
                     (the axis will be from minimum to maximum)

       ::Plotchart::determineScaleFromList values inverted
              Determine "pretty" numbers from the given list of values and return a list containing the minimum,
              maximum and stepsize that can be used for a (linear) axis.

              float values (in)
                     List of values that will be examined. May contain missing values (empty strings)

              boolean inverted (in)
                     Optional  argument:  if  1, then the returned list produces an inverted axis. Defaults to 0
                     (the axis will be from minimum to maximum)

MISSING VALUES

       Often data that need to be plotted contain gaps - in a series of measurement data, they can occur because
       the  equipment  failed,  a  sample  was  not collected correctly or for many other reasons. The Plotchart
       handles these gaps by assuming that one or both coordinates of such data points are an empty string:

                  #
                  # Create the plot with its x- and y-axes
                  #
                  set s [::Plotchart::createXYPlot .c {0.0 100.0 10.0} {0.0 100.0 20.0}]

                  foreach {x y} {0.0 32.0 10.0 {} 25.0 60.0 78.0 11.0 } {
                      $s plot series1 $x $y
                  }

       The effect varies according to the type of plot:

       •      For xy-plots, radial plots and strip charts the missing data  point  causes  a  gap  in  the  line
              through the points.

       •      For barchats, missing values are treated as if a value of zero was given.

       •      For time charts and Gantt charts missing values cause errors - there is no use for them there.

OTHER OUTPUT FORMATS

       Besides  output  to  the  canvas  on  screen,  the module is capable, via canvas postscript, of producing
       PostScript files. One may wonder whether it is possible to extend this set  of  output  formats  and  the
       answer  is  "yes".  This  section  tries  to  sum up the aspects of using this module for another sort of
       output.

       One way you can create output files in a different format, is by examining the  contents  of  the  canvas
       after  everything has been drawn and render that contents in the right form. This is probably the easiest
       way, as it involves nothing more than the re-creation of all the elements in the plot  that  are  already
       there.

       The drawback of that method is that you need to have a display, which is not always the case if you run a
       CGI server or something like that.

       An alternative is to emulate the canvas command. For  this  to  work,  you  need  to  know  which  canvas
       subcommands  are  used  and what for. Obviously, the create subcommand is used to create the lines, texts
       and other items. But also the raise and lower subcommands are used, because with  these  the  module  can
       influence  the  drawing  order - important to simulate a clipping rectangle around the axes. (The routine
       DrawMask is responsible for this  -  if  the  output  format  supports  proper  clipping  areas,  then  a
       redefinition of this routine might just solve this).

       Furthermore,  the  module  uses  the  cget subcommand to find out the sizes of the canvas. A more mundane
       aspect of this is that the module currently assumes that the text is 14 pixels high and that 80 pixels in
       width suffice for the axis' labels. No "hook" is provided to customise this.

       In summary:

       •      Emulate the create subcommand to create all the items in the correct format

       •      Emulate the cget subcommand for the options -width and -height to allow the correct calculation of
              the rectangle's position and size

       •      Solve the problem of raising and lowering the  items  so  that  they  are  properly  clipped,  for
              instance by redefining the routine DrawMask.

       •      Take care of the currently fixed text size properties

SPECIAL EFFECTS

       As  an  example of some special effects you can achieve, here is the code for a plot where the area below
       the data line varies in colour:

              canvas .c  -background white -width 400 -height 200
              pack .c -fill both

              set s [::Plotchart::createXYPlot .c {0.0 100.0 10.0} {0.0 100.0 20.0}]

              $s background gradient green top-down

              $s dataconfig series1 -filled up -fillcolour white

              $s plot series1  0.0 20.0
              $s plot series1 10.0 20.0
              $s plot series1 30.0 50.0
              $s plot series1 35.0 45.0
              $s plot series1 45.0 25.0
              $s plot series1 75.0 55.0
              $s plot series1 100.0 55.0

              $s plaintext 30.0 60.0 "Peak" south

       The trick is to fill the background with a colour that changes from green at the  top  to  white  at  the
       bottom.  Then  the area above the data line is filled with a white polygon. Thus the green shading varies
       with the height of the line.

ROOM FOR IMPROVEMENT

       In this version there are a lot of things that still need to be implemented:

       •      More robust  handling  of  incorrect  calls  (right  now  the  procedures  may  fail  when  called
              incorrectly):

              •      The axis drawing routines can not handle inverse axes right now.

              •      If the user provides an invalid date/time string, the routines simply throw an error.

RESIZING

       Plotchart  has  not been designed to create plots and charts that keep track of the data that are put in.
       This means that if an application needs to allow the user to resize the window holding the plot or chart,
       it must take care to redraw the complete plot.

       The code below is a simple example of how to do that:

              package require Plotchart

              grid [canvas .c -background white] -sticky news
              grid columnconfigure . 0 -weight 1
              grid rowconfigure . 0 -weight 1

              bind .c <Configure> {doResize}

              proc doPlot {} {
                  #
                  # Clean up the contents (see also the note below!)
                  #
                  .c delete all

                  #
                  # (Re)draw the bar chart
                  #
                  set p [::Plotchart::createBarchart .c {x y z} {0 100 10} 3]
                  $p plot R {10 30 40} red
                  $p plot G {30 40 60} green
              }

              proc doResize {} {
                  global redo

                  #
                  # To avoid redrawing the plot many times during resizing,
                  # cancel the callback, until the last one is left.
                  #
                  if { [info exists redo] } {
                      after cancel $redo
                  }

                  set redo [after 50 doPlot]
              }
       Please  note: The code above will work fine for barcharts and many other types of plots, but as Plotchart
       keeps some private information for xy plots, more is needed in these  cases.  This  actually  requires  a
       command "destroyPlot" to take care of such details. A next version of Plotchart may have that.

       Alternatively,  you  can use the xyplot package which is built on top of Plotchart. This package supports
       zooming in and zooming out, as well as resizing the plot as  a  whole.  Here  is  a  small  demonstration
       program:

              # xyplot_demo.tcl --
              #     Demonstration of the xyplot package
              #

              package require xyplot

              set xydata1 {}
              set xydata2 {}
              set xydata3 {}
              set xydata4 {}
              for { set i 0 } { $i < 1024 } { incr i } {
                  lappend xydata1 [expr {$i-1000}] [expr {$i * sin($i/4096.0*3.1415*2) * (sin($i/256.0*3.1415*2))}]
                  lappend xydata2 [expr {$i-1000}] [expr {$i * sin($i/4096.0*3.1415*2) * (sin($i/256.0*3.1415*2) + 0.25 * sin($i/256.0*3.1415*6))}]
                  lappend xydata3 [expr {$i-1000}] [expr {$i * sin($i/4096.0*3.1415*2) * (sin($i/256.0*3.1415*2) + 0.25 * sin($i/256.0*3.1415*6) + 0.0625 * sin($i/256.0*3.1415*10))}]
                  lappend xydata4 [expr {$i-1000}] [expr {$i * sin($i/4096.0*3.1415*2) * (sin($i/256.0*3.1415*2) + 0.25 * sin($i/256.0*3.1415*6) + 0.0625 * sin($i/256.0*3.1415*10) + 0.015625 * sin($i/256.0*3.1415*14))}]
              }

              set xyp [xyplot .xyp -xformat "%5.0f" -yformat "%5.0f" -title "XY plot testing" -background gray90]
              pack $xyp -fill both -expand true

              set s1 [$xyp add_data sf1 $xydata1 -legend "Serie 1 data" -color red]
              set s2 [$xyp add_data sf2 $xydata2 -legend "Serie 2 data" -color green]
              set s3 [$xyp add_data sf3 $xydata3 -legend "Serie 3 data" -color blue]
              set s4 [$xyp add_data sf4 $xydata4 -legend "Serie 4 data" -color orange]

              set xyp2 [xyplot .xyp2 -xticks 8 -yticks 4 -yformat %.2f -xformat %.0f]
              pack $xyp2 -fill both -expand true

              set s1 [$xyp2 add_data sf1 $xydata1]
              set s2 [$xyp2 add_data sf2 $xydata2]
              set s3 [$xyp2 add_data sf3 $xydata3]
              set s4 [$xyp2 add_data sf4 $xydata4]

       Zooming  in  is  done by selecting a rectangle with the left mouse button pressed. Zooming out is done by
       pressing the right mouse button. If you resize the window, the canvases inside are resized  too.  If  you
       zoom in, you can scroll the plot via the scrollbars that are automatically attached.

ZOOMING IN

       As  the  Plotchart  package  does  not  keep  track  of the data itself, rescaling an existing plot - for
       instance when zooming in - would have to be done by redefining the plot and redrawing the data.  However,
       the canvas widget offers a way out by scaling and moving items, so that zooming in becomes a bit simpler.

       Whether zooming is indeed useful, depends on the type of plot. Currently it is defined for XY-plots only.
       The method is called "rescale" and simply redraws the axes and scales and moves the data  items  so  that
       they conform to the new axes. The drawback is that any symbols are scaled by the same amount. The rescale
       method works best for plots that only have lines, not symbols.

       The method works very simply:

                 $p rescale {newxmin newxmax newxstep} {newymin newymax newystep}

CONFIGURATION OPTIONS

       The commands plotconfig and plotstyle can be used to set all manner of options. The syntax is:

       ::Plotchart::plotconfig charttype component property value
              Set a new value for the property of a component in a particular chart or plot type  or  query  its
              current  value.  Changed  properties  only have effect for the consecutive plots, not for the ones
              already created. Each argument is optional.

              Note: The plotstyle command offers a more flexible way to control the configuration options.

              string charttype (in)
                     The type of chart or plot (see the configuration type that is  mentioned  for  each  create
                     command).  If  not  given  or empty, a list of chart types is returned. If it is given, the
                     properties for that particular type are used.

              string component (in)
                     The component of the plot/chart: leftaxis, rightaxis, background, margin and so on. If  not
                     given  or  empty, a list of components is returned. If it is given, the properties for that
                     particular component will be set for that particular type of chart.

              string property (in)
                     The property of the component of the plot/chart: textcolor, thickness  of  the  axis  line,
                     etc.  If  not  given  or  empty,  a  list  of  properties is returned. If it is given, that
                     particular property for that particular component will be set for that particular  type  of
                     chart.

              string value (in)
                     The  new  value for the property. If empty, the current value is returned.  If the value is
                     "default", the default value will be restored.

                     Note, that in some cases an empty value is useful. Use "none" in this  case  -  it  can  be
                     useful for colours and for formats.

       ::Plotchart::plotstyle subcmd style args
              Manipulate  the style in which subsequent plots will be drawn. The default style is "default", but
              you can define and load any number of other styles.

              string subcmd (in)
                     The subcommand to be executed:

                     •      configure - this subcommand allows you to set the options per chart type.  It  takes
                            the same options as the plotconfig command.

                     •      current - return the current style

                     •      load - make the given style the active style for subsequent plots and charts

                     •      names - return the list of currently defined styles

              string style (in)
                     The name of the plot style to manipulate

              list args (in)
                     The new options for the style - see the plotconfig command for details

       Below is a detailed list of the components and properties:

       •      Axes come in a wide variety:

              •      leftaxis, rightaxis, topaxis, bottomaxis for the plots with a rectangular shape.

              •      xaxis, yaxis and zaxis are used for the 3D plots

              •      axis, this represents the radial and tangential axes of a polar plot

              All axes have the following properties:

              •      color - the colour of the line and the tickmarks

              •      thickness - the width of the line of the axis itself, not the tickmarks

              •      ticklength - the length of the tickmarks in pixels. A positive value is outward, a negative
                     value is inward.

              •      font - the font for the labels and the text at the axis

              •      format - the format for rendering the (numerical) labels. For  the  time  axis  it  is  the
                     format for a date and time.

              •      textcolor - the colour for the labels and the text.

              •      labeloffset - space (in pixels) between the tickmark and the actual label

              •      minorticks - number of minor tickmarks between the major tickmarks

              •      shownumbers - show the numbers/labels or not.

              •      showaxle - show the axis line or not.

       •      The  margin is important for the layout. Currently only the rectangular plots allow the margins to
              be set: left, right, top and bottom.  The values are in pixels.

       •      The text component is meant for any text appearing via the plaintext  subcommand.  The  properties
              are: textcolor, font and anchor (positioning of the text relative to the given coordinates).

       •      The  background  has  two  properties:  outercolor,  the  colour  outside  of the actual plot, and
              innercolor, the colour inside the plot. (Note: only "outercolor" has now been implemented).

       •      The mask has one property only: draw. If set to 1, the default,  white  rectangles  are  drawn  to
              mimick  the  effects  of  clipping  -  excess  data  are made invisible this way.  Otherwise these
              rectangles are not drawn. This is useful to control the layout more  tightly,  for  instance  with
              multiple plots in one canvas.

       •      The  title  component has the same properties as the text component (but it is independent of that
              component). It also has a background property: If not set (or set to the empty string) this is the
              same as the outercolor property of the background component, otherwise it is a separate colour.

       •      The  legend  has three properties: background, border and position.  See the legend subcommand for
              the meaning.

       •      The bar components is used  for  all  barchart-like  plots  and  has  three  properties:  barwidth
              (relative  width  of  the bars in relation to the items along the axis), innermargin (the relative
              width of the gaps between bars or groups of bars) and the outline colour.

       •      The labels component is used to describe the appearance of the labels of  piecharts  and  "spiral"
              piecharts. The properties are:

              •      textcolor - colour of the label text

              •      font - font to be used for the label text

              •      placement - out of the circle or in the circle

              •      sorted - the data are sorted in ascending order first

              •      shownumbers - the labels are combined with the numbers according to the format

              •      format  -  the  format to be used (defaults to: "%s (%g)") if the numbers are to shown. The
                     format command gets the label first, then the number)

              •      formatright - if given, the format to be used for labels and numbers appearing to the right
                     of the pie. The format command gets the number first, then the label. (Defaults to "")

       •      The slice component has properties to control the appearance of the sections in the pie diagram:

              •      outline - the colour of the line around the slices (default: black)

              •      outlinewidth - width of the line around the slices (default: 1 pixel)

              •      startangle - the angle w.r.t. positive x-axis where the first slice starts

              •      direction - the direction in which to draw the slices (default: +, that is clockwise)

       •      The  table  charts  use  the  general  components  title  and margin and further more the specific
              components header, oddrow, evenrow, cell and frame:

              •      header, oddrow and evenrow have the properties: background, font, color, height and  anchor
                     with obvious meanings.

              •      The  cell component defines in addition leftspace, rightspace and topspace for fine-grained
                     control of the spacing inside the cell. These are not set via the cellconfigure  subcommand
                     however.

              •      Finally  the  frame component uses color, outerwidth (for the width of the line surrounding
                     the whole table) and innerwidth (for the width of lines separating columns and rows).

       See the examples in plotdemos7.tcl for its use.

SCROLLING FOR TIMECHARTS AND GANTT CHARTS

       For two types of plots automatic scrolling management has been implemented: timecharts and Gantt  charts.
       The  subcommands hscroll and vscroll associate (existing) scrollbars to the plot, in much the same way as
       for text and canvas widgets.

       Once the association is made, the scrollbars are automatically updated if:

       •      You add an item with a period wider than the current one.

       •      You add a vertical line for a time beyond the current bounds.

       •      You add an extra item beyond the number that was used to create the chart.

       For instance:

              package require Plotchart

              canvas .c -width 400 -height 200
              scrollbar .y -orient vertical
              scrollbar .x -orient horizontal

              grid .c .y -sticky news
              grid .x    -sticky news

              source plotchart.tcl

              set s [::Plotchart::createTimechart .c "1 january 2004"  "31 december 2004" 4]

              $s period "Spring" "1 march 2004" "1 june 2004" green
              $s period "Summer" "1 june 2004" "1 september 2004" yellow
              $s vertline "1 jan" "1 january 2004"
              $s vertline "1 apr" "1 april 2004"
              $s vertline "1 jul" "1 july 2004"
              $s vertline "1 oct" "1 october 2004"
              $s vertline "1 jan" "1 january 2005"
              $s vertline "1 apr" "1 april 2005"
              $s vertline "1 jul" "1 july 2005"
              $s milestone "Longest day" "21 july 2004"
              $s milestone "Longest day 2" "21 july 2004"
              $s milestone "Longest day 3" "21 july 2004"
              $s milestone "Longest day 4" "21 july 2004"
              $s milestone "Longest day 5" "21 july 2004"
              $s milestone "Longest day 6" "21 july 2004"
              $s title "Seasons (northern hemisphere)"

              $s vscroll .y
              $s hscroll .x

       The original extent of the chart is from 1 january 2004 to 31 december 2004. But because of the  addition
       of  vertical  lines  in  2005  and  more  items than was specified at the creation of the chart, both the
       horizontal and the vertical scrollbar will be enabled.

SPECIALISED PLOTS

       Most of the plot and chart types described above have a fairly general use and you  simply  prepares  the
       data  to be plotted yourself. This section describes several plot types that are more specialised, in the
       sense that they have specific purposes and you pass raw data that are  then  processed  in  the  plotting
       routines.

       Currently there are the following types:

       •      Target diagrams are used to assess the capacity of numerical models to reproduce measurement data.
              They are described in detail in:

              Jason K. Joliff et al.
                  Summary diagrams for coupled hydrodynamic-ecosystem model skill assessment
                  Journal of Marine Systems 76 (2009) 64-82
                  DOI: 10.1016/j.jmarsys.2008.05.014

       •      Performance  profiles  are  used  for  comparing  the  performance   of   numerical   methods   or
              implementations thereof with each other. For more information:

              Desmond Higham and Nicholas Higham
                  Matlab Guide
                  SIAM, 2005, Philadephia

       Most of the general methods for XY-plots work for these plots as well, but their creation and the methods
       to plot the data are very specific.

       ::Plotchart::createTargetDiagram w limits scale
              Create a new target diagram with circles indicating specific limits.  The  x-axis  represents  the
              unbiased  "root-mean-square  difference"  (typically  varying  between  -1  and  1) and the y-axis
              represents the normalised bias.

              Data points closer to the origin represent better results than data points further away.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              list limits (in)
                     List of radii for the circles that represent the limits (for instance: 0.5 and 0.7)

              double scale (in)
                     Scale for the axes - defaults to 1, but if the model results are a poor fit, then that  may
                     be too small a value. Both axes are scaled in the same way.

       $target plot series xvalues yvalues
              The  plot method takes two series of data of the same length, the first one representing the model
              results, the second one represent the measurements or, more general, the  data  that  need  to  be
              reproduced.

              string series (in)
                     Name  of  the  series  (it  will  be plotted as a symbol that is configured via the $target
                     dataconfig command (see the XY-plot equivalent for an explanation)

              list xvalues (in)
                     List of model results (missing values are represented as empty strings)

              list yvalues (in)
                     List of measured values (missing values are represented as empty strings; only if both  the
                     x and the y values are given, is the pair used in the computations)

       ::Plotchart::createPerformanceProfile w max
              Create a diagram to show the performance of various numerical methods (or solvers). The idea is to
              first run these methods on a set of problems and measure their performance. The smaller the number
              the  better.  Then  these  methods  are compared via a so-called performance profile: the data are
              scaled and ordered, such that the best method ends up highest.

              Because of the nature of the plot all data must be given at once.

              widget w (in)
                     Name of the existing canvas widget to hold the plot.

              float max (in)
                     Maximum value for the x-axis (the x-axis is the scaled performance of the series).

       $performance plot series_and_data_pairs
              Plot the data for each given method. The data are identified by the series name and the appearance
              is controlled via prior dataconfig subcommand.

              list series_and_data_pairs (in)
                     List of series names and data. All data must be given at once.

       The command plotmethod can be used to add new methods for a particular plot or chart type. It is intended
       to help you develop specialised graphical displays.

       ::Plotchart::plotmethod charttype methodname plotproc
              Adds a new method for the given plot or chart type. The method is implemented by  the  command  or
              procedure  given  in the plotproc argument. The procedure will be called with two extra arguments,
              the name of the created plot and the canvas widget that contains (see the example below).

              string charttype (in)
                     The type of plot or chart that the new method should be added to.

              string methodname (in)
                     Name of the method to be used.

              string plotproc (in)
                     Name of the command or procedure that implements the method.

       Here is a trivial example of how to use this:

              #
              # The custom method "doodle" always adds the text "DOODLE"
              # to the plot
              #
              proc doodle {p w x y} {
                  $p plaintext $x $y "DOODLE"
              }
              ::Plotchart::plotmethod xyplot doodle doodle

              #
              # Use it
              pack [canvas .c]

              set p [::Plotchart::createXYPlot .c {0 100 10} {0 20 5}]

              $p doodle 40 10

TABLE CHARTS

       To show what you can do with table charts, here is a simple example that plots a number of  random  data.
       The colours depend on the range that the data belong to. For this the procedure setColor is used.

              package require Plotchart

              pack [canvas .c -bg white -height 300] -fill both -expand yes

              ::Plotchart::plotconfig table frame outerwidth 3
              ::Plotchart::plotconfig table frame color red

              set t [::Plotchart::createTableChart .c {"Column 1" "Column 2" "Column 3"} 80]

              proc setColor {table widget row col value} {
                  $table cellconfigure -background white -color black
                  if { $value < 2.0 } {
                      $table cellconfigure -background red -color white
                  }
                  if { $value > 6.0 } {
                      $table cellconfigure -background green
                  }

                  return [format "%6.3f" $value]
              }

              # Command must already exist ...
              $t formatcommand setColor

              $t title "Demonstration of table charts"
              $t separator

              for {set i 0} {$i < 9} {incr i} {
                  set row {}

                  for {set j 0} {$j < 3} {incr j} {
                      lappend row [expr {10.0 * rand()}]
                  }

                  if { $i == 3 } {
                      $t separator
                  }

                  $t row $row
              }

CONTROL DISPLAYS

       TODO

ARRANGING MULTIPLE PLOTS IN A CANVAS

       The  command  plotpack  allows you to copy the contents of a plot into another canvas widget. This canvas
       widget does not act as a composite plot, but it can be saved as a PostScript file for instance: Note: the
       command simply takes a snapshot of the plots/charts as they are at that moment.

       ::Plotchart::plotpack w dir args
              Copy  the  contents  of  the  plots/charts  into  another  widget, in a manner similar to the pack
              geometry manager.

              widget w (in)
                     The name of the canvas widget to copy the plots/charts into

              string dir (in)
                     The direction of the arrangement - top, left, bottom or right

              list args (in)
                     List of plots/charts to be copied.

       For example:

                  set p1 [createXYPlot ...]
                  set p2 [createBarchart ...]

                  ... fill the plots ...

                  toplevel .t
                  pack [canvas .t.c2 -width ...]

                  #
                  # Copy the two plots above each other in the new canvas
                  #
                  plotpack .t.c2 top $p1 $p2

       A different method is to use the -box and -axesbox options when creating the plot. These control the area
       in the canvas where the plot or chart will be drawn.

       The -box option takes as its value a list of four numbers:

       •      X-coordinate  of  the  upper-left corner of the area that will contain the plot or chart (simply a
              canvas coordinate)

       •      Y-coordinate of the upper-left corner

       •      Width of the area

       •      Height of the area

       Specifying the width and height makes it easier to reposition the area with respect to other plots.

       The -axesbox option is meant to make aligning the axes of a plot with those of other  plots  easier.  The
       option takes a list of six arguments:

       •      Identification  of the plot with respect to which it should be positioned (the command returned by
              the creation command).

       •      The anchor position that should be used (n, nw, ...)

       •      X-coordinate of the upper-left corner of the area that  will  contain  the  plot  or  chart.  This
              coordinates is taken relative to the anchor position

       •      Y-coordinate of the upper-left corner

       •      Width of the axis area

       •      Height of the axis area

       With  this  option the area the axes occupy is first determined and the complete area is derived from the
       margins.

       For example:

                  set p2 [::Plotchart::createXYPlot .c {0 10 1} {-5 5 2.5} -axesbox [list $p1 ne 0 0 200 200]]

       will create a second plot whose left axis coincides with the right axis of plot "\$p1" and the top of the
       axis is at the same heigt as well - because the axes are positioned at a point 0 pixels to the left and 0
       pixels below the north-east corner.

INTERACTIVE USE

       Plotchart has several features for interactive use (cf. NOTES ON TAGS):

       •      The legend can be moved around by pressing mouse button 1 in the legend's box and keeping it down.

       •      You can use the bindplot and bindlast commands to define actions that are to  be  taken  when  the
              user  clicks  on  an  element  of  the  plot  or  chart.   (see below, see also the sample code in
              plotdemos12.tcl)

       •      Piecharts can show an "exploded" segment that you can select with mouse button 1.

       If you require different forms of interaction, not covered by Plotchart itself, you can use the  tags  on
       the various canvas elements to define other bindings.

       The bindplot and bindlast are defined as follows:

       $anyplot bindplot event command args
              Register a command that will be run whenever the given event occurs in the plot.

              string event
                     The event that you want to bind the command to

              string command
                     Name  of  the command/procedure that you want to run. The following arguments are prefixed:
                     the x- and y-coordinates of the point in the plot (the world  coordinates!),  so  that  the
                     procedure has the signature:

                         cmd $xworld $yworld $string1 $string2 $string3

                     assuming the argument "command" is: {cmd A B C}

       $anyplot bindlast series event command
              Register  a  command  that  will be run when the event occurs within the neighbourhood of the last
              point added to the given series. (You can use directly after inserting  a  data  point.  All  such
              commands will remain active).

              string event
                     The event that you want to bind the command to

              list command
                     Name  of  the command/procedure that you want to run. The following arguments are prefixed:
                     the x- and y-coordinates of the point in the plot (the world  coordinates!),  so  that  the
                     procedure has the signature:

                         cmd $xworld $yworld $string1 $string2 $string3

                     assuming the argument "command" is: {cmd A B C}

       Here  is  an  example  -  show  the  values  of the data points in an annotation (from the sample code in
       plotdemos12.tcl):

              #
              # Procedure for showing an annotation
              #
              proc showAnnotation {xcoord ycoord plot w} {

                  $plot balloon $xcoord $ycoord "Data point: [format "%.3f, %.3f" $xcoord $ycoord]" north

                  after 2000 [list removeAnnotation $w]
              }

              #
              # Procedure for erase an annotation
              #
              proc removeAnnotation {w} {

                  # Use the tags to remove all annotations
                  $w delete BalloonText
                  $w delete BalloonFrame
              }

              #
              # Create a simple plot and a label
              #
              pack [canvas .c -bg white] [label .l -textvariable coords]

              set p [::Plotchart::createXYPlot .c {0 1000 200} {0 10 1}]

              $p dataconfig series1 -type both -symbol cross

              foreach x {1 2 5 10 20 50 100 200 500 1000} {
                  $p plot series1 $x [expr {log($x)}]

                  #
                  # Show the annotation for each data point
                  #
                  $p bindlast series1 <Enter> [list showAnnotation $p %W]
              }

NOTES ON TAGS

       The implementation of Plotchart relies heavily on the canvas's ability to identify graphical  objects  by
       tags and to change the drawing order of the objects. This section documents the tags that are used.

       (Note:  the  tags  are not always used consistently - see the notes appearing with the various tags. This
       section describes the current state.)

       General graphical objects:mask - Used to manipulate the opaque rectangles that ensure data  outside  the  viewport  are  not
              shown.

       •      topmask, horizmask, vertmask - specialised tags, used for scrollable plots.

       •      title - Used for title strings.

       •      BalloonText, BalloonFrame - Used to manipulate balloon text.

       •      PlainText - Used to manipulate ordinary text without any decoration.

       •      background - Tag used for gradient and image backgrounds (and for gradient-filled bars).

       •      xaxis,  yaxis - Tags used for all objects related to horizontal or vertical axes.  (also: both for
              numerical axes and axes with labels as in barcharts).  Note, however, that the text along the axes
              has no particular tag.

       •      raxis - Tag used for all objects related to a right axis.

       •      taxis - Tag used for all objects related to a time axis.

       •      axis3d - Tag used for 3D axes

       •      xtickline, ytickline - Tags used for ticklines.

       •      legend, legengb, legendobj - Tags used for the legend. The latter is used to manipulate the legend
              as a whole.

       •      legend_series - Tag used to control the  appearance  of  the  legend  entry  ("series"  should  be
              replaced by the series name).

       •      object  -  used  as standard tag for all objects drawn with the ::Plotchart::drawobject procedure.
              Tags given at object creation time are added to this tag.

       XY-plots (all types of axes):data - The general tag to identify graphical objects associated with data.  data_seriesname -  The
              tag  specific  to  a  data  series  ("seriesname"  should  be replaced).  band - The horizontal or
              vertical band drawn with the xband otr yband subcommands have this tag by the actual name).  xtext
              - The text labelling the xaxis.  ytext - The text labelling hte yaxis horizontically.  vtext - The
              text labelling the yaxis vertically.

       Items such as labelled dots only have the "data" tag.

       Piecharts and spiral pies:segment_segmentnumber - The tag identifying the segment,  the  string  "segmentnumber"  should  be
              replaced by the actual number. This tag is used to explode the segments.

       Barcharts:

       Barcharts use the same tags as xy-plots (but for gradient-filled bars the data_seriesname is not used).

       Histograms and isometric plots:

       Currently the only tag used is "data".

       Time-charts:

       As  these plots are scrollable, several tags are used specific to the scrolling: vertscroll, horizscroll,
       below, lowest, above, timeline, tline.  Each item also  has  a  tag  of  the  form  "item_number",  where
       "number" is to be replaced by the actual sequence number of the item.

       Gantt charts:

       In  addition  to  the  tags  described  for  the  time-charts,  the following tags are used: description,
       completed, summary and summarybar.

       Radial charts and polar plots:

       Currently the radial lines indicating the grid have no tags. The graphical objects associated  with  data
       only have the "data" tag.

       Windroses:

       Only  the  tag  data_number  is currently used ("number" should be replaced by the sequence number of the
       data, starting at 0.

       Contour and isoline plots:

       No tags are used.

       3D plots and 3D ribbon plots:

       No tags are used for the data objects, only for the axes.

       Charts decorated with 3D effects:

       The following tags are used to identify various types of graphical objects: platform, background,  d,  u,
       ticklines.

       The text associated with the bars has no tags. The ribbon lines and areas have no tags either.

       Tables:

       Tags used are: frame, cellbg and celltext In addition: To implement multiple plots and charts in a single
       canvas, all items also get as a tag the plot/chart they belong to. This enables Plotchart  to  manipulate
       only those items.

TODO - SOME PRIVATE NOTES

       I have the following wishlist:

       •      Isometric plots - allow new items to be implemented easily.

       •      A general 3D viewer - emphasis on geometry, not a ray-tracer.

       •      Several improvements for boxplots:

              •      Height of the box scales with the logarithm of the number of points

              •      Marker line to indicate a "current" value

              •      Box drawn from quantiles

KEYWORDS

       3D   bars,   3D   surfaces,  bar  charts,  charts,  coordinate  transformations,  coordinates,  graphical
       presentation, isometric plots, pie charts, plotting, polar plots, strip charts, tables, time charts,  xy-
       plots

       Copyright (c) 2011 Arjen Markus <arjenmarkus@users.sourceforge.net>