oracular (3) grid.3tk.gz

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NAME

       grid - Geometry manager that arranges widgets in a grid

SYNOPSIS

       grid option arg ?arg ...?
________________________________________________________________________________________________________________

DESCRIPTION

       The  grid command is used to communicate with the grid geometry manager that arranges widgets in rows and
       columns inside of another window, called the geometry container (or container window).  The grid  command
       can have any of several forms, depending on the option argument:

       grid window ?window ...? ?options?
              If the first argument to grid is suitable as the first window argument to grid configure, either a
              window name (any value starting with .) or one  of  the  characters  x  or  ^  (see  the  RELATIVE
              PLACEMENT section below), then the command is processed in the same way as grid configure.

       grid anchor window ?anchor?
              The anchor value controls how to place the grid within the container window when no row/column has
              any weight.  See THE GRID ALGORITHM below for further details.  The default anchor is nw.

       grid bbox window ?column row? ?column2 row2?
              With no arguments, the bounding box (in pixels)  of  the  grid  is  returned.   The  return  value
              consists  of  4 integers.  The first two are the pixel offset from the container window (x then y)
              of the top-left corner of the grid, and the second two integers are the width and  height  of  the
              grid,  also  in  pixels.   If  a  single column and row is specified on the command line, then the
              bounding box for that cell is returned, where the top left cell is numbered from  zero.   If  both
              column  and  row  arguments  are  specified,  then  the bounding box spanning the rows and columns
              indicated is returned.

       grid columnconfigure window index ?-option value...?
              Query or set the column properties of the index column of the  geometry  container,  window.   The
              valid options are -minsize, -weight, -uniform and -pad.  If one or more options are provided, then
              index may be given as a list of column indices to which the configuration options will operate on.
              Indices may be integers, window names or the keyword all. For all the options apply to all columns
              currently occupied be content windows. For a window name, that window must be a  content  of  this
              container  and  the  options apply to all columns currently occupied be the content.  The -minsize
              option sets the minimum size, in screen units, that  will  be  permitted  for  this  column.   The
              -weight option (an integer value) sets the relative weight for apportioning any extra spaces among
              columns.  A weight of zero (0) indicates the column will not deviate from its requested  size.   A
              column  whose weight is two will grow at twice the rate as a column of weight one when extra space
              is allocated to the layout.  The -uniform option, when a non-empty value is supplied,  places  the
              column in a uniform group with other columns that have the same value for -uniform.  The space for
              columns belonging to a uniform group is allocated  so  that  their  sizes  are  always  in  strict
              proportion  to  their -weight values.  See THE GRID ALGORITHM below for further details.  The -pad
              option specifies the number of screen units that will be added to  the  largest  window  contained
              completely  in  that  column  when  the  grid geometry manager requests a size from the containing
              window.  If only an option is specified, with no value,  the  current  value  of  that  option  is
              returned.   If  only  the  container  window  and index is specified, all the current settings are
              returned in a list of “-option value” pairs.

       grid configure window ?window ...? ?options?
              The arguments consist of the names of one or more content windows followed by pairs  of  arguments
              that specify how to manage the content.  The characters -,  x and ^, can be specified instead of a
              window name to alter the default location of a window, as  described  in  the  RELATIVE  PLACEMENT
              section, below.  The following options are supported:

              -column n
                     Insert  the  window  so  that it occupies the nth column in the grid.  Column numbers start
                     with 0.  If this option is not supplied, then the window is arranged just to the  right  of
                     previous  window  specified  on this call to grid, or column “0” if it is the first window.
                     For each x that immediately precedes the window, the column position is incremented by one.
                     Thus the x represents a blank column for this row in the grid.

              -columnspan n
                     Insert  the  window  so that it occupies n columns in the grid.  The default is one column,
                     unless the window name is followed by a -, in which case the columnspan is incremented once
                     for each immediately following -.

              -in container
                     Insert  the window(s) in the container window given by container.  The default is the first
                     window's parent window.

              -ipadx amount
                     The amount specifies how much horizontal internal padding to leave  on  each  side  of  the
                     content.   This  is  space  is added inside the content border.  The amount must be a valid
                     screen distance, such as 2 or .5c.  It defaults to 0.

              -ipady amount
                     The amount specifies how much vertical internal padding to leave on the top and  bottom  of
                     the content.  This space is added inside the content border.  The amount  defaults to 0.

              -padx amount
                     The  amount  specifies  how  much  horizontal external padding to leave on each side of the
                     content, in screen units.  Amount may be a list of two values to specify padding  for  left
                     and  right  separately.  The amount defaults to 0.  This space is added outside the content
                     border.

              -pady amount
                     The amount specifies how much vertical external padding to leave on the top and  bottom  of
                     the  content,  in  screen units.  Amount may be a list of two values to specify padding for
                     top and bottom separately.  The amount defaults to 0.  This  space  is  added  outside  the
                     content border.

              -row n Insert  the content so that it occupies the nth row in the grid.  Row numbers start with 0.
                     If this option is not supplied, then the content  is  arranged  on  the  same  row  as  the
                     previous content specified on this call to grid, or the next row after the highest occupied
                     row if this is the first content.

              -rowspan n
                     Insert the content so that it occupies n rows in the grid.  The default is one row.  If the
                     next grid command contains ^ characters instead of content that line up with the columns of
                     this content, then the rowspan of this content is extended by one.

              -sticky style
                     If a content's cell is larger than its requested dimensions, this option  may  be  used  to
                     position  (or  stretch) the content within its cell.  Style  is a string that contains zero
                     or more of the characters n, s, e or w.  The  string  can  optionally  contains  spaces  or
                     commas,  but  they are ignored.  Each letter refers to a side (north, south, east, or west)
                     that the content will “stick” to.  If both n and s (or e and w) are specified, the  content
                     will  be  stretched to fill the entire height (or width) of its cavity.  The -sticky option
                     subsumes the combination of -anchor and -fill that is used by pack.   The  default  is  “”,
                     which causes the content to be centered in its cavity, at its requested size.

              If  any of the content is already managed by the geometry manager then any unspecified options for
              them retain their previous values rather than receiving default values.

       grid forget window ?window ...?
              Removes each of the windows from grid for its container and unmaps  their  windows.   The  content
              will no longer be managed by the grid geometry manager.  The configuration options for that window
              are forgotten, so that if the window is managed once  more  by  the  grid  geometry  manager,  the
              initial default settings are used.

       grid info window
              Returns  a  list whose elements are the current configuration state of the content given by window
              in the same option-value form that might be specified to grid configure.  The first  two  elements
              of the list are “-in container” where container is the windows's container window.

       grid location window x y
              Given   x and y values in screen units relative to the container window, the column and row number
              at that x and y location is returned.  For locations that are above or to the left of the grid, -1
              is returned.

       grid propagate window ?boolean?
              If  boolean has a true boolean value such as 1 or on then propagation is enabled for window, which
              must be a window name (see GEOMETRY PROPAGATION below).  If boolean has a false boolean value then
              propagation  is  disabled  for  window.  In either of these cases an empty string is returned.  If
              boolean is omitted then the command returns 0 or 1 to indicate whether  propagation  is  currently
              enabled for window.  Propagation is enabled by default.

       grid rowconfigure window index ?-option value...?
              Query  or  set  the  row  properties  of  the index row of the geometry window, window.  The valid
              options are -minsize, -weight, -uniform and -pad.  If one or more options are provided, then index
              may be given as a list of row indices to which the configuration options will operate on.  Indices
              may be integers, window names or the keyword all. For all the options apply to all rows  currently
              occupied  by  content  windows.  For  a  window name, that window must be a content window of this
              container and the options apply to all rows currently  occupied  by  the  container  window.   The
              -minsize  option sets the minimum size, in screen units, that will be permitted for this row.  The
              -weight option (an integer value) sets the relative weight for apportioning any extra spaces among
              rows.   A  weight  of  zero (0) indicates the row will not deviate from its requested size.  A row
              whose weight is two will grow at twice the rate as a  row  of  weight  one  when  extra  space  is
              allocated  to the layout.  The -uniform option, when a non-empty value is supplied, places the row
              in a uniform group with other rows that have the same value for  -uniform.   The  space  for  rows
              belonging  to  a uniform group is allocated so that their sizes are always in strict proportion to
              their -weight values.  See THE  GRID  ALGORITHM  below  for  further  details.   The  -pad  option
              specifies the number of screen units that will be added to the largest window contained completely
              in that row when the grid geometry manager requests a size from the containing window.  If only an
              option  is  specified,  with  no value, the current value of that option is returned.  If only the
              container window and index is specified, all the current  settings  are  returned  in  a  list  of
              “-option value” pairs.

       grid remove window ?window ...?
              Removes  each  of  the  windows from grid for its container and unmaps their windows.  The content
              will no longer be managed by the grid geometry manager.  However, the  configuration  options  for
              that  window  are  remembered,  so  that  if  the  content window is managed once more by the grid
              geometry manager, the previous values are retained.

       grid size container
              Returns the size of the grid (in columns then rows) for container.  The size is determined  either
              by  the content occupying the largest row or column, or the largest column or row with a -minsize,
              -weight, or -pad that is non-zero.

       grid slaves window ?-option value?
              If no options are supplied, a list of all of the content in window  are  returned,  most  recently
              managed  first.  Option can be either -row or -column which causes only the content in the row (or
              column) specified by value to be returned.                                                         │

       grid content window ?-option value?                                                                       │
              Synonym for grid slaves window ?-option value?.

RELATIVE PLACEMENT

       The grid command contains a limited set of  capabilities  that  permit  layouts  to  be  created  without
       specifying  the  row  and  column  information  for each content.  This permits content to be rearranged,
       added, or removed without the need to explicitly specify row and column information.  When no  column  or
       row  information is specified for a content, default values are chosen for -column, -row, -columnspan and
       -rowspan at the time the content is managed. The values are chosen based upon the current layout  of  the
       grid,  the  position of the content relative to other contents in the same grid command, and the presence
       of the characters -, x, and ^ in grid command where content names are normally expected.

              -      This increases the -columnspan of the content to the left.   Several  -'s  in  a  row  will
                     successively increase the number of columns spanned. A - may not follow a ^ or a x, nor may
                     it be the first content argument to grid configure.

              x      This leaves an empty column between the content on the left and the content on the right.

              ^      This extends the -rowspan of the content above the ^'s in the grid.  The number of ^'s in a
                     row must match the number of columns spanned by the content above it.

THE GRID ALGORITHM

       The  grid  geometry  manager  lays  out  its content in three steps.  In the first step, the minimum size
       needed to fit all of the content is computed, then (if propagation is turned on), a request  is  made  of
       the container window to become that size.  In the second step, the requested size is compared against the
       actual size of the container.  If the sizes are different, then spaces is added to or taken away from the
       layout  as  needed.   For the final step, each content is positioned in its row(s) and column(s) based on
       the setting of its sticky flag.

       To compute the minimum size of a layout, the grid geometry manager  first  looks  at  all  content  whose
       -columnspan and -rowspan values are one, and computes the nominal size of each row or column to be either
       the minsize for that row or column, or the sum of the padding plus  the  size  of  the  largest  content,
       whichever  is  greater.   After that the rows or columns in each uniform group adapt to each other.  Then
       the content whose row-spans or column-spans are greater than one are examined.  If a  group  of  rows  or
       columns  need to be increased in size in order to accommodate these content, then extra space is added to
       each row or column in the group according to its weight.  For each group whose weights are all zero,  the
       additional space is apportioned equally.

       When  multiple  rows  or  columns  belong  to  a  uniform group, the space allocated to them is always in
       proportion to their weights. (A weight of zero is considered to be 1.)  In other words, a row  or  column
       configured  with  -weight  1  -uniform  a  will  have  exactly  the  same size as any other row or column
       configured with -weight 1 -uniform a.  A row or column configured with  -weight  2  -uniform  b  will  be
       exactly twice as large as one that is configured with -weight 1 -uniform b.

       More technically, each row or column in the group will have a size equal to k*weight for some constant k.
       The constant k is chosen so that no row or column becomes smaller than its minimum size.  For example, if
       all  rows  or columns in a group have the same weight, then each row or column will have the same size as
       the largest row or column in the group.

       For containers whose size is larger than the  requested  layout,  the  additional  space  is  apportioned
       according to the row and column weights.  If all of the weights are zero, the layout is placed within its
       container according to the anchor value.  For containers whose size is smaller than the requested layout,
       space  is  taken  away  from  columns and rows according to their weights.  However, once a column or row
       shrinks to its minsize, its weight is taken to be zero.  If more space needs to be removed from a  layout
       than would be permitted, as when all the rows or columns are at their minimum sizes, the layout is placed
       and clipped according to the anchor value.

GEOMETRY PROPAGATION

       The grid geometry manager normally computes how large a container must be to just exactly meet the  needs
       of  its  content,  and it sets the requested width and height of the container to these dimensions.  This
       causes geometry information to propagate up through a window hierarchy to a top-level window so that  the
       entire  sub-tree  sizes itself to fit the needs of the leaf windows.  However, the grid propagate command
       may be used to turn off propagation for one or more containers.  If propagation  is  disabled  then  grid
       will not set the requested width and height of the container window.  This may be useful if, for example,
       you wish for a container window to have a fixed size that you specify.

RESTRICTIONS ON CONTAINER WINDOWS

       The container for each content must either be the content's parent (the default) or a descendant  of  the
       content's  parent.   This  restriction  is necessary to guarantee that the content can be placed over any
       part of its container that is visible without danger of the content being  clipped  by  its  parent.   In
       addition, all content in one call to grid must have the same container.

STACKING ORDER

       If  the  container  for a content is not its parent then you must make sure that the content is higher in
       the stacking order than the container.  Otherwise the container will obscure  the  content  and  it  will
       appear  as  if  the  content has not been managed correctly.  The easiest way to make sure the content is
       higher than the container is to create the container window first:  the most recently created window will
       be highest in the stacking order.

CREDITS

       The  grid  command  is based on ideas taken from the GridBag geometry manager written by Doug. Stein, and
       the blt_table geometry manager, written by George Howlett.

EXAMPLES

       A toplevel window containing a text widget and two scrollbars:

              # Make the widgets
              toplevel .t
              text .t.txt -wrap none -xscroll {.t.h set} -yscroll {.t.v set}
              scrollbar .t.v -orient vertical   -command {.t.txt yview}
              scrollbar .t.h -orient horizontal -command {.t.txt xview}

              # Lay them out
              grid .t.txt .t.v -sticky nsew
              grid .t.h        -sticky nsew

              # Tell the text widget to take all the extra room
              grid rowconfigure    .t .t.txt -weight 1
              grid columnconfigure .t .t.txt -weight 1

       Three widgets of equal width, despite their different “natural” widths:

              button .b -text "Foo"
              entry .e -textvariable foo ; set foo "Hello World!"
              label .l -text "This is a fairly long piece of text"

              grid .b .e .l -sticky ew
              grid columnconfigure . "all" -uniform allTheSame

SEE ALSO

       pack(3tk), place(3tk)

KEYWORDS

       geometry manager, location, grid, cell, propagation, size, pack