NAME

       Tk_CanvasPsY, Tk_CanvasPsBitmap, Tk_CanvasPsColor, Tk_CanvasPsFont, Tk_CanvasPsPath, Tk_CanvasPsStipple -
       utility procedures for generating Postscript for canvases

SYNOPSIS

       #include <tk.h>

       double
       Tk_CanvasPsY(canvas, canvasY)

       int
       Tk_CanvasPsBitmap(interp, canvas, bitmap, x, y, width, height)

       int
       Tk_CanvasPsColor(interp, canvas, colorPtr)

       int
       Tk_CanvasPsFont(interp, canvas, tkFont)

       Tk_CanvasPsPath(interp, canvas, coordPtr, numPoints)

       int
       Tk_CanvasPsStipple(interp, canvas, bitmap)

ARGUMENTS

       Tk_Canvas canvas (in)                A token that identifies a canvas  widget  for  which  Postscript  is
                                            being generated.

       double canvasY (in)                  Y-coordinate in the space of the canvas.

       Tcl_Interp *interp (in/out)          A  Tcl  interpreter;   Postscript  is appended to its result, or the
                                            result may be replaced with an error message.

       Pixmap bitmap (in)                   Bitmap to use for generating Postscript.

       int x (in)                           X-coordinate within bitmap of left edge of region to output.

       int y (in)                           Y-coordinate within bitmap of top edge of region to output.

       int width (in)                       Width of region of bitmap to output, in pixels.

       int height (in)                      Height of region of bitmap to output, in pixels.

       XColor *colorPtr (in)                Information about color value to set in Postscript.

       Tk_Font tkFont (in)                  Font for which Postscript is to be generated.

       double *coordPtr (in)                Pointer to an array of coordinates for one or more points  specified
                                            in  canvas  coordinates.  The order of values in coordPtr is x1, y1,
                                            x2, y2, x3, y3, and so on.

       int numPoints (in)                   Number of points at coordPtr.
________________________________________________________________________________________________________________

DESCRIPTION

       These procedures are called by canvas type managers to carry out common functions related  to  generating
       Postscript.   Most  of  the  procedures take a canvas argument, which refers to a canvas widget for which
       Postscript is being generated.

       Tk_CanvasPsY takes as argument a y-coordinate in the space of a canvas and returns the value that  should
       be  used  for  that  point in the Postscript currently being generated for canvas.  Y coordinates require
       transformation because Postscript uses an origin at the lower-left corner whereas X uses an origin at the
       upper-left corner.  Canvas x coordinates can be used directly in Postscript without transformation.

       Tk_CanvasPsBitmap  generates Postscript to describe a region of a bitmap.  The Postscript is generated in
       proper image data format for Postscript, i.e., as data between angle brackets, one bit  per  pixel.   The
       Postscript is appended to the result of interpreter interp and TCL_OK is returned unless an error occurs,
       in which case TCL_ERROR is returned and the interpreter result is overwritten with an error message.

       Tk_CanvasPsColor generates Postscript to set the current color to correspond to  its  colorPtr  argument,
       taking  into account any color map specified in the postscript command.  It appends the Postscript to the
       interpreter interp's result and returns TCL_OK unless  an  error  occurs,  in  which  case  TCL_ERROR  is
       returned and the interpreter's result is overwritten with an error message.

       Tk_CanvasPsFont  generates  Postscript that sets the current font to match tkFont as closely as possible.
       Tk_CanvasPsFont takes into account any font map specified in the postscript command, and it does the best
       it  can at mapping X fonts to Postscript fonts.  It appends the Postscript to interpreter interp's result
       and returns TCL_OK unless an error occurs, in which case TCL_ERROR  is  returned  and  the  interpreter's
       result is overwritten with an error message.

       Tk_CanvasPsPath  generates  Postscript to set the current path to the set of points given by coordPtr and
       numPoints.  It appends the resulting Postscript to the result of interpreter interp.

       Tk_CanvasPsStipple generates Postscript that will fill the current path in  stippled  fashion.   It  uses
       bitmap  as the stipple pattern and the current Postscript color;  ones in the stipple bitmap are drawn in
       the current color, and zeroes are not drawn at all.  The Postscript is appended to  interpreter  interp's
       result  and  TCL_OK  is  returned,  unless  an  error occurs, in which case TCL_ERROR is returned and the
       interpreter's result is overwritten with an error message.

KEYWORDS

       bitmap, canvas, color, font, path, Postscript, stipple