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Tk_CanvasPs(3)		      Tk Library Procedures		  Tk_CanvasPs(3)

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NAME
     Tk_CanvasPsY, Tk_CanvasPsBitmap, Tk_CanvasPsColor, Tk_CanvasPsFont, Tk_Can-
     vasPsPath,  Tk_CanvasPsStipple  -	utility  procedures for generating Post-
     script 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  wid-
					  get for which Postscript is being gen-
					  erated.

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

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

     Pixmap bitmap (in) 		  Bitmap to  use  for  generating  Post-
					  script.

     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.
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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 cur-
     rently 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  di-
     rectly 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 corre-
     spond 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 inter-
     preter 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  Post-
     script 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  in-
     terpreter	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  over-
     written with an error message.

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

Tk				       4.0			  Tk_CanvasPs(3)

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