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 interp->result and  TCL_OK  is
       returned unless an error occurs, in which case TCL_ERROR is returned and interp->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 interp->result and returns TCL_OK unless an error occurs,  in
       which case TCL_ERROR is returned and interp->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 interp->result and returns TCL_OK unless an error occurs, in which  case
       TCL_ERROR is returned and interp->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 interp->result.

       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 interp->result and TCL_OK is returned, unless an error occurs,
       in which case TCL_ERROR is returned  and  interp->result  is  overwritten  with  an  error
       message.

KEYWORDS

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