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 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  out-
                                            put, in pixels.

       int            height      (in)      Height of region of bitmap to out-
                                            put, in pixels.

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 Post-
       script 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  Post-
       script  currently  being  generated  for canvas.  Y coordinates require
       transformation because Postscript uses an origin at the lower-left cor-
       ner  whereas X uses an origin at the upper-left corner.  Canvas x coor-
       dinates can be used directly in Postscript without transformation.

       Tk_CanvasPsBitmap generates Postscript to describe a region of  a  bit-
       map.  The Postscript is generated in proper image data format for Post-
       script, 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 cor-
       respond 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 over-
       written with an error message.

KEYWORDS

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