Tk_CanvasPs(3) Tk Library Procedures Tk_CanvasPs(3)

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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.
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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 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

Tk 4.0 Tk_CanvasPs(3)