tk_canvasps(3)
NAME
Tk_CanvasPsY, Tk_CanvasPsBitmap, Tk_CanvasPsColor, Tk_Can
vasPsFont, 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 identi
- fies 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 argu
ment, 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 coor
dinates can be used directly in Postscript without trans
formation.
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_CanvasPs
Font 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