Tk_CanvasPsY(3) Tk Library Procedures Tk_CanvasPsY(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, fontStructPtr)
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 inter-
preter;
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
Tk 4.0 1
Tk_CanvasPsY(3) Tk Library Procedures Tk_CanvasPsY(3)
left edge of
region to out-
put.
int y (in) Y-coordinate
within bitmap of
top edge of
region to out-
put.
int width (in) Width of region
of bitmap to
output, in pix-
els.
int height (in) Height of region
of bitmap to
output, in pix-
els.
XColor *colorPtr (in) Information
about color
value to set in
Postscript.
XFontStruct *fontStructPtr (in) Font for which
Postscript is to
be generated.
double *coordPtr (in) Pointer to an
array of coordi-
nates for one or
more points
specified in
canvas coordi-
nates. 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 4.0 2
Tk_CanvasPsY(3) Tk Library Procedures Tk_CanvasPsY(3)
Tk_CanvasY 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 fontStructPtr 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
Tk 4.0 3
