Tk_CanvasPs(3)

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
A token that identifies a canvas widget for which Postscript is being generated. Y-coordinate in the space of the canvas. A Tcl interpreter; Postscript is appended to its result, or the result may be replaced with an error message. Bitmap to use for generating Postscript. X-coordinate within bitmap of left edge of region to output. Y-coordinate within bitmap of top edge of region to output. Width of region of bitmap to output, in pixels. Height of region of bitmap to output, in pixels. Information about color value to set in Postscript. Font for which Postscript is to be generated. 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. 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