Tk\_CanvasPs(3) Tk Library Procedures Tk\_CanvasPs(3)

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# [NAME](#NAME)

Tk\_CanvasPsY, Tk\_CanvasPsBitmap, Tk\_CanvasPsColor, Tk\_CanvasPsFont, Tk\_CanvasPsPath, Tk\_CanvasPsStipple - utility procedures for generating Postscript for canvases

# [SYNOPSIS](#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](#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.

Tcl\_Size *numPoints* (in)

Number of points at *coordPtr*.

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# [DESCRIPTION](#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](#KEYWORDS)

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

4.0 Tk

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Document: Tk_CanvasPsY(3) from tk 9.0.4-r2 (Chainguard OS)
Source: https://downloads.sourceforge.net/sourceforge/tcl/tk9.0.4-src.tar.gz