How to clear CANVAS in sunview

[Ellery Chan]

The easiest way that I know to clear a canvas is:

    pw_writebackground (canvas_pixwin(canvas), 0, 0, width, height, PIX_SRC);

or, for color canvases:

    pw_writebackground (canvas_pixwin(canvas), 0, 0, width, height,
                        PIX_SRC | PIX_COLOR(bg_color));

You only need to supply your own repaint procedure if you want to refresh
the display manually when previously covered parts of your canvas become
exposed.  If CANVAS_RETAINED is set to TRUE, the canvas is repainted
automatically from a backing pixrect kept in memory.  I hope this helps.

 Ellery Chan                     | ARPA  : ellery at trantor.harris-atd.com
 Harris Corp., MS 3A-1912        | USENET: ...!uunet!x102a!trantor!ellery
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