Re: [AD] Using system mouse cursor

[Chris <kcat@xxxxxxxxxx>]

Evert Glebbeek wrote:
> Don't the Allegro docs state that Allegro will use a hardware cursor when 
> possible? I think this could be extended to mean a hardware or system 
> cursor on modern platforms. If it's possible to use the system's native 
> pointer, then we don't even need to draw the sprite ourselves in those 
> cases, and we probably don't need to scare the mouse either.

I completely agree, and that's the main reason for doing this (so we 
don't have to draw to the screen in a timer (which is dangerous), and so 
the program doesn't waste time hiding and showing the mouse, potentially 
causing droppings). The problem seems to be that you need a somewhat 
recent version of X to be able to use non-monochrome mouse pointers.

All you need to do is make a pixmap of the right size, copy the mouse 
bitmap data into it, and set it as the mouse/cursor image. Allegro 
currently does this to hide the mouse image in X:

/* Create invisible X cursor.  */
pixmap = XCreatePixmap(_xwin.display, _xwin.window, 1, 1, 1);
if (pixmap != None) {
   GC temp_gc;
   XColor color;

   gcmask = GCFunction | GCForeground | GCBackground;
   gcvalues.function = GXcopy;
   gcvalues.foreground = 0;
   gcvalues.background = 0;
   temp_gc = XCreateGC(_xwin.display, pixmap, gcmask, &gcvalues);
   XDrawPoint(_xwin.display, pixmap, temp_gc, 0, 0);
   XFreeGC(_xwin.display, temp_gc);
   color.pixel = 0;
   color.red = color.green = color.blue = 0;
   color.flags = DoRed | DoGreen | DoBlue;
   _xwin.cursor = XCreatePixmapCursor(_xwin.display, pixmap, pixmap, 
&color, &color, 0, 0);
   XDefineCursor(_xwin.display, _xwin.window, _xwin.cursor);
   XFreePixmap(_xwin.display, pixmap);
}
else {
   _xwin.cursor = XCreateFontCursor(_xwin.display, _xwin.cursor_shape);
   XDefineCursor(_xwin.display, _xwin.window, _xwin.cursor);
}

I don't think that should be too hard to extend to use data from a 
bitmap if multi-colored cursors are available.

- Kitty Cat