Re: pixmap/pixbuf confusion

[Owen Taylor <otaylor redhat com>]

On Sun, 2003-07-13 at 13:08, Michael Koppelman wrote:

> > That it did seem to grab the current window was just one way a "random"
> > uninitialised buffer could turn out. Deal with it.
>
> It didn't "seem" to grab the current window, it did grab the current 
> window 100 times out of 100. You only notice a problem if you change 
> the size of the pixmap to a size different from the window. From my 
> limited data (and without looking at the source) it seems to me that 
> the data is initialized with the current window. Otherwise it is a 
> miraculous (but not impossible) coincidence that with a thousand other 
> processes going it happened to use my window's old memory every time.

GTK+ draws by:

 * Creating a pixmap
 * Drawing to the pixmap
 * Copying the pixmap to the window

Therefore, if you create a pixmap the size of a window, and you are
doing most of the drawing on the system, it's not all that surprising
that you end up with contents of the pixmap GTK+ used to draw the
window with last time.

I think you'd find in many other cases that the uninitialized memory
was something entirely different in most cases; you were just
getting lucky/unlucky.

Regards,
                                        Owen