Re: Random crashes on very wide picture

"Dariusz J. Garbowski" wrote:
> 
> I happend to "torture-test" GQview with somewhat bizarre sized image:
> 40784x100, which you can find at
> 
> http://www.tawbaware.com/maxlyons/gigapixel_strip.jpg
[...]
> GQview can be crashed on this image when randomly zooming in/out and
> switching from fullscreen to windowed mode. It may take some "torturing"
> to get GQview crash but eventually it dies with segmentation fault. It
> can be observed with 1.4.5, 1.5.4 and 1.5.5. Crash does not happen with
> reasonably sized images (I got bored while trying to make it happen with
> 1024x768 image ;-)
> 
> There is additional issue of zooming in/out that causes most right part
> of that wide image to be corrupted.

The point of the start of the corruption is exactly 32768 pixels from the left
of the image, it looks like the gdk-pixbuf scaler in gtk+ is broken past that
point. If you always stay at the original image size it is fine since the scaler
is not used.

The valgrind debugger reports the gdk-pixbuf scaler accessing random memory when
the corruption occurs.

My guess is that gdk-pixbuf is using a 16 bit signed integer internally and it
overflows when the image is this size.

I have filed a bug with GTK+, if you wish to follow the bug it is here:

  http://bugzilla.gnome.org/show_bug.cgi?id=163090


Greetings,
John


-- 
John Ellis <[email protected]>

http://gqview.sourceforge.net <GQview> | http://gqapplets.sourceforge.net
http://gqmpeg.sourceforge.net <GQmpeg> |                  <panel applets>


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