[cairo] [cairo-commit] 2 commits - src/cairo-image-surface.c test/operator-source.c test/operator-source.image16.ref.png test/operator-source.pdf.rgb24.ref.png test/operator-source.quartz.argb32.ref.png test/operator-source.quartz.rgb24.ref.png test/operator-source.ref.png test/operator-source.rgb24.ref.png test/operator-source.svg12.argb32.xfail.png test/operator-source.svg12.rgb24.xfail.png test/operator-source.xlib-fallback.ref.png test/operator-source.xlib.ref.png test/operator-source.xlib.rgb24.ref.png

[Uli Schlachter]

Hi,

On 02.04.2011 21:03, Soeren Sandmann wrote:
> The patch:
> 
> +    /* The below code breaks for operator source. This can best be seen with
> +     * multiple boxes where black is drawn to dst outside of the boxes. */
> +    if (op == CAIRO_OPERATOR_SOURCE)
> +       return CAIRO_INT_STATUS_UNSUPPORTED;
> 
> looks a little suspicious to me: Should it really check for SOURCE, or
> should it check for bounded operators that are unbounded in pixman?
> SOURCE is one such operator, but there are others.

The original test case that was sent to the mailing list causes two boxes which
look like the letter "L" to be filled. The "background" is first painted red and
the L is then filled with green.

I tested this code with all cairo operators and only "source" painted something
outside of the boxes in the area of the L's extents. I don't think I checked
whether _composite_unaligned_boxes() was used, but all other operators had the
area outside of the L unaffected.

So, it might be that _composite_unaligned_boxes() has bugs with other operators,
too, but I didn't manage to hit them.

Which other operators should cause similar problems?

Cheers,
Uli

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