Bucket Tool regressions with Cairo renderer

[ScislaC]

The Bucket Tool no longer seems to detect boundaries correctly after the merge of the Cairo branch. The expected behavior still exists in 0.48. In short, it seems to be confused with white & transparency.

I am attaching a test file. Reset the paint bucket tool to default options and try to fill the rectangles. Top left has a white fill. Top right has no fill. Bottom is the above two stacked, with transparent on top. Note that it can't even detect boundaries on the bottom one (look at trunk screenshot status bar).

[su_v (suv-lp)]

Not reproduced with Inkscape 0.48.2, Inkscape 0.48+devel r10325
Reproduced with r9598 of the cairo-rendering branch and Inkscape 0.48+devel r10599

(all tested on Mac OS X 10.5.8 (i386)).

[ScislaC (scislac)]

The behavior has improved, but is still different from 0.48. Tested w/ r11630.

[Tavmjong Bah (tavmjong-free)]

This may be related to the Trace Bitmap, Multiple scans, Brightness steps being broken (other scan types work).

[ScislaC (scislac)]

Indeed it is, as that is how the tool works. It is completely based off of the tracing functionality.

[Tavmjong Bah (tavmjong-free)]

Just checked in a fix (r11949). A handful of multiplies by 255 were missing.

Interesting changes from 0.48 -> 0.49 (Cairo)

RGBA -> ARGB
0.49 uses premultiplied alpha.
0.49 ignores background alpha.

The latter provokes a question. In 0.49 changing the alpha of the background has no effect. Is this an intended change from 0.48? The bucket fill code in one place explicitly ignores background alpha but it was used in other places (I changed it to ignore it everywhere). Is this what we should be doing? Being able to set the background alpha doesn't seem to be all that useful.

The problem with Trace Bitmap, Multiple scans, Brightness steps appears to be a different bug.

[su_v (suv-lp)]

On 10/12/2012 18:25, Tavmjong Bah wrote:
> The latter provokes a question. In 0.49 changing the alpha of the
> background has no effect. Is this an intended change from 0.48?

In current trunk the color for the canvas ignores the page background alpha (it is still used in bitmap export), committed as fix for bug #169623 in r10784:
<https://bugs.launchpad.net/inkscape/+bug/169623>
<https://bugs.launchpad.net/inkscape/+bug/169623/comments/16>
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/10784>

[Tavmjong Bah (tavmjong-free)]

OK, it would make sense then to ignore alpha during a bucket fill. I've changed the tooltip in the Document Preferences to reflect the new behaviour.

[John Smith (john-smithi)]

Should the status be updated to "Fix committed" ?

[ScislaC (scislac)]

I can no longer reproduce here, closing.