245377 - CSS background images have broken transparency

Status: RESOLVED FIXED

(Core Graveyard :: Image: Painting, defect)

Description

[Crispin Flowerday (not receiving bug mail)]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8a2) Gecko/20040601 Galeon/1.3.15.99
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8a2) Gecko/20040601 Galeon/1.3.15.99

If you have a background image set using CSS, that uses transparency, the
transparent parts are no longer handled correctly. This is a regression, 1.6 and
the 1.7 branch are confirmed to work

Reproducible: Always
Steps to Reproduce:
1. Go to the test case listed in the url field
Actual Results:  
Observe that the background on the image in the bottom right is pink

Expected Results:  
As the background is transparent, it should be blue

Comment 1

[Boris Zbarsky [:bzbarsky]]

tor, could this be your drawtile changes?

Comment 2

[tor]

Attachment: handle 8-bit alpha images that only have 1-bit alpha information

Comment 3

[Crispin Flowerday (not receiving bug mail)]

backing out the patch to bug 244506 fixes this.

Comment 4

[tor]

Attachment: small fix

Comment 5

[Boris Zbarsky [:bzbarsky]]

Would a 3-byte memset be faster/better than 3 assignments?  (I somehow doubt it
would, but.....)

Comment 6

[tor]

I think three bytes are below the threshold that would be useful to memset.
If we really wanted to speed this up (if it starts showing in any profiles),
you would look at mAlphaBits and construct runs to memset.

Comment 7

[tor]

Checked in.