59386 - When overlapping PNG images with pure transparancy there is a faint residue that is displayed

Status: VERIFIED FIXED

(Core Graveyard :: GFX, defect, P3)

Description

[dcone (gone)]

This bug an offshoot of bug number 51179, and has a patch posted in that bug.  I 
am making a new bug because the platforms seem to need different solutions to 
solve this

Comment 1

[tor]

Taking responsibility to check in the fix to my code (already has r=bryner
and sr=blizzard recorded in bug 51179).

Comment 2

[tenthumbs]

I going to suggest a more aggressive patch. It dereferences pointers only once
which seems to give egcs a better chance of optimizing without interfering with gcc 2.95.2.

Comment 3

[tenthumbs]

Attachment: nsImageGTK.cpp diff

Comment 4

[tor]

Attachment: variant of tenthumb's patch

Comment 5

[tor]

Ok, cleaning up this code somewhat with a macro while fixing the problem
seems worthwhile.  My patch fixes the other two compositing areas, uses
the proper spelling of alpha, and removes the two local variables that
are only used once.

Comment 6

[Brian Ryner (not reading)]

r=bryner on this patch as well

Comment 7

[Christopher Blizzard (:blizzard)]

sr=blizzard

Comment 8

[tor]

Fix checked into the trunk.

Comment 9

[tenthumbs]

For the record, I know how to spell alpha. I was trying to avoid name collisions. :-)

Also, gcc is clever and knows how to optimize division by 255 so it's not
necessary to do anything clever.

Comment 10

[Chris Petersen]

Marking verified in the Feb 26th build.