691699 - Opaque black PNGs not rendering on Macs (gets transparent/not drawn) on 10.5

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Stephen Morley]

Attachment: black.png

User Agent: Mozilla/5.0 (Windows NT 6.0; rv:7.0.1) Gecko/20100101 Firefox/7.0.1
Build ID: 20110928134238

Steps to reproduce:

Loaded a page containing some entirely opaque entirely black PNGs in Firefox 7.0.1 for Mac.


Actual results:

The black PNGs were not rendered. Furthermore, the space they occupied was not redrawn when scrolling, leading to text being 'smeared' across their location. When viewing an image in isolation (e.g. by loading the attached file in Firefox) nothing is displayed until attempting to drag the image, at which point Firefox makes the image semi-transparent and the black colour returns.


Expected results:

Opaque black PNGs should render correctly.

Comment 1

[Stephen Morley]

Please note that I reported this bug from a PC so the user agent added by the bug report wizard above is not relevant. The bug applies to Firefox 7.0.1 for Mac OS X 10.5.8.

Comment 2

[Stephen Morley]

Attachment: not-black.png

The attached not-black.png is a solid rgb(1,1,1) and demonstrates that even a slightly non-black image does not exhibit the problem.

Comment 3

[:aceman]

There is something similar in bug 689962, but that is with a 1-bit per color image. Your image is 24bit.

Can you attach a screenshot of what you see?

Comment 4

[Boris Zbarsky [:bzbarsky]]

Loading the black.png attachment worskforme on 10.6.8 and Firefox 7....

I wonder whether this is somehow graphics card specific.

Comment 5

[Stephen Morley]

I have put a demonstration page here:

http://www.spotonnet.co.uk/bug-691699.html

Comment 6

[Stephen Morley]

Attachment: Screenshot of the demonstration page

On this Mac the image is rendered as a white space, with no other graphic anomalies. From the system information:

Model identifier: iMac 9,1
Graphics card: NVIDIA GeForce 9400 (revision 0x00b1)

Comment 7

[Stephen Morley]

Attachment: Screenshot of the demonstration page

On this Mac the image is rendered as a white space, and resizing and scrolling causes neighbouring content to be 'smeared' across the space. From the system information:

Model identifier: iMac 6,1
Graphics card: NVIDIA GeForce 7300 GT (revision 0x00a1)

Comment 8

[:aceman]

So 2 different renderings on different cards?

Could you please see if you see bug 690710 on these machines? One reporter there also has Nvidia 9400.

Comment 9

[Stephen Morley]

I can confirm that bug 690710 is also exhibited by the two Macs. On the one with the GeForce 9400 a white space is shown, while on the one with the GeForce 7300 GT that area of the page just isn't drawn and neighbouring content gets smeared into it when scrolling and resizing.

Comment 10

[Pipe Draven]

I can see the bug, just like in bug 689962

Comment 11

[:aceman]

Thanks for confirmation.

Comment 12

[philippe (part-time)]

Bug 691780 might be the same, or related at least.

1. Note that I don't see any problems with the attached image here. The test case displays fine. But there is some smearing when scrolling horizontally.

2. in bug 691780 comment 7 I noted a regression range. Is that the same for this bug here ? Nobody seems to have checked ?

Comment 13

[:aceman]

We have the regression range in bug 689962 comment 26. Yours does not look the same as ours. Your range does not contain the cairo update we suspect as the culprit.

Comment 14

[Cameron Kaiser [:spectre]]

This gets fixed by short-circuiting _reduce_op (bug 720035). Are we sure this isn't the same issue as bug 689962?

Comment 15

[Gregory Pappas [:gregp]]

Unable to reproduce in current versions.