HTML5 Canvas converted to data url image in update 45 is rendered different in latest updates (running on Mac 10.11)

UNCONFIRMED
Unassigned

Status

()

P3
normal
UNCONFIRMED
2 years ago
2 years ago

People

(Reporter: arellano.nvs, Unassigned)

Tracking

51 Branch
Points:
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Firefox Tracking Flags

(Not tracked)

Details

(Whiteboard: [gfx-noted])

Attachments

(2 attachments)

(Reporter)

Description

2 years ago
Created attachment 8844099 [details]
testCase.html

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36

Steps to reproduce:

Create a test case (attached) to draw into a canvas element, so that can be converted to data url and finally be downloaded as a .png file. This test case was executed in several updates of Firefox (45, 46, 48, 50 and 51)


Actual results:

PNG image created in update 45 is different to the ones crated on updates 46, 48, 50 and 51. Same situation while creating an image in update 46 and then compared with 48, 50 and 51. 

In order to compare images, I used the following tool: https://huddle.github.io/Resemble.js/


Expected results:

Since same code is being executed, PNG image created in update 45 should be identical to the ones created in latest updates.
(Reporter)

Updated

2 years ago
Summary: HTML5 Canvas converted to data url image in update 45 is rendered different in latest updates → HTML5 Canvas converted to data url image in update 45 is rendered different in latest updates (running on Mac 10.11)
Can you attach the images you get?  Also, it would be amazingly useful if you could run mozregression and narrow down the patch that modified this behaviour.
And to clarify, there was a change introduced between 45 and 46, and then a change introduced between 46 and 47, but 47 through 51 are the same?
I would expect some potential changes in canvas when we update to a new version of the Skia graphics library, or if the acceleration gets enabled/disabled, for some reason. Depending on the magnitude of changes, it may or may not be expected.
Priority: -- → P3
Whiteboard: [gfx-noted]
(Reporter)

Comment 2

2 years ago
Created attachment 8844129 [details]
testsImages.zip

Attached you will find images generated with updates 45, 46, 47, 48, 50 and 51
(Reporter)

Comment 3

2 years ago
(In reply to Milan Sreckovic [:milan] from comment #1)
> Can you attach the images you get?  Also, it would be amazingly useful if
> you could run mozregression and narrow down the patch that modified this
> behaviour.
> And to clarify, there was a change introduced between 45 and 46, and then a
> change introduced between 46 and 47, but 47 through 51 are the same?
> I would expect some potential changes in canvas when we update to a new
> version of the Skia graphics library, or if the acceleration gets
> enabled/disabled, for some reason. Depending on the magnitude of changes, it
> may or may not be expected.

Thanks for your prompt response.
Attached you will find a zip file including the images mentioned in the description.
I noticed that following situations with images generated in Firefox:

- Images in 46 and 47 are the same (they differ to 45)
- Image in 47 is different to those in 48, 50 and 51
- Images in 48, 50 and 51 are the same (they differ to 45)

Hope it helps.
In the relevant timeframe, we updated the low level graphics library in 46 (bug 1082598), 47 (bug 1246756), 49 (bug 1265131) and 52 (bug 1299435.)  We also dealt with some font rendering issues during the same timeframe.  I expect these are the results of that.
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