Canvas drawImage makes incorrect offset




8 years ago
8 years ago


(Reporter: stechz, Unassigned)


Mac OS X

Firefox Tracking Flags

(Not tracked)



(1 attachment)



8 years ago
Created attachment 486091 [details]
Test case

This only happens on nightlies, not the betas or 3.6 (or Google Chrome).

STR: See attached page

Expected: canvas drawn image doesn't move
Actual: canvas drawn image shifts left and right with respect to canvas element

Comment 1

8 years ago
i see the using 3.6.7 on the mac.

I also noticed that the canvas isn't really the thing shifting back and forth, but rather the document itself.

You can verify this by zooming into the page until there is a scrollbar.  Then notice that the scroll indicator shows the document moving to the left and to the right.

Comment 2

8 years ago
In nightly, it is weird that only the drawn image moves and not the canvas background.
In 3.6.11, I see the "Expected" behavior in the test case.
> In nightly, it is weird that only the drawn image moves and not the canvas
> background.

A layers issue possibly?  Note that as far as I can tell I can't reproduce in a nightly on OSX....

Comment 5

8 years ago
bz, could you try resizing your window, and maximizing it?  It really isn't str yet, but I think I don't see the problem anymore after doing that.

Comment 6

8 years ago
Build ID: 20101026030724
GPU accelerated windows: yep

Adapter Description0x22600,0x22600,0x20400
Vendor ID2600
Device ID2600

Nothing strange looking in my preferences or extensions.
Ah, if I maximize the window I see the jiggle.  Depending on the zoom level it looks like background jiggles too, in some cases, but not in others....  So that may just be a rounding issue of some sort.
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