User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a6pre) Gecko/20100623 Minefield/3.7a6pre Build Identifier: IE's Mr Potato canvas demo has a problem displaying the background under the latest minefield build. Instead of a sky-blue background, a gradient gray background is displayed. You can see something is wrong when you click on "shoot" and a blue rectangle appears for a short period of time. Reproducible: Always Demo's background displays properly on Chromium & Opera. P.S. Now that chrome, Opera, and now IE have all made original browser "advertising" with potatoes, surely the mozilla team feels the pressure to come up with its one about:potato? :o)

This worksforme on trunk (on Mac). Is this Windows-only?

Mozilla/5.0 (Windows NT 5.1; rv:2.0b8pre) Gecko/20101125 Firefox/4.0b8pre I see this on winXP

Do you see it if you disable hardware acceleration?

(In reply to comment #6) > Do you see it if you disable hardware acceleration? How do you do that?

Tools > Options > Advanced > General > uncheck "use hardware acceleration when available" (no change or me)

I see this on my PC with 4.0b8pre (Win7, HW accel on and off), as well as with 3.6.13. I don't see it in 4.0b8pre on my Mac.

I see this bug also (completely identical) with deactivated HW acceleration. My System: Windows Vista 64Bit SP2, nVidia GeForce 8800 GT, driver version in device manager: 8.17.12.5896.

Hmm. Sounds like we're doing something weird with the image scaling (taking into account pixels from outside the image or something?).

Is this just that we're antialiasing and IE isn't. https://developer.mozilla.org/en/Canvas_tutorial/Using_images#Controlling_image_scaling_behavior Turning off antialiasing has a dramatic effect on the reduced testcase.

This is weird. I don't know what we're doing but our behavior is definitely broken, and should block I think.

This isn't a regression, though (see comment 9). I agree that we should fix this soon; I just think we can release Firefox 4 with this bug. Let's target it at .x and make this one of the first bugs we fix after we're out of blockers.

This displays correctly for me on Nightly on Windows 7. Please reopen if you're still seeing the wrong background displayed.