717572 - Background flickering while an image is loading

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Jérôme Vouillon]

I have a Web page where an image element is superposed over a canvas
element.  The idea is that the canvas element provides a low quality
version of an image which is eventually replaced by a final higher
quality image.

Previously, the image contents was loaded progressively over the canvas,
in a smooth way (the part not yet loaded was transparent). Now, I get
a dark background (instead of the canvas) for a short time when the
image starts loading. Then, the canvas becomes visible again, while
being progressively replaced by the image. The bug is especially
visible over a slow network.


To see this, go to the following page:

   http://www.pps.jussieu.fr/~vouillon/bug2/

Then, when you click on one of the small images on the page, a
larger version of the image is displayed as described above.
Some images are small and loaded quickly, so you may have to click
on several images before seeing the flickering.


Using mozregression, it seems the regression was introduced by
the following changeset:

    changeset:   79230:8b89d7037306
    user:        Matt Woodrow <[e-mail]>
    date:        Wed Oct 26 16:24:58 2011 +1300
    summary:     Bug 695275 - Fix conversion of ThebesLayers to ImageLayers. r=roc


The bug still occurs in Firefox Nightly.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Yeah, this looks wrong.  Over here (on Mac) I never even see the canvas previews, just the black, with a nightly.

Matt, can you take a look please?

Comment 3

[Timothy Nikkel (:tnikkel)]

Is this still happening?

Comment 4

[Loic]

Jérôme, is it still an issue on your side with FF32?

Comment 5

[Jérôme Vouillon]

No, this is fixed now. Thanks!