1998144 - Fill with gray pixels for partially rendered images

Status: RESOLVED DUPLICATE of bug 1556156

(Core :: Graphics: ImageLib, enhancement)

Description

[Kagami Rosylight [:saschanaz] (they/them)]

Currently partially decoded JPEG images are filled with white pixels, if such image is not encoded in a progressive format. It would be nice if we can use black pixels on dark mode instead.

For example, it's sometimes annoying if you load a high resolution non-progressive JPEG file served from an abroad Mastodon server that is not cached by any CDN. Clicking such image would temporarily fill your mobile screen with bright white pixels.

Comment 1

[Timothy Nikkel (:tnikkel)]

Bug 1556156 is the bug to draw these pixels as transparent like we used to before webrender. It needs some work on the web render side to work.

Here is the place where we clear to white
https://searchfox.org/firefox-main/rev/f6385e6644d5d4343d33b692810275c434122199/image/imgFrame.cpp#112

Comment 2

[Kagami Rosylight [:saschanaz] (they/them)]

Transparent pixels would be much better. But if that's hard I would be happy to have black pixels until we get to that.

Comment 3

[Kagami Rosylight [:saschanaz] (they/them)]

Err that was a mistake

Comment 4

[Kagami Rosylight [:saschanaz] (they/them)]

(the question is, is it really easier to detect dark mode from image frame instead of doing transparency unconditionally? 🤔)

Comment 5

[Kagami Rosylight [:saschanaz] (they/them)]

Or we could use gray pixels regardless of the color mode.

Comment 6

[Timothy Nikkel (:tnikkel)]

This would also not solve cases like bug 1808149 where the website itself is using black type theme even in light mode.

Comment 7

[Kagami Rosylight [:saschanaz] (they/them)]

Gray sounds like the better fallback in that case, and also just easier.

Comment 8

[Kagami Rosylight [:saschanaz] (they/them)]

Well, I tried filling 0x33, but that ended up being glassy gray. Then I tried 0 which made it fully transparent. Huh?

Comment 9

[Kagami Rosylight [:saschanaz] (they/them)]

Attachment: WIP: Bug 1998144 - Clear surface with 0 instead of 0xFF r=tnikkel

Comment 10

[Kagami Rosylight [:saschanaz] (they/them)]

Giving up on this, can't do anything other than 0xFF without causing weird issue, as tnikkel said... Let's do bug 1556156 🙂