Bug 252225

(In reply to kdwkleung from comment #0)
> Created attachment 464980 [details]
> Screenshot showing the missing iMac on https://www.apple.com/imac-24/
> 
> On https://www.apple.com/imac-24/, much web content is not loaded, including
> the iMac directly after "Only 11.5 mm. Now that’s thin."

It looks like you are using a GTK4 build of WebKitGTK, could you confirm this?

OTOH, I cannot reproduce this with a GTK3 build of the current 2.38.4 stable
release; so it looks like either a regression or something related to GTK4.

Indeed. I’m using the GTK 4 Epiphany Technology Preview.

I can reproduce in Ephy Tech Preview.

I can repro with GTK3 build.

It seems we are failing to paint a canvas:

<canvas class="hero-flow" data-composite-canvas="" data-component-list="FlowComposite" data-base-path="/105/media/us/imac-24/2021/5e004d75-3ad6-4bb9-ab59-41f891fc52f0/anim/" data-viewport-size="large" data-flow-width="2016" data-flow-height="1744" data-flow-load-keyframe="{"start": "a0t - 180vh", "end": "a0b + 150vh", "anchors": ["[data-design-section]"], "breakpointMask": "LM", "disabledWhen":["no-enhance-xp"]}" data-chapter-one-anim-name="design-hero" data-chapter-two-anim-name="design-stand" data-chapter-three-anim-name="design-power-cable" data-chapter-one-progress-keyframe="{"start": "a0t - 5vh", "end": "a0b + 30vh", "anchors":["[data-left-copy]"], "breakpointMask": "LM", "disabledWhen":["no-enhance-xp"]}" data-chapter-two-progress-keyframe="{"start": "a0t + 290vh", "end": "a0t + 400vh", "anchors": ["[data-overlay-container]"], "breakpointMask": "LM", "disabledWhen":["no-enhance-xp"]}" data-chapter-three-progress-keyframe="{"start": "a0t + 450vh", "end": "a0t + 600vh", "anchors": ["[data-overlay-container]"], "breakpointMask": "LM", "disabledWhen":["no-enhance-xp"]}" data-anim-classname="{"start": "a0t + 120vh", "end": "a0t + 325vh", "cssClass": "js-will-change", "toggle": true, "anchors":["[data-overlay-container]"], "breakpointMask": "LM", "disabledWhen": ["no-enhance-xp"]}" data-anim-keyframe-1="{"start": "a0b + 13vh", "end": "a0b + 80vh", "y": [null, 0], "anchors":["[data-left-copy]"], "breakpointMask": "LM", "disabledWhen": ["no-enhance-xp"]}" data-anim-keyframe-2="{"start": "a0t + 295vh", "end": "a0t + 390vh", "x": [null, 200], "y": [null, 50], "anchors":["[data-overlay-container]"], "breakpointMask": "LM", "disabledWhen": ["no-enhance-xp"]}" data-anim-keyframe-3="{"start": "a0t + 455vh", "end": "a0t + 545vh", "x": [null, 250], "y": [null, 290], "anchors":["[data-overlay-container]"], "breakpointMask": "LM", "disabledWhen": ["no-enhance-xp"]}" width="2016" height="1744" style="transform: matrix(1, 0, 0, 1, 0, 120);"></canvas>

It seems this problem can be solved by using env var WEBKIT_NICOSIA_PAINTING_THREADS=4. Problem persists without. Tested on WebKitGTK 2.40, Gnome Web 44

(In reply to kdwkleung from comment #6)
> It seems this problem can be solved by using env var
> WEBKIT_NICOSIA_PAINTING_THREADS=4. Problem persists without. Tested on
> WebKitGTK 2.40, Gnome Web 44

It's weird that using more painting threads solves this problem.

Correction: it does work without the env var now in WebKitGTK 2.40. However there are multiple glitches (flickering) on the main iMac animation (the one that animates while you scroll) without the env var.