Bug 264268

Summary: Green artifact when rendering using transparent canvas
Product: WebKit Reporter: clementfoure2005
Component: CanvasAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: dino, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: Other   
Hardware: PC   
OS: Linux   
URL: https://github.com/SquitchYT/Tess/tree/dev
Attachments:
Description Flags
Comparison between expected and current rendering none

Description clementfoure2005 2023-11-06 10:40:41 PST 
Created attachment 468494 [details]
Comparison between expected and current rendering

I'm currently developing an app using a framework called Tauri, which uses WebKit to render the frontend part on Linux & macOS. I use a library called xterm.js (https://github.com/xtermjs/xterm.js/) with its canvas plugin to render a terminal in my page. If I ask xterm.js to use transparency on the canvas element, green artifacts appear all over the text. This seems to be a bug that occurred with WebKit because other webview like those used in Chrome or Firefox, display the canvas content as expected. More importantly, this issue also occurred when using a WebGL 1 or 2 context.
Comment 1 Radar WebKit Bug Importer 2023-11-13 10:41:13 PST 
<rdar://problem/118342988>
Comment 2 clementfoure2005 2024-02-09 08:14:41 PST 
I am still blocked by this issue. More importantly, it's also occurring on gnome web. You can reproduce this issue by going to https://tessapp.dev with gnome web (epiphany), and you will see that the fake terminal has a rendering issue.