1547612 - Use Lanczos for upscaling images

Status: NEW

(Core :: Graphics: ImageLib, enhancement, P3)

Description

[Artem S. Tashkinov]

Attachment: firefox_vs_lanczos.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:66.0) Gecko/20100101 Firefox/66.0

Steps to reproduce:

Currently Firefox uses bicubic (?) for image upscaling and this algo is not optimal specially for text.

Expected results:

See the attached screenshot:

Firefox 67 beta 14 vs. Lanczos.

Comment 1

[Dmitriy]

This can be done at high performance using shaders. For example, madvr renderer can upscale hundreds of frames per second using lanczos on modern discrete video cards.

Comment 2

[BugBot [:suhaib / :marco]]

In the process of migrating remaining bugs to the new severity system, the severity for this bug cannot be automatically determined. Please retriage this bug using the new severity system.

Comment 3

[Artem S. Tashkinov]

This bug appears dormant, but the underlying assumptions may deserve re-evaluation. When it was filed, display scaling was less common. Today, HiDPI displays, fractional desktop scaling, browser zoom, screenshots, documentation, and web applications make image resampling quality far more user-visible.

The attached comparison demonstrates a substantial readability difference, particularly for screenshots and text-containing images. Given modern hardware and Firefox's GPU-based rendering architecture, it may be worth revisiting whether the current quality/performance tradeoff remains appropriate.

Comment 4

[Will]

When you say upscale, are you referring to the fact that on a "Retina" display Mac or Windows equivalent, all 1x images/assets get upscaled? There is a Firefox extension for this but the OS display scaling must be at 200% and the browser webpage zoom must be at default for the integer upscaling to work https://tanalin.com/en/projects/smart-upscale/

Comment 5

[Artem S. Tashkinov]

(In reply to Will from comment #4)

When you say upscale, are you referring to the fact that on a "Retina" display Mac or Windows equivalent, all 1x images/assets get upscaled? There is a Firefox extension for this but the OS display scaling must be at 200% and the browser webpage zoom must be at default for the integer upscaling to work https://tanalin.com/en/projects/smart-upscale/

I'm talking about zooming in/out when pressing Ctrl + + and Ctrl + - or using Default Zoom != 100% in Settings.

Comment 6

[08xjcec48]

Please don't add "Feature request" to titles. This is already marked as an enhancement bug.