Are there plans to include gamma blending and stem darkening for rendering?

[kkanungo17]

As described by this freetype article: https://freetype.org/freetype2/docs/hinting/text-rendering-general.html

[xalt7x]

Related to:

• iced-rs "web-colors" feature flag PR
• "COSMIC: More Alpha, More Fun!" (screenshot shows the usage of "web-colors" in cosmic-text).

[kkanungo17]

Yes, we finally got a DE with gamma blending for text. Now just waiting on stem darkening.

[xalt7x]

Now just waiting on stem darkening.

I'd like it as well, but unfortunately, on Linux stem darkening might not look good with some OTF fonts.
For example, see issues with Noto Sans OTF:

• https://bugzilla.opensuse.org/attachment.cgi?id=859236
• https://bugreports.qt.io/browse/QTBUG-95336
• https://gitlab.gnome.org/GNOME/gtk/-/issues/6078

Pop!_OS currently uses OTF versions of Fira fonts.

I hope that either the developers of Freetype, the maintainers of iced, or the maintainers of COSMIC will be able to tweak/fix it somehow.

[kkanungo17]

I think the problem with those is that the fonts either aren't gamma blended (GTK), or use a value that doesn't match the display (I think Qt uses 1.8 instead of 2.2). I'm just guessing though, let's see what COSMIC devs come up with.

EDIT: Though this does raise the interesting question, what if the display in question doesn't use 2.2?

[ryuukk]

+1, text looks blurry

We also need subpixel rendering

[kkanungo17]

@xalt7x Actually taking a closer look, COSMIC actually went from correct rendering to wrong rendering lol. This feature actually enables the option to not do blending in linear space and instead do it the "wrong" way to follow existing methods.

I can see why they decided to do it, linear space blending on its own makes fonts too light, but the correct way to fix that is stem darkening, not going back to the old wrong way of doing things.

[kkanungo17]

Patrick Walton had reverse engineered the metrics Apple uses for stem darkening, maybe this can be used as a basis to darken text that become light due to gamma correct rendering: https://x.com/pcwalton/status/918991457532354560