Modern Text Rendering with Linux

#1

Post by daww » Sun, Aug 04, 2019, 11:59 AM UTC

Modern Text Rendering with Linux
mrandri19.github.io

Re: Modern Text Rendering with Linux

#2

Post by robin_reala » Sun, Aug 04, 2019, 1:14 PM UTC

Do projects like Pathfinder fit into this stack anywhere? At a guess you could replace Freetype with it, but I guess it does more?

Re: Modern Text Rendering with Linux

#3

Post by Jasper_ » Sun, Aug 04, 2019, 1:28 PM UTC

This is missing a text layout engine: separating a string of texts into multiple blocks with word wrap. This is handled in GTK+ through Pango and in Qt with an internal algorithm. I don't believe FreeBiDi/ICU is used in either.

Re: Modern Text Rendering with Linux

#4

Post by Jasper_ » Sun, Aug 04, 2019, 1:28 PM UTC

robin_reala wrote: post #2

Do projects like Pathfinder fit into this stack anywhere? At a guess you could replace Freetype with it, but I guess it does more?

Pathfinder replaces FreeType. It doesn't do more, and shouldn't: it's focused on glyph (and image) rendering.

Re: Modern Text Rendering with Linux

#5

Post by daww » Sun, Aug 04, 2019, 1:30 PM UTC

robin_reala wrote: post #2

Do projects like Pathfinder fit into this stack anywhere? At a guess you could replace Freetype with it, but I guess it does more?

Interesting question, from my understanding Pathfinder is only concerned with rendering so it doesn't completely replace FreeType: you still need some software to extract the curves path data from the font file. This can be done in rust with skribo and font-kit

You can check out this issue for more info: https://github.com/servo/pathfinder/issues/143

Re: Modern Text Rendering with Linux

#6

Post by sayusyz » Sun, Aug 04, 2019, 3:54 PM UTC

Great detailed pictures. I'm curious where general hinting belongs.

Re: Modern Text Rendering with Linux

#7

Post by Jasper_ » Sun, Aug 04, 2019, 4:02 PM UTC

sayusyz wrote: post #6

Great detailed pictures. I'm curious where general hinting belongs.

"Hinting" is a combination of techniques. Subpixel placement hinting is done by the shaper, which would be HarfBuzz in this case. Metrics hinting (adjusting the glyph width) is done by a combination of the shaper and the renderer, which would be HarfBuzz and FreeType. Outline hinting (fitting outline to the grid by distoring shapes without) is done by FreeType.

Behdad Esfahboh, the author of HarfBuzz, has a great paper on the different choices and tradeoffs here: https://docs.google.com/document/d/1wpzgGMqXgit6FBVaO76epnnF...

Re: Modern Text Rendering with Linux

#8

Post by criddell » Sun, Aug 04, 2019, 4:10 PM UTC

Jasper_ wrote: post #7

sayusyz wrote: post #6

Great detailed pictures. I'm curious where general hinting belongs.

"Hinting" is a combination of techniques. Subpixel placement hinting is done by the shaper, which would be HarfBuzz in this case. Metrics hinting (adjusting the glyph width) is done by a combination of the shaper and the renderer, which would be HarfBuzz and FreeType. Outline hinting (fitting outline to the grid by distoring shapes without) is done by FreeType. Behdad Esfahboh, the author of HarfBuzz, has a great pap…

Now that very high dpi screens are so popular and inexpensive, is subpixel rendering worth doing anymore?

Re: Modern Text Rendering with Linux

#9

Post by raphlinus » Sun, Aug 04, 2019, 4:18 PM UTC

criddell wrote: post #8

Jasper_ wrote: post #7

Earlier quoted context omitted.

"Hinting" is a combination of techniques. Subpixel placement hinting is done by the shaper, which would be HarfBuzz in this case. Metrics hinting (adjusting the glyph width) is done by a combination of the shaper and the renderer, which would be HarfBuzz and FreeType. Outline hinting (fitting outline to the grid by distoring shapes without) is done by FreeType. Behdad Esfahboh, the author of HarfBuzz, has a great pap…

Now that very high dpi screens are so popular and inexpensive, is subpixel rendering worth doing anymore?

It's important to make the distinction between subpixel positioning and subpixel (RGB) rendering. I'd personally say yes to the former, even at high dpi, and no to the latter if you're on a mobile device. The kerning errors you get from quantizing the position of glyphs to integer pixels are, to my eyes, a noticeable degradation of quality.

Re: Modern Text Rendering with Linux

#10

Post by Matthias247 » Sun, Aug 04, 2019, 4:58 PM UTC

criddell wrote: post #8

Jasper_ wrote: post #7

Earlier quoted context omitted.

"Hinting" is a combination of techniques. Subpixel placement hinting is done by the shaper, which would be HarfBuzz in this case. Metrics hinting (adjusting the glyph width) is done by a combination of the shaper and the renderer, which would be HarfBuzz and FreeType. Outline hinting (fitting outline to the grid by distoring shapes without) is done by FreeType. Behdad Esfahboh, the author of HarfBuzz, has a great pap…

Now that very high dpi screens are so popular and inexpensive, is subpixel rendering worth doing anymore?

I don’t know the details, but on my 4K screen different applications font rendering looks very has a very noticeable difference in quality. Eg IntelliJ looks great, and afaik uses some form of subpixel Rendering. Where’s VS Code looks kind of crappy since the update to macOS Mojave, which as far as I understood changed font rendering