4 ms·

Also, do you think if multi-channel signed distance field is a good approach for GUI text rendering? I understand, for games, it can support extreme zooming wi

Also, do you think if multi-channel signed distance field is a good approach for GUI text rendering? I understand, for games, it can support extreme zooming with small textures. But for GUI (for example a text editor), we only occasionally resize fonts. I looked at some of the open source projects (mostly terminal emulators), they simply rasterize fonts onto a texture map using CPU. I wonder if signed distance field is really necessary.

raphlinus 4y ago
I'm not a fan of distance fields for GUI text rendering. Their main advantage in games is super-easy integration into the rendering pipeline (they're basically just a texture and a simple shader), but the quality is not quite as good as standard font rendering. There are other issues, including fairly large texture RAM requirements for CJK fonts, and no easy way to do do variable fonts. My main work these days is piet-gpu, which is intended to do 2D graphics (including font rendering) "the right way." In the meantime, using existing platform glyph rendering capabilities makes sense and will certainly give the best visual match to platform text.
modeless 4y ago
The best GPU accelerated text rendering I know of is https://sluglibrary.com/ https://sluglibrary.com/. Not based on distance fields. Unfortunately not open source, though it is a one-man project. Maybe someday one of the big tech companies will pay him a whole ton of money to open source it.
- pcwalton 4y ago
  For most text rendering in the 2D UI use case, I'm not sure there is that much to solve anymore. Aggressive caching of rendered glyphs solves almost all the problems in practice. From what I can tell, Slug is targeted at games and 3D, where there are still interesting problems, but those aren't the 2D UI case.
  - moonchild 4y ago
    Even in 2-d, it is nice to have smooth zoom in/out. The only way to do this that I know of that doesn't compromise on quality is to re-render every frame, and the only way I know to do that fast is to use the gpu. I believe pathfinder can do it (correct me if I'm wrong). I know I'm working on something that can do it too. Moving a bit farther from the strictly 'text' realm there are authoring tools for vector graphics, where you would like to be able to view the changes you make in real time. CPU can do it (since it's probably the only complex thing onscreen, and changes are likely localised anyway if you really need the extra cycles), but GPU can do it better.
    - modeless 4y ago
      Yeah, existing techniques work fine if you want to make something similar to existing systems. But it's a shame to write a whole new GUI library and still have the same old limitations. Zooming is underused in existing systems, probably related to the fact that it's hard to make it work well with commonly used techniques.
    - pcwalton 4y ago
      Honestly, there are so few different glyphs on a typical page, and CPUs are so fast, that it usually isn't that hard to just rerender every glyph on CPU and aggressively reuse glyph images in order to hit 60 FPS during pinch zoom, at least for Latin text. CJK may be a different story, but I kind of doubt it. In 2022, smooth font rendering during pinch zoom is yet another case in which we in the software field dropped the ball, but it didn't matter because hardware picked up the slack.
      - moonchild 4y ago
        I wouldn't say it 'doesn't matter'. We get by, sure; but that doesn't mean the situation is ideal. On my laptop, if I try pinch-zooming, safari seems to do bilinear scaling, and firefox CPU usage will dramatically spike. The former is noticeably ugly; the latter is bad for battery life, and may stutter if work is being done in the background (laptops and phones don't yet have hundreds of cores).
- bogwog 4y ago
  The problem with slug is not that it isn't open source, it's that it's patent encumbered[1]. If it weren't for the patents, it'd be possible to implement an open source version. For font rendering, there are a lot of existing techniques out there, but whichever is best depends on your requirements. There are no silver bullets, and slug certainly isn't one. I will say though that most applications probably don't need hardware accelerated font rendering. A software renderer like Freetype2 is going to offer much higher quality results than anything like slug ever could, and with proper caching you can achieve good realtime performance. For a real world example of a text-heavy application that does this, see Lite-XL[2] 1: The landing page doesn't even mention the word "patent", so here's some evidence: https://twitter.com/ericlengyel/status/1159917092331642880?lang=en https://twitter.com/ericlengyel/status/1159917092331642880?l... 2: https://lite-xl.com/ https://lite-xl.com/

raphlinus 4y ago

I'm not a fan of distance fields for GUI text rendering. Their main advantage in games is super-easy integration into the rendering pipeline (they're basically just a texture and a simple shader), but the quality is not quite as good as standard font rendering. There are other issues, including fairly large texture RAM requirements for CJK fonts, and no easy way to do do variable fonts. My main work these days is piet-gpu, which is intended to do 2D graphics (including font rendering) "the right way." In the meantime, using existing platform glyph rendering capabilities makes sense and will certainly give the best visual match to platform text.

modeless 4y ago

The best GPU accelerated text rendering I know of is https://sluglibrary.com/ https://sluglibrary.com/. Not based on distance fields. Unfortunately not open source, though it is a one-man project. Maybe someday one of the big tech companies will pay him a whole ton of money to open source it.

pcwalton 4y ago
For most text rendering in the 2D UI use case, I'm not sure there is that much to solve anymore. Aggressive caching of rendered glyphs solves almost all the problems in practice. From what I can tell, Slug is targeted at games and 3D, where there are still interesting problems, but those aren't the 2D UI case.
- moonchild 4y ago
  Even in 2-d, it is nice to have smooth zoom in/out. The only way to do this that I know of that doesn't compromise on quality is to re-render every frame, and the only way I know to do that fast is to use the gpu. I believe pathfinder can do it (correct me if I'm wrong). I know I'm working on something that can do it too. Moving a bit farther from the strictly 'text' realm there are authoring tools for vector graphics, where you would like to be able to view the changes you make in real time. CPU can do it (since it's probably the only complex thing onscreen, and changes are likely localised anyway if you really need the extra cycles), but GPU can do it better.
  - modeless 4y ago
    Yeah, existing techniques work fine if you want to make something similar to existing systems. But it's a shame to write a whole new GUI library and still have the same old limitations. Zooming is underused in existing systems, probably related to the fact that it's hard to make it work well with commonly used techniques.
  - pcwalton 4y ago
    Honestly, there are so few different glyphs on a typical page, and CPUs are so fast, that it usually isn't that hard to just rerender every glyph on CPU and aggressively reuse glyph images in order to hit 60 FPS during pinch zoom, at least for Latin text. CJK may be a different story, but I kind of doubt it. In 2022, smooth font rendering during pinch zoom is yet another case in which we in the software field dropped the ball, but it didn't matter because hardware picked up the slack.
    - moonchild 4y ago
      I wouldn't say it 'doesn't matter'. We get by, sure; but that doesn't mean the situation is ideal. On my laptop, if I try pinch-zooming, safari seems to do bilinear scaling, and firefox CPU usage will dramatically spike. The former is noticeably ugly; the latter is bad for battery life, and may stutter if work is being done in the background (laptops and phones don't yet have hundreds of cores).
bogwog 4y ago
The problem with slug is not that it isn't open source, it's that it's patent encumbered[1]. If it weren't for the patents, it'd be possible to implement an open source version. For font rendering, there are a lot of existing techniques out there, but whichever is best depends on your requirements. There are no silver bullets, and slug certainly isn't one. I will say though that most applications probably don't need hardware accelerated font rendering. A software renderer like Freetype2 is going to offer much higher quality results than anything like slug ever could, and with proper caching you can achieve good realtime performance. For a real world example of a text-heavy application that does this, see Lite-XL[2] 1: The landing page doesn't even mention the word "patent", so here's some evidence: https://twitter.com/ericlengyel/status/1159917092331642880?lang=en https://twitter.com/ericlengyel/status/1159917092331642880?l... 2: https://lite-xl.com/ https://lite-xl.com/