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I've recently been learning about how fonts render based on subpixel layouts in monitor panels. Windows assumes that all panels use RGB layout, and their Clear

I've recently been learning about how fonts render based on subpixel layouts in monitor panels. Windows assumes that all panels use RGB layout, and their ClearType software will render fonts with that assumption in mind. Unfortunately, this leads to visible text fringing on new display types, like the alternative stripe pattern used on WOLED monitors, or the triangular pattern used on QD-OLED. Some third-party tools exist to tweak how ClearType works, like MacType[1] or Better ClearType Tuner[2]. Unfortunately, these tools don't work in Chrome/electron, which seems to implement its own font rendering. Reading this, I guess that's through FreeType. I hope that as new panel technologies start becoming more prevalent, that somebody takes the initiative to help define a standard for communicating subpixel layouts from displays to the graphics layer, which text (or graphics) rendering engines can then make use of to improve type hinting. I do see some efforts in that area from Blur Busters[3] (the UFO Test guy), but still not much recognition from vendors. Note I'm still learning about this topic, so please let me know if I'm mistaken about any points here. [1] https://github.com/snowie2000/mactype https://github.com/snowie2000/mactype [2] https://github.com/bp2008/BetterClearTypeTuner https://github.com/bp2008/BetterClearTypeTuner [3] https://github.com/microsoft/PowerToys/issues/25595 https://github.com/microsoft/PowerToys/issues/25595

cosmic_cheese 2y ago
I may be totally off the mark here, but my understanding is that the alternative pixel arrangements found in current WOLED and QD-OLED monitors are suboptimal in various ways (despite the otherwise excellent qualities of these displays) and so panel manufacturers are working towards OLED panels built with traditional RGB subpixel arrangements that don’t forfeit the benefits of current WOLED and QD-OLED tech. That being the case, it may end up being that in the near future, alternative arrangements end up being abandoned and become one of the many quirky “stepping stone” technologies that litter display technology history. While it’s still a good idea to support them better in software, that might put into context why there hasn’t been more efforts put into doing so.
TheRealPomax 2y ago
Mandatory reading when getting into this topic: http://rastertragedy.com/ http://rastertragedy.com/
kiicia 2y ago
For me, being old time user, (ab)using any subpixel layouts for text rendering and antialiasing is counterproductive and (especially with current pixel densities, but also in general) introduces much more issues that it actually ever solved “Whole pixel/grayscale antialiasing” should be enough and then specialized display controller would handle the rest
- tadfisher 2y ago
  Agreed, but layouts such as Pentile don't actually have all three subpixel components in a logical pixel, so you'll still get artifacts even with grayscale AA. You can compensate for this by masking those missing components. https://github.com/snowie2000/mactype/issues/932 https://github.com/snowie2000/mactype/issues/932
  - kiicia 2y ago
    surprising info, I thought this was supposed to be the part about "display controller taking care of any additional issues", thanks for link with details, will read it with interest
wkat4242 2y ago
I'm pretty sure windows dropped subpixel anti-aliasing a few years ago. When it did exist there was a wizard to determine and set the subpixel layout. Personally I don't bother anymore anyway since I have a HiDPI display (about 200dpi, 4K@24"). I think that's a better solution, simply have enough pixels to look smooth. It's what phones do too of course.
- cosmic_cheese 2y ago
  macOS dropped it a few years ago, primarily because there are no Macs with non-HiDPI displays any more (reducing benefit of subpixel AA) and to improve uniformity with iOS apps running on macOS via Catalyst (iOS has never supported subpixel AA, since it doesn’t play nice with frequently adjusted orientations). Windows I believe still uses RGB subpixel AA, because OLED monitor users still need to tweak ClearType settings to make text not look bad.
  - hnuser123456 2y ago
    I didn't have to do any cleartype tuning on my LG C2. But maybe since it's a TV they have room for conventional subpixel layouts.
  - grishka 2y ago
    > because there are no Macs with non-HiDPI displays any more That is not true. Apple still sells Macs that don't come with a screen, namely Mac Mini, Mac Studio, and Mac Pro. People use these with non-HiDPI monitors they already own all the time.
    - thyristan 2y ago
      Subpixel AA for Macs is useless anyways, the fonts will look blurry no matter what you do on a Mac.
      - cosmic_cheese 2y ago
        They’re fine to my eye, at least as good as well tuned freetype (as found on Ubuntu) as long as you’re either using a 2x HiDPI display or are using a “normal” DPI monitor with above average density (e.g. 2560x1440 27”) and have subpixel AA forced on. Where it falls apart is at densities any lower, for example it struggles on those awful 1366x768 15.6” panels that it seemed like every other laptop was built with for a while. Similarly 24” 1080p and 32” 2560x1440 are pretty bad.
tadfisher 2y ago
The standard is EDID-DDDB, and subpixel layout is a major part of that specification. However I believe display manufacturers are dropping the ball here. https://glenwing.github.io/docs/VESA-EEDID-DDDB-1.pdf https://glenwing.github.io/docs/VESA-EEDID-DDDB-1.pdf
RKFADU_UOFCCLEL 2y ago
Windows has always allowed you to change subpixel layout, its right there in the clear type settings.
zozbot234 2y ago
Sub-pixel anti-aliasing requires outputing a pixel-perfect image to the screen, which is a challenge when you're also doing rendering on the GPU. You generally can't rely on any non-trivial part of the standard 3D-rendering pipeline (except for simple blitting/compositing) and have to use the GPU's compute stack instead to address those requirements. This adds quite a bit of complexity.
deleted 2y ago
[deleted]

cosmic_cheese 2y ago

I may be totally off the mark here, but my understanding is that the alternative pixel arrangements found in current WOLED and QD-OLED monitors are suboptimal in various ways (despite the otherwise excellent qualities of these displays) and so panel manufacturers are working towards OLED panels built with traditional RGB subpixel arrangements that don’t forfeit the benefits of current WOLED and QD-OLED tech. That being the case, it may end up being that in the near future, alternative arrangements end up being abandoned and become one of the many quirky “stepping stone” technologies that litter display technology history. While it’s still a good idea to support them better in software, that might put into context why there hasn’t been more efforts put into doing so.

TheRealPomax 2y ago

Mandatory reading when getting into this topic: http://rastertragedy.com/ http://rastertragedy.com/

kiicia 2y ago

For me, being old time user, (ab)using any subpixel layouts for text rendering and antialiasing is counterproductive and (especially with current pixel densities, but also in general) introduces much more issues that it actually ever solved “Whole pixel/grayscale antialiasing” should be enough and then specialized display controller would handle the rest

tadfisher 2y ago
Agreed, but layouts such as Pentile don't actually have all three subpixel components in a logical pixel, so you'll still get artifacts even with grayscale AA. You can compensate for this by masking those missing components. https://github.com/snowie2000/mactype/issues/932 https://github.com/snowie2000/mactype/issues/932
- kiicia 2y ago
  surprising info, I thought this was supposed to be the part about "display controller taking care of any additional issues", thanks for link with details, will read it with interest

wkat4242 2y ago

I'm pretty sure windows dropped subpixel anti-aliasing a few years ago. When it did exist there was a wizard to determine and set the subpixel layout. Personally I don't bother anymore anyway since I have a HiDPI display (about 200dpi, 4K@24"). I think that's a better solution, simply have enough pixels to look smooth. It's what phones do too of course.

cosmic_cheese 2y ago
macOS dropped it a few years ago, primarily because there are no Macs with non-HiDPI displays any more (reducing benefit of subpixel AA) and to improve uniformity with iOS apps running on macOS via Catalyst (iOS has never supported subpixel AA, since it doesn’t play nice with frequently adjusted orientations). Windows I believe still uses RGB subpixel AA, because OLED monitor users still need to tweak ClearType settings to make text not look bad.
- hnuser123456 2y ago
  I didn't have to do any cleartype tuning on my LG C2. But maybe since it's a TV they have room for conventional subpixel layouts.
- grishka 2y ago
  > because there are no Macs with non-HiDPI displays any more That is not true. Apple still sells Macs that don't come with a screen, namely Mac Mini, Mac Studio, and Mac Pro. People use these with non-HiDPI monitors they already own all the time.
  - thyristan 2y ago
    Subpixel AA for Macs is useless anyways, the fonts will look blurry no matter what you do on a Mac.
    - cosmic_cheese 2y ago
      They’re fine to my eye, at least as good as well tuned freetype (as found on Ubuntu) as long as you’re either using a 2x HiDPI display or are using a “normal” DPI monitor with above average density (e.g. 2560x1440 27”) and have subpixel AA forced on. Where it falls apart is at densities any lower, for example it struggles on those awful 1366x768 15.6” panels that it seemed like every other laptop was built with for a while. Similarly 24” 1080p and 32” 2560x1440 are pretty bad.

tadfisher 2y ago

The standard is EDID-DDDB, and subpixel layout is a major part of that specification. However I believe display manufacturers are dropping the ball here. https://glenwing.github.io/docs/VESA-EEDID-DDDB-1.pdf https://glenwing.github.io/docs/VESA-EEDID-DDDB-1.pdf

RKFADU_UOFCCLEL 2y ago

Windows has always allowed you to change subpixel layout, its right there in the clear type settings.

zozbot234 2y ago

Sub-pixel anti-aliasing requires outputing a pixel-perfect image to the screen, which is a challenge when you're also doing rendering on the GPU. You generally can't rely on any non-trivial part of the standard 3D-rendering pipeline (except for simple blitting/compositing) and have to use the GPU's compute stack instead to address those requirements. This adds quite a bit of complexity.

deleted 2y ago

[deleted]