4 ms·

Why is that impossible on a Pentile matrix? Fundamentally subpixel antialiasing is just recognizing that the samples for different colour channels are offset fr

Why is that impossible on a Pentile matrix? Fundamentally subpixel antialiasing is just recognizing that the samples for different colour channels are offset from one another, and on that level of generality it doesn’t really matter how those samples are arranged geometrically. If the sample density depends on the channel, well, you’ll have to weight those samples, but still, how is that a problem? I recognize that fitting that into a scanline rasterizer in a device that doesn’t really have samples arranged in scanlines might be a bit tricky and that there might be less urgency to squeeze the last dregs of resolution out of a ≥300 dpi display than out of a 96 dpi one, but I disagree that this can’t be done.

bjourne 5y ago
The reason it works on traditional flat panels is that there is a one to one correspondence between the image data and the panel layout. That is not the case with PenTile displays and there many different subpixel arrangements so it is not possible to predict what subpixels on the display will lit up for a given subpixel in the image data. For best results you also need fonts designed for subpixel rendering so even if subpixel rendering was practical on PenTile displays you would carefully need to tune the fonts for every possible PenTile subpixel arrangement.
- BlueTemplar 5y ago
  Why would you need to "predict" the layout ? Surely the display can communicate such information among all the other characteristics it already does ? Are you saying that many fonts are specifically designed for "3 column (and specific RGB order ?)" subpixel rendering ?
  - mananaysiempre 5y ago
    Well, getting the hardware (manufacturers) to tell you what the hell it (their stuff) is doing is always a problem and even extremely complicated designs and massive marketing efforts like USB only kind of solve the problem for the most common of the common cases, but that’s kind of a truism. Re you second point, I originally wanted to say something like “fonts aren’t, renderers are”, but in the meantime I read the Raster Tragedy[1] and it seems like the answer to your question is quite literally yes, hinting bytecode is in fact designed for a subpixel grid with a 1:3 aspect ratio (mostly by virtue of the font designer writing and checking it by feel using one). Shoehorning outline fonts and WYSIWYG layout onto low-resolution (≤ 150 dpi or so at 10 pt) displays is that much of a hack, and now I really, really want it to die, all the complaints about elitist designers notwithstanding. (That I find 200- and 300-dpi tablets and phones much more pleasant to work on is a mere coincidence, I assure you.) [1]: http://rastertragedy.com/ http://rastertragedy.com/
maskros 5y ago
As you mention they're not just offset differently, they're also at different resolutions. In theory you can achieve something similar by rendering at a higher resolution and downsampling with an appropriate filter, but then you're using a completely different algorithm that has nothing to do with the RGB "subpixel" cleartype rendering anymore.
mnw21cam 5y ago
> subpixel antialiasing is just recognizing that the samples for different colour channels are offset from one another The reason this doesn't work for Pentile displays is because the samples for the different colour channels are not offset from one another.

bjourne 5y ago

The reason it works on traditional flat panels is that there is a one to one correspondence between the image data and the panel layout. That is not the case with PenTile displays and there many different subpixel arrangements so it is not possible to predict what subpixels on the display will lit up for a given subpixel in the image data. For best results you also need fonts designed for subpixel rendering so even if subpixel rendering was practical on PenTile displays you would carefully need to tune the fonts for every possible PenTile subpixel arrangement.

BlueTemplar 5y ago
Why would you need to "predict" the layout ? Surely the display can communicate such information among all the other characteristics it already does ? Are you saying that many fonts are specifically designed for "3 column (and specific RGB order ?)" subpixel rendering ?
- mananaysiempre 5y ago
  Well, getting the hardware (manufacturers) to tell you what the hell it (their stuff) is doing is always a problem and even extremely complicated designs and massive marketing efforts like USB only kind of solve the problem for the most common of the common cases, but that’s kind of a truism. Re you second point, I originally wanted to say something like “fonts aren’t, renderers are”, but in the meantime I read the Raster Tragedy[1] and it seems like the answer to your question is quite literally yes, hinting bytecode is in fact designed for a subpixel grid with a 1:3 aspect ratio (mostly by virtue of the font designer writing and checking it by feel using one). Shoehorning outline fonts and WYSIWYG layout onto low-resolution (≤ 150 dpi or so at 10 pt) displays is that much of a hack, and now I really, really want it to die, all the complaints about elitist designers notwithstanding. (That I find 200- and 300-dpi tablets and phones much more pleasant to work on is a mere coincidence, I assure you.) [1]: http://rastertragedy.com/ http://rastertragedy.com/

maskros 5y ago

As you mention they're not just offset differently, they're also at different resolutions. In theory you can achieve something similar by rendering at a higher resolution and downsampling with an appropriate filter, but then you're using a completely different algorithm that has nothing to do with the RGB "subpixel" cleartype rendering anymore.

mnw21cam 5y ago

> subpixel antialiasing is just recognizing that the samples for different colour channels are offset from one another The reason this doesn't work for Pentile displays is because the samples for the different colour channels are not offset from one another.