I think I get the idea of what Vitor is suggesting, *in the theoretical sense*, but I am not convinced that it matters. Anyway, here is how I understand it, with 2 issues about HD displays:
- HD displays require high-bandwidth data transport
- HD displays can present itself as X x Y to the computer/application, when physically it is really 2X x 2Y, etc.
The first issue is that vendor drivers on the host send RGB data through a compression filter with RGB -> HUV transformation plus down-sampling in the chroma channels, through the wire and decompress on the device with the reverse HUV -> RGB.
So you can get fringing (and colour fringing) from the first - it is the same sort of compression artifacts as the default jpeg 422 / 420 down-sampling, where you throw away the lower bits in the H and U channels.
The 2nd other issue about HD, is that the reported pixel geometry of the display to the computer, is not the same as how the physical pixels are actually on the screen.
I haven't read the original post carefully enough, so some of this is probably made up by me.
The bottom line is, if you have a HD display, you probably should switch off subpixel rendering. There is no need to have subpixel rendering in that situation anyway..
On Monday 9 June 2025 at 19:11:29 BST, Alexei Podtelezhnikov <apodtele@gmail.com> wrote:
If you are referring to color fringing when the text is moving and RGB are firing up with some delay. I have no idea how to synchronize it. This is likely out of scope of FreeType.
> On Jun 9, 2025, at 14:01, Alexei Podtelezhnikov <
apodtele@gmail.com> wrote:
>
> Vitor,
>
> Frankly, I can hardly relate your problem description to font rendering. Can you possibly rephrase it? In FreeType speak LCD rendering is just triplicated for 3 arbitrary color channels with slight differences depending how these channels are spatially shifted. Regular antialiasing is just a special case assuming that three channels are not shifted at all. Note that FreeType does not assign color to the channels.
>
> Alexei
>>
>>