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Comment by vetinari | Hacker News Reader

It's still integer only scaling.

OSX uses slightly different trick - it creates a framebuffer that is @2 scale and lets the hardware to scale it down. (iOS goes even further and has @3 scaling).

Which is the right approach - for example, one of the rMBP options is to have 1440x900 (2880x1800) resolution, which to the native 2560x1600 is the ratio 9/8. Nobody is going to track that 9-th pixel for each block of 8 pixels in software. Using hw scaler is simpler, cheaper and has smaller margin for errors.

Frankly, implementing fractional scaling is waste of time, resources and would produce software that is slow, buggy and bloated.

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I'm aware of how OSX implements scaling. It's still rendering at a resolution that is a non-integer multiple of the screen's native resolution and then scaling it to the native resolution. How is this not fractional scaling?

User space software stack is not aware of it, the frameworks know only of scale 1, 2 and 3 (on iOS). Nothing between it. That's why it is integer scaling.

The fact that the framebuffer size is not the same as display resolution is known only to the driver and it is not something that is requested to be implemented for Linux.

> User space software stack is not aware of it, the frameworks know only of scale 1, 2 and 3 (on iOS). Nothing between it. That's why it is integer scaling.

Well whatever the case might be, whether it's kernel's fault, GNOME's fault, Wayland's fault or device driver fault, fact of matter is that one can easily get 1920x1200 resolution on Retina Macbook 15" with sharp font and images, and cannot on Fedora. This is why perhaps people are making "a fuss".

OS X CAN do fractional scaling as far as user is concerned (doesn't matter who scales it up or down), while Fedora cannot (with Wayland, at least).

>User space software stack is not aware of it, the frameworks know only of scale 1, 2 and 3 (on iOS). Nothing between it. That's why it is integer scaling.

It doesn't matter whether they know it or not, since they work transparently great with the scaling factor. In fact it's even better than having the software stack aware of it (simpler, less room for errors).

The end result is that fractional scaling resolutions works on OS X and not on Wayland (from what I read, haven't checked Wayland myself recently).

Whatever the mechanism, it does have it and it IS fractional scaling on non-integral multiple of the screen DPI.

Oh, that's right. I'd forgotten about that.

Thanks.

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