Cursor sizes on wayland

[Aleix Pol]

On Mon, May 14, 2018 at 7:42 PM, David Edmundson
<david at davidedmundson.co.uk> wrote:
> We definitely need to scale the cursor image to device pixels in DRM Output.
> That's code we need to add that I simply haven't done yet; it wasn't a high
> priority as we also have the concept of just cursors being bigger X-style.
> Your Qt patch will allow us to do that whilst keeping assets drawn in native
> resolutions.
>
>> For a cursor wl_surface KWin neither emits the output information nor uses
>> the scale information. Both would be relative easy to implement. But only
>> makes sense if toolkits support it. Last time I looked at Qt code, Qt did
>> not (but that's some time ago).
>
> I think having cursors match the surface is absolutely fine (Qt's current
> state). If everything was working properly in the worst case it gets
> upscaled/downscaled, but should still be the same size on screen.
>
> ---
>
> However, that's all somewhat unrelated to the bug Aleix showed me.
>
> Me not implementing wl_output style scaling would put the cursor simply
> always too small or always too big. Especially as Qt didn't do anything at
> the time.
> Yet we saw it bounce about all over the place. That seems more a bug of the
> X-style scaling
>
> David

I don't think the scaling of the cursor matches the scaling of the
client. I can clearly see the cursor twice the size on the low dpi
screens while windows are about as big.

Aleix