Kwin Maintainers Approval for Rounding Bottom Corners

[Vlad Zahorodnii]

On 6/28/21 12:25 PM, Martin Flöser wrote:
> Am Samstag, 26. Juni 2021, 00:25:29 CEST schrieb Aleix Pol:
>> Are you sure this is something that needs tackling at KWin level? if KWin
>> cuts down there's the possibility that an app might get cut off. An
>> application (e
>> g. at kirigami level) could decide though to have round corners by offering
>> a transparent mask. Would that be more in line with what you are after?
> 
> I absolutely agree with Aleix here. This is nothing a window manager should
> do. This can break applications in horrible and unexpected ways. Please do not
> go down this route. We do not know what the application draws and how it
> interacts with the window - where there are controls, etc.

Right, besides the technical issues with client-side decorated 
applications, rounding corners on the compositor side will effectively 
kill optimizations such as directly scanning out sub-surfaces on 
hardware planes. The compositor will be forced to perform compositing.

It's totally understandable why VDG wants the bottom window corners be 
rounded by the compositor, but it's simply not possible due to various 
technical reasons.

Cheers,
Vlad

> Just imagine a video application without borders and you cut off pixels or a
> virtual machine where the virtualized operating system is not square.
> 
> If you want to do design, please do it in parts of your design. Don't force it
> on apps which are not controlled by us. And if we do it only for our
> controlled apps the better place to implement it, is in the apps or Breeze
> style.
> 
> Cheers
> Martin
> 
>