Fwd: [PATCH] Implement DwmIsCompositionEnabled

[Anonymous Meerkat]

(forwarding to wine-devel as I forgot to do so in the reply)

---------- Forwarded message ---------
From: Joel Leclerc 
Date: Thu, 3 Oct 2019 at 04:18
Subject: Re: [PATCH] Implement DwmIsCompositionEnabled
To: Dmitry Timoshkov
> For that particular bug report just making DwmIsCompositionEnabled()
> return TRUE is enough according to the bug comments

The problem is that doing this might break other applications, since
DWM is currently not fully implemented in Wine. Adding a registry
value that is disabled by default more closely mirrors the way Windows
does it (Windows uses this registry value to determine whether to
enable composition or not), and will hopefully prevent regressions as
well. Even if it's enabled by default, I believe using a registry
value would still allow greater flexibility for the end-user if an
error results due to this being enabled.
> Besides, reading a DWORD
> value from the registry could be done in less lines of code and without
> passing not initialzied values to the registry APIs.

Unfortunately I'm not very familiar with Windows's API, and this is my
first patch, so I'm not very familiar with Wine's codebase either.
Could you share an example, or another function in Wine's code that
implements this in a better way?

Thanks for reviewing this.

On Thu, 3 Oct 2019 at 03:36, Dmitry Timoshkov  wrote:
> Joel Leclerc  wrote:
> > Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=39469
>
> For that particular bug report just making DwmIsCompositionEnabled()
> return TRUE is enough according to the bug comments, reading the value
> from registry doesn't add anything useful. Besides, reading a DWORD
> value from the registry could be done in less lines of code and without
> passing not initialzied values to the registry APIs.
>
> --
> Dmitry.

[Dmitry Timoshkov]

Anonymous Meerkat  wrote:
> > For that particular bug report just making DwmIsCompositionEnabled()
> > return TRUE is enough according to the bug comments
>
> The problem is that doing this might break other applications, since
> DWM is currently not fully implemented in Wine. Adding a registry
> value that is disabled by default more closely mirrors the way Windows
> does it (Windows uses this registry value to determine whether to
> enable composition or not), and will hopefully prevent regressions as
> well. Even if it's enabled by default, I believe using a registry
> value would still allow greater flexibility for the end-user if an
> error results due to this being enabled.

Adding a winecfg option to reflect that registry value could make
things for a user much easier.
> > Besides, reading a DWORD
> > value from the registry could be done in less lines of code and without
> > passing not initialzied values to the registry APIs.
>
> Unfortunately I'm not very familiar with Windows's API, and this is my
> first patch, so I'm not very familiar with Wine's codebase either.
> Could you share an example, or another function in Wine's code that
> implements this in a better way?

Here is an example:
https://source.winehq.org/git/wine.git/blob/HEAD:/dlls/gdi32/gdiobj.c#l610

[Anonymous Meerkat]

> Adding a winecfg option to reflect that registry value could make
> things for a user much easier.

I agree. I was about to suggest the same, but I'll wait until a
verdict is out on the registry patch before moving on to the
user-interface component.
> Here is an example:
> https://source.winehq.org/git/wine.git/blob/HEAD:/dlls/gdi32/gdiobj.c#l610

Thank you, I also missed a RegCloseKey call. I've submitted v2.