[PATCH] comctl32: Add partial support for LVM_SETBKIMAGE.

[Zhiyi Zhang]

On 6/10/22 16:42, Dmitry Timoshkov wrote:
> Zhiyi Zhang <zzhang at codeweavers.com> wrote:
>
> Thanks for the review.
>
>> Also, I found LVM_SETBKIMAGE is acting a bit weird on Windows. For example,
>> if a LVM_SETBKIMAGE message trying to set a bitmap
>> is sent the second time. The second message returns FALSE and the background
>> image gets reset to none(from LVM_GETBKIMAGE). I don't know if we should
>> implement such a behavior but I would be more comfortable with some tests.
> According to my testing LVM_SETBKIMAGE always returns 0.

If LVM_SETBKIMAGE for a bitmap succeeds, it does return TRUE.

>  Regarding calling
> LVM_SETBKIMAGE again with the same hbitmap I'd guess that the control first
> destroys previosuly assigned bitmap, and that leads to a being assigned bitmap
> gets destroyed. The conrol then probably verifies bitmap validity before saving
> it internally, and that would explain why LVM_GETBKIMAGE returns 0.
>
Right, this make sense. It would be nice to add a test for this. MSDN doesn't mention that the bitmap
will be managed by the control after the message.

Thanks,
Zhiyi