fix bug:when returning from fullscreen to normalscreen,missing surface.border.background

[LazyCuteLion]

fix bug:when returning from fullscreen to normalscreen, the CornerRadius background has issue it's like a mask color (when play alpha video)

[SuRGeoNix]

That was causing issues so I revert it (eg with normal/fullscreen on sample project)

[LazyCuteLion]

That was causing issues so I revert it (eg with normal/fullscreen on sample project)

oh,i tested it again,the problem is : 1、open fullscreen 2、return to normalscreen 3、open fullscrenn again（yes, the location to right-bottom）

but when play with alpha video,there has some issues with background if revert this commit.
can you try this:
#492
https://github.com/LazyCuteLion/Flyleaf/tree/alpha_video

[LazyCuteLion]

i test FlyleafPlayer (Custom - MVVM) (WPF),it is ok!
FlyleafHost use standAlone has this issues.

[SuRGeoNix]

@LazyCuteLion you suggest adding this only in case of non-standalone mode?

[LazyCuteLion]

yes,i push a new commit,but i don't know if should create a merge? can you check this? (it is a way to work well with play alpha video,and fix this bug. i tested it many times,it seems to be ok)
LazyCuteLion@86596a7

[LazyCuteLion]

nothing but,if not play with alpha video,this issues is no issues.
i'm not sure about the changes to the files(renderer and sharder) has any other effect,although everything seems well so far.

[SuRGeoNix]

I've included the fix for normal/fullscreen however we should review the alpha support separately.

[LazyCuteLion]

the branch of alpha_video only support wpf,winui3 get nowhere.
thank you very much for your precious time. @SuRGeoNix