On Tue, 20 Feb 2024 07:21:18 GMT, Sergey Bylokhov <s...@openjdk.org> wrote:
>> This how it is done in >> [RepaintManager](https://github.com/openjdk/jdk/blob/69a11c7f7ea7c4195a8ee56391bdf04c75bd8156/src/java.desktop/share/classes/javax/swing/RepaintManager.java#L1711), >> it uses background color of the component. > > That code was added by me to implement the shaped windows on macOS, that is > the only platform we support the translucent backbuffer in RepaintManager. > For the translucent backbuffer and even opaque component it is necessary to > clear its content since the rendering inside of the components assumes the > simple "fillrect" will clear the component which is not true if the composite > is not Src. > But probably at that place we always start rendering from the Window? in that > case the usage of background is a right thing. I am not sure that the usage > of the component background is a correct thing, and probably 0,0,0 should > work better. > > I suggest to check that we do not fill the background twice, by the code > added in the patch, and the code inside of the paintToOffscreen(). For > example if there are the container and the component inside, if the component > is not opaque and has no any content, will the container be fully visible? or > we will see the background of the component(which should not be there). Yeah, got your point. I will check that whether background is not filled twice. If yes then we have to use 0,0,0 to fill background else we will retain the component background color. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/17081#discussion_r1495375909
