plugins/screenshot: Don't include alpha channel when screenshot is opaque

Kai Uwe Broulikrequested to merge
work/kbroulik/screenshot-noalpha into master

A full screen and region screenshot is always fully opaque. There's no need to include the alpha channel in this case.

Dolphin for example adds a shadow around thumbnails only when they’re opaque but also e.g QtQuick Image can skip alpha blending when it's opaque.

Before:

Screenshot_xyz.png: PNG image data, ..., 8-bit/color RGBA, non-interlaced

After:

Screenshot_xyz.png: PNG image data, ... 8-bit/color RGB, non-interlaced

We could do the same for window screenshots that don’t include shadow and decoration, if we could check whether it’s fully opaque?

Edited by Kai Uwe Broulik

Merge request reports