Screenshooter issues with output scales
The screenshooter example doesn't work with multiple outputs with a different scale each.
Pixel buffers are just copied to the output image without scaling. This means views will look bigger on HiDPI screens in the resulting image, and more importantly some outputs can be be copied on top of each other (for instance try a scale=2 output with a scale=1 output on the right).
Fractional scaling makes this even more difficult, because the screenshooter has no way to know the real output scale. That can be solved by implementing xdg-output which provides outputs' logical position and size.
From here we have to make a decision:
- Support output scales, we'll probably need to use a proper image library to scale buffers
- Only allow to screenshot one output with the screenshooter