By default Qt tries to avoid potentially costly color matching by
not assigning an sRGB color space to our backingstore, even if
that's what we in practice fill it with.
We used to do this by assigning the display's color space, which
effectively opts out of color matching, similar to the old behavior
of the device RGB color space (which nowadays implies sRGB).
By picking up the color space from the NSWindow instead, we allow
the user to override the color space to trigger color matching,
for example by explicitly setting it to NSColorSpace.sRGBColorSpace.
NSWindow will fall back to the screen's color space if the window
doesn't have one set.
Task-number: QTBUG-47660
Change-Id: Iac8177e85e86fe9044a41eb2c93fbf26bb83c248
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
e6498362fd