Images are converted to ARGB32 format, then each byte (ie: each pixel
channel) in the read image is allowed to deviate by some specified
amount from the corresponding byte in the expected image, to allow for
rounding errors etc.
By default, no deviation is permitted, but the XCF tests are allowed a
deviation of 1, as the alpha blending can result in rounding errors
(depending on whether hardware acceleration is used, for example). In
the end, we are not too concerned about a small deviation that is
invisible to the human eye.
REVIEW: 116567
This is intended as an aid when writing and debugging imageformat
plugins. It creates a file containing the bytes of QImage::bits(),
which can then be viewed in Okteta.
REVIEW: 116532