bugfix for dirty sprite when using a source rect #899
The test is still failing because this update is removing code (lines 1102-1104 in the original code) that is unrelated to fixing this issue. The removal of those lines breaks current usage and is inconsistent with other parts of the code (lines 1063-1067:
The originator did a good job of fixing the original issue, but making an unrelated functionality breaking change (granted this is a minor one) would be best done via a separate update. It would also be useful to include some related tests and update the documentation stating that this functionality has been changed and may break existing code.