Open corranwebster opened 1 year ago
This is causing test failures for the Chaco test suite when run with non-agg backends: https://github.com/enthought/chaco/pull/891
Work-around is to explicitly call gc.clear()
before drawing anything in tests.
It looks like the Celiagg backend starts out with a completely transparent image, but the Image/agg backend starts out filled with white. It looks like Quartz and Cairo also start out transparent, QPainter doesn't initialize to anything, so Agg is probably the odd-one out.
Celiagg initializes with zeros: https://github.com/enthought/enable/blob/0ae01f00da730bcc84821e7ab9eb394df777795e/kiva/celiagg.py#L112
Agg initializes with 255: https://github.com/enthought/enable/blob/0ae01f00da730bcc84821e7ab9eb394df777795e/kiva/agg/__init__.py#L38-L44