Fix 5266335: bad DIRTY/invalidation logic
The DIRTY flag is used to track which elements of the view hierarchy need
to be redrawn on the next drawing operation. This flag is set on the parent
hierarchy of a view when that view is invalidated. There is an optimization for
opaque views that tells the parent that it is dirty, but that it need not
redraw its own content because the view will cover it (since it is opaque).
This dirty-opaque logic breaks down in the current code because we only set
these dirty flags on the parent hierarchy, not on the view itself. In the situation
raised by this bug, we would invalidate the parent container directly (which does
not case the dirty flag to be set), then we would invalidate a child of that view.
Because the child is opaque, the DIRTY_OPAQUE flag would be set on the parent
container. This would cause us, in the later rendering process, to skip the
drawing on that parent container, assuming that it was only asked to be redrawn
because of its opaque child's invalidation.
The fix is to now set the DIRTY flag on an invalidated view, not just on its parent
hierarchy. The DIRTY_OPAQUE logic will avoid setting the opaque flag on views/parents
that are already marked DIRTY, thus an invalidated parent will be correctly drawn
during the drawing process.
Change-Id: Ib5e014a125a4f5168f6a5a3166e941474659aca5
1 file changed