Summary:
The old logic results in broken rendering if the sample was bigger than the
area to render, due to normalized texture rect being 0 in the respective
dimansion. As well as stretched mapping of the sample for fractional
relationships between the area to render and the sample size.
Test Plan:
Borders of backgrounds of FluffyBunny theme render properly, no other
regressions seen (but unsure what else might rely on that artifact).
Reviewers: #plasma, mart
Reviewed By: #plasma, mart
Subscribers: apol, sitter, kde-frameworks-devel
Tags: #frameworks
Differential Revision: https://phabricator.kde.org/D19787
0ffe183d71