Created attachment 18827 [details] Repro file Reported in https://github.com/sumatrapdfreader/sumatrapdf/issues/913 The blue gradient at the top (behind LANL) is more "bandy" than rendered by e.g. Chrome (i.e. Foxit).
Another file that likely has the same root cause is in https://github.com/sumatrapdfreader/sumatrapdf/issues/912
The white stripes are caused by anti-aliased rendering drawing multiple thin rectangular paths. Each rectangle has semi-transparent edges that let the white background show through due to anti-aliasing; and when these are drawn in sequence these white "gaps" appear. If you render without anti-aliasing the gradient is rendered fully solid. This is an unfortunate side-effect of implementing anti-aliasing using coverage-based opacity instead of using multi-sampling (rendering at a higher resolution and down-sampling the final result). The only "solutions" to this problem is disabling anti-aliasing either locally (by grid-fitting rectangle fills so they land perfectly on the pixel grid) or globally.