Bug#454550: Here is a conflict of our interests

[Alexander E. Patrakov]

Zack Weinberg wrote:
> Have you looked at my test cases?  Do you agree that those are
> rendered better without interpolation?

Yes, and you have described them very well. Rendering them with interpolation 
produces clearly wrong results. However, questions stand 1) whether representing 
such sets of rectangles with low-resolution bitmaps is valid according to the 
PostScript and PDF specifications (hint: importing this into CorelDraw under 
Windows gives a warning about a low-resolution bitmap), and 2) if the standard 
does allow interpolation in this case, how widespread is this assumption of 
non-interpolated rendering in (broken) software that creates such files.

In either case, your "don't interpolate on upscaling" heuristic looks good 
enough in theory, but is not currently implementable in practice for PostScript 
files processed via Ghostscript (because there is no such command line option 
for Evince to pass to Ghostscript). And that's a bug in Ghostscript.

-- 
Alexander E. Patrakov