[racket-dev] [plt] Push #28945: master branch updated

At Fri, 27 Jun 2014 13:43:46 -0400, Sam Tobin-Hochstadt wrote:
> On Fri, Jun 27, 2014 at 12:30 PM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> > At Fri, 27 Jun 2014 11:56:39 -0400, Sam Tobin-Hochstadt wrote:
> >> On Fri, Jun 27, 2014 at 11:45 AM, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> >> > For some reason, the way that PDF fragments are pulled in by `pdflatex`
> >> > makes the fragments look worse in some PDF viewers/machines than the
> >> > way that PS fragments are pulled in by `latex` plus `dvips`. I think it
> >> > has to do with heuristics in PDF viewers, and I think there's no
> >> > difference when going to a printer.
> >>
> >> My impression was that PDF was supposed to be a pixel-accurate format,
> >> at least when self-contained and not using system fonts, and thus
> >> there wouldn't be any such heuristics. Is that not true?
> >
> > PDF is a vector-graphics format, not a raster-graphics format (so it
> > doesn't really say anything about pixels).
> 
> Right -- what I meant was that at a given size, rendering should be
> pixel-accurate, so that you shouldn't see differences between
> different viewers (unlike, say, HTML, which doesn't prescribe layout
> nearly as precisely).

Maybe the alignment problem (now fixed) in Robby's example obscured the
issue. It's just about the smoothness of the rendering.

That is, PDF specifies exactly where things should be on a cartesian
plane, but renderers draw the same image with different pixels
depending on the display resolution, how much time the renderer spends
on anti-aliasing, and so on. The "look worse" part above was meant only
about the appearance of shape edges, and not about shapes being in the
wrong location.