SVG output without image smoothing

[Dima K. <gn...@di...>]

Hi.

I'm seeing that currently our svg output produces blurred images. I'm
attaching a patch to (sorta) fix this.

Demo script:

  set terminal svg standalone
  set output "/tmp/tst.svg"
  set view map
  splot [0:10][0:10] '++' using 1:2:($1+$2) with image

The images before and after the patch are attached. Using firefox, you
can see the before-patch image containing smoothed pixels, while the
after-patch image contains pixels with crisp edges, which is what we
want I think.

Unfortunate caveat: apparently firefox and chrome can't agree on what to
call this property. Firefox wants "crisp-edges" to do this, while Chrome
wants "pixelated". So today, this patch will do the right thing on
Firefox, but not on Chrome. Anybody know how to make this work on both
(and the others, I guess)?

I'm on the fence about whether patching gnuplot to work with just one of
the two is better than keeping them both blurry in the same way.