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From: Ingo Thies <ingo.thies@gmx.de>
Newsgroups: comp.graphics.apps.gnuplot
Subject: Postscript fill pattern broken?
Date: Sun, 17 Jul 2011 15:00:17 +0200
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Hi,

I have noticed some strange behaviour with fill patterns in Postscript. 
I don't know since when it is present, but at least gnuplot 4.4 or later 
(CVS version from July) seems to be affected.

When I try to use pattern fill in Postscript the pattern for fillecurves 
appears to be extremely pixeled, rather than smooth as in the style test 
page.

I am wondering how the patterns on the test page (i.e. with the command 
"test") are actually created. But obviously not using the actual 
commands for pattern-filled rectangles.

Here is an example script (note that the current gnuplot syntax only 
works with data-based curves rather than functions for fill between two 
curves; for this reason 'set table' is used. If there is an easier way, 
please describe this in the manual, if not already done so):

reset
set term push
set term postscript eps size 15cm,10cm "Helvetica" 20
set output 'testfill.eps'
set samples 100
set xrange [-2.*pi:+2.*pi]
set yrange [-1.1:2.4]
set table 'tmp.asc'
plot sin(x)+0.5
unset table
set style fill pattern 4
plot 'tmp.asc' u 1:($2-0.5):($2+0.5) w filledcu
unset output
set term pop

I would have expected that "fill pattern" would draw lines, but actually 
a pixeled pattern is used (use the magnifying function in ghostview). 
But please note that the sample pattern in the key looks OK, only the 
plotted pattern looks chunky.

Is there a workaround, or is this an old and not yet resolved bug?

Best whishes,

Ingo