[Gretl-users] missing pixels at beginning of ylabel

Allin Cottrell cottrell at wfu.edu
Sun Nov 1 11:20:00 EST 2009

On Sun, 1 Nov 2009, Alan G Isaac wrote:

> 1. I'm having a some trouble replicating this problem on a
> recent gnuplot download, and I'm wondering if the gretl version
> of gnuplot (for Windows) compiles in support for pngcairo and if
> that takes over as the PNG backend for the gretl version? (If I
> use a downloaded gretl, the PNG back end does not give me the
> problem, but if I change pngcairo to png I still get the problem
> with gretl.)

This can get a bit confusing.  Historically, there are two
back-ends for producing PNG in gnuplot (maybe 3 if you go back far
enough?).  One uses the libgd graphics library, and one (a newer
addition) uses the pango and cairo libraries.  The wgnuplot.exe
that ships with gretl uses the cairo-based PNG writer exclusively.
(It does not support libgd, which is a mess code-wise and has poor
support for font selection.)

If you have a build of gnuplot that includes libgd support then
the gnuplot command "set term png" uses the libgd-based writer,
and "set term pngcairo" uses the cairo-based one, if available. If
libgd support is not present but cairo support is, then both "set
term png" and "set term pngcairo" have the same effect: use the
cairo driver.

> 2. Just out of curiosity, how did you get the help to work in
> gretl's gnuplot (I'm on Vista), and is that something you could
> give back to gnuplot?

Hmm, I wasn't aware of doing anything special. I just built the
help using the tools in the gnuplot source tree (slightly adapted
for a cross-build on Linux), plus Microsoft's hcw.exe (running
under wine) to compile the final .hlp file.


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