Bug#778318: gnuplot5: when using the pdfcairo terminal, lines are much thicker than with gnuplot4

[Vincent Lefevre]

Package: gnuplot5
Version: 5.0.0~rc+dfsg2-1
Severity: important

When using the pdfcairo terminal, lines are much thicker than with
gnuplot4, so that old plot code is not compatible with gnuplot5,
though this incompatibility is not listed on

  http://www.gnuplot.info/ReleaseNotes_5_0.html

This can be seen with:

for i in 4 5
do
  gnuplot$i <<EOF
set terminal pdfcairo lw 10
set output 'out$i.pdf'
plot '-' using 1:2 t '' with line
0 0
10 10
e
EOF
done

when both gnuplot4 and gnuplot5 are installed.

I've attached the produced out4.pdf and out5.pdf files.

Getting too thick lines is annoying in some cases as details can be
lost (or become less visible).

-- System Information:
Debian Release: 8.0
  APT prefers unstable
  APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.16.0-4-amd64 (SMP w/8 CPU cores)
Locale: LANG=POSIX, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)

Versions of packages gnuplot5 depends on:
ii  gnuplot5-qt [gnuplot5-nox]  5.0.0~rc+dfsg2-1

gnuplot5 recommends no packages.

Versions of packages gnuplot5 suggests:
ii  gnuplot5-doc  5.0.0~rc+dfsg2-1

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