Recent changes to 2819: unreadable label on y-axis in png output

#2819 unreadable label on y-axis in png output

Ethan Merritt — Mon, 22 Dec 2025 00:52:24 -0000

status: open-upstream-bug --> pending-fixed

#2819 unreadable label on y-axis in png output

Ethan Merritt — Tue, 22 Jul 2025 20:01:37 -0000

status: open --> open-upstream-bug
Group: -->
Priority: -->

#2819 unreadable label on y-axis in png output

Ethan Merritt — Tue, 22 Jul 2025 20:01:19 -0000

Duplicate report of fallout from a long-standing upstream problem.
See in particular
https://sourceforge.net/p/gnuplot/bugs/2194/

Long story short: the harfbuzz and pango font-handling libraries underwent major changes, and various other libraries (cairo in particular) did not stay in sync with them. Some versions work with each other and others don't. It also depends on what fonts are requested. Gnuplot (and probably other programs on your machine) are victims of this. You may be able to fix it by upgrading/downgrading library versions to find a set that play nicely with each other. Gnuplot will magically start working. Maybe.

I realize you are reporting a problem with the libgd-based png terminal, not the cairo-based png terminal. For what it's worth, I see the same problem if I used the distro-provided libgd but the problem goes away if I build libgd from source. So again it's probably a library version problem.

Fix: Change library versions or rebuild libgd from source
Work-around: Use "set term pngcairo" instead

unreadable label on y-axis in png output

Anonymous — Tue, 22 Jul 2025 18:31:01 -0000

affected versions (at least): 6.0.2 (as in ubuntu plucky) and 6.0.3 (tar.gz from sourceforge.net)

how to reproduce:
- start gnuplot (in your favourite temp or empty directory)
- run commands:
set ylabel "the y axis"
set xlabel "x axis"
set terminal png size 1200,800
set output "sin.png"
plot sin(x)
- check the generated png file (sin.png) using your favourite image viewer
- find the y-axis label is not rendered properly while the x-axis label is just fine (sample output file attached)
- note: same (erroneous) behaviour on y2-axis (not shown in sample script/output)
- note: earlier versions of gnuplot (as in earlier versions of ubuntu) worked fine
- note: gui output (qt?) works fine

expected behaviour:
- the y-axis label should be rendered properly

actual behaviour:
- the y-axis label is not rendered properly

note: I've reported this issue also on lunchpad (https://bugs.launchpad.net/ubuntu/+source/gnuplot/+bug/2117206) but to date it seems to have gone unnoticed over yonder :-(

unreadable label on y-axis in png output

Anonymous — Tue, 22 Jul 2025 18:31:01 -0000

Ticket 2819 has been modified: unreadable label on y-axis in png output
Edited By: Ethan Merritt (sfeam)
Status updated: 'open' => 'open-upstream-bug'

unreadable label on y-axis in png output

Anonymous — Tue, 22 Jul 2025 18:31:01 -0000

Ticket 2819 has been modified: unreadable label on y-axis in png output
Edited By: Ethan Merritt (sfeam)
Status updated: 'open-upstream-bug' => 'pending-fixed'