Description: screenruler is a small ruby script that shows a ruler on the screen, it is available from this webpage https://launchpad.net/screenruler. There is an AUR package for an old version, named gruler.
When it is launched it gives the following error message

/usr/share/screenruler/utils/canvas.rb:40:in `block in initialize': undefined method `create_cairo_context' for #<Gdk::Pixmap:0x139a5f0 ptr=0x1522c90>
from /usr/bin/screenruler:74:in `call'
from /usr/bin/screenruler:74:in `main'
from /usr/bin/screenruler:74:in `<main>'
Shutting down...

searching the net, I've found that this bug is blamed by screenruler's author on a wrong ruby installation and that the problem can be solved by recompiling ruby-gtk2 with rcairo already installed. I did recompile ruby-gtk2 from abs (which requires ruby-rcairo anyway) and installed it. The error message became

/usr/share/screenruler/ruler_window.rb:167:in `draw': undefined method `create_pango_layout' for #<Cairo::Context:0x000000028afcf0>
from /usr/share/screenruler/ruler_window.rb:51:in `block in initialize'
from /usr/share/screenruler/utils/canvas.rb:40:in `call'
from /usr/share/screenruler/utils/canvas.rb:40:in `block in initialize'
from /usr/bin/screenruler:74:in `call'
from /usr/bin/screenruler:74:in `main'
from /usr/bin/screenruler:74:in `<main>'
Shutting down...

searched again and it seems to be a similar problem solved in a similar way. By recompiling ruby-pango with rcairo already installed. After recompiling and installing ruby-pango, it works.


Additional info:
* package version(s) ruby-gtk2 and ruby-pango 0.19.1
* config and/or log files etc.


Steps to reproduce: download screenruler from https://launchpad.net/screenruler, unpack it, cd into screenruler-0.85 and run ./screenruler.rb.