By default, our use of Python's logging module
is noisy about errors, warnings, and general informational stuff,
but silent about anything with a lower priority.
To see all messages, set the MYPAINT_DEBUG environment variable.
MYPAINT_DEBUG=1 ./mypaint -c /tmp/cfgtmp_throwaway_1
MyPaint normally logs Python exception backtraces to the terminal and to a dialog within the application.
To debug segfaults in C/C++ code, use gdb with a debug build,
after first making sure you have debugging symbols for Python and GTK3.
sudo apt-get install gdb python2.7-dbg libgtk-3-0-dbg
scons debug=1
export MYPAINT_DEBUG=1
gdb -ex r --args python ./mypaint -c /tmp/cfgtmp_throwaway_2
Execute bt within the gdb environment for a full backtrace.
See also: https://wiki.python.org/moin/DebuggingWithGdb
MyPaint can run the cProfile code profiler interactively if you find
that performance is lagging in a particular area, and want to figure out
what functions need optimizing. Assigning the "Start/Stop Profiling..."
command to a spare function key like F9 allows profiling to be flipped
on and off quickly while you do something that needs profiling.
When profiling stops, MyPaint creates a temporary output folder and writes its output files there. It then opens the temp folder in your desktop environment's file and directory browser. You get a single uniquely named temporary profiling folder for each instance of MyPaint you run.
One word of warning: the temporary folders are removed at the end of the MyPaint session to avoid tempdir clutter. If you need to keep the profiler's output, be sure to copy them safely somewhere first.
The most convenient output we support is graphical (PNG format).
Install gprof2dot.py
and graphviz for the prettiest results.
If you need to run the commands manually on .pstat output,
try:
gprof2dot.py -f pstats -o output.dot output.pstat
dot -Tpng -o output.png output.dot
Our profiler tries to do this for you.