Tomáš Kuzma

Complex plotting demo

Try to get the demo.py to work. It draws 3d scatter plot with live data, you should be able to rotate by dragging the mouse; q should cleanly exit (closing the figure should not).

It should look like this (speed and fluency may vary):

The matplotlib library handles the plotting by using different backends: combination of a GUI toolkit (Tk, Qt5, Qt4, GTK3, GTK or wx) and a renderer (Agg, Cairo or sometimes toolkit-native, with no suffix). The matplotlib.use('…') line in the beginning of demo.py or util.py selects a backend. If one is not provided, matplotlib selects a reasonable combination which has the necessary libraries present.

Figures embedded in GUIs usually only have limited functionality and don’t update during execution. Launch python3 file.py directly from a console if you encounter such problems. (Or persuade your GUI to let the figures float free, e.g. %matplotlib notebook for Jupyter.)

Lab computers

Windows

• Start menu > Anaconda > prompt > python:
  • backends TkAgg, Qt5Agg (default) work
• Start menu > Anaconda > spyder:
  • interactive plots just won’t work (for me, anyway)
• Start menu > Anaconda > Jupyter:
  • start with %matplotlib notebook (interactive HTML/JS figures)
  • remove waitforbuttonpress(…) from util.py:88
• Start menu > Python 3.6
  • needed libraries are not installed
  • may work with pip install --user numpy scipy matplotlib

Linux

• “Start” menu > Konsole > python3:
  • backends TkAgg, Qt5Agg (default), GTK3Cairo work

Self-installation

Get a working Python 3.5+ going. Stir in numpy, scipy and matplotlib (probably using pip3 install; add a pinch of --user if you’re not an admin).

Alternatively: get an Anaconda 3.5+ installer bundle, which includes all of the above.

Linux

• easy: tk bindings are included in default Python. agg is included in matplotlib.

• medium: install pyqt5 / pyqt4 for Qt5Agg / Qt4Agg backends

• hard: get wx, gtk2, gtk3 to work with Python 3.*

• why bother: get pycairo* to work

Windows

• easy: tk bindings are included in default Python. agg is included in matplotlib.

• hard: install pyqt5, pyqt4, wx, gtk3 or gtk2

• why bother: get pycairo* to work

MacOS X

No idea. Default pycharm(?) doesn’t work properly.