matplotlib widget for Qt 4, Python 3

Question

I'm writing a GUI application in Python 3 using PyQt4 and matplotlib. User would have to select certain field names, then programm would read corresponding values from the database, process them and draw a plot with some statistics out of it. User could change then field names or certain options for statistics representation and (automatically) redraw the plot.

I found some Qt widget in this chapter: Matplotlib for Python Developers, Embedding Matplotlib in Qt 4. But there also some example widget here: mpl widget.

I don't have much experience with Qt design and wonder what might be the difference btw those two? So far I've tried the first one and it allows me to display a matplotlib plot (histogram) within Qt GUI, but I can't test all the features, like updating the plot after changing any parameters, because it is not implemented yet.

Any advice, good reference or available widgets are welcome.

Answer 1

The advantage of the mpl widget is that you can see it while designing your interface in QtDesigner, and some things set up automatically for you. If you look at the code, you'll see it's also based on the "embedding" example you give. On the other hand, you can always have a placeholder qwidget (or whatever) in the interface to put your plot widget into, and then you don't have to carry the mpl_widget file around as a dependency.

The even simplest solution might be to use matplotlib's pylab interface, which will produce figure windows independent from your main application. You need to ensure that interactive mode is on, and the backend is set to qt4 before attempting to plot anything. Figures are easy to manage (e.g., plt.close('all') ).