backend_qt5 (1.4.0): Not saving the figure with NavigationToolbar (solved)

[getzze]

Bug also reported here: https://bugs.archlinux.org/task/41790
When clicking on the Save button on the NavigationToolbar, I get an error:
Format "png)')" is not supported. Supported formats: eps, jpeg, jpg, pdf, pgf, png, ps, raw, rgba, svg, svgz, tif, tiff.

I tracked the bug to be coming from the output of the _getSaveFileName function, that is supposed to be a string but is a tuple in reality. In qt_compat.py, _getSaveFileName links to QtWidgets.QtFileDialog.getSaveFileName.
In pyqt4, this function returns a string, but the doc pyqt4/5 differences says that in pyqt5 the functions returns a tuple (filename, extension), as for getSaveFileNameAndFilter in pyqt4.

Commenting line 96 in qt_compat.py solved the problem, because _getSaveFileName is then correctly defined in line 117 (only returning the first element of the tuple).

[tacaswell]

@mfitzp can you take a look at this? (Let me know if I should stop pestering you with these issues).

[getzze]

Also, I realized that some classes (at least one) have changed between QtCore and QtGui (QtWidgets mainly in pyqt5) in the 4->5 transition. For instance, QSortFilterProxyModel is in QtGui in PyQt4 and in QtCore in PyQt5... Then there may be some unpredicted problems with the shim at the end of qt_compat.py

[mfitzp]

@tacaswell I'm happy to have a look, I have a drop-in wrapper for getSaveFileName that should fix this bug. Happy to keep looking at these issues, but I am currently writing up a PhD and moving to the Netherlands (11 days!) so may be a bit of lag.

@getzze The qt_compat only aims to shim the things that are actually used in the Qt backend. It would be nice to have a complete API compatibility layer - not least because of duplications of effort applying similar compatibility layers in other projects - but it's a big task. If you're interested we could have a go?

[tacaswell]

@mfitzp Good luck!

[mfitzp]

The opened PR #3469 should fix this. It updates all APIs to present a PyQt5/PySide like interface returning a tuple and then handles this in the backend.

[tacaswell]

Closed by #3469 which is on this branch as fe125ec