Hi Johannes! Thanks for your reply! Unfortunately the plt.show() does not show anything when called from the processing plugin's "processAlgorithm()" function. When called from the python console, it works fine instead. I also detected that "fig.tight_layout()" stucks QGIS, when used in a processing plugin. But fortunately, in the meantime I've also detected, that I can save the whole plot to a PDF file by using "plt.savefig(pdf_name)". And that's already a great benefit for me.
Best regards Am Mi., 15. Feb. 2023 um 09:39 Uhr schrieb Johannes Kröger (WhereGroup) < johannes.kroe...@wheregroup.com>: > Hi Manfred, > > not what you asked but: Are you sure you need a second QMainWindow or > maybe a non-modal QDialog or a QDockWidget would be sufficient? Those might > be easier to use. Or maybe even just using the window that plt.show() > creates? > > Cheers, Hannes > Am 14.02.23 um 22:11 schrieb Manfred Strahlhofer via QGIS-User: > > Hello! > > There is a problem when using "matplotlib.backends" and drawing plots when > called from a QGIS processing plugin. I am using the following test code: > # sample code below draws a canvas with a plot > # however closing this plot canvas crashes the plugin (cannot be restarted) > # and further qgis can't be closed with the X button > # originates from: > https://matplotlib.org/stable/gallery/user_interfaces/embedding_in_qt_sgskip.html#sphx-glr-gallery-user-interfaces-embedding-in-qt-sgskip-py > import sys > import time > import numpy as np > from matplotlib.backends.qt_compat import QtWidgets > from matplotlib.backends.backend_qtagg import ( > FigureCanvas, NavigationToolbar2QT as NavigationToolbar) > from matplotlib.figure import Figure > class ApplicationWindow(QtWidgets.QMainWindow): > def __init__(self): > super().__init__() > self._main = QtWidgets.QWidget() > self.setCentralWidget(self._main) > layout = QtWidgets.QVBoxLayout(self._main) > static_canvas = FigureCanvas(Figure(figsize=(5, 3))) > # Ideally one would use self.addToolBar here, but it is slightly > # incompatible between PyQt6 and other bindings, so we just add > the > # toolbar as a plain widget instead. > layout.addWidget(NavigationToolbar(static_canvas, self)) > layout.addWidget(static_canvas) > dynamic_canvas = FigureCanvas(Figure(figsize=(5, 3))) > layout.addWidget(dynamic_canvas) > layout.addWidget(NavigationToolbar(dynamic_canvas, self)) > self._static_ax = static_canvas.figure.subplots() > t = np.linspace(0, 10, 501) > self._static_ax.plot(t, np.tan(t), ".") > self._dynamic_ax = dynamic_canvas.figure.subplots() > t = np.linspace(0, 10, 101) > # Set up a Line2D. > self._line, = self._dynamic_ax.plot(t, np.sin(t + time.time())) > self._timer = dynamic_canvas.new_timer(50) > self._timer.add_callback(self._update_canvas) > self._timer.start() > def _update_canvas(self): > t = np.linspace(0, 10, 101) > # Shift the sinusoid as a function of time. > self._line.set_data(t, np.sin(t + time.time())) > self._line.figure.canvas.draw() > def test_plot(): > # Check whether there is already a running QApplication (e.g., if > running > # from an IDE). > #qapp = QtWidgets.QApplication.instance() this stucks QGIS! > #if not qapp: > qapp = QtWidgets.QApplication(sys.argv) # this stucks QGIS main > window when the dialog's close button is pressed > app = ApplicationWindow() > app.show() > app.activateWindow() > app.raise_() > qapp.exec() > #app.exit() > > When using "qapp = QtWidgets.QApplication.instance()", QGIS stucks > completely and no plot is shown ever. > When using "qapp = QtWidgets.QApplication(sys.argv)", the plot is shown > and updated correctly. But when pressing the "close button" of the plot > window, there are some strange effects (cannot start a plugin again) and > the "close button" of the QGIS main window is disabled. Have to shut down > qgis-bin.exe from the windows task-manager. > I am using: > QGIS Version 3.24.1 Tisler > matplotlib 3.5.1 > Windows 10 > > Anybody have a solution for this problem? > Thanks a lot. > > > > > _______________________________________________ > QGIS-User mailing listqgis-u...@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > -- > Johannes Kröger / GIS-Entwickler/-Berater > > ********************************************** > FOSSGIS Konferenz > 15.-18. März 2023 in Berlinhttps://fossgis-konferenz.de/2023/ > > WhereGroup-Beiträge auf der > FOSSGIShttps://wheregroup.com/unternehmen/aktuelles/ > ********************************************** > > WhereGroup GmbH > Grevenweg 89 > 20537 Hamburg > Germany > > Tel: +49 (0)228 / 90 90 38 - 36 > Fax: +49 (0)228 / 90 90 38 - 11 > johannes.kroe...@wheregroup.comwww.wheregroup.com > Geschäftsführer: > Olaf Knopp, Peter Stamm > Amtsgericht Bonn, HRB 9885 > ------------------------------- > >
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