15.2.136. camcops_server.cc_modules.cc_plot

camcops_server/cc_modules/cc_plot.py

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Copyright (C) 2012, University of Cambridge, Department of Psychiatry. Created by Rudolf Cardinal (rnc1001@cam.ac.uk).

This file is part of CamCOPS.

CamCOPS is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

CamCOPS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with CamCOPS. If not, see <https://www.gnu.org/licenses/>.

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Plotting functions.

PROPER WAY TO USE MATPLOTLIB:

• https://jbarillari.blogspot.co.uk/2009/09/threadsafety-and-matplotlibpylab.html?m=1

• https://sjohannes.wordpress.com/2010/06/11/using-matplotlib-in-a-web-application/amp/

• https://matplotlib.org/faq/howto_faq.html#howto-webapp

• https://matplotlib.org/examples/api/agg_oo.html#api-agg-oo

In summary: matplotlib is easy to use in a way that has global state, but that will break in a threading application. Using the Figure() API is safe. Thus:

from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
from matplotlib.figure import Figure

fig = Figure()
canvas = FigureCanvas(fig)
ax = fig.add_subplot(111)
ax.plot([1, 2, 3])
ax.set_title('hi mom')
ax.grid(True)
ax.set_xlabel('time')
ax.set_ylabel('volts')
canvas.print_figure('test')