New upstream version 0.6.0+dfsg

1 files changed, 128 insertions, 0 deletions

diff --git a/examples/plotUpdateFromThread.py b/examples/plotUpdateFromThread.py
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+# coding: utf-8
+# /*##########################################################################
+#
+# Copyright (c) 2017 European Synchrotron Radiation Facility
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# ###########################################################################*/
+"""This script illustrates the update of a silx.gui.plot widget from a thread.
+
+The problem is that plot and GUI methods should be called from the main thread.
+To safely update the plot from another thread, one need to make the update
+asynchronously from the main thread.
+In this example, this is achieved through a Qt signal.
+
+In this example we create a subclass of :class:`silx.gui.plot.Plot1D`
+that adds a thread-safe method to add curves:
+:meth:`ThreadSafePlot1D.addCurveThreadSafe`.
+This thread-safe method is then called from a thread to update the plot.
+"""
+
+__authors__ = ["T. Vincent"]
+__license__ = "MIT"
+__date__ = "05/09/2017"
+
+
+import threading
+import time
+
+import numpy
+
+from silx.gui import qt
+from silx.gui.plot import Plot1D
+
+
+class ThreadSafePlot1D(Plot1D):
+    """Add a thread-safe :meth:`addCurveThreadSafe` method to Plot1D.
+    """
+
+    _sigAddCurve = qt.Signal(tuple, dict)
+    """Signal used to perform addCurve in the main thread.
+
+    It takes args and kwargs as arguments.
+    """
+
+    def __init__(self, parent=None):
+        super(ThreadSafePlot1D, self).__init__(parent)
+        # Connect the signal to the method actually calling addCurve
+        self._sigAddCurve.connect(self.__addCurve)
+
+    def __addCurve(self, args, kwargs):
+        """Private method calling addCurve from _sigAddCurve"""
+        self.addCurve(*args, **kwargs)
+
+    def addCurveThreadSafe(self, *args, **kwargs):
+        """Thread-safe version of :meth:`silx.gui.plot.Plot.addCurve`
+
+        This method takes the same arguments as Plot.addCurve.
+
+        WARNING: This method does not return a value as opposed to Plot.addCurve
+        """
+        self._sigAddCurve.emit(args, kwargs)
+
+
+class UpdateThread(threading.Thread):
+    """Thread updating the curve of a :class:`ThreadSafePlot1D`
+
+    :param plot1d: The ThreadSafePlot1D to update."""
+
+    def __init__(self, plot1d):
+        self.plot1d = plot1d
+        self.running = False
+        super(UpdateThread, self).__init__()
+
+    def start(self):
+        """Start the update thread"""
+        self.running = True
+        super(UpdateThread, self).start()
+
+    def run(self):
+        """Method implementing thread loop that updates the plot"""
+        while self.running:
+            time.sleep(1)
+            self.plot1d.addCurveThreadSafe(
+                numpy.arange(1000), numpy.random.random(1000), resetzoom=False)
+
+    def stop(self):
+        """Stop the update thread"""
+        self.running = False
+        self.join(2)
+
+
+def main():
+    global app
+    app = qt.QApplication([])
+
+    # Create a ThreadSafePlot1D, set its limits and display it
+    plot1d = ThreadSafePlot1D()
+    plot1d.setLimits(0., 1000., 0., 1.)
+    plot1d.show()
+
+    # Create the thread that calls ThreadSafePlot1D.addCurveThreadSafe
+    updateThread = UpdateThread(plot1d)
+    updateThread.start()  # Start updating the plot
+
+    app.exec_()
+
+    updateThread.stop()  # Stop updating the plot
+
+
+if __name__ == '__main__':
+    main()