cpascual · March 8, 2023 09:38 · Oct 2, 2018 · Oct 2, 2018 · Oct 2, 2018 · Oct 2, 2018
diff --git a/autopantool.py b/autopantool.py
@@ -1,3 +1,8 @@
+# Demo of a "tool" for pyqtgraph that, when attached to a plot item it adds a menu
+# action that, when toggled, checks for new data periodically and auto pans the X axis.
+# The new-data-checking period is dynamically adjusted depending on the range being 
+# displayed
+# 
 # Snippet adapted from the taurus_pyqtgraph.autopantool module to be used without taurus.
 # See: 
 # https://github.com/taurus-org/taurus_pyqtgraph/blob/master/taurus_pyqtgraph/autopantool.py

diff --git a/autopantool.py b/autopantool.py
@@ -105,7 +105,7 @@ def updateRange(self):
     autopan.attachToPlotItem(w.getPlotItem())
 
     # add a curve that appends a new point every 500ms
-    c = pg.PlotDataItem()
+    c = pg.PlotDataItem(symbol='o')
     idx = 40
     max_points = 10000
     xdata = np.arange(max_points)

diff --git a/autopantool.py b/autopantool.py
@@ -1,4 +1,5 @@
-# Snippet adapted from: 
+# Snippet adapted from the taurus_pyqtgraph.autopantool module to be used without taurus.
+# See: 
 # https://github.com/taurus-org/taurus_pyqtgraph/blob/master/taurus_pyqtgraph/autopantool.py
 
 

diff --git a/autopantool.py b/autopantool.py
@@ -0,0 +1,131 @@
+# Snippet adapted from: 
+# https://github.com/taurus-org/taurus_pyqtgraph/blob/master/taurus_pyqtgraph/autopantool.py
+
+
+from PyQt4 import QtGui, QtCore
+
+
+class XAutoPanTool(QtGui.QAction):
+    """
+    A tool that provides the "AutoPan" for the X axis of a plot
+    (aka "oscilloscope mode"). It is implemented as an Action, and provides a
+    method to attach it to a :class:`pyqtgraph.PlotItem` (which adds an action
+    to the X Axis context menu) 
+    """
+
+    def __init__(self, parent=None):
+        QtGui.QAction.__init__(self, 'Auto Pan', parent)
+        self.setCheckable(True)
+        self.toggled.connect(self._onToggled)
+        self._timer = QtCore.QTimer()
+        self._timer.timeout.connect(self.updateRange)
+        self._originalXAutoRange = None
+        self._viewBox = None
+        self._XactionMenu = None
+        self._scrollStep = 0.2
+
+    def attachToPlotItem(self, plot_item):
+        """Use this method to add this tool to a plot
+
+        :param plot_item: (PlotItem)
+        """
+        self._viewBox = plot_item.getViewBox()
+        self._addToMenu(self._viewBox.menu)
+        self._originalXAutoRange = self._viewBox.autoRangeEnabled()[0]
+        self._viewBox.sigXRangeChanged.connect(self._onXRangeChanged)
+
+    def _addToMenu(self, menu):
+        for m in menu.axes:
+            if m.title() == 'X Axis':
+                x_menu = m
+                self._XactionMenu = x_menu.actions()[0]
+                x_menu.insertAction(self._XactionMenu, self)
+                self.setParent(menu)
+
+    def _onToggled(self, checked):
+        if checked:
+            self._originalXAutoRange = self._viewBox.autoRangeEnabled()[0]
+            self._viewBox.enableAutoRange(x=False)
+
+            axisXrange = self._viewBox.state['viewRange'][0]
+            x_range = axisXrange[1] - axisXrange[0]
+
+            t = int(x_range/10.)*1000
+            t = min(3000, t)
+            t = max(50, t)
+            self._timer.start(t)
+        else:
+            self._timer.stop()
+            self._viewBox.enableAutoRange(x=self._originalXAutoRange)
+
+        self._XactionMenu.setEnabled(not checked)
+
+    def _onXRangeChanged(self):
+        self.setChecked(False)
+
+    def updateRange(self):
+        """Pans the x axis (change the viewbox range maintaining width but
+        ensuring that the right-most point is shown
+        """
+        if len(self._viewBox.addedItems) < 1:
+            self._timer.stop()
+
+        children_bounds = self._viewBox.childrenBounds()
+        _, boundMax = children_bounds[0]
+
+        axis_X_range, _ = self._viewBox.state['viewRange']
+
+        x_range = axis_X_range[1] - axis_X_range[0]
+
+        if boundMax > axis_X_range[1] or boundMax < axis_X_range[0]:
+            x_min = boundMax - axis_X_range[1]
+            x_max = boundMax - axis_X_range[0]
+            step = min(max(x_range * self._scrollStep, x_min), x_max)
+
+            self._viewBox.sigXRangeChanged.disconnect(self._onXRangeChanged)
+            self._viewBox.setXRange(axis_X_range[0]+step, axis_X_range[1]+step,
+                                    padding=0.0, update=False)
+            self._viewBox.sigXRangeChanged.connect(self._onXRangeChanged)
+
+
+
+if __name__ == '__main__':
+    import sys
+    import numpy as np
+    import pyqtgraph as pg
+
+    app = QtGui.QApplication([])
+
+    # use a standard Plot
+    w = pg.PlotWidget()
+
+    # add the XAutoPanTool
+    autopan = XAutoPanTool()
+    autopan.attachToPlotItem(w.getPlotItem())
+
+    # add a curve that appends a new point every 500ms
+    c = pg.PlotDataItem()
+    idx = 40
+    max_points = 10000
+    xdata = np.arange(max_points)
+    ydata = np.random.rand(max_points)
+    c.setData(xdata[:idx], ydata[:idx])
+
+    def addPoint():
+        global idx
+        idx += 1
+        c.setData(xdata[:idx], ydata[:idx])
+
+    t = QtCore.QTimer()
+    t.timeout.connect(addPoint)
+    t.start(500)
+
+    w.addItem(c)
+
+    # enable the AutoPan (same as checking "Auto Pan" in Context menu -> X Axis)
+    autopan.toggle()
+
+    # go
+    w.show()
+
+    sys.exit(app.exec_())
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