added multicursor

svn path=/trunk/matplotlib/; revision=2504

Author: jdh2358

examples/widgets/multicursor.py

@@ -0,0 +1,16 @@
+from matplotlib.widgets import MultiCursor
+from pylab import figure, show, nx
+
+t = nx.arange(0.0, 2.0, 0.01)
+s1 = nx.sin(2*nx.pi*t)
+s2 = nx.sin(4*nx.pi*t)
+fig = figure()
+ax1 = fig.add_subplot(211)
+ax1.plot(t, s1)
+
+
+ax2 = fig.add_subplot(212, sharex=ax1)
+ax2.plot(t, s2)
+
+multi = MultiCursor(fig.canvas, (ax1, ax2), color='r', lw=1)
+show()

lib/matplotlib/widgets.py

@@ -675,6 +675,71 @@ def _update(self):
 
         return False
 
+class MultiCursor:
+    """
+    Provide a vertical line cursor shared between multiple axes
+
+    from matplotlib.widgets import MultiCursor
+    from pylab import figure, show, nx
+
+    t = nx.arange(0.0, 2.0, 0.01)
+    s1 = nx.sin(2*nx.pi*t)
+    s2 = nx.sin(4*nx.pi*t)
+    fig = figure()
+    ax1 = fig.add_subplot(211)
+    ax1.plot(t, s1)
+
+
+    ax2 = fig.add_subplot(212, sharex=ax1)
+    ax2.plot(t, s2)
+
+    multi = MultiCursor(fig.canvas, (ax1, ax2), color='r', lw=1)
+    show()
+
+    """
+    def __init__(self, canvas, axes, useblit=True, **lineprops):
+        self.canvas = canvas
+        self.canvas.mpl_connect('motion_notify_event', self.onmove)
+        self.canvas.mpl_connect('draw_event', self.clear)
+        self.axes = axes
+        self.lines = [ax.axvline(1, visible=False, **lineprops) for ax in axes]
+
+        self.visible = True
+        self.useblit = useblit
+        self.background = None
+        self.needclear = False
+
+
+    def clear(self, event):
+        'clear the cursor'
+        if self.useblit:
+            self.background = self.canvas.copy_from_bbox(self.canvas.figure.bbox)
+        for line in self.lines: line.set_visible(False)
+
+
+    def onmove(self, event):
+
+        if event.inaxes is None: return
+        self.needclear = True
+        if not self.visible: return 
+
+        for line in self.lines:
+            line.set_xdata((event.xdata, event.xdata))
+            line.set_visible(self.visible)
+        self._update()
+
+
+    def _update(self):
+        if self.useblit:
+            if self.background is not None:
+                self.canvas.restore_region(self.background)
+            for ax, line in zip(self.axes, self.lines):
+                ax.draw_artist(line)
+            self.canvas.blit(self.canvas.figure.bbox)
+        else:
+
+            self.canvas.draw_idle()
+
 class SpanSelector:
     """
     Select a min/max range of the x or y axes for a matplotlib Axes