Added mouse interaction.

pelson · pelson · commit af924e7ed5ee · 2014-05-08T16:38:08.000+01:00
diff --git a/examples/animation/rain.py b/examples/animation/rain.py
@@ -21,9 +21,9 @@
 # Create rain data
 n_drops = 50
 rain_drops = np.zeros(n_drops, dtype=[('position', float, 2),
-                                 ('size',     float, 1),
-                                 ('growth',   float, 1),
-                                 ('color',    float, 4)])
+                                      ('size',     float, 1),
+                                      ('growth',   float, 1),
+                                      ('color',    float, 4)])
 
 # Initialize the raindrops in random positions and with
 # random growth rates.
@@ -36,6 +36,10 @@
                   s=rain_drops['size'], lw=0.5, edgecolors=rain_drops['color'],
                   facecolors='none')
 
+# Keep hold of the mouse coordinates (x, y, animation_age) so that we can seed
+# more dropplets near the mouse.
+mouse_info = [None, None, None]
+
 
 def update(frame_number):
     # Get an index which we can use to re-spawn the oldest raindrop.
@@ -48,9 +52,21 @@ def update(frame_number):
     # Make all circles bigger.
     rain_drops['size'] += rain_drops['growth']
 
+
+    # Compute a new position for the next raindrop. Base this on the
+    # last mouse position, otherwise just use the original uniform
+    # distribution.     
+    mouse_x, mouse_y, age = mouse_info
+    if age is not None and age < 1000 and age % 3 == 0:
+        mouse_info[2] += 1
+        new_position = [np.random.normal(loc=mouse_x, scale=0.15),
+                        np.random.normal(loc=mouse_y, scale=0.15)]
+    else:
+        new_position = np.random.uniform(0, 1, 2)
+
     # Pick a new position for oldest rain drop, resetting its size,
     # color and growth factor.
-    rain_drops['position'][current_index] = np.random.uniform(0, 1, 2)
+    rain_drops['position'][current_index] = new_position
     rain_drops['size'][current_index] = 5
     rain_drops['color'][current_index] = (0, 0, 0, 1)
     rain_drops['growth'][current_index] = np.random.uniform(50, 200)
@@ -59,7 +75,16 @@ def update(frame_number):
     scat.set_edgecolors(rain_drops['color'])
     scat.set_sizes(rain_drops['size'])
     scat.set_offsets(rain_drops['position'])
-    
+
+
+def on_mouse_over(event):
+    if event.inaxes:
+        mouse_info[0] = event.xdata
+        mouse_info[1] = event.ydata
+        mouse_info[2] = 0
+
+cid = fig.canvas.mpl_connect('motion_notify_event', on_mouse_over)
+
 
 # Construct the animation, using the update function as the animation
 # director.
