python async example exits on esc and avoids GC

python wrapper example demo_cv_async now avoids temporary
reallocations on video bgr reordering that provoqued GC stalls.

Also adds gracefull exit on ESC by using the Kill signal.

Signed-off-by: David García Garzón <[email protected]>

wrappers/python/demo_cv_async.py

@@ -6,6 +6,8 @@
 cv.NamedWindow('Depth')
 cv.NamedWindow('RGB')
 
+die = False
+
 def display_depth(dev, data, timestamp):
     data -= np.min(data.ravel())
     data *= 65536 / np.max(data.ravel())
@@ -15,18 +17,32 @@ def display_depth(dev, data, timestamp):
     cv.SetData(image, data.tostring(),
                data.dtype.itemsize * data.shape[1])
     cv.ShowImage('Depth', image)
-    cv.WaitKey(5)
+    global die
+    if cv.WaitKey(5) == 27 : die = True
+
+rgb = None
 
+lastVideo = None
 
 def display_rgb(dev, data, timestamp):
+    global rgb
+    if rgb is None :
+        rgb = np.zeros(data.shape, np.uint8)
+    rgb[:] = data[:, :, ::-1]
     image = cv.CreateImageHeader((data.shape[1], data.shape[0]),
                                  cv.IPL_DEPTH_8U,
                                  3)
     # Note: We swap from RGB to BGR here
-    cv.SetData(image, data[:, :, ::-1].tostring(),
+    cv.SetData(image, rgb,
                data.dtype.itemsize * 3 * data.shape[1])
     cv.ShowImage('RGB', image)
-    cv.WaitKey(5)
+    global die
+    if cv.WaitKey(5) == 27 : die = True
+
+def body(context, device) :
+    if die : raise freenect.Kill
 
 freenect.runloop(depth=display_depth,
-                 video=display_rgb)
+                 video=display_rgb,
+                 body=body)
+