Merge "b/3331379 reduce ping-to-zoom jitter." into honeycomb

core/java/android/webkit/ZoomManager.java

@@ -149,6 +149,12 @@ class ZoomManager {
 
     private static float MINIMUM_SCALE_INCREMENT = 0.01f;
 
+    /*
+     *  The touch points could be changed even the fingers stop moving.
+     *  We use the following to filter out the zooming jitters.
+     */
+    private static float MINIMUM_SCALE_WITHOUT_JITTER = 0.05f;
+
     /*
      * The following member variables are only to be used for animating zoom. If
      * mZoomScale is non-zero then we are in the middle of a zoom animation. The
@@ -684,6 +690,10 @@ class ZoomManager {
                 } else {
                     scale = Math.max(scale, mActualScale * 0.8f);
                 }
+                // if the scale change is too small, regard it as jitter and skip it.
+                if (Math.abs(scale - mActualScale) < MINIMUM_SCALE_WITHOUT_JITTER) {
+                    return false;
+                }
                 setZoomCenter(detector.getFocusX(), detector.getFocusY());
                 setZoomScale(scale, false);
                 mWebView.invalidate();