Gallery2: Clear the undefined buffer for the first 15 frames

The view is undefined before the first frame of camera preview data
come up.
This makes the UI has random corruption when open camera
and exit quickly.
However, we have no way to know the timing of the first frame.

It will take about 700~800ms before first camera preview data comes up,
and the time of drawing one frame is about 50ms,
so need to clear 15 frames before first camera preview data comes up.

Change-Id: Ibc9a5662a15ad58919384ce00cb3a7557b17cae8

1 files changed, 15 insertions, 2 deletions

diff --git a/src/com/android/gallery3d/ui/GLRootView.java b/src/com/android/gallery3d/ui/GLRootView.java
index 10aaac7bf..13bb30c8e 100644
--- a/src/com/android/gallery3d/ui/GLRootView.java
+++ b/src/com/android/gallery3d/ui/GLRootView.java
@@ -66,6 +66,7 @@ public class GLRootView extends GLSurfaceView
     private static final boolean DEBUG_FPS = false;
     private int mFrameCount = 0;
     private long mFrameCountingStart = 0;
+    private int mClearCount = 0;
 
     private static final boolean DEBUG_INVALIDATE = false;
     private int mInvalidateColor = 0;
@@ -339,8 +340,14 @@ public class GLRootView extends GLSurfaceView
 
     @Override
     public void onDrawFrame(GL10 gl) {
-        //clear the undefined buffer before draw
-        mCanvas.clearBuffer();
+        //The view is undefined before the first frame of camera preview data
+        //come up. This makes the UI has random corruption when open camera
+        //and exit quickly. However, we have no way to know the timing of
+        //the first frame. So, we clear the buffer for first 15 frames.
+        if(mFirstDraw || (mClearCount < 15)){
+            mCanvas.clearBuffer();
+            mClearCount++;
+        }
 
         AnimationTime.update();
         long t0;
@@ -542,6 +549,12 @@ public class GLRootView extends GLSurfaceView
     }
 
     @Override
+    public void onResume() {
+        super.onResume();
+        mClearCount = 0;
+    }
+
+    @Override
     public void setOrientationSource(OrientationSource source) {
         mOrientationSource = source;
     }