Fix artifact with clipped webview content

We were incorrectly calculating the webview viewport in cases
where the viewport was clipped. We now pass down null for the
viewport, which is an indicator for the native code to noop
drawGL calls with a null viewport.

Change-Id: Iecf191eb447869819e357a15a360f0f08c47c273

1 files changed, 18 insertions, 11 deletions

diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index 6363299..baa37b5 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -350,6 +350,7 @@ public class WebView extends AbsoluteLayout
     private ZoomManager mZoomManager;
 
     private Rect mGLRectViewport = new Rect();
+    private boolean mGLViewportEmpty = false;
 
     /**
      *  Transportation object for returning WebView across thread boundaries.
@@ -4071,7 +4072,8 @@ public class WebView extends AbsoluteLayout
         }
 
         if (canvas.isHardwareAccelerated()) {
-            int functor = nativeGetDrawGLFunction(mGLRectViewport, getScale(), extras);
+            int functor = nativeGetDrawGLFunction(mGLViewportEmpty ? null : mGLRectViewport,
+                    getScale(), extras);
             ((HardwareCanvas) canvas).callDrawGLFunction(functor);
         } else {
             DrawFilter df = null;
@@ -5155,16 +5157,21 @@ public class WebView extends AbsoluteLayout
 
     void setGLRectViewport() {
         // Use the getGlobalVisibleRect() to get the intersection among the parents
-        getGlobalVisibleRect(mGLRectViewport);
-
-        // Then need to invert the Y axis, just for GL
-        View rootView = getRootView();
-        int rootViewHeight = rootView.getHeight();
-        int savedWebViewBottom = mGLRectViewport.bottom;
-        mGLRectViewport.bottom = rootViewHeight - mGLRectViewport.top - getVisibleTitleHeight();
-        mGLRectViewport.top = rootViewHeight - savedWebViewBottom;
-
-        nativeUpdateDrawGLFunction(mGLRectViewport);
+        // visible == false means we're clipped - send a null rect down to indicate that
+        // we should not draw
+        boolean visible = getGlobalVisibleRect(mGLRectViewport);
+        if (visible) {
+            // Then need to invert the Y axis, just for GL
+            View rootView = getRootView();
+            int rootViewHeight = rootView.getHeight();
+            int savedWebViewBottom = mGLRectViewport.bottom;
+            mGLRectViewport.bottom = rootViewHeight - mGLRectViewport.top - getVisibleTitleHeight();
+            mGLRectViewport.top = rootViewHeight - savedWebViewBottom;
+            mGLViewportEmpty = false;
+        } else {
+            mGLViewportEmpty = true;
+        }
+        nativeUpdateDrawGLFunction(mGLViewportEmpty ? null : mGLRectViewport);
     }
 
     /**