bug 755070 - Scrolling causes after paint notifications which causes screenshotting which causes checkerboarding r=kats,cjones

embedding/android/GeckoAppShell.java

@@ -577,8 +577,10 @@ public class GeckoAppShell
 
     // these 2 stubs are never called in XUL Fennec, but we need them so that
     // the JNI code shared between XUL and Native Fennec doesn't die.
-    public static void notifyScreenShot(final ByteBuffer data, final int tabId, final int x, final int y,
-                                        final int width, final int height, final int token) {
+    public static void notifyScreenShot(final ByteBuffer data, final int tabId, 
+                                        final int left, final int top,
+                                        final int right, final int bottom, 
+                                        final int bufferWidth, final int bufferHeight, final int token) {
     }
 
     public static void notifyPaintedRect(float top, float left, float bottom, float right) {

ipc/chromium/src/base/message_loop.cc

@@ -256,6 +256,14 @@ void MessageLoop::PostNonNestableDelayedTask(
   PostTask_Helper(from_here, task, delay_ms, false);
 }
 
+void MessageLoop::PostIdleTask(
+    const tracked_objects::Location& from_here, Task* task) {
+  DCHECK(current() == this);
+  task->SetBirthPlace(from_here);
+  PendingTask pending_task(task, false);
+  deferred_non_nestable_work_queue_.push(pending_task);
+}
+
 // Possibly called on a background thread!
 void MessageLoop::PostTask_Helper(
     const tracked_objects::Location& from_here, Task* task, int delay_ms,

ipc/chromium/src/base/message_loop.h

@@ -121,6 +121,10 @@ public:
   void PostNonNestableDelayedTask(
       const tracked_objects::Location& from_here, Task* task, int delay_ms);
 
+  // PostIdleTask is not thread safe and should be called on this thread
+  void PostIdleTask(
+      const tracked_objects::Location& from_here, Task* task);
+
   // A variant on PostTask that deletes the given object.  This is useful
   // if the object needs to live until the next run of the MessageLoop (for
   // example, deleting a RenderProcessHost from within an IPC callback is not

mobile/android/base/GeckoApp.java

@@ -768,7 +768,7 @@ abstract public class GeckoApp
 
             int dw = tab.getThumbnailWidth();
             int dh = tab.getThumbnailHeight();
-            GeckoAppShell.sendEventToGecko(GeckoEvent.createScreenshotEvent(tab.getId(), 0, 0, 0, 0, 0, 0, dw, dh, GeckoAppShell.SCREENSHOT_THUMBNAIL));
+            GeckoAppShell.sendEventToGecko(GeckoEvent.createScreenshotEvent(tab.getId(), 0, 0, 0, 0, 0, 0, dw, dh, dw, dh, GeckoAppShell.SCREENSHOT_THUMBNAIL, tab.getThumbnailBuffer()));
         }
     }
     

mobile/android/base/GeckoAppShell.java

@@ -15,6 +15,7 @@ import org.mozilla.gecko.gfx.ScreenshotLayer;
 import org.mozilla.gecko.FloatUtils;
 import org.mozilla.gecko.gfx.ImmutableViewportMetrics;
 import org.mozilla.gecko.gfx.ViewportMetrics;
+import org.mozilla.gecko.gfx.RectUtils;
 
 import java.io.*;
 import java.lang.reflect.*;
@@ -82,8 +83,8 @@ public class GeckoAppShell
     public static final String SHORTCUT_TYPE_BOOKMARK = "bookmark";
 
     static public final int SCREENSHOT_THUMBNAIL = 0;
-    static public final int SCREENSHOT_WHOLE_PAGE = 1;
-    static public final int SCREENSHOT_UPDATE = 2;
+    static public final int SCREENSHOT_CHECKERBOARD = 1;
+    static public final int SCREENSHOT_CHECKERBOARD_AND_UPDATE = 2;
 
     static public final int RESTORE_NONE = 0;
     static public final int RESTORE_OOM = 1;
@@ -97,11 +98,6 @@ public class GeckoAppShell
     private static Boolean sNSSLibsLoaded = false;
     private static Boolean sLibsSetup = false;
     private static File sGREDir = null;
-    private static RectF sCheckerboardPageRect;
-    private static float sLastCheckerboardWidthRatio, sLastCheckerboardHeightRatio;
-    private static RepaintRunnable sRepaintRunnable = new RepaintRunnable();
-    static private int sMaxTextureSize = 0;
-
     private static Map<String, CopyOnWriteArrayList<GeckoEventListener>> mEventListeners
             = new HashMap<String, CopyOnWriteArrayList<GeckoEventListener>>();
 
@@ -127,8 +123,6 @@ public class GeckoAppShell
 
     private static Handler sGeckoHandler;
 
-    private static boolean sDisableScreenshot = false;
-
     /* The Android-side API: API methods that Android calls */
 
     // Initialization methods
@@ -536,44 +530,11 @@ public class GeckoAppShell
     }
 
     // Called by AndroidBridge using JNI
-    public static void notifyScreenShot(final ByteBuffer data, final int tabId, final int x, final int y,
-                                        final int width, final int height, final int token) {
-        getHandler().post(new Runnable() {
-            public void run() {
-                try {
-                    final Tab tab = Tabs.getInstance().getTab(tabId);
-                    if (tab == null)
-                        return;
-
-                    if (!Tabs.getInstance().isSelectedTab(tab) && SCREENSHOT_THUMBNAIL != token)
-                        return;
-
-                    Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
-                    b.copyPixelsFromBuffer(data);
-                    switch (token) {
-                    case SCREENSHOT_WHOLE_PAGE:
-                        GeckoApp.mAppContext.getLayerController()
-                            .getView().getRenderer()
-                            .setCheckerboardBitmap(b, sCheckerboardPageRect);
-                        break;
-                    case SCREENSHOT_UPDATE:
-                        GeckoApp.mAppContext.getLayerController().getView().getRenderer().
-                            updateCheckerboardBitmap(
-                                b, sLastCheckerboardWidthRatio * x,
-                                sLastCheckerboardHeightRatio * y,
-                                sLastCheckerboardWidthRatio * width,
-                                sLastCheckerboardHeightRatio * height,
-                                sCheckerboardPageRect);
-                        break;
-                    case SCREENSHOT_THUMBNAIL:
-                        GeckoApp.mAppContext.processThumbnail(tab, b, null);
-                        break;
-                    }
-                } finally {
-                    freeDirectBuffer(data);
-                }
-            }
-        });
+    public static void notifyScreenShot(final ByteBuffer data, final int tabId, 
+                                        final int left, final int top,
+                                        final int right, final int bottom, 
+                                        final int bufferWidth, final int bufferHeight, final int token) {
+        ScreenshotHandler.notifyScreenShot(data, tabId, left, top, right, bottom, bufferWidth, bufferHeight, token);
     }
 
     private static CountDownLatch sGeckoPendingAcks = null;
@@ -2145,6 +2106,31 @@ public class GeckoAppShell
         if (!GeckoApp.mAppContext.showFilePicker(aMimeType, new AsyncResultHandler(id)))
             GeckoAppShell.notifyFilePickerResult("", id);
     }
+    public static void screenshotWholePage(Tab tab) {
+        ScreenshotHandler.screenshotWholePage(tab);
+    }
+
+    // Called by AndroidBridge using JNI
+    public static void notifyPaintedRect(float top, float left, float bottom, float right) {
+        ScreenshotHandler.notifyPaintedRect(top, left, bottom, right);
+    }
+
+    public static void notifyWakeLockChanged(String topic, String state) {
+        GeckoApp.mAppContext.notifyWakeLockChanged(topic, state);
+    }
+}
+
+class ScreenshotHandler {
+    private static Queue<PendingScreenshot> sPendingScreenshots = new LinkedList<PendingScreenshot>();
+    private static RectF sCheckerboardPageRect;
+    private static float sLastCheckerboardWidthRatio, sLastCheckerboardHeightRatio;
+    private static RepaintRunnable sRepaintRunnable = new RepaintRunnable();
+    private static int sMaxTextureSize = 0;
+    private static final String LOGTAG = "GeckoScreenshot";
+    private static boolean sDisableScreenshot = false;
+    private static ByteBuffer sWholePageScreenshotBuffer;
+    private static int sCheckerboardBufferWidth, sCheckerboardBufferHeight;
+    private static Rect sAcumulatedRect = new Rect();
 
     static class RepaintRunnable implements Runnable {
         private boolean mIsRepaintRunnablePosted = false;
@@ -2167,25 +2153,40 @@ public class GeckoAppShell
                 mIsRepaintRunnablePosted = false;
             }
 
+
             Tab tab = Tabs.getInstance().getSelectedTab();
-            GeckoAppShell.screenshotWholePage(tab);
+            ImmutableViewportMetrics viewport = GeckoApp.mAppContext.getLayerController().getViewportMetrics();
+            
+            if (RectUtils.fuzzyEquals(sCheckerboardPageRect, viewport.getCssPageRect())) {
+                float width = right - left;
+                float height = bottom - top;
+                scheduleCheckerboardScreenshotEvent(tab.getId(), 
+                                                    (int)left, (int)top, (int)width, (int)height, 
+                                                    (int)(sLastCheckerboardWidthRatio * left), 
+                                                    (int)(sLastCheckerboardHeightRatio * top),
+                                                    (int)(sLastCheckerboardWidthRatio * width),
+                                                    (int)(sLastCheckerboardHeightRatio * height),
+                                                    sCheckerboardBufferWidth, sCheckerboardBufferHeight);
+            } else {
+                GeckoAppShell.screenshotWholePage(tab);
+            }
         }
 
         void addRectToRepaint(float top, float left, float bottom, float right) {
             synchronized(this) {
-                mDirtyTop = Math.min(top, mDirtyTop);
-                mDirtyLeft = Math.min(left, mDirtyLeft);
-                mDirtyBottom = Math.max(bottom, mDirtyBottom);
-                mDirtyRight = Math.max(right, mDirtyRight);
+                ImmutableViewportMetrics viewport = GeckoApp.mAppContext.getLayerController().getViewportMetrics();
+                mDirtyTop = Math.max(sCheckerboardPageRect.top, Math.min(top, mDirtyTop));
+                mDirtyLeft = Math.max(sCheckerboardPageRect.left, Math.min(left, mDirtyLeft));
+                mDirtyBottom = Math.min(sCheckerboardPageRect.bottom, Math.max(bottom, mDirtyBottom));
+                mDirtyRight = Math.min(sCheckerboardPageRect.right, Math.max(right, mDirtyRight));
                 if (!mIsRepaintRunnablePosted) {
-                    getHandler().postDelayed(this, 5000);
+                    GeckoAppShell.getHandler().postDelayed(this, 5000);
                     mIsRepaintRunnablePosted = true;
                 }
             }
         }
     }
 
-    // Called by AndroidBridge using JNI
     public static void notifyPaintedRect(float top, float left, float bottom, float right) {
         sRepaintRunnable.addRectToRepaint(top, left, bottom, right);
     }
@@ -2212,7 +2213,9 @@ public class GeckoAppShell
             sMaxTextureSize = maxTextureSize[0];
             if (sMaxTextureSize == 0)
                 return;
+            sWholePageScreenshotBuffer = GeckoAppShell.allocateDirectBuffer(ScreenshotLayer.getMaxNumPixels() * 2 /* 16 bpp */);
         }
+
         ImmutableViewportMetrics viewport = GeckoApp.mAppContext.getLayerController().getViewportMetrics();
         Log.i(LOGTAG, "Taking whole-screen screenshot, viewport: " + viewport);
         // source width and height to screenshot
@@ -2220,6 +2223,8 @@ public class GeckoAppShell
         float sy = viewport.cssPageRectTop;
         float sw = viewport.cssPageRectRight - viewport.cssPageRectLeft;
         float sh = viewport.cssPageRectBottom - viewport.cssPageRectTop;
+        if (sw == 0 || sh == 0)
+            return;
         int maxPixels = Math.min(ScreenshotLayer.getMaxNumPixels(), sMaxTextureSize * sMaxTextureSize);
         // 2Mb of 16bit image data
         // may be bumped by up to 4x for power of 2 alignment
@@ -2233,18 +2238,123 @@ public class GeckoAppShell
         int dy = 0;
         int dw = clamp(minTextureSize, idealDstWidth, sMaxTextureSize);
         int dh = maxPixels / dw;
+        sCheckerboardBufferWidth = dw;
+        sCheckerboardBufferHeight = dh;
 
         sLastCheckerboardWidthRatio = dw / sw;
         sLastCheckerboardHeightRatio = dh / sh;
         sCheckerboardPageRect = viewport.getCssPageRect();
-
-        GeckoAppShell.sendEventToGecko(GeckoEvent.createScreenshotEvent(tab.getId(),
-                (int)FloatMath.ceil(sx), (int)FloatMath.ceil(sy),
-                (int)FloatMath.floor(sw), (int)FloatMath.floor(sh),
-                dx, dy, dw, dh, GeckoAppShell.SCREENSHOT_WHOLE_PAGE));
+        scheduleCheckerboardScreenshotEvent(tab.getId(), (int)sx, (int)sy, (int)sw, (int)sh, dx, dy, dw, dh, dw, dh);
     }
 
-    public static void notifyWakeLockChanged(String topic, String state) {
-        GeckoApp.mAppContext.notifyWakeLockChanged(topic, state);
+    static void scheduleCheckerboardScreenshotEvent(int tabId, int sx, int sy, int sw, int sh, int dx, int dy, int dw, int dh, int bw, int bh) {
+        float totalSize = sw * sh;
+        int numSlices = (int) Math.ceil(totalSize / 100000);
+        if (numSlices == 0)
+            return;
+        int srcSliceSize = (int) Math.ceil(sh / numSlices);
+        int dstSliceSize = (int) Math.ceil(dh / numSlices);
+        for (int i = 0; i < numSlices; i++) {
+            GeckoEvent event =
+                GeckoEvent.createScreenshotEvent(tabId, 
+                                                 sx, sy + srcSliceSize * i,  sw, srcSliceSize, 
+                                                 dx, dy + dstSliceSize * i,  dw, dstSliceSize, bw, bh,
+                                                 i < numSlices - 1 ? 
+                                                 GeckoAppShell.SCREENSHOT_CHECKERBOARD
+                                                 : GeckoAppShell.SCREENSHOT_CHECKERBOARD_AND_UPDATE,
+                                                 sWholePageScreenshotBuffer);
+            synchronized(sPendingScreenshots) {
+                sPendingScreenshots.add(new PendingScreenshot(tabId, event));
+                if (sPendingScreenshots.size() == 1)
+                    sendNextEventToGecko();
+            }
+        }
+    }
+
+    static void sendNextEventToGecko() {
+        synchronized(sPendingScreenshots) {
+            if (sPendingScreenshots.isEmpty())
+                return;
+            GeckoAppShell.sendEventToGecko(sPendingScreenshots.element().getEvent());
+        }
+    }
+    
+    static class PendingScreenshot {
+        private final GeckoEvent mEvent;
+        private final int mTabId;
+
+        PendingScreenshot(int tabId, GeckoEvent event) {
+            mTabId = tabId;
+            mEvent = event;
+        }
+
+        GeckoEvent getEvent() {
+            return mEvent;
+        }
+
+    }
+
+    public static void notifyScreenShot(final ByteBuffer data, final int tabId, 
+                                        final int left, final int top,
+                                        final int right, final int bottom, 
+                                        final int bufferWidth, final int bufferHeight, final int token) {
+
+        GeckoAppShell.getHandler().post(new Runnable() {
+            public void run() {
+                final Tab tab = Tabs.getInstance().getTab(tabId);
+                if (tab == null) {
+                    if (token == GeckoAppShell.SCREENSHOT_CHECKERBOARD ||
+                        token == GeckoAppShell.SCREENSHOT_CHECKERBOARD_AND_UPDATE) {
+                        synchronized(sPendingScreenshots) {
+                            sPendingScreenshots.remove();
+                            sendNextEventToGecko();
+                        }
+                    }
+                    return;
+                }
+
+                switch (token) {
+                    case GeckoAppShell.SCREENSHOT_CHECKERBOARD:
+                    {
+                        // screenshots are always processed sequentially, with the last one 
+                        // marked with the SCREENSHOT_CHECKERBOARD_AND_UPDATE token
+                        synchronized (sAcumulatedRect) {
+                            sAcumulatedRect.union(left, top, right, bottom);
+                        }
+                        synchronized(sPendingScreenshots) {
+                            sPendingScreenshots.remove();
+                            sendNextEventToGecko();
+                        }
+                        break;
+                    }
+                    case GeckoAppShell.SCREENSHOT_CHECKERBOARD_AND_UPDATE:
+                    {
+                        final Rect rect;
+                        synchronized (sAcumulatedRect) {
+                            sAcumulatedRect.union(left, top, right, bottom);
+                            rect = new Rect(sAcumulatedRect);
+                            sAcumulatedRect.setEmpty();
+                        }
+                        GeckoApp.mAppContext.getLayerController()
+                            .getView().getRenderer()
+                            .setCheckerboardBitmap(data, bufferWidth, bufferHeight, sCheckerboardPageRect, rect);
+                        synchronized(sPendingScreenshots) {
+                            sPendingScreenshots.remove();
+                            sendNextEventToGecko();
+                        }
+                        break;
+                    }
+                    case GeckoAppShell.SCREENSHOT_THUMBNAIL:
+                    {
+                        if (Tabs.getInstance().isSelectedTab(tab)) {
+                            Bitmap b = tab.getThumbnailBitmap();
+                            b.copyPixelsFromBuffer(data);
+                            GeckoApp.mAppContext.processThumbnail(tab, b, null);
+                        }
+                        break;
+                    }
+                }
+            }
+        });
     }
 }

mobile/android/base/GeckoEvent.java

@@ -23,6 +23,7 @@ import android.text.format.Time;
 import android.os.SystemClock;
 import java.lang.Math;
 import java.lang.System;
+import java.nio.ByteBuffer;
 
 import android.util.Log;
 
@@ -116,6 +117,8 @@ public class GeckoEvent {
 
     public short mScreenOrientation;
 
+    public ByteBuffer mBuffer;
+
     private GeckoEvent(int evType) {
         mType = evType;
     }
@@ -456,15 +459,17 @@ public class GeckoEvent {
         return event;
     }
 
-    public static GeckoEvent createScreenshotEvent(int tabId, int sx, int sy, int sw, int sh, int dx, int dy, int dw, int dh, int token) {
+    public static GeckoEvent createScreenshotEvent(int tabId, int sx, int sy, int sw, int sh, int dx, int dy, int dw, int dh, int bw, int bh, int token, ByteBuffer buffer) {
         GeckoEvent event = new GeckoEvent(SCREENSHOT);
-        event.mPoints = new Point[4];
+        event.mPoints = new Point[5];
         event.mPoints[0] = new Point(sx, sy);
         event.mPoints[1] = new Point(sw, sh);
         event.mPoints[2] = new Point(dx, dy);
         event.mPoints[3] = new Point(dw, dh);
+        event.mPoints[4] = new Point(bw, bh);
         event.mMetaState = tabId;
         event.mFlags = token;
+        event.mBuffer = buffer;
         return event;
     }
 

mobile/android/base/Tab.java

@@ -21,6 +21,7 @@ import org.json.JSONObject;
 import org.mozilla.gecko.db.BrowserDB;
 import org.mozilla.gecko.gfx.Layer;
 
+import java.nio.ByteBuffer;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -65,6 +66,8 @@ public final class Tab {
     private ContentObserver mContentObserver;
     private int mCheckerboardColor = Color.WHITE;
     private int mState;
+    private ByteBuffer mThumbnailBuffer;
+    private Bitmap mThumbnailBitmap;
 
     public static final int STATE_DELAYED = 0;
     public static final int STATE_LOADING = 1;
@@ -140,6 +143,31 @@ public final class Tab {
         return mThumbnail;
     }
 
+    synchronized public ByteBuffer getThumbnailBuffer() {
+        int capacity = getThumbnailWidth() * getThumbnailHeight() * 2 /* 16 bpp */;
+        if (mThumbnailBuffer != null && mThumbnailBuffer.capacity() == capacity)
+            return mThumbnailBuffer;
+        if (mThumbnailBuffer != null)
+            GeckoAppShell.freeDirectBuffer(mThumbnailBuffer); // not calling freeBuffer() because it would deadlock
+        return mThumbnailBuffer = GeckoAppShell.allocateDirectBuffer(capacity);
+    }
+
+    public Bitmap getThumbnailBitmap() {
+        if (mThumbnailBitmap != null)
+            return mThumbnailBitmap;
+        return mThumbnailBitmap = Bitmap.createBitmap(getThumbnailWidth(), getThumbnailHeight(), Bitmap.Config.RGB_565);
+    }
+
+    public void finalize() {
+        freeBuffer();
+    }
+
+    synchronized void freeBuffer() {
+        if (mThumbnailBuffer != null)
+            GeckoAppShell.freeDirectBuffer(mThumbnailBuffer);
+        mThumbnailBuffer = null;
+    }
+
     float getDensity() {
         if (sDensity == 0.0f) {
             sDensity = GeckoApp.mAppContext.getDisplayMetrics().density;
@@ -161,13 +189,10 @@ public final class Tab {
             public void run() {
                 if (b != null) {
                     try {
-                        Bitmap bitmap = Bitmap.createScaledBitmap(b, getThumbnailWidth(), getThumbnailHeight(), false);
-
                         if (mState == Tab.STATE_SUCCESS)
-                            saveThumbnailToDB(new BitmapDrawable(bitmap));
+                            saveThumbnailToDB(new BitmapDrawable(b));
 
-                        mThumbnail = new BitmapDrawable(bitmap);
-                        b.recycle();
+                        mThumbnail = new BitmapDrawable(b);
                     } catch (OutOfMemoryError oom) {
                         Log.e(LOGTAG, "Unable to create/scale bitmap", oom);
                         mThumbnail = null;

mobile/android/base/Tabs.java

@@ -77,8 +77,10 @@ public class Tabs implements GeckoEventListener {
 
     public void removeTab(int id) {
         if (tabs.containsKey(id)) {
-            order.remove(getTab(id));
+            Tab tab = getTab(id);
+            order.remove(tab);
             tabs.remove(id);
+            tab.freeBuffer();
             Log.i(LOGTAG, "Removed a tab with id: " + id);
         }
     }

mobile/android/base/gfx/IntSize.java

@@ -71,5 +71,11 @@ public class IntSize {
     public IntSize nextPowerOfTwo() {
         return new IntSize(nextPowerOfTwo(width), nextPowerOfTwo(height));
     }
+
+    public static boolean isPowerOfTwo(int value) {
+        if (value == 0)
+            return false;
+        return (value & (value - 1)) == 0;
+    }
 }
 

mobile/android/base/gfx/LayerRenderer.java

@@ -134,8 +134,8 @@ public class LayerRenderer {
         "    gl_FragColor = texture2D(sTexture, vTexCoord);\n" +
         "}\n";
 
-    public void setCheckerboardBitmap(Bitmap bitmap, RectF pageRect) {
-        mCheckerboardLayer.setBitmap(bitmap);
+    public void setCheckerboardBitmap(ByteBuffer data, int width, int height, RectF pageRect, Rect copyRect) {
+        mCheckerboardLayer.setBitmap(data, width, height, copyRect);
         mCheckerboardLayer.beginTransaction();
         try {
             mCheckerboardLayer.setPosition(RectUtils.round(pageRect));

mobile/android/base/gfx/ScreenshotLayer.java

@@ -35,6 +35,7 @@ public class ScreenshotLayer extends SingleTileLayer {
     private IntSize mImageSize;
     // Whether we have an up-to-date image to draw
     private boolean mHasImage;
+    private static String LOGTAG = "GeckoScreenshot";
 
     public static int getMaxNumPixels() {
         return SCREENSHOT_SIZE_LIMIT;
@@ -44,6 +45,19 @@ public class ScreenshotLayer extends SingleTileLayer {
         mHasImage = false;
     }
 
+    void setBitmap(ByteBuffer data, int width, int height, Rect rect) {
+        mImageSize = new IntSize(width, height);
+        if (IntSize.isPowerOfTwo(width) && IntSize.isPowerOfTwo(height)) {
+            mBufferSize = mImageSize;
+            mHasImage = true;
+            mImage.setBitmap(data, width, height, CairoImage.FORMAT_RGB16_565, rect);
+        } else {
+            Bitmap b = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
+            b.copyPixelsFromBuffer(data);
+            setBitmap(b);
+        }
+    }
+    
     void setBitmap(Bitmap bitmap) {
         mImageSize = new IntSize(bitmap.getWidth(), bitmap.getHeight());
         int width = IntSize.nextPowerOfTwo(bitmap.getWidth());
@@ -116,7 +130,21 @@ public class ScreenshotLayer extends SingleTileLayer {
             }
         }
 
-        void setBitmap(Bitmap bitmap, int width, int height, int format) {
+        void copyBuffer(ByteBuffer src, ByteBuffer dst, Rect rect, int stride) {
+            int start = rect.left + rect.top * stride;
+            int end = Math.min(Math.min(rect.right + (rect.bottom - 1) * stride, src.capacity()), dst.limit());
+            dst.position(start);
+            src.position(start).limit(end);
+            dst.put(src);
+        }
+
+        synchronized void setBitmap(ByteBuffer data, int width, int height, int format, Rect rect) {
+            mSize = new IntSize(width, height);
+            mFormat = format;
+            copyBuffer(data.asReadOnlyBuffer(), mBuffer.duplicate(), rect, width * 2);
+        }
+
+        synchronized void setBitmap(Bitmap bitmap, int width, int height, int format) {
             Bitmap tmp;
             mSize = new IntSize(width, height);
             mFormat = format;
@@ -138,10 +166,10 @@ public class ScreenshotLayer extends SingleTileLayer {
         }
 
         @Override
-        public ByteBuffer getBuffer() { return mBuffer; }
+        synchronized public ByteBuffer getBuffer() { return mBuffer; }
         @Override
-        public IntSize getSize() { return mSize; }
+        synchronized public IntSize getSize() { return mSize; }
         @Override
-        public int getFormat() { return mFormat; }
+        synchronized public int getFormat() { return mFormat; }
     }
 }

widget/android/AndroidBridge.cpp

@@ -88,7 +88,7 @@ AndroidBridge::Init(JNIEnv *jEnv,
     jNotifyIME = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "notifyIME", "(II)V");
     jNotifyIMEEnabled = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "notifyIMEEnabled", "(ILjava/lang/String;Ljava/lang/String;Z)V");
     jNotifyIMEChange = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "notifyIMEChange", "(Ljava/lang/String;III)V");
-    jNotifyScreenShot = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "notifyScreenShot", "(Ljava/nio/ByteBuffer;IIIIII)V");
+    jNotifyScreenShot = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "notifyScreenShot", "(Ljava/nio/ByteBuffer;IIIIIIII)V");
     jAcknowledgeEventSync = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "acknowledgeEventSync", "()V");
 
     jEnableLocation = (jmethodID) jEnv->GetStaticMethodID(jGeckoAppShellClass, "enableLocation", "(Z)V");
@@ -2369,9 +2369,13 @@ jobject JNICALL
 Java_org_mozilla_gecko_GeckoAppShell_allocateDirectBuffer(JNIEnv *env, jclass, jlong size);
 
 
-nsresult AndroidBridge::TakeScreenshot(nsIDOMWindow *window, PRInt32 srcX, PRInt32 srcY, PRInt32 srcW, PRInt32 srcH, PRInt32 dstW, PRInt32 dstH, PRInt32 tabId, float scale, PRInt32 token)
+nsresult AndroidBridge::TakeScreenshot(nsIDOMWindow *window, PRInt32 srcX, PRInt32 srcY, PRInt32 srcW, PRInt32 srcH, PRInt32 dstX, PRInt32 dstY, PRInt32 dstW, PRInt32 dstH, PRInt32 bufW, PRInt32 bufH, PRInt32 tabId, PRInt32 token, jobject buffer)
 {
     nsresult rv;
+    float scale = 1.0;
+ 
+    if (!buffer)
+        return NS_OK;
 
     // take a screenshot, as wide as possible, proportional to the destination size
     if (!srcW && !srcH) {
@@ -2432,21 +2436,18 @@ nsresult AndroidBridge::TakeScreenshot(nsIDOMWindow *window, PRInt32 srcX, PRInt
              nsPresContext::CSSPixelsToAppUnits(srcW / scale),
              nsPresContext::CSSPixelsToAppUnits(srcH / scale));
 
-    PRUint32 stride = dstW * 2;
-    PRUint32 bufferSize = dstH * stride;
-
-    jobject buffer = Java_org_mozilla_gecko_GeckoAppShell_allocateDirectBuffer(env, NULL, bufferSize);
-    if (!buffer)
-        return NS_OK;
+    PRUint32 stride = bufW * 2 /* 16 bpp */;
 
     void* data = env->GetDirectBufferAddress(buffer);
-    memset(data, 0, bufferSize);
-    nsRefPtr<gfxImageSurface> surf = new gfxImageSurface(static_cast<unsigned char*>(data), nsIntSize(dstW, dstH), stride, gfxASurface::ImageFormatRGB16_565);
+    nsRefPtr<gfxImageSurface> surf = new gfxImageSurface(static_cast<unsigned char*>(data), nsIntSize(bufW, bufH), stride, gfxASurface::ImageFormatRGB16_565);
     nsRefPtr<gfxContext> context = new gfxContext(surf);
+    gfxPoint pt(dstX, dstY);
+    context->Translate(pt);
     context->Scale(scale * dstW / srcW, scale * dstH / srcH);
     rv = presShell->RenderDocument(r, renderDocFlags, bgColor, context);
     NS_ENSURE_SUCCESS(rv, rv);
-    env->CallStaticVoidMethod(AndroidBridge::Bridge()->mGeckoAppShellClass, AndroidBridge::Bridge()->jNotifyScreenShot, buffer, tabId, srcX * dstW / srcW , srcY * dstH / srcH, dstW, dstH, token);
+    env->CallStaticVoidMethod(AndroidBridge::Bridge()->mGeckoAppShellClass, AndroidBridge::Bridge()->jNotifyScreenShot, 
+                              buffer, tabId, dstX, dstY, dstX + dstW, dstY + dstH, bufW, bufH, token);
     return NS_OK;
 }
 

widget/android/AndroidBridge.h

@@ -155,7 +155,7 @@ public:
         SCREENSHOT_UPDATE = 2
     };
 
-    nsresult TakeScreenshot(nsIDOMWindow *window, PRInt32 srcX, PRInt32 srcY, PRInt32 srcW, PRInt32 srcH, PRInt32 dstW, PRInt32 dstH, PRInt32 tabId, float scale, PRInt32 token);
+    nsresult TakeScreenshot(nsIDOMWindow *window, PRInt32 srcX, PRInt32 srcY, PRInt32 srcW, PRInt32 srcH, PRInt32 dstY, PRInt32 dstX, PRInt32 dstW, PRInt32 dstH, PRInt32 bufW, PRInt32 bufH, PRInt32 tabId, PRInt32 token, jobject buffer);
 
     static void NotifyPaintedRect(float top, float left, float bottom, float right);
 

widget/android/AndroidJavaWrappers.cpp

@@ -42,6 +42,7 @@ jfieldID AndroidGeckoEvent::jLocationField = 0;
 jfieldID AndroidGeckoEvent::jBandwidthField = 0;
 jfieldID AndroidGeckoEvent::jCanBeMeteredField = 0;
 jfieldID AndroidGeckoEvent::jScreenOrientationField = 0;
+jfieldID AndroidGeckoEvent::jByteBufferField = 0;
 
 jclass AndroidPoint::jPointClass = 0;
 jfieldID AndroidPoint::jXField = 0;
@@ -103,6 +104,12 @@ jmethodID AndroidGeckoSurfaceView::jGetHolderMethod = 0;
 #define getMethod(fname, ftype) \
     ((jmethodID) jEnv->GetMethodID(jClass, fname, ftype))
 
+RefCountedJavaObject::~RefCountedJavaObject() {
+    if (mObject)
+        GetJNIForThread()->DeleteGlobalRef(mObject);
+    mObject = NULL;
+}
+
 void
 mozilla::InitAndroidJavaWrappers(JNIEnv *jEnv)
 {
@@ -154,6 +161,7 @@ AndroidGeckoEvent::InitGeckoEventClass(JNIEnv *jEnv)
     jBandwidthField = getField("mBandwidth", "D");
     jCanBeMeteredField = getField("mCanBeMetered", "Z");
     jScreenOrientationField = getField("mScreenOrientation", "S");
+    jByteBufferField = getField("mBuffer", "Ljava/nio/ByteBuffer;");
 }
 
 void
@@ -498,7 +506,8 @@ AndroidGeckoEvent::Init(JNIEnv *jenv, jobject jobj)
         case SCREENSHOT: {
             mMetaState = jenv->GetIntField(jobj, jMetaStateField);
             mFlags = jenv->GetIntField(jobj, jFlagsField);
-            ReadPointArray(mPoints, jenv, jPoints, 4);
+            ReadPointArray(mPoints, jenv, jPoints, 5);
+            mByteBuffer = new RefCountedJavaObject(jenv, jenv->GetObjectField(jobj, jByteBufferField));
             break;
         }
 

widget/android/AndroidJavaWrappers.h

@@ -41,6 +41,27 @@ void InitAndroidJavaWrappers(JNIEnv *jEnv);
  * handle it.
  */
 
+class RefCountedJavaObject {
+public:
+    RefCountedJavaObject(JNIEnv* env, jobject obj) : mRefCnt(0), mObject(env->NewGlobalRef(obj)) {}
+
+    ~RefCountedJavaObject();
+
+    PRInt32 AddRef() { return ++mRefCnt; }
+
+    PRInt32 Release() {
+        PRInt32 refcnt = --mRefCnt;
+        if (refcnt == 0)
+            delete this;
+        return refcnt;
+    }
+
+    jobject GetObject() { return mObject; }
+private:
+    PRInt32 mRefCnt;
+    jobject mObject;
+};
+
 class WrappedJavaObject {
 public:
     WrappedJavaObject() :
@@ -576,6 +597,7 @@ public:
     double Bandwidth() { return mBandwidth; }
     bool CanBeMetered() { return mCanBeMetered; }
     short ScreenOrientation() { return mScreenOrientation; }
+    RefCountedJavaObject* ByteBuffer() { return mByteBuffer; }
 
 protected:
     int mAction;
@@ -600,6 +622,7 @@ protected:
     double mBandwidth;
     bool mCanBeMetered;
     short mScreenOrientation;
+    nsRefPtr<RefCountedJavaObject> mByteBuffer;
 
     void ReadIntArray(nsTArray<int> &aVals,
                       JNIEnv *jenv,
@@ -653,6 +676,7 @@ protected:
     static jfieldID jCanBeMeteredField;
 
     static jfieldID jScreenOrientationField;
+    static jfieldID jByteBufferField;
 
 public:
     enum {

widget/android/nsAppShell.cpp

@@ -6,6 +6,8 @@
 // Make sure the order of included headers
 #include "base/basictypes.h"
 #include "nspr/prtypes.h"
+#include "base/message_loop.h"
+#include "base/task.h"
 
 #include "mozilla/Hal.h"
 #include "nsAppShell.h"
@@ -65,6 +67,34 @@ nsAppShell *nsAppShell::gAppShell = nsnull;
 
 NS_IMPL_ISUPPORTS_INHERITED1(nsAppShell, nsBaseAppShell, nsIObserver)
 
+class ScreenshotRunnable : public nsRunnable {
+public:
+    ScreenshotRunnable(nsIAndroidBrowserApp* aBrowserApp, int aTabId, nsTArray<nsIntPoint>& aPoints, int aToken, RefCountedJavaObject* aBuffer):
+        mBrowserApp(aBrowserApp), mTabId(aTabId), mPoints(aPoints), mToken(aToken), mBuffer(aBuffer) {}
+
+    virtual nsresult Run() {
+        nsCOMPtr<nsIDOMWindow> domWindow;
+        nsCOMPtr<nsIBrowserTab> tab;
+        mBrowserApp->GetBrowserTab(mTabId, getter_AddRefs(tab));
+        if (!tab)
+            return NS_OK;
+
+        tab->GetWindow(getter_AddRefs(domWindow));
+        if (!domWindow)
+            return NS_OK;
+
+        NS_ASSERTION(mPoints.Length() == 5, "Screenshot event does not have enough coordinates");
+
+        AndroidBridge::Bridge()->TakeScreenshot(domWindow, mPoints[0].x, mPoints[0].y, mPoints[1].x, mPoints[1].y, mPoints[2].x, mPoints[2].y, mPoints[3].x, mPoints[3].y, mPoints[4].x, mPoints[4].y, mTabId, mToken, mBuffer->GetObject());
+        return NS_OK;
+    }
+private:
+    nsCOMPtr<nsIAndroidBrowserApp> mBrowserApp;
+    nsTArray<nsIntPoint> mPoints;
+    int mTabId, mToken;
+    nsRefPtr<RefCountedJavaObject> mBuffer;
+};
+
 class AfterPaintListener : public nsIDOMEventListener {
   public:
     NS_DECL_ISUPPORTS
@@ -91,23 +121,15 @@ class AfterPaintListener : public nsIDOMEventListener {
         if (!paintEvent)
             return NS_OK;
 
-        nsCOMPtr<nsIDOMClientRectList> rects;
-        paintEvent->GetClientRects(getter_AddRefs(rects));
-        if (!rects)
-            return NS_OK;
-        PRUint32 length;
-        rects->GetLength(&length);
-        for (PRUint32 i = 0; i < length; ++i) {
-            float top, left, bottom, right;
-            nsCOMPtr<nsIDOMClientRect> rect = rects->GetItemAt(i);
-            if (!rect)
-                continue;
-            rect->GetTop(&top);
-            rect->GetLeft(&left);
-            rect->GetRight(&right);
-            rect->GetBottom(&bottom);
-            AndroidBridge::NotifyPaintedRect(top, left, bottom, right);
-        }
+        nsCOMPtr<nsIDOMClientRect> rect;
+        paintEvent->GetBoundingClientRect(getter_AddRefs(rect));
+        float top, left, bottom, right;
+        rect->GetTop(&top);
+        rect->GetLeft(&left);
+        rect->GetRight(&right);
+        rect->GetBottom(&bottom);
+        __android_log_print(ANDROID_LOG_INFO, "GeckoScreenshot", "rect: %f, %f, %f, %f", top, left, right, bottom);
+        AndroidBridge::NotifyPaintedRect(top, left, bottom, right);
         return NS_OK;
     }
 
@@ -460,21 +482,13 @@ nsAppShell::ProcessNextNativeEvent(bool mayWait)
             break;
 
         PRInt32 token = curEvent->Flags();
-
-        nsCOMPtr<nsIDOMWindow> domWindow;
-        nsCOMPtr<nsIBrowserTab> tab;
-        mBrowserApp->GetBrowserTab(curEvent->MetaState(), getter_AddRefs(tab));
-        if (!tab)
-            break;
-
-        tab->GetWindow(getter_AddRefs(domWindow));
-        if (!domWindow)
-            break;
-
-        float scale = 1.0;
+        PRInt32 tabId = curEvent->MetaState();
         nsTArray<nsIntPoint> points = curEvent->Points();
-        NS_ASSERTION(points.Length() == 4, "Screenshot event does not have enough coordinates");
-        bridge->TakeScreenshot(domWindow, points[0].x, points[0].y, points[1].x, points[1].y, points[3].x, points[3].y, curEvent->MetaState(), scale, curEvent->Flags());
+        RefCountedJavaObject* buffer = curEvent->ByteBuffer();
+        nsCOMPtr<ScreenshotRunnable> sr = 
+            new ScreenshotRunnable(mBrowserApp, tabId, points, token, buffer);
+        MessageLoop::current()->PostIdleTask(
+            FROM_HERE, NewRunnableMethod(sr.get(), &ScreenshotRunnable::Run));
         break;
     }