Bug 708307 - Decouple texture size from tile size. r=pcwalton a=android-only

This removes the hard-coded limit of 1024x2048 tile sizes, and allows for
arbitrary tile-sizes. It will still only allocate texture sizes in powers of
two, however. It replaces the tile size with a buffered-area size, which can be
re-allocated as the screen dimensions change.

mobile/android/base/GeckoAppShell.java

@@ -491,15 +491,6 @@ public class GeckoAppShell
     /*
      *  The Gecko-side API: API methods that Gecko calls
      */
-    public static void scheduleRedraw() {
-        // Redraw everything
-        Rect rect = new Rect(0, 0, LayerController.TILE_WIDTH, LayerController.TILE_HEIGHT);
-        GeckoEvent event = new GeckoEvent(GeckoEvent.DRAW, rect);
-        event.mNativeWindow = 0;
-        sendEventToGecko(event);
-    }
-
-
     public static void notifyIME(int type, int state) {
         mInputConnection.notifyIME(type, state);
     }

mobile/android/base/gfx/BufferedCairoImage.java

@@ -46,21 +46,22 @@ import java.nio.ByteBuffer;
 /** A Cairo image that simply saves a buffer of pixel data. */
 public class BufferedCairoImage extends CairoImage {
     private ByteBuffer mBuffer;
-    private int mWidth, mHeight, mFormat;
+    private IntSize mSize;
+    private int mFormat;
     private boolean mNeedToFreeBuffer = false;
 
     /** Creates a buffered Cairo image from a byte buffer. */
     public BufferedCairoImage(ByteBuffer inBuffer, int inWidth, int inHeight, int inFormat) {
-        mBuffer = inBuffer; mWidth = inWidth; mHeight = inHeight; mFormat = inFormat;
+        mBuffer = inBuffer; mSize = new IntSize(inWidth, inHeight); mFormat = inFormat;
     }
 
     /** Creates a buffered Cairo image from an Android bitmap. */
     public BufferedCairoImage(Bitmap bitmap) {
         mFormat = CairoUtils.bitmapConfigToCairoFormat(bitmap.getConfig());
-        mWidth = bitmap.getWidth();
-        mHeight = bitmap.getHeight();
+        mSize = new IntSize(bitmap.getWidth(), bitmap.getHeight());
         mNeedToFreeBuffer = true;
-        mBuffer = GeckoAppShell.allocateDirectBuffer(mWidth * mHeight * 4);
+        // XXX Why is this * 4? Shouldn't it depend on mFormat?
+        mBuffer = GeckoAppShell.allocateDirectBuffer(mSize.getArea() * 4);
         bitmap.copyPixelsToBuffer(mBuffer.asIntBuffer());
     }
 
@@ -78,9 +79,7 @@ public class BufferedCairoImage extends CairoImage {
    @Override
     public ByteBuffer getBuffer() { return mBuffer; }
     @Override
-    public int getWidth() { return mWidth; }
-    @Override
-    public int getHeight() { return mHeight; }
+    public IntSize getSize() { return mSize; }
     @Override
     public int getFormat() { return mFormat; }
 }

mobile/android/base/gfx/CairoImage.java

@@ -45,8 +45,7 @@ import java.nio.ByteBuffer;
 public abstract class CairoImage {
     public abstract ByteBuffer getBuffer();
 
-    public abstract int getWidth();
-    public abstract int getHeight();
+    public abstract IntSize getSize();
     public abstract int getFormat();
 
     public static final int FORMAT_INVALID = -1;

mobile/android/base/gfx/GeckoSoftwareLayerClient.java

@@ -72,8 +72,9 @@ public class GeckoSoftwareLayerClient extends LayerClient implements GeckoEventL
     private static final String LOGTAG = "GeckoSoftwareLayerClient";
 
     private Context mContext;
-    private int mWidth, mHeight, mFormat;
+    private int mFormat;
     private IntSize mScreenSize, mViewportSize;
+    private IntSize mBufferSize;
     private ByteBuffer mBuffer;
     private final SingleTileLayer mTileLayer;
 
@@ -97,21 +98,15 @@ public class GeckoSoftwareLayerClient extends LayerClient implements GeckoEventL
     public GeckoSoftwareLayerClient(Context context) {
         mContext = context;
 
-        mWidth = LayerController.TILE_WIDTH;
-        mHeight = LayerController.TILE_HEIGHT;
+        mScreenSize = new IntSize(0, 0);
+        mBufferSize = new IntSize(0, 0);
         mFormat = CairoImage.FORMAT_RGB16_565;
 
-        mScreenSize = new IntSize(1, 1);
-
-        mBuffer = GeckoAppShell.allocateDirectBuffer(mWidth * mHeight * 2);
-
         mCairoImage = new CairoImage() {
             @Override
             public ByteBuffer getBuffer() { return mBuffer; }
             @Override
-            public int getWidth() { return mWidth; }
-            @Override
-            public int getHeight() { return mHeight; }
+            public IntSize getSize() { return mBufferSize; }
             @Override
             public int getFormat() { return mFormat; }
         };
@@ -141,7 +136,6 @@ public class GeckoSoftwareLayerClient extends LayerClient implements GeckoEventL
             layerController.notifyPanZoomControllerOfGeometryChange(false);
         }
 
-        geometryChanged();
         GeckoAppShell.registerGeckoEventListener("Viewport:Update", this);
         GeckoAppShell.registerGeckoEventListener("Viewport:UpdateLater", this);
     }
@@ -209,7 +203,7 @@ public class GeckoSoftwareLayerClient extends LayerClient implements GeckoEventL
 
     public Bitmap getBitmap() {
         try {
-            Bitmap b = Bitmap.createBitmap(mWidth, mHeight,
+            Bitmap b = Bitmap.createBitmap(mBufferSize.width, mBufferSize.height,
                                            CairoUtils.cairoFormatTobitmapConfig(mFormat));
             b.copyPixelsFromBuffer(mBuffer.asIntBuffer());
             return b;
@@ -241,9 +235,28 @@ public class GeckoSoftwareLayerClient extends LayerClient implements GeckoEventL
         if (metrics.widthPixels != mScreenSize.width ||
             metrics.heightPixels != mScreenSize.height) {
             mScreenSize = new IntSize(metrics.widthPixels, metrics.heightPixels);
+            int maxSize = getLayerController().getView().getMaxTextureSize();
+
+            // XXX Introduce tiling to solve this?
+            if (mScreenSize.width > maxSize || mScreenSize.height > maxSize)
+                throw new RuntimeException("Screen size of " + mScreenSize + " larger than maximum texture size of " + maxSize);
+
+            // Round to next power of two until we use NPOT texture support
+            mBufferSize = new IntSize(Math.min(maxSize, IntSize.nextPowerOfTwo(mScreenSize.width + LayerController.MIN_BUFFER.width)),
+                                      Math.min(maxSize, IntSize.nextPowerOfTwo(mScreenSize.height + LayerController.MIN_BUFFER.height)));
+
+            // Free the old buffer first, if it exists
+            if (mBuffer != null) {
+                GeckoAppShell.freeDirectBuffer(mBuffer);
+                mBuffer = null;
+            }
+
+            // * 2 because it's a 16-bit buffer (so 2 bytes per pixel).
+            mBuffer = GeckoAppShell.allocateDirectBuffer(mBufferSize.getArea() * 2);
+
             Log.i(LOGTAG, "Screen-size changed to " + mScreenSize);
             GeckoEvent event = new GeckoEvent(GeckoEvent.SIZE_CHANGED,
-                                              LayerController.TILE_WIDTH, LayerController.TILE_HEIGHT,
+                                              mBufferSize.width, mBufferSize.height,
                                               metrics.widthPixels, metrics.heightPixels);
             GeckoAppShell.sendEventToGecko(event);
         }
@@ -289,7 +302,7 @@ public class GeckoSoftwareLayerClient extends LayerClient implements GeckoEventL
         ViewportMetrics viewportMetrics =
             new ViewportMetrics(getLayerController().getViewportMetrics());
 
-        PointF viewportOffset = viewportMetrics.getOptimumViewportOffset();
+        PointF viewportOffset = viewportMetrics.getOptimumViewportOffset(mBufferSize);
         viewportMetrics.setViewportOffset(viewportOffset);
         viewportMetrics.setViewport(viewportMetrics.getClampedViewport());
 

mobile/android/base/gfx/IntSize.java

@@ -62,10 +62,18 @@ public class IntSize {
         }
     }
 
+    public int getArea() {
+        return width * height;
+    }
+
     public boolean equals(IntSize size) {
         return ((size.width == width) && (size.height == height));
     }
 
+    public boolean isPositive() {
+        return (width > 0 && height > 0);
+    }
+
     @Override
     public String toString() { return "(" + width + "," + height + ")"; }
 
@@ -73,5 +81,23 @@ public class IntSize {
         return new IntSize((int)Math.round(width * factor),
                            (int)Math.round(height * factor));
     }
+
+    /* Returns the power of two that is greater than or equal to value */
+    public static int nextPowerOfTwo(int value) {
+        // code taken from http://acius2.blogspot.com/2007/11/calculating-next-power-of-2.html
+        if (0 == value--) {
+            return 1;
+        }
+        value = (value >> 1) | value;
+        value = (value >> 2) | value;
+        value = (value >> 4) | value;
+        value = (value >> 8) | value;
+        value = (value >> 16) | value;
+        return value + 1;
+    }
+
+    public IntSize nextPowerOfTwo() {
+        return new IntSize(nextPowerOfTwo(width), nextPowerOfTwo(height));
+    }
 }
 

mobile/android/base/gfx/Layer.java

@@ -80,6 +80,9 @@ public abstract class Layer {
     /** Subclasses override this function to draw the layer. */
     public abstract void draw(RenderContext context);
 
+    /** Subclasses override this function to provide access to the size of the layer. */
+    public abstract IntSize getSize();
+
     /** Given the intrinsic size of the layer, returns the pixel boundaries of the layer rect. */
     protected RectF getBounds(RenderContext context, FloatSize size) {
         float scaleFactor = context.zoomFactor / mResolution;
@@ -168,20 +171,6 @@ public abstract class Layer {
         }
     }
 
-    /* Returns the power of two that is greater than or equal to value */
-    protected static int nextPowerOfTwo(int value) {
-        // code taken from http://acius2.blogspot.com/2007/11/calculating-next-power-of-2.html
-        if (0 == value--) {
-            return 1;
-        }
-        value = (value >> 1) | value;
-        value = (value >> 2) | value;
-        value = (value >> 4) | value;
-        value = (value >> 8) | value;
-        value = (value >> 16) | value;
-        return value + 1;
-    }
-
     public static class RenderContext {
         public final RectF viewport;
         public final FloatSize pageSize;

mobile/android/base/gfx/LayerController.java

@@ -85,9 +85,11 @@ public class LayerController {
 
     private boolean mForceRedraw;
 
-    /* NB: These must be powers of two due to the OpenGL ES 1.x restriction on NPOT textures. */
-    public static final int TILE_WIDTH = 1024;
-    public static final int TILE_HEIGHT = 2048;
+    /* The extra area on the sides of the page that we want to buffer to help with
+     * smooth, asynchronous scrolling. Depending on a device's support for NPOT
+     * textures, this may be rounded up to the nearest power of two.
+     */
+    public static final IntSize MIN_BUFFER = new IntSize(512, 1024);
 
     /* If the visible rect is within the danger zone (measured in pixels from each edge of a tile),
      * we start aggressively redrawing to minimize checkerboarding. */
@@ -293,8 +295,12 @@ public class LayerController {
     }
 
     private RectF getTileRect() {
+        if (mRootLayer == null)
+            return new RectF();
+
         float x = mRootLayer.getOrigin().x, y = mRootLayer.getOrigin().y;
-        return new RectF(x, y, x + TILE_WIDTH, y + TILE_HEIGHT);
+        IntSize layerSize = mRootLayer.getSize();
+        return new RectF(x, y, x + layerSize.width, y + layerSize.height);
     }
 
     public RectF restrictToPageSize(RectF aRect) {

mobile/android/base/gfx/LayerRenderer.java

@@ -90,6 +90,7 @@ public class LayerRenderer implements GLSurfaceView.Renderer {
     private final ScrollbarLayer mVertScrollLayer;
     private final FadeRunnable mFadeRunnable;
     private RenderContext mLastPageContext;
+    private int mMaxTextureSize;
 
     // Dropped frames display
     private int[] mFrameTimings;
@@ -122,12 +123,17 @@ public class LayerRenderer implements GLSurfaceView.Renderer {
     public void onSurfaceCreated(GL10 gl, EGLConfig config) {
         checkFrameRateMonitorEnabled();
 
-        gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
-        gl.glClearDepthf(1.0f);             /* FIXME: Is this needed? */
         gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
-        gl.glShadeModel(GL10.GL_SMOOTH);    /* FIXME: Is this needed? */
         gl.glDisable(GL10.GL_DITHER);
         gl.glEnable(GL10.GL_TEXTURE_2D);
+
+        int maxTextureSizeResult[] = new int[1];
+        gl.glGetIntegerv(GL10.GL_MAX_TEXTURE_SIZE, maxTextureSizeResult, 0);
+        mMaxTextureSize = maxTextureSizeResult[0];
+    }
+
+    public int getMaxTextureSize() {
+        return mMaxTextureSize;
     }
 
     /**

mobile/android/base/gfx/LayerView.java

@@ -167,5 +167,9 @@ public class LayerView extends GLSurfaceView {
             return System.nanoTime() - mRenderTime;
         }
     }
+
+    public int getMaxTextureSize() {
+        return mRenderer.getMaxTextureSize();
+    }
 }
 

mobile/android/base/gfx/ScrollbarLayer.java

@@ -82,7 +82,8 @@ public class ScrollbarLayer extends TileLayer {
         mVertical = vertical;
         mBuffer = buffer;
 
-        mBitmap = Bitmap.createBitmap(image.getWidth(), image.getHeight(), Bitmap.Config.ARGB_8888);
+        IntSize size = image.getSize();
+        mBitmap = Bitmap.createBitmap(size.width, size.height, Bitmap.Config.ARGB_8888);
         mCanvas = new Canvas(mBitmap);
     }
 
@@ -100,7 +101,7 @@ public class ScrollbarLayer extends TileLayer {
     public static ScrollbarLayer create(boolean vertical) {
         // just create an empty image for now, it will get drawn
         // on demand anyway
-        int imageSize = nextPowerOfTwo(BAR_SIZE);
+        int imageSize = IntSize.nextPowerOfTwo(BAR_SIZE);
         ByteBuffer buffer = GeckoAppShell.allocateDirectBuffer(imageSize * imageSize * 4);
         CairoImage image = new BufferedCairoImage(buffer, imageSize, imageSize, CairoImage.FORMAT_ARGB32);
         return new ScrollbarLayer(image, vertical, buffer);

mobile/android/base/gfx/TileLayer.java

@@ -39,6 +39,7 @@ package org.mozilla.gecko.gfx;
 
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.opengl.GLES20;
 import android.util.Log;
 import javax.microedition.khronos.opengles.GL10;
 import javax.microedition.khronos.opengles.GL11Ext;
@@ -58,27 +59,18 @@ public abstract class TileLayer extends Layer {
     private final ArrayList<Rect> mDirtyRects;
     private final CairoImage mImage;
     private final boolean mRepeat;
-    private final IntSize mSize;
+    private IntSize mSize;
     private int[] mTextureIDs;
 
     public TileLayer(boolean repeat, CairoImage image) {
         mRepeat = repeat;
         mImage = image;
-        mSize = new IntSize(image.getWidth(), image.getHeight());
+        mSize = new IntSize(0, 0);
         mDirtyRects = new ArrayList<Rect>();
-
-        /*
-         * Assert that the image has a power-of-two size. OpenGL ES < 2.0 doesn't support NPOT
-         * textures and OpenGL ES doesn't seem to let us efficiently slice up a NPOT bitmap.
-         */
-        int width = mImage.getWidth(), height = mImage.getHeight();
-        if ((width & (width - 1)) != 0 || (height & (height - 1)) != 0) {
-            throw new RuntimeException("TileLayer: NPOT images are unsupported (dimensions are " +
-                                       width + "x" + height + ")");
-        }
     }
 
-    public IntSize getSize() { return mSize; }
+    @Override
+    public IntSize getSize() { return mImage.getSize(); }
 
     protected boolean repeats() { return mRepeat; }
     protected int getTextureID() { return mTextureIDs[0]; }
@@ -101,13 +93,49 @@ public abstract class TileLayer extends Layer {
     }
 
     public void invalidate() {
-        invalidate(new Rect(0, 0, mSize.width, mSize.height));
+        IntSize bufferSize = mImage.getSize();
+        invalidate(new Rect(0, 0, bufferSize.width, bufferSize.height));
+    }
+
+    private void validateTexture() {
+        /* Calculate the ideal texture size. This must be a power of two if
+         * the texture is repeated or OpenGL ES 2.0 isn't supported, as
+         * OpenGL ES 2.0 is required for NPOT texture support (without
+         * extensions), but doesn't support repeating NPOT textures.
+         *
+         * XXX Currently, we don't pick a GLES 2.0 context, so always round.
+         */
+        IntSize bufferSize = mImage.getSize();
+        IntSize textureSize = bufferSize;
+
+        textureSize = bufferSize.nextPowerOfTwo();
+
+        if (!textureSize.equals(mSize)) {
+            mSize = textureSize;
+
+            // Delete the old texture
+            if (mTextureIDs != null) {
+                TextureReaper.get().add(mTextureIDs);
+                mTextureIDs = null;
+
+                // XXX This won't be freed until the next frame is drawn, so we
+                //     temporarily have a larger-than-necessary memory requirement.
+                //     Is this what we want?
+            }
+        }
     }
 
     @Override
     protected void performUpdates(GL10 gl) {
         super.performUpdates(gl);
 
+        // Reallocate the texture if the size has changed
+        validateTexture();
+
+        // Don't do any work if the image has an invalid size.
+        if (!mImage.getSize().isPositive())
+            return;
+
         if (mTextureIDs == null) {
             uploadFullTexture(gl);
         } else {
@@ -119,43 +147,58 @@ public abstract class TileLayer extends Layer {
     }
 
     private void uploadFullTexture(GL10 gl) {
-        mTextureIDs = new int[1];
-        gl.glGenTextures(mTextureIDs.length, mTextureIDs, 0);
-
-        int cairoFormat = mImage.getFormat();
-        CairoGLInfo glInfo = new CairoGLInfo(cairoFormat);
-
-        bindAndSetGLParameters(gl);
-
-        gl.glTexImage2D(gl.GL_TEXTURE_2D, 0, glInfo.internalFormat, mSize.width, mSize.height,
-                        0, glInfo.format, glInfo.type, mImage.getBuffer());
+        IntSize bufferSize = mImage.getSize();
+        uploadDirtyRect(gl, new Rect(0, 0, bufferSize.width, bufferSize.height));
     }
-
+ 
     private void uploadDirtyRect(GL10 gl, Rect dirtyRect) {
-        if (mTextureIDs == null)
-            throw new RuntimeException("uploadDirtyRect() called with null texture ID!");
+        boolean newlyCreated = false;
+
+        if (mTextureIDs == null) {
+            mTextureIDs = new int[1];
+            gl.glGenTextures(mTextureIDs.length, mTextureIDs, 0);
+            newlyCreated = true;
+        }
+
+        IntSize bufferSize = mImage.getSize();
+        Rect bufferRect = new Rect(0, 0, bufferSize.width, bufferSize.height);
 
-        int width = mSize.width;
         int cairoFormat = mImage.getFormat();
         CairoGLInfo glInfo = new CairoGLInfo(cairoFormat);
 
         bindAndSetGLParameters(gl);
 
+        if (newlyCreated || dirtyRect.equals(bufferRect)) {
+            if (mSize.equals(bufferSize)) {
+                gl.glTexImage2D(gl.GL_TEXTURE_2D, 0, glInfo.internalFormat, mSize.width, mSize.height,
+                                0, glInfo.format, glInfo.type, mImage.getBuffer());
+                return;
+            } else {
+                gl.glTexImage2D(gl.GL_TEXTURE_2D, 0, glInfo.internalFormat, mSize.width, mSize.height,
+                                0, glInfo.format, glInfo.type, null);
+                gl.glTexSubImage2D(gl.GL_TEXTURE_2D, 0, 0, 0, bufferSize.width, bufferSize.height,
+                                   glInfo.format, glInfo.type, mImage.getBuffer());
+                return;
+            }
+        }
+
         /*
          * Upload the changed rect. We have to widen to the full width of the texture
          * because we can't count on the device having support for GL_EXT_unpack_subimage,
          * and going line-by-line is too slow.
+         *
+         * XXX We should still use GL_EXT_unpack_subimage when available.
          */
         Buffer viewBuffer = mImage.getBuffer().slice();
         int bpp = CairoUtils.bitsPerPixelForCairoFormat(cairoFormat) / 8;
-        int position = dirtyRect.top * width * bpp;
+        int position = dirtyRect.top * bufferSize.width * bpp;
         if (position > viewBuffer.limit()) {
             Log.e(LOGTAG, "### Position outside tile! " + dirtyRect.top);
             return;
         }
 
         viewBuffer.position(position);
-        gl.glTexSubImage2D(gl.GL_TEXTURE_2D, 0, 0, dirtyRect.top, width, dirtyRect.height(),
+        gl.glTexSubImage2D(gl.GL_TEXTURE_2D, 0, 0, dirtyRect.top, bufferSize.width, dirtyRect.height(),
                            glInfo.format, glInfo.type, viewBuffer);
     }
 

mobile/android/base/gfx/ViewportMetrics.java

@@ -44,6 +44,7 @@ import android.graphics.Rect;
 import android.graphics.RectF;
 import org.mozilla.gecko.FloatUtils;
 import org.mozilla.gecko.gfx.FloatSize;
+import org.mozilla.gecko.gfx.IntSize;
 import org.mozilla.gecko.gfx.LayerController;
 import org.mozilla.gecko.gfx.RectUtils;
 import org.json.JSONException;
@@ -64,8 +65,7 @@ public class ViewportMetrics {
     private float mZoomFactor;
 
     public ViewportMetrics() {
-        mPageSize = new FloatSize(LayerController.TILE_WIDTH,
-                                  LayerController.TILE_HEIGHT);
+        mPageSize = new FloatSize(1, 1);
         mViewportRect = new RectF(0, 0, 1, 1);
         mViewportOffset = new PointF(0, 0);
         mZoomFactor = 1.0f;
@@ -96,13 +96,13 @@ public class ViewportMetrics {
         mZoomFactor = zoom;
     }
 
-    public PointF getOptimumViewportOffset() {
+    public PointF getOptimumViewportOffset(IntSize displayportSize) {
         // XXX We currently always position the viewport in the centre of the
         //     displayport, but we might want to optimise this during panning
         //     to minimise checkerboarding.
         Point optimumOffset =
-            new Point((int)Math.round((LayerController.TILE_WIDTH - mViewportRect.width()) / 2),
-                      (int)Math.round((LayerController.TILE_HEIGHT - mViewportRect.height()) / 2));
+            new Point((int)Math.round((displayportSize.width - mViewportRect.width()) / 2),
+                      (int)Math.round((displayportSize.height - mViewportRect.height()) / 2));
 
         /* XXX Until bug #524925 is fixed, changing the viewport origin will
          * probably cause things to be slower than just having a smaller usable

widget/src/android/nsWindow.cpp

@@ -79,10 +79,6 @@ using mozilla::unused;
 
 #include "nsStringGlue.h"
 
-// NB: Keep these in sync with LayerController.java in mobile/android/base and embedding/android/.
-#define TILE_WIDTH      1024
-#define TILE_HEIGHT     2048
-
 using namespace mozilla;
 using namespace mozilla::widget;
 
@@ -310,7 +306,7 @@ nsWindow::ConfigureChildren(const nsTArray<nsIWidget::Configuration>& config)
 void
 nsWindow::RedrawAll()
 {
-    nsIntRect entireRect(0, 0, TILE_WIDTH, TILE_HEIGHT);
+    nsIntRect entireRect(0, 0, gAndroidBounds.width, gAndroidBounds.height);
     AndroidGeckoEvent *event = new AndroidGeckoEvent(AndroidGeckoEvent::DRAW, entireRect);
     nsAppShell::gAppShell->PostEvent(event);
 }
@@ -1018,7 +1014,7 @@ nsWindow::DrawTo(gfxASurface *targetSurface, const nsIntRect &invalidRect)
     if (coveringChildIndex == -1) {
         nsPaintEvent event(true, NS_PAINT, this);
 
-        nsIntRect tileRect(0, 0, TILE_WIDTH, TILE_HEIGHT);
+        nsIntRect tileRect(0, 0, gAndroidBounds.width, gAndroidBounds.height);
         event.region = boundsRect.Intersect(invalidRect).Intersect(tileRect);
 
         switch (GetLayerManager(nsnull)->GetBackendType()) {
@@ -1112,7 +1108,7 @@ nsWindow::OnDraw(AndroidGeckoEvent *ae)
 
     unsigned char *bits = client.LockBufferBits();
     nsRefPtr<gfxImageSurface> targetSurface =
-        new gfxImageSurface(bits, gfxIntSize(TILE_WIDTH, TILE_HEIGHT), TILE_WIDTH * 2,
+        new gfxImageSurface(bits, gfxIntSize(gAndroidBounds.width, gAndroidBounds.height), gAndroidBounds.width * 2,
                             gfxASurface::ImageFormatRGB16_565);
     if (targetSurface->CairoStatus()) {
         ALOG("### Failed to create a valid surface from the bitmap");