Bug 564991. Part 6: Make BasicLayers support retained ThebesLayer contents. r=cjones,sr=vlad

embedding/browser/webBrowser/nsWebBrowser.cpp

@@ -1669,6 +1669,7 @@ NS_IMETHODIMP nsWebBrowser::EnsureDocShellTreeOwner()
 static void DrawThebesLayer(ThebesLayer* aLayer,
                             gfxContext* aContext,
                             const nsIntRegion& aRegionToDraw,
+                            const nsIntRegion& aRegionToInvalidate,
                             void* aCallbackData)
 {
   nscolor* color = static_cast<nscolor*>(aCallbackData);

gfx/layers/Layers.h

@@ -156,10 +156,17 @@ public:
   /**
    * Function called to draw the contents of each ThebesLayer.
    * aRegionToDraw contains the region that needs to be drawn.
-   * This would normally be a subregion of the visible region. Drawing is
+   * This would normally be a subregion of the visible region.
-   * not necessarily clipped to aRegionToDraw.
+   * The callee must draw all of aRegionToDraw. Drawing outside
+   * aRegionToDraw will be clipped out or ignored.
    * The callee must draw all of aRegionToDraw.
    * 
+   * aRegionToInvalidate contains a region whose contents have been
+   * changed by the layer manager and which must therefore be invalidated.
+   * For example, this could be non-empty if the layer internally switched
+   * from RGBA to RGB or back ... we might want to repaint it to
+   * consistently use subpixel-AA or not.
+   * 
    * aContext must not be used after the call has returned.
    * We guarantee that buffered contents in the visible
    * region are valid once drawing is complete.
@@ -167,6 +174,7 @@ public:
   typedef void (* DrawThebesLayerCallback)(ThebesLayer* aLayer,
                                            gfxContext* aContext,
                                            const nsIntRegion& aRegionToDraw,
+                                           const nsIntRegion& aRegionToInvalidate,
                                            void* aCallbackData);
   /**
    * Finish the construction phase of the transaction, perform the

gfx/layers/Makefile.in

@@ -68,12 +68,13 @@ EXPORTS = \
 CPPSRCS = \
         BasicImages.cpp \
         BasicLayers.cpp \
-        LayerManagerOGL.cpp \
+        ThebesLayerBuffer.cpp \
+        CanvasLayerOGL.cpp \
         ColorLayerOGL.cpp \
-        ThebesLayerOGL.cpp \
         ContainerLayerOGL.cpp \
         ImageLayerOGL.cpp \
-	CanvasLayerOGL.cpp \
+        LayerManagerOGL.cpp \
+        ThebesLayerOGL.cpp \
         $(NULL)
 
 ifeq ($(MOZ_WIDGET_TOOLKIT),windows)

gfx/layers/basic/BasicLayers.cpp

@@ -44,7 +44,9 @@
 #include "gfxContext.h"
 #include "gfxImageSurface.h"
 #include "gfxPattern.h"
+#include "gfxPlatform.h"
 #include "gfxUtils.h"
+#include "ThebesLayerBuffer.h"
 
 #include "GLContext.h"
 
@@ -210,12 +212,28 @@ BasicContainerLayer::RemoveChildInternal(Layer* aChild)
   NS_RELEASE(aChild);
 }
 
-/**
+// Returns true if it's OK to save the contents of aLayer in an
- * BasicThebesLayer does not currently retain any buffers. This
+// opaque surface (a surface without an alpha channel).
- * makes the implementation fairly simple. During a transaction the
+// If we can use a surface without an alpha channel, we should, because
- * valid region is just the visible region, and between transactions
+// it will often make painting of antialiased text faster and higher
- * the valid region is empty.
+// quality.
- */
+static PRBool
+UseOpaqueSurface(Layer* aLayer)
+{
+  // If the visible content in the layer is opaque, there is no need
+  // for an alpha channel.
+  if (aLayer->IsOpaqueContent())
+    return PR_TRUE;
+  // Also, if this layer is the bottommost layer in a container which
+  // doesn't need an alpha channel, we can use an opaque surface for this
+  // layer too. Any transparent areas must be covered by something else
+  // in the container.
+  BasicContainerLayer* parent =
+    static_cast<BasicContainerLayer*>(aLayer->GetParent());
+  return parent && parent->GetFirstChild() == aLayer &&
+         UseOpaqueSurface(parent);
+}
+
 class BasicThebesLayer : public ThebesLayer, BasicImplData {
 public:
   BasicThebesLayer(BasicLayerManager* aLayerManager) :
@@ -238,6 +256,7 @@ public:
   {
     NS_ASSERTION(BasicManager()->InConstruction(),
                  "Can only set properties in construction phase");
+    mValidRegion.Sub(mValidRegion, aRegion);
   }
 
   virtual void Paint(gfxContext* aContext,
@@ -249,6 +268,8 @@ protected:
   {
     return static_cast<BasicLayerManager*>(mManager);
   }
+
+  ThebesLayerBuffer mBuffer;
 };
 
 void
@@ -261,7 +282,40 @@ BasicThebesLayer::Paint(gfxContext* aContext,
   gfxContext* target = BasicManager()->GetTarget();
   NS_ASSERTION(target, "We shouldn't be called if there's no target");
 
-  aCallback(this, target, mVisibleRegion, aCallbackData);
+  if (!BasicManager()->IsRetained()) {
+    mValidRegion.SetEmpty();
+    mBuffer.Clear();
+    aCallback(this, target, mVisibleRegion, nsIntRegion(), aCallbackData);
+    return;
+  }
+
+  PRUint32 flags = 0;
+  if (UseOpaqueSurface(this)) {
+    flags |= ThebesLayerBuffer::OPAQUE_CONTENT;
+  }
+
+  {
+    ThebesLayerBuffer::PaintState state =
+      mBuffer.BeginPaint(this, aContext, flags);
+    mValidRegion.Sub(mValidRegion, state.mRegionToInvalidate);
+
+    if (state.mContext) {
+      // The area that became invalid and is visible needs to be repainted
+      // (this could be the whole visible area if our buffer switched
+      // from RGB to RGBA, because we might need to repaint with
+      // subpixel AA)
+      state.mRegionToInvalidate.And(state.mRegionToInvalidate, mVisibleRegion);
+      aCallback(this, state.mContext, state.mRegionToDraw,
+                state.mRegionToInvalidate, aCallbackData);
+      mValidRegion.Or(mValidRegion, state.mRegionToDraw);
+    } else {
+      NS_ASSERTION(state.mRegionToDraw.IsEmpty() &&
+                   state.mRegionToInvalidate.IsEmpty(),
+                   "If we need to draw, we should have a context");
+    }
+  }
+
+  mBuffer.DrawTo(this, flags, target);
 }
 
 class BasicImageLayer : public ImageLayer, BasicImplData {
@@ -280,7 +334,7 @@ public:
   {
     NS_ASSERTION(BasicManager()->InConstruction(),
                  "Can only set properties in construction phase");
-    mVisibleRegion = aRegion;
+    ImageLayer::SetVisibleRegion(aRegion);
   }
 
   virtual void Paint(gfxContext* aContext,
@@ -354,7 +408,7 @@ public:
   {
     NS_ASSERTION(BasicManager()->InConstruction(),
                  "Can only set properties in construction phase");
-    mVisibleRegion = aRegion;
+    ColorLayer::SetVisibleRegion(aRegion);
   }
 
   virtual void Paint(gfxContext* aContext,
@@ -521,28 +575,37 @@ BasicLayerManager::BasicLayerManager(gfxContext* aContext) :
 #ifdef DEBUG
   , mPhase(PHASE_NONE)
 #endif
+  , mRetain(PR_FALSE)
 {
   MOZ_COUNT_CTOR(BasicLayerManager);
 }
 
 BasicLayerManager::~BasicLayerManager()
 {
-  NS_ASSERTION(mPhase == PHASE_NONE, "Died during transaction?");
+  NS_ASSERTION(!InTransaction(), "Died during transaction?");
   MOZ_COUNT_DTOR(BasicLayerManager);
 }
 
 void
 BasicLayerManager::SetDefaultTarget(gfxContext* aContext)
 {
-  NS_ASSERTION(mPhase == PHASE_NONE,
+  NS_ASSERTION(!InTransaction(),
                "Must set default target outside transaction");
   mDefaultTarget = aContext;
 }
 
+void
+BasicLayerManager::SetRetain(PRBool aRetain)
+{
+  NS_ASSERTION(!InTransaction(),
+               "Must set retained mode outside transaction");
+  mRetain = aRetain;
+}
+
 void
 BasicLayerManager::BeginTransaction()
 {
-  NS_ASSERTION(mPhase == PHASE_NONE, "Nested transactions not allowed");
+  NS_ASSERTION(!InTransaction(), "Nested transactions not allowed");
 #ifdef DEBUG
   mPhase = PHASE_CONSTRUCTION;
 #endif
@@ -552,7 +615,7 @@ BasicLayerManager::BeginTransaction()
 void
 BasicLayerManager::BeginTransactionWithTarget(gfxContext* aTarget)
 {
-  NS_ASSERTION(mPhase == PHASE_NONE, "Nested transactions not allowed");
+  NS_ASSERTION(!InTransaction(), "Nested transactions not allowed");
 #ifdef DEBUG
   mPhase = PHASE_CONSTRUCTION;
 #endif
@@ -564,7 +627,7 @@ BasicLayerManager::EndTransaction(DrawThebesLayerCallback aCallback,
                                   void* aCallbackData)
 {
   NS_ASSERTION(mRoot, "Root not set");
-  NS_ASSERTION(mPhase == PHASE_CONSTRUCTION, "Should be in construction phase");
+  NS_ASSERTION(InConstruction(), "Should be in construction phase");
 #ifdef DEBUG
   mPhase = PHASE_DRAWING;
 #endif
@@ -577,8 +640,6 @@ BasicLayerManager::EndTransaction(DrawThebesLayerCallback aCallback,
 #ifdef DEBUG
   mPhase = PHASE_NONE;
 #endif
-  // No retained layers supported for now
-  mRoot = nsnull;
 }
 
 void
@@ -607,28 +668,6 @@ NeedsState(Layer* aLayer)
          !aLayer->GetTransform().IsIdentity();
 }
 
-// Returns true if it's OK to save the contents of aLayer in an
-// opaque surface (a surface without an alpha channel).
-// If we can use a surface without an alpha channel, we should, because
-// it will often make painting of antialiased text faster and higher
-// quality.
-static PRBool
-UseOpaqueSurface(Layer* aLayer)
-{
-  // If the visible content in the layer is opaque, there is no need
-  // for an alpha channel.
-  if (aLayer->IsOpaqueContent())
-    return PR_TRUE;
-  // Also, if this layer is the bottommost layer in a container which
-  // doesn't need an alpha channel, we can use an opaque surface for this
-  // layer too. Any transparent areas must be covered by something else
-  // in the container.
-  BasicContainerLayer* parent =
-    static_cast<BasicContainerLayer*>(aLayer->GetParent());
-  return parent && parent->GetFirstChild() == aLayer &&
-         UseOpaqueSurface(parent);
-}
-
 void
 BasicLayerManager::PaintLayer(Layer* aLayer,
                               DrawThebesLayerCallback aCallback,

gfx/layers/basic/BasicLayers.h

@@ -51,9 +51,6 @@ class BasicThebesLayer;
 
 /**
  * This is a cairo/Thebes-only, main-thread-only implementation of layers.
- * Currently it only supports immediate mode but we will probably
- * extend it to support retained buffers. In other words, currently,
- * no buffers are retained between transactions.
  * 
  * In each transaction, the client sets up the layer tree and then during
  * the drawing phase, each ThebesLayer is painted directly into the target
@@ -70,6 +67,13 @@ public:
   BasicLayerManager(gfxContext* aContext);
   virtual ~BasicLayerManager();
 
+  /**
+   * When aRetain is true, we will try to retain the visible contents of
+   * ThebesLayers as cairo surfaces. This can only be called outside a
+   * transaction.
+   */
+  void SetRetain(PRBool aRetain);
+
   /**
    * Set the default target context that will be used when BeginTransaction
    * is called. This can only be called outside a transaction.
@@ -94,8 +98,10 @@ public:
 #ifdef DEBUG
   PRBool InConstruction() { return mPhase == PHASE_CONSTRUCTION; }
   PRBool InDrawing() { return mPhase == PHASE_DRAWING; }
+  PRBool InTransaction() { return mPhase != PHASE_NONE; }
 #endif
   gfxContext* GetTarget() { return mTarget; }
+  PRBool IsRetained() { return mRetain; }
 
 private:
   // Paints aLayer to mTarget.
@@ -112,6 +118,8 @@ private:
   enum TransactionPhase { PHASE_NONE, PHASE_CONSTRUCTION, PHASE_DRAWING };
   TransactionPhase mPhase;
 #endif
+
+  PRPackedBool mRetain;
 };
 
 }

gfx/layers/basic/ThebesLayerBuffer.cpp

@@ -0,0 +1,264 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla Corporation code.
+ *
+ * The Initial Developer of the Original Code is Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Robert O'Callahan <robert@ocallahan.org>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "ThebesLayerBuffer.h"
+#include "Layers.h"
+#include "gfxContext.h"
+#include "gfxPlatform.h"
+
+namespace mozilla {
+namespace layers {
+
+static void
+ClipToRegion(gfxContext* aContext, const nsIntRegion& aRegion)
+{
+  aContext->NewPath();
+  nsIntRegionRectIterator iter(aRegion);
+  const nsIntRect* r;
+  while ((r = iter.Next()) != nsnull) {
+    aContext->Rectangle(gfxRect(r->x, r->y, r->width, r->height));
+  }
+  aContext->Clip();
+}
+
+nsIntRect
+ThebesLayerBuffer::GetQuadrantRectangle(XSide aXSide, YSide aYSide)
+{
+  // quadrantTranslation is the amount we translate the top-left
+  // of the quadrant by to get coordinates relative to the layer
+  nsIntPoint quadrantTranslation = -mBufferRotation;
+  quadrantTranslation.x += aXSide == LEFT ? mBufferRect.width : 0;
+  quadrantTranslation.y += aYSide == TOP ? mBufferRect.height : 0;
+  return mBufferRect + quadrantTranslation;
+}
+
+/**
+ * @param aXSide LEFT means we draw from the left side of the buffer (which
+ * is drawn on the right side of mBufferRect). RIGHT means we draw from
+ * the right side of the buffer (which is drawn on the left side of
+ * mBufferRect).
+ * @param aYSide TOP means we draw from the top side of the buffer (which
+ * is drawn on the bottom side of mBufferRect). BOTTOM means we draw from
+ * the bottom side of the buffer (which is drawn on the top side of
+ * mBufferRect).
+ */
+void
+ThebesLayerBuffer::DrawBufferQuadrant(gfxContext* aTarget,
+                                      XSide aXSide, YSide aYSide)
+{
+  // The rectangle that we're going to fill. Basically we're going to
+  // render the buffer at mBufferRect + quadrantTranslation to get the
+  // pixels in the right place, but we're only going to paint within
+  // mBufferRect
+  nsIntRect quadrantRect = GetQuadrantRectangle(aXSide, aYSide);
+  nsIntRect fillRect;
+  if (!fillRect.IntersectRect(mBufferRect, quadrantRect))
+    return;
+
+  aTarget->NewPath();
+  aTarget->Rectangle(gfxRect(fillRect.x, fillRect.y, fillRect.width, fillRect.height),
+                     PR_TRUE);
+  aTarget->SetSource(mBuffer, gfxPoint(quadrantRect.x, quadrantRect.y));
+  aTarget->Fill();
+}
+
+void
+ThebesLayerBuffer::DrawBufferWithRotation(gfxContext* aTarget)
+{
+  // Draw four quadrants. We could use REPEAT_, but it's probably better
+  // not to, to be performance-safe.
+  DrawBufferQuadrant(aTarget, LEFT, TOP);
+  DrawBufferQuadrant(aTarget, RIGHT, TOP);
+  DrawBufferQuadrant(aTarget, LEFT, BOTTOM);
+  DrawBufferQuadrant(aTarget, RIGHT, BOTTOM);
+}
+
+static void
+WrapRotationAxis(PRInt32* aRotationPoint, PRInt32 aSize)
+{
+  if (*aRotationPoint < 0) {
+    *aRotationPoint += aSize;
+  } else if (*aRotationPoint >= aSize) {
+    *aRotationPoint -= aSize;
+  }
+}
+
+static already_AddRefed<gfxASurface>
+CreateBuffer(gfxASurface* aTargetSurface, gfxASurface::gfxContentType aType,
+             const nsIntSize& aSize)
+{
+  return aTargetSurface->CreateSimilarSurface(aType, gfxIntSize(aSize.width, aSize.height));
+}
+
+ThebesLayerBuffer::PaintState
+ThebesLayerBuffer::BeginPaint(ThebesLayer* aLayer, gfxContext* aTarget,
+                              PRUint32 aFlags)
+{
+  PaintState result;
+
+  gfxASurface::gfxContentType desiredContentType = gfxASurface::CONTENT_COLOR_ALPHA;
+  nsRefPtr<gfxASurface> targetSurface = aTarget->CurrentSurface();
+  if (targetSurface->AreSimilarSurfacesSensitiveToContentType()) {
+    if (aFlags & OPAQUE_CONTENT) {
+      desiredContentType = gfxASurface::CONTENT_COLOR;
+    }
+    if (mBuffer && desiredContentType != mBuffer->GetContentType()) {
+      result.mRegionToInvalidate = aLayer->GetValidRegion();
+      Clear();
+    }
+  }
+
+  result.mRegionToDraw.Sub(aLayer->GetVisibleRegion(), aLayer->GetValidRegion());
+  if (result.mRegionToDraw.IsEmpty())
+    return result;
+  nsIntRect drawBounds = result.mRegionToDraw.GetBounds();
+
+  nsIntRect visibleBounds = aLayer->GetVisibleRegion().GetBounds();
+  nsRefPtr<gfxASurface> destBuffer;
+  nsIntRect destBufferRect;
+
+  if (mBufferRect.width >= visibleBounds.width &&
+      mBufferRect.height >= visibleBounds.height) {
+    // The current buffer is big enough to hold the visible area.
+    if (mBufferRect.Contains(visibleBounds)) {
+      // We don't need to adjust mBufferRect.
+      destBufferRect = mBufferRect;
+    } else {
+      // The buffer's big enough but doesn't contain everything that's
+      // going to be visible. We'll move it.
+      destBufferRect = nsIntRect(visibleBounds.TopLeft(), mBufferRect.Size());
+    }
+    nsIntRect keepArea;
+    if (keepArea.IntersectRect(destBufferRect, mBufferRect)) {
+      // Set mBufferRotation so that the pixels currently in mBuffer
+      // will still be rendered in the right place when mBufferRect
+      // changes to destBufferRect.
+      nsIntPoint newRotation = mBufferRotation +
+        (destBufferRect.TopLeft() - mBufferRect.TopLeft());
+      WrapRotationAxis(&newRotation.x, mBufferRect.width);
+      WrapRotationAxis(&newRotation.y, mBufferRect.height);
+      NS_ASSERTION(nsIntRect(nsIntPoint(0,0), mBufferRect.Size()).Contains(newRotation),
+                   "newRotation out of bounds");
+      PRInt32 xBoundary = destBufferRect.XMost() - newRotation.x;
+      PRInt32 yBoundary = destBufferRect.YMost() - newRotation.y;
+      if ((drawBounds.x < xBoundary && xBoundary < drawBounds.XMost()) ||
+          (drawBounds.y < yBoundary && yBoundary < drawBounds.YMost())) {
+        // The stuff we need to redraw will wrap around an edge of the
+        // buffer, so we will need to do a self-copy
+        if (mBufferRotation == nsIntPoint(0,0)) {
+          destBuffer = mBuffer;
+        } else {
+          // We can't do a real self-copy because the buffer is rotated.
+          // So allocate a new buffer for the destination.
+          destBufferRect = visibleBounds;
+          destBuffer = CreateBuffer(targetSurface, desiredContentType, destBufferRect.Size());
+          if (!destBuffer)
+            return result;
+        }
+      } else {
+        mBufferRect = destBufferRect;
+        mBufferRotation = newRotation;
+      }
+    } else {
+      // No pixels are going to be kept. The whole visible region
+      // will be redrawn, so we don't need to copy anything, so we don't
+      // set destBuffer.
+      mBufferRect = destBufferRect;
+      mBufferRotation = nsIntPoint(0,0);
+    }
+  } else {
+    // The buffer's not big enough, so allocate a new one
+    destBufferRect = visibleBounds;
+    destBuffer = CreateBuffer(targetSurface, desiredContentType, destBufferRect.Size());
+    if (!destBuffer)
+      return result;
+  }
+
+  if (destBuffer) {
+    if (mBuffer) {
+      // Copy the bits
+      nsRefPtr<gfxContext> tmpCtx = new gfxContext(destBuffer);
+      nsIntPoint offset = -destBufferRect.TopLeft();
+      tmpCtx->SetOperator(gfxContext::OPERATOR_SOURCE);
+      tmpCtx->Translate(gfxPoint(offset.x, offset.y));
+      DrawBufferWithRotation(tmpCtx);
+    }
+
+    mBuffer = destBuffer.forget();
+    mBufferRect = destBufferRect;
+    mBufferRotation = nsIntPoint(0,0);
+  }
+
+  nsIntRegion invalidate;
+  invalidate.Sub(aLayer->GetValidRegion(), destBufferRect);
+  result.mRegionToInvalidate.Or(result.mRegionToInvalidate, invalidate);
+
+  result.mContext = new gfxContext(mBuffer);
+
+  // Figure out which quadrant to draw in
+  PRInt32 xBoundary = mBufferRect.XMost() - mBufferRotation.x;
+  PRInt32 yBoundary = mBufferRect.YMost() - mBufferRotation.y;
+  XSide sideX = drawBounds.XMost() <= xBoundary ? RIGHT : LEFT;
+  YSide sideY = drawBounds.YMost() <= yBoundary ? BOTTOM : TOP;
+  nsIntRect quadrantRect = GetQuadrantRectangle(sideX, sideY);
+  NS_ASSERTION(quadrantRect.Contains(drawBounds), "Messed up quadrants");
+  result.mContext->Translate(-gfxPoint(quadrantRect.x, quadrantRect.y));
+
+  ClipToRegion(result.mContext, result.mRegionToDraw);
+  if (desiredContentType == gfxASurface::CONTENT_COLOR_ALPHA) {
+    result.mContext->SetOperator(gfxContext::OPERATOR_CLEAR);
+    result.mContext->Paint();
+    result.mContext->SetOperator(gfxContext::OPERATOR_OVER);
+  }
+  return result;
+}
+
+void
+ThebesLayerBuffer::DrawTo(ThebesLayer* aLayer, PRUint32 aFlags, gfxContext* aTarget)
+{
+  aTarget->Save();
+  ClipToRegion(aTarget, aLayer->GetVisibleRegion());
+  if (aFlags & OPAQUE_CONTENT) {
+    aTarget->SetOperator(gfxContext::OPERATOR_SOURCE);
+  }
+  DrawBufferWithRotation(aTarget);
+  aTarget->Restore();
+}
+
+}
+}
+

gfx/layers/basic/ThebesLayerBuffer.h

@@ -0,0 +1,156 @@
+/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla Corporation code.
+ *
+ * The Initial Developer of the Original Code is Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Robert O'Callahan <robert@ocallahan.org>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef THEBESLAYERBUFFER_H_
+#define THEBESLAYERBUFFER_H_
+
+#include "gfxContext.h"
+#include "gfxASurface.h"
+#include "nsRegion.h"
+
+namespace mozilla {
+namespace layers {
+
+class ThebesLayer;
+
+/**
+ * This class encapsulates the buffer used to retain ThebesLayer contents,
+ * i.e., the contents of the layer's GetVisibleRegion().
+ * 
+ * This is a cairo/Thebes surface, but with a literal twist. Scrolling
+ * causes the layer's visible region to move. We want to keep
+ * reusing the same surface if the region size hasn't changed, but we don't
+ * want to keep moving the contents of the surface around in memory. So
+ * we use a trick.
+ * Consider just the vertical case, and suppose the buffer is H pixels
+ * high and we're scrolling down by N pixels. Instead of copying the
+ * buffer contents up by N pixels, we leave the buffer contents in place,
+ * and paint content rows H to H+N-1 into rows 0 to N-1 of the buffer.
+ * Then we can refresh the screen by painting rows N to H-1 of the buffer
+ * at row 0 on the screen, and then painting rows 0 to N-1 of the buffer
+ * at row H-N on the screen.
+ * mBufferRotation.y would be N in this example.
+ */
+class ThebesLayerBuffer {
+public:
+  ThebesLayerBuffer() : mBufferRotation(0,0)
+  {
+    MOZ_COUNT_CTOR(ThebesLayerBuffer);
+  }
+  ~ThebesLayerBuffer()
+  {
+    MOZ_COUNT_DTOR(ThebesLayerBuffer);
+  }
+
+  /**
+   * Wipe out all retained contents. Call this when the entire
+   * buffer becomes invalid.
+   */
+  void Clear()
+  {
+    mBuffer = nsnull;
+    mBufferRect.Empty();
+  }
+
+  /**
+   * This is returned by BeginPaint. The caller should draw into mContext.
+   * mRegionToDraw must be drawn. mRegionToInvalidate has been invalidated
+   * by ThebesLayerBuffer and must be redrawn on the screen.
+   * mRegionToInvalidate is set when the buffer has changed from
+   * opaque to transparent or vice versa, since the details of rendering can
+   * depend on the buffer type.
+   */
+  struct PaintState {
+    nsRefPtr<gfxContext> mContext;
+    nsIntRegion mRegionToDraw;
+    nsIntRegion mRegionToInvalidate;
+  };
+  /**
+   * Pass OPAQUE_CONTENT when we have determined that everything visible
+   * in the buffer will be rendered with opaque pixels.
+   */
+  enum {
+    OPAQUE_CONTENT = 0x01
+  };
+  /**
+   * Start a drawing operation. Ths returns a PaintState describing what
+   * needs to be drawn to bring the buffer up to date in the visible region.
+   * This queries aLayer to get the currently valid and visible regions.
+   * The returned mContext may be null if mRegionToDraw is empty.
+   * Otherwise it must not be null.
+   * mRegionToInvalidate will contain mRegionToDraw.
+   */
+  PaintState BeginPaint(ThebesLayer* aLayer, gfxContext* aTarget,
+                        PRUint32 aFlags);
+  /**
+   * Complete the drawing operation. The region to draw must have been drawn
+   * before this is called. The contents of the buffer are drawn to aTarget.
+   */
+  void DrawTo(ThebesLayer* aLayer, PRUint32 aFlags, gfxContext* aTarget);
+
+protected:
+  enum XSide {
+    LEFT, RIGHT
+  };
+  enum YSide {
+    TOP, BOTTOM
+  };
+  nsIntRect GetQuadrantRectangle(XSide aXSide, YSide aYSide);
+  void DrawBufferQuadrant(gfxContext* aTarget, XSide aXSide, YSide aYSide);
+  void DrawBufferWithRotation(gfxContext* aTarget);
+
+private:
+  nsRefPtr<gfxASurface> mBuffer;
+  /** The area of the ThebesLayer that is covered by the buffer as a whole */
+  nsIntRect             mBufferRect;
+  /**
+   * The x and y rotation of the buffer. Conceptually the buffer
+   * has its origin translated to mBufferRect.TopLeft() - mBufferRotation,
+   * is tiled to fill the plane, and the result is clipped to mBufferRect.
+   * So the pixel at mBufferRotation within the buffer is what gets painted at
+   * mBufferRect.TopLeft().
+   * This is "rotation" in the sense of rotating items in a linear buffer,
+   * where items falling off the end of the buffer are returned to the
+   * buffer at the other end, not 2D rotation!
+   */
+  nsIntPoint            mBufferRotation;
+};
+
+}
+}
+
+#endif /* THEBESLAYERBUFFER_H_ */

gfx/layers/d3d9/ThebesLayerD3D9.cpp

@@ -106,7 +106,7 @@ ThebesLayerD3D9::RenderLayer()
     context = new gfxContext(destinationSurface);
     context->Translate(gfxPoint(-mInvalidatedRect.x, -mInvalidatedRect.y));
     LayerManagerD3D9::CallbackInfo cbInfo = mD3DManager->GetCallbackInfo();
-    cbInfo.Callback(this, context, region, cbInfo.CallbackData);
+    cbInfo.Callback(this, context, region, nsIntRegion(), cbInfo.CallbackData);
 
     nsRefPtr<IDirect3DTexture9> tmpTexture;
     device()->CreateTexture(mInvalidatedRect.width, mInvalidatedRect.height, 1,

gfx/layers/opengl/LayerManagerOGL.h

@@ -184,7 +184,8 @@ public:
     NS_ASSERTION(mThebesLayerCallback,
                  "CallThebesLayerDrawCallback without callback!");
     mThebesLayerCallback(aLayer, aContext,
-                         aRegionToDraw, mThebesLayerCallbackData);
+                         aRegionToDraw, nsIntRegion(),
+                         mThebesLayerCallbackData);
   }
 
   GLenum FBOTextureTarget() { return mFBOTextureTarget; }

layout/base/FrameLayerBuilder.cpp

@@ -475,8 +475,12 @@ FrameLayerBuilder::MakeContainerLayerFor(nsDisplayListBuilder* aBuilder,
 FrameLayerBuilder::DrawThebesLayer(ThebesLayer* aLayer,
                                    gfxContext* aContext,
                                    const nsIntRegion& aRegionToDraw,
+                                   const nsIntRegion& aRegionToInvalidate,
                                    void* aCallbackData)
 {
+  // For now, we can ignore aRegionToInvalidate since we don't
+  // use retained layers.
+
   LayerItems* layerItems = static_cast<LayerItems*>(aLayer->GetUserData());
   nsDisplayListBuilder* builder =
     static_cast<nsDisplayListBuilder*>(aCallbackData);

layout/base/FrameLayerBuilder.h

@@ -69,6 +69,7 @@ public:
   static void DrawThebesLayer(ThebesLayer* aLayer,
                               gfxContext* aContext,
                               const nsIntRegion& aRegionToDraw,
+                              const nsIntRegion& aRegionToInvalidate,
                               void* aCallbackData);
 };
 

layout/base/nsPresShell.cpp

@@ -5817,6 +5817,7 @@ struct PaintParams {
 static void DrawThebesLayer(ThebesLayer* aLayer,
                             gfxContext* aContext,
                             const nsIntRegion& aRegionToDraw,
+                            const nsIntRegion& aRegionToInvalidate,
                             void* aCallbackData)
 {
   PaintParams* params = static_cast<PaintParams*>(aCallbackData);