From 2999f08ed4cbf1992548be987b15e2f8b71aaec7 Mon Sep 17 00:00:00 2001
From: Matt Woodrow <mwoodrow@mozilla.com>
Date: Mon, 1 Sep 2014 15:23:40 +1200
Subject: [PATCH] Bug 1057212 - Avoid copying all the tiles when doing
 PushGroupAndCopyBackground. r=Bas

---
 gfx/2d/DrawTargetTiled.cpp | 46 --------------------------------------
 gfx/2d/DrawTargetTiled.h   | 43 +++++++++++++++++++++++++++++++++++
 gfx/2d/moz.build           |  1 +
 gfx/thebes/gfxContext.cpp  | 29 ++++++++++++++++++++----
 4 files changed, 69 insertions(+), 50 deletions(-)

diff --git a/gfx/2d/DrawTargetTiled.cpp b/gfx/2d/DrawTargetTiled.cpp
index de7f93aada1..75f7b5c2057 100644
--- a/gfx/2d/DrawTargetTiled.cpp
+++ b/gfx/2d/DrawTargetTiled.cpp
@@ -45,52 +45,6 @@ DrawTargetTiled::Init(const TileSet& aTiles)
   return true;
 }
 
-class SnapshotTiled : public SourceSurface
-{
-public:
-  SnapshotTiled(const vector<TileInternal>& aTiles, const IntRect& aRect)
-    : mRect(aRect)
-  {
-    for (size_t i = 0; i < aTiles.size(); i++) {
-      mSnapshots.push_back(aTiles[i].mDrawTarget->Snapshot());
-      mOrigins.push_back(aTiles[i].mTileOrigin);
-    }
-  }
-
-  virtual SurfaceType GetType() const { return SurfaceType::TILED; }
-  virtual IntSize GetSize() const { return IntSize(mRect.XMost(), mRect.YMost()); }
-  virtual SurfaceFormat GetFormat() const { return mSnapshots[0]->GetFormat(); }
-
-  virtual TemporaryRef<DataSourceSurface> GetDataSurface()
-  {
-    RefPtr<DataSourceSurface> surf = Factory::CreateDataSourceSurface(GetSize(), GetFormat());
-    if (MOZ2D_WARN_IF(!surf)) {
-      return nullptr;
-    }
-
-    DataSourceSurface::MappedSurface mappedSurf;
-    surf->Map(DataSourceSurface::MapType::WRITE, &mappedSurf);
-
-    {
-      RefPtr<DrawTarget> dt =
-        Factory::CreateDrawTargetForData(BackendType::CAIRO, mappedSurf.mData,
-        GetSize(), mappedSurf.mStride, GetFormat());
-
-      for (size_t i = 0; i < mSnapshots.size(); i++) {
-        RefPtr<DataSourceSurface> dataSurf = mSnapshots[i]->GetDataSurface();
-        dt->CopySurface(dataSurf, IntRect(IntPoint(0, 0), mSnapshots[i]->GetSize()), mOrigins[i]);
-      }
-    }
-    surf->Unmap();
-
-    return surf.forget();
-  }
-private:
-  vector<RefPtr<SourceSurface>> mSnapshots;
-  vector<IntPoint> mOrigins;
-  IntRect mRect;
-};
-
 TemporaryRef<SourceSurface>
 DrawTargetTiled::Snapshot()
 {
diff --git a/gfx/2d/DrawTargetTiled.h b/gfx/2d/DrawTargetTiled.h
index de948797a73..b29f7c7251a 100644
--- a/gfx/2d/DrawTargetTiled.h
+++ b/gfx/2d/DrawTargetTiled.h
@@ -149,6 +149,49 @@ private:
   IntRect mRect;
 };
 
+class SnapshotTiled : public SourceSurface
+{
+public:
+  SnapshotTiled(const std::vector<TileInternal>& aTiles, const IntRect& aRect)
+    : mRect(aRect)
+  {
+    for (size_t i = 0; i < aTiles.size(); i++) {
+      mSnapshots.push_back(aTiles[i].mDrawTarget->Snapshot());
+      mOrigins.push_back(aTiles[i].mTileOrigin);
+    }
+  }
+
+  virtual SurfaceType GetType() const { return SurfaceType::TILED; }
+  virtual IntSize GetSize() const { return IntSize(mRect.XMost(), mRect.YMost()); }
+  virtual SurfaceFormat GetFormat() const { return mSnapshots[0]->GetFormat(); }
+
+  virtual TemporaryRef<DataSourceSurface> GetDataSurface()
+  {
+    RefPtr<DataSourceSurface> surf = Factory::CreateDataSourceSurface(GetSize(), GetFormat());
+
+    DataSourceSurface::MappedSurface mappedSurf;
+    surf->Map(DataSourceSurface::MapType::WRITE, &mappedSurf);
+
+    {
+      RefPtr<DrawTarget> dt =
+        Factory::CreateDrawTargetForData(BackendType::CAIRO, mappedSurf.mData,
+        GetSize(), mappedSurf.mStride, GetFormat());
+
+      for (size_t i = 0; i < mSnapshots.size(); i++) {
+        RefPtr<DataSourceSurface> dataSurf = mSnapshots[i]->GetDataSurface();
+        dt->CopySurface(dataSurf, IntRect(IntPoint(0, 0), mSnapshots[i]->GetSize()), mOrigins[i]);
+      }
+    }
+    surf->Unmap();
+
+    return surf.forget();
+  }
+
+  std::vector<RefPtr<SourceSurface>> mSnapshots;
+  std::vector<IntPoint> mOrigins;
+  IntRect mRect;
+};
+
 }
 }
 
diff --git a/gfx/2d/moz.build b/gfx/2d/moz.build
index 8802518e37e..31a7228178f 100644
--- a/gfx/2d/moz.build
+++ b/gfx/2d/moz.build
@@ -21,6 +21,7 @@ EXPORTS.mozilla.gfx += [
     'BorrowedContext.h',
     'Coord.h',
     'DataSurfaceHelpers.h',
+    'DrawTargetTiled.h',
     'Filters.h',
     'Helpers.h',
     'Logging.h',
diff --git a/gfx/thebes/gfxContext.cpp b/gfx/thebes/gfxContext.cpp
index ecb586d7e61..58daf12dabd 100644
--- a/gfx/thebes/gfxContext.cpp
+++ b/gfx/thebes/gfxContext.cpp
@@ -24,6 +24,7 @@
 #include "GeckoProfiler.h"
 #include "gfx2DGlue.h"
 #include "mozilla/gfx/PathHelpers.h"
+#include "mozilla/gfx/DrawTargetTiled.h"
 #include <algorithm>
 
 #if CAIRO_HAS_DWRITE_FONT
@@ -1118,12 +1119,32 @@ gfxContext::PushGroupAndCopyBackground(gfxContentType content)
 
     Point offset = CurrentState().deviceOffset - oldDeviceOffset;
     Rect surfRect(0, 0, Float(mDT->GetSize().width), Float(mDT->GetSize().height));
-    Rect sourceRect = surfRect;
-    sourceRect.x += offset.x;
-    sourceRect.y += offset.y;
+    Rect sourceRect = surfRect + offset;
 
     mDT->SetTransform(Matrix());
-    mDT->DrawSurface(source, surfRect, sourceRect);
+
+    // XXX: It's really sad that we have to do this (for performance).
+    // Once DrawTarget gets a PushLayer API we can implement this within
+    // DrawTargetTiled.
+    if (source->GetType() == SurfaceType::TILED) {
+      SnapshotTiled *sourceTiled = static_cast<SnapshotTiled*>(source.get());
+      for (uint32_t i = 0; i < sourceTiled->mSnapshots.size(); i++) {
+        Rect tileSourceRect = sourceRect.Intersect(Rect(sourceTiled->mOrigins[i].x,
+                                                        sourceTiled->mOrigins[i].y,
+                                                        sourceTiled->mSnapshots[i]->GetSize().width,
+                                                        sourceTiled->mSnapshots[i]->GetSize().height));
+
+        if (tileSourceRect.IsEmpty()) {
+          continue;
+        }
+        Rect tileDestRect = tileSourceRect - offset;
+        tileSourceRect -= sourceTiled->mOrigins[i];
+
+        mDT->DrawSurface(sourceTiled->mSnapshots[i], tileDestRect, tileSourceRect);
+      }
+    } else {
+      mDT->DrawSurface(source, surfRect, sourceRect);
+    }
     mDT->SetOpaqueRect(oldDT->GetOpaqueRect());
 
     PushClipsToDT(mDT);