Merge WebKit at r75315: Initial merge by git.

Change-Id: I570314b346ce101c935ed22a626b48c2af266b84

1 files changed, 403 insertions, 0 deletions

diff --git a/Source/WebCore/platform/graphics/TiledBackingStore.cpp b/Source/WebCore/platform/graphics/TiledBackingStore.cpp
new file mode 100644
index 0000000..1d6f237
--- /dev/null
+++ b/Source/WebCore/platform/graphics/TiledBackingStore.cpp
@@ -0,0 +1,403 @@
+/*
+ Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
+ 
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public
+ License as published by the Free Software Foundation; either
+ version 2 of the License, or (at your option) any later version.
+ 
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Library General Public License for more details.
+ 
+ You should have received a copy of the GNU Library General Public License
+ along with this library; see the file COPYING.LIB.  If not, write to
+ the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA.
+ */
+
+#include "config.h"
+#include "TiledBackingStore.h"
+
+#if ENABLE(TILED_BACKING_STORE)
+
+#include "GraphicsContext.h"
+#include "TiledBackingStoreClient.h"
+
+namespace WebCore {
+    
+static const int defaultTileWidth = 512;
+static const int defaultTileHeight = 512;
+
+TiledBackingStore::TiledBackingStore(TiledBackingStoreClient* client)
+    : m_client(client)
+    , m_tileBufferUpdateTimer(new TileTimer(this, &TiledBackingStore::tileBufferUpdateTimerFired))
+    , m_tileCreationTimer(new TileTimer(this, &TiledBackingStore::tileCreationTimerFired))
+    , m_tileSize(defaultTileWidth, defaultTileHeight)
+    , m_tileCreationDelay(0.01)
+    , m_keepAreaMultiplier(2.f, 3.5f)
+    , m_coverAreaMultiplier(1.5f, 2.5f)
+    , m_contentsScale(1.f)
+    , m_pendingScale(0)
+    , m_contentsFrozen(false)
+{
+}
+
+TiledBackingStore::~TiledBackingStore()
+{
+    delete m_tileBufferUpdateTimer;
+    delete m_tileCreationTimer;
+}
+    
+void TiledBackingStore::setTileSize(const IntSize& size)
+{
+    m_tileSize = size;
+    m_tiles.clear();
+    startTileCreationTimer();
+}
+
+void TiledBackingStore::setTileCreationDelay(double delay)
+{
+    m_tileCreationDelay = delay;
+}
+
+void TiledBackingStore::setKeepAndCoverAreaMultipliers(const FloatSize& keepMultiplier, const FloatSize& coverMultiplier)
+{
+    m_keepAreaMultiplier = keepMultiplier;
+    m_coverAreaMultiplier = coverMultiplier;
+    startTileCreationTimer();
+}
+
+void TiledBackingStore::invalidate(const IntRect& contentsDirtyRect)
+{
+    IntRect dirtyRect(mapFromContents(contentsDirtyRect));
+    
+    Tile::Coordinate topLeft = tileCoordinateForPoint(dirtyRect.topLeft());
+    Tile::Coordinate bottomRight = tileCoordinateForPoint(dirtyRect.bottomRight());
+    
+    for (unsigned yCoordinate = topLeft.y(); yCoordinate <= bottomRight.y(); ++yCoordinate) {
+        for (unsigned xCoordinate = topLeft.x(); xCoordinate <= bottomRight.x(); ++xCoordinate) {
+            RefPtr<Tile> currentTile = tileAt(Tile::Coordinate(xCoordinate, yCoordinate));
+            if (!currentTile)
+                continue;
+            currentTile->invalidate(dirtyRect);
+        }
+    }
+
+    startTileBufferUpdateTimer();
+}
+
+void TiledBackingStore::updateTileBuffers()
+{
+    if (m_contentsFrozen)
+        return;
+    
+    Vector<IntRect> paintedArea;
+    Vector<RefPtr<Tile> > dirtyTiles;
+    TileMap::iterator end = m_tiles.end();
+    for (TileMap::iterator it = m_tiles.begin(); it != end; ++it) {
+        if (!it->second->isDirty())
+            continue;
+        dirtyTiles.append(it->second);
+        // FIXME: should not request system repaint for the full tile.
+        paintedArea.append(mapToContents(it->second->rect()));
+    }
+    
+    if (dirtyTiles.isEmpty())
+        return;
+    
+    m_client->tiledBackingStorePaintBegin();
+
+    // FIXME: In single threaded case, tile back buffers could be updated asynchronously 
+    // one by one and then swapped to front in one go. This would minimize the time spent
+    // blocking on tile updates.
+    unsigned size = dirtyTiles.size();
+    for (unsigned n = 0; n < size; ++n)
+        dirtyTiles[n]->updateBackBuffer();
+
+    for (unsigned n = 0; n < size; ++n)
+        dirtyTiles[n]->swapBackBufferToFront();
+
+    m_client->tiledBackingStorePaintEnd(paintedArea);
+}
+
+void TiledBackingStore::paint(GraphicsContext* context, const IntRect& rect)
+{
+    context->save();
+    
+    // Assumes the backing store is painted with the scale transform applied.
+    // Since tile content is already scaled, first revert the scaling from the painter.
+    context->scale(FloatSize(1.f / m_contentsScale, 1.f / m_contentsScale));
+    
+    IntRect dirtyRect = mapFromContents(rect);
+    
+    Tile::Coordinate topLeft = tileCoordinateForPoint(dirtyRect.topLeft());
+    Tile::Coordinate bottomRight = tileCoordinateForPoint(dirtyRect.bottomRight());
+
+    for (unsigned yCoordinate = topLeft.y(); yCoordinate <= bottomRight.y(); ++yCoordinate) {
+        for (unsigned xCoordinate = topLeft.x(); xCoordinate <= bottomRight.x(); ++xCoordinate) {
+            Tile::Coordinate currentCoordinate(xCoordinate, yCoordinate);
+            RefPtr<Tile> currentTile = tileAt(currentCoordinate);
+            if (currentTile && currentTile->isReadyToPaint())
+                currentTile->paint(context, dirtyRect);
+            else {
+                IntRect tileRect = tileRectForCoordinate(currentCoordinate);
+                IntRect target = intersection(tileRect, dirtyRect);
+                if (target.isEmpty())
+                    continue;
+                Tile::paintCheckerPattern(context, FloatRect(target));
+            }
+        }
+    }
+    context->restore();
+}
+
+void TiledBackingStore::adjustVisibleRect()
+{
+    IntRect visibleRect = mapFromContents(m_client->tiledBackingStoreVisibleRect());
+    if (m_previousVisibleRect == visibleRect)
+        return;
+    m_previousVisibleRect = visibleRect;
+
+    startTileCreationTimer();
+}
+
+void TiledBackingStore::setContentsScale(float scale)
+{
+    if (m_pendingScale == m_contentsScale) {
+        m_pendingScale = 0;
+        return;
+    }
+    m_pendingScale = scale;
+    if (m_contentsFrozen)
+        return;
+    commitScaleChange();
+}
+    
+void TiledBackingStore::commitScaleChange()
+{
+    m_contentsScale = m_pendingScale;
+    m_pendingScale = 0;
+    m_tiles.clear();
+    createTiles();
+}
+
+double TiledBackingStore::tileDistance(const IntRect& viewport, const Tile::Coordinate& tileCoordinate)
+{
+    if (viewport.intersects(tileRectForCoordinate(tileCoordinate)))
+        return 0;
+    
+    IntPoint viewCenter = viewport.location() + IntSize(viewport.width() / 2, viewport.height() / 2);
+    Tile::Coordinate centerCoordinate = tileCoordinateForPoint(viewCenter);
+    
+    // Manhattan distance, biased so that vertical distances are shorter.
+    const double horizontalBias = 1.3;
+    return abs(centerCoordinate.y() - tileCoordinate.y()) + horizontalBias * abs(centerCoordinate.x() - tileCoordinate.x());
+}
+
+void TiledBackingStore::createTiles()
+{
+    if (m_contentsFrozen)
+        return;
+    
+    IntRect visibleRect = mapFromContents(m_client->tiledBackingStoreVisibleRect());
+    m_previousVisibleRect = visibleRect;
+
+    if (visibleRect.isEmpty())
+        return;
+
+    // Remove tiles that extend outside the current contents rect.
+    dropOverhangingTiles();
+
+    IntRect keepRect = visibleRect;
+    keepRect.inflateX(visibleRect.width() * (m_keepAreaMultiplier.width() - 1.f));
+    keepRect.inflateY(visibleRect.height() * (m_keepAreaMultiplier.height() - 1.f));
+    keepRect.intersect(contentsRect());
+    
+    dropTilesOutsideRect(keepRect);
+    
+    IntRect coverRect = visibleRect;
+    coverRect.inflateX(visibleRect.width() * (m_coverAreaMultiplier.width() - 1.f));
+    coverRect.inflateY(visibleRect.height() * (m_coverAreaMultiplier.height() - 1.f));
+    coverRect.intersect(contentsRect());
+    
+    // Search for the tile position closest to the viewport center that does not yet contain a tile. 
+    // Which position is considered the closest depends on the tileDistance function.
+    double shortestDistance = std::numeric_limits<double>::infinity();
+    Vector<Tile::Coordinate> tilesToCreate;
+    unsigned requiredTileCount = 0;
+    Tile::Coordinate topLeft = tileCoordinateForPoint(coverRect.topLeft());
+    Tile::Coordinate bottomRight = tileCoordinateForPoint(coverRect.bottomRight());
+    for (unsigned yCoordinate = topLeft.y(); yCoordinate <= bottomRight.y(); ++yCoordinate) {
+        for (unsigned xCoordinate = topLeft.x(); xCoordinate <= bottomRight.x(); ++xCoordinate) {
+            Tile::Coordinate currentCoordinate(xCoordinate, yCoordinate);
+            if (tileAt(currentCoordinate))
+                continue;
+            ++requiredTileCount;
+            // Distance is 0 for all currently visible tiles.
+            double distance = tileDistance(visibleRect, currentCoordinate);
+            if (distance > shortestDistance)
+                continue;
+            if (distance < shortestDistance) {
+                tilesToCreate.clear();
+                shortestDistance = distance;
+            }
+            tilesToCreate.append(currentCoordinate);
+        }
+    }
+    
+    // Now construct the tile(s)
+    unsigned tilesToCreateCount = tilesToCreate.size();
+    for (unsigned n = 0; n < tilesToCreateCount; ++n) {
+        Tile::Coordinate coordinate = tilesToCreate[n];
+        setTile(coordinate, Tile::create(this, coordinate));
+    }
+    requiredTileCount -= tilesToCreateCount;
+    
+    // Paint the content of the newly created tiles
+    if (tilesToCreateCount)
+        updateTileBuffers();
+
+    // Keep creating tiles until the whole coverRect is covered.
+    if (requiredTileCount)
+        m_tileCreationTimer->startOneShot(m_tileCreationDelay);
+}
+
+void TiledBackingStore::dropOverhangingTiles()
+{    
+    IntRect contentsRect = this->contentsRect();
+
+    Vector<Tile::Coordinate> tilesToRemove;
+    TileMap::iterator end = m_tiles.end();
+    for (TileMap::iterator it = m_tiles.begin(); it != end; ++it) {
+        Tile::Coordinate tileCoordinate = it->second->coordinate();
+        IntRect tileRect = it->second->rect();
+        IntRect expectedTileRect = tileRectForCoordinate(tileCoordinate);
+        if (expectedTileRect != tileRect || !contentsRect.contains(tileRect))
+            tilesToRemove.append(tileCoordinate);
+    }
+    unsigned removeCount = tilesToRemove.size();
+    for (unsigned n = 0; n < removeCount; ++n)
+        removeTile(tilesToRemove[n]);
+}
+
+void TiledBackingStore::dropTilesOutsideRect(const IntRect& keepRect)
+{
+    FloatRect keepRectF = keepRect;
+
+    Vector<Tile::Coordinate> toRemove;
+    TileMap::iterator end = m_tiles.end();
+    for (TileMap::iterator it = m_tiles.begin(); it != end; ++it) {
+        Tile::Coordinate coordinate = it->second->coordinate();
+        FloatRect tileRect = it->second->rect();
+        if (!tileRect.intersects(keepRectF))
+            toRemove.append(coordinate);
+    }
+    unsigned removeCount = toRemove.size();
+    for (unsigned n = 0; n < removeCount; ++n)
+        removeTile(toRemove[n]);
+}
+
+PassRefPtr<Tile> TiledBackingStore::tileAt(const Tile::Coordinate& coordinate) const
+{
+    return m_tiles.get(coordinate);
+}
+
+void TiledBackingStore::setTile(const Tile::Coordinate& coordinate, PassRefPtr<Tile> tile)
+{
+    m_tiles.set(coordinate, tile);
+}
+
+void TiledBackingStore::removeTile(const Tile::Coordinate& coordinate)
+{
+    m_tiles.remove(coordinate);
+}
+
+IntRect TiledBackingStore::mapToContents(const IntRect& rect) const
+{
+    return enclosingIntRect(FloatRect(rect.x() / m_contentsScale,
+        rect.y() / m_contentsScale,
+        rect.width() / m_contentsScale,
+        rect.height() / m_contentsScale));
+}
+
+IntRect TiledBackingStore::mapFromContents(const IntRect& rect) const
+{
+    return enclosingIntRect(FloatRect(rect.x() * m_contentsScale,
+        rect.y() * m_contentsScale,
+        rect.width() * m_contentsScale,
+        rect.height() * m_contentsScale));
+}
+
+IntRect TiledBackingStore::contentsRect() const
+{
+    return mapFromContents(m_client->tiledBackingStoreContentsRect());
+}
+
+IntRect TiledBackingStore::tileRectForCoordinate(const Tile::Coordinate& coordinate) const
+{
+    IntRect rect(coordinate.x() * m_tileSize.width(),
+        coordinate.y() * m_tileSize.height(),
+        m_tileSize.width(),
+        m_tileSize.height());
+
+    rect.intersect(contentsRect());
+    return rect;
+}
+    
+Tile::Coordinate TiledBackingStore::tileCoordinateForPoint(const IntPoint& point) const
+{
+    int x = point.x() / m_tileSize.width();
+    int y = point.y() / m_tileSize.height();
+    return Tile::Coordinate(std::max(x, 0), std::max(y, 0));
+}
+
+
+void TiledBackingStore::startTileBufferUpdateTimer()
+{
+    if (m_tileBufferUpdateTimer->isActive() || m_contentsFrozen)
+        return;
+    m_tileBufferUpdateTimer->startOneShot(0);
+}
+
+void TiledBackingStore::tileBufferUpdateTimerFired(TileTimer*)
+{
+    updateTileBuffers();
+}
+
+void TiledBackingStore::startTileCreationTimer()
+{
+    if (m_tileCreationTimer->isActive() || m_contentsFrozen)
+        return;
+    m_tileCreationTimer->startOneShot(0);
+}
+
+void TiledBackingStore::tileCreationTimerFired(TileTimer*)
+{
+    createTiles();
+}
+
+void TiledBackingStore::setContentsFrozen(bool freeze)
+{
+    if (m_contentsFrozen == freeze)
+        return;
+
+    m_contentsFrozen = freeze;
+
+    // Restart the timers. There might be pending invalidations that
+    // were not painted or created because tiles are not created or
+    // painted when in frozen state.
+    if (m_contentsFrozen)
+        return;
+    if (m_pendingScale)
+        commitScaleChange();
+    else {
+        startTileCreationTimer();
+        startTileBufferUpdateTimer();
+    }
+}
+
+}
+
+#endif