void TiledDrawingAreaProxy::paint(const IntRect& rect, PlatformDrawingContext context)
{
if (m_isWaitingForDidSetFrameNotification) {
WebPageProxy* page = this->page();
if (!page->isValid())
return;
if (page->process()->isLaunching())
return;
}
adjustVisibleRect();
GraphicsContext gc(context);
gc.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.
gc.scale(FloatSize(1 / m_contentsScale, 1 / m_contentsScale));
IntRect dirtyRect = mapFromContents(rect);
TiledDrawingAreaTile::Coordinate topLeft = tileCoordinateForPoint(dirtyRect.topLeft());
TiledDrawingAreaTile::Coordinate bottomRight = tileCoordinateForPoint(dirtyRect.bottomRight());
for (unsigned yCoordinate = topLeft.y(); yCoordinate <= bottomRight.y(); ++yCoordinate) {
for (unsigned xCoordinate = topLeft.x(); xCoordinate <= bottomRight.x(); ++xCoordinate) {
TiledDrawingAreaTile::Coordinate currentCoordinate(xCoordinate, yCoordinate);
RefPtr<TiledDrawingAreaTile> currentTile = tileAt(currentCoordinate);
if (currentTile && currentTile->isReadyToPaint())
currentTile->paint(&gc, dirtyRect);
else {
IntRect tileRect = tileRectForCoordinate(currentCoordinate);
IntRect target = intersection(tileRect, dirtyRect);
if (target.isEmpty())
continue;
TiledDrawingAreaTile::paintCheckerPattern(&gc, FloatRect(target));
}
}
}
gc.restore();
}
double TiledDrawingAreaProxy::tileDistance(const IntRect& viewport, const TiledDrawingAreaTile::Coordinate& tileCoordinate)
{
if (viewport.intersects(tileRectForCoordinate(tileCoordinate)))
return 0;
IntPoint viewCenter = viewport.location() + IntSize(viewport.width() / 2, viewport.height() / 2);
TiledDrawingAreaTile::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 TiledDrawingAreaProxy::createTiles()
{
IntRect visibleRect = mapFromContents(webViewVisibleRect());
m_previousVisibleRect = visibleRect;
if (visibleRect.isEmpty())
return;
// Resize tiles on edges in case the contents size has changed.
bool didResizeTiles = resizeEdgeTiles();
// Remove tiles outside out current maximum keep rect.
dropTilesOutsideRect(calculateKeepRect(visibleRect));
// Cover the cover rect with tiles.
IntRect coverRect = calculateCoverRect(visibleRect);
// 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<TiledDrawingAreaTile::Coordinate> tilesToCreate;
unsigned requiredTileCount = 0;
bool hasVisibleCheckers = false;
TiledDrawingAreaTile::Coordinate topLeft = tileCoordinateForPoint(coverRect.topLeft());
TiledDrawingAreaTile::Coordinate bottomRight = tileCoordinateForPoint(coverRect.bottomRight());
for (unsigned yCoordinate = topLeft.y(); yCoordinate <= bottomRight.y(); ++yCoordinate) {
for (unsigned xCoordinate = topLeft.x(); xCoordinate <= bottomRight.x(); ++xCoordinate) {
TiledDrawingAreaTile::Coordinate currentCoordinate(xCoordinate, yCoordinate);
// Distance is 0 for all currently visible tiles.
double distance = tileDistance(visibleRect, currentCoordinate);
RefPtr<TiledDrawingAreaTile> tile = tileAt(currentCoordinate);
if (!distance && (!tile || !tile->isReadyToPaint()))
hasVisibleCheckers = true;
if (tile)
continue;
++requiredTileCount;
if (distance > shortestDistance)
continue;
if (distance < shortestDistance) {
tilesToCreate.clear();
shortestDistance = distance;
}
tilesToCreate.append(currentCoordinate);
}
}
if (hasVisibleCheckers && shortestDistance > 0)
return;
// Now construct the tile(s).
unsigned tilesToCreateCount = tilesToCreate.size();
for (unsigned n = 0; n < tilesToCreateCount; ++n)
createTile(tilesToCreate[n]);
requiredTileCount -= tilesToCreateCount;
// Paint the content of the newly created tiles.
if (tilesToCreateCount || didResizeTiles)
updateTileBuffers();
// Keep creating tiles until the whole coverRect is covered.
if (requiredTileCount)
m_tileCreationTimer.startOneShot(m_tileCreationDelay);
}