WebTransformationMatrix CCLayerImpl::quadTransform() const
{
WebTransformationMatrix quadTransformation = drawTransform();
float offsetX = -0.5 * bounds().width();
float offsetY = -0.5 * bounds().height();
quadTransformation.translate(offsetX, offsetY);
return quadTransformation;
}
void CCDamageTracker::extendDamageForLayer(CCLayerImpl* layer, FloatRect& targetDamageRect)
{
// There are two ways that a layer can damage a region of the target surface:
// 1. Property change (e.g. opacity, position, transforms):
// - the entire region of the layer itself damages the surface.
// - the old layer region also damages the surface, because this region is now exposed.
// - note that in many cases the old and new layer rects may overlap, which is fine.
//
// 2. Repaint/update: If a region of the layer that was repainted/updated, that
// region damages the surface.
//
// Property changes take priority over update rects.
//
// This method is called when we want to consider how a layer contributes to its
// targetRenderSurface, even if that layer owns the targetRenderSurface itself.
// To consider how a layer's targetSurface contributes to the ancestorSurface,
// extendDamageForRenderSurface() must be called instead.
// Compute the layer's "originTransform" by translating the drawTransform.
WebTransformationMatrix originTransform = layer->drawTransform();
originTransform.translate(-0.5 * layer->bounds().width(), -0.5 * layer->bounds().height());
bool layerIsNew = false;
FloatRect oldLayerRect = removeRectFromCurrentFrame(layer->id(), layerIsNew);
FloatRect layerRectInTargetSpace = CCMathUtil::mapClippedRect(originTransform, FloatRect(FloatPoint::zero(), layer->bounds()));
saveRectForNextFrame(layer->id(), layerRectInTargetSpace);
if (layerIsNew || layerNeedsToRedrawOntoItsTargetSurface(layer)) {
// If a layer is new or has changed, then its entire layer rect affects the target surface.
targetDamageRect.uniteIfNonZero(layerRectInTargetSpace);
// The layer's old region is now exposed on the target surface, too.
// Note oldLayerRect is already in target space.
targetDamageRect.uniteIfNonZero(oldLayerRect);
} else if (!layer->updateRect().isEmpty()) {
// If the layer properties havent changed, then the the target surface is only
// affected by the layer's update area, which could be empty.
FloatRect updateRectInTargetSpace = CCMathUtil::mapClippedRect(originTransform, layer->updateRect());
targetDamageRect.uniteIfNonZero(updateRectInTargetSpace);
}
}