michael@0: 
michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: #include "SkCanvasStack.h"
michael@0: 
michael@0: SkCanvasStack::SkCanvasStack(int width, int height)
michael@0:         : INHERITED(width, height) {}
michael@0: 
michael@0: SkCanvasStack::~SkCanvasStack() {
michael@0:     this->removeAll();
michael@0: }
michael@0: 
michael@0: void SkCanvasStack::pushCanvas(SkCanvas* canvas, const SkIPoint& origin) {
michael@0:     if (canvas) {
michael@0:         // compute the bounds of this canvas
michael@0:         const SkIRect canvasBounds = SkIRect::MakeSize(canvas->getDeviceSize());
michael@0: 
michael@0:         // push the canvas onto the stack
michael@0:         this->INHERITED::addCanvas(canvas);
michael@0: 
michael@0:         // push the canvas data onto the stack
michael@0:         CanvasData* data = &fCanvasData.push_back();
michael@0:         data->origin = origin;
michael@0:         data->requiredClip.setRect(canvasBounds);
michael@0: 
michael@0:         // subtract this region from the canvas objects already on the stack.
michael@0:         // This ensures they do not draw into the space occupied by the layers
michael@0:         // above them.
michael@0:         for (int i = fList.count() - 1; i > 0; --i) {
michael@0:             SkIRect localBounds = canvasBounds;
michael@0:             localBounds.offset(origin - fCanvasData[i-1].origin);
michael@0: 
michael@0:             fCanvasData[i-1].requiredClip.op(localBounds, SkRegion::kDifference_Op);
michael@0:             fList[i-1]->clipRegion(fCanvasData[i-1].requiredClip);
michael@0:         }
michael@0:     }
michael@0:     SkASSERT(fList.count() == fCanvasData.count());
michael@0: }
michael@0: 
michael@0: void SkCanvasStack::removeAll() {
michael@0:     fCanvasData.reset();
michael@0:     this->INHERITED::removeAll();
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Traverse all canvases (e.g. layers) the stack and ensure that they are clipped
michael@0:  * to their bounds and that the area covered by any canvas higher in the stack is
michael@0:  * also clipped out.
michael@0:  */
michael@0: void SkCanvasStack::clipToZOrderedBounds() {
michael@0:     SkASSERT(fList.count() == fCanvasData.count());
michael@0:     for (int i = 0; i < fList.count(); ++i) {
michael@0:         fList[i]->clipRegion(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op);
michael@0:     }
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: /**
michael@0:  * We need to handle setMatrix specially as it overwrites the matrix in each
michael@0:  * canvas unlike all other matrix operations (i.e. translate, scale, etc) which
michael@0:  * just pre-concatenate with the existing matrix.
michael@0:  */
michael@0: void SkCanvasStack::didSetMatrix(const SkMatrix& matrix) {
michael@0:     SkASSERT(fList.count() == fCanvasData.count());
michael@0:     for (int i = 0; i < fList.count(); ++i) {
michael@0: 
michael@0:         SkMatrix tempMatrix = matrix;
michael@0:         tempMatrix.postTranslate(SkIntToScalar(-fCanvasData[i].origin.x()),
michael@0:                                  SkIntToScalar(-fCanvasData[i].origin.y()));
michael@0:         fList[i]->setMatrix(tempMatrix);
michael@0:     }
michael@0:     this->SkCanvas::didSetMatrix(matrix);
michael@0: }
michael@0: 
michael@0: void SkCanvasStack::onClipRect(const SkRect& r, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
michael@0:     this->INHERITED::onClipRect(r, op, edgeStyle);
michael@0:     this->clipToZOrderedBounds();
michael@0: }
michael@0: 
michael@0: void SkCanvasStack::onClipRRect(const SkRRect& rr, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
michael@0:     this->INHERITED::onClipRRect(rr, op, edgeStyle);
michael@0:     this->clipToZOrderedBounds();
michael@0: }
michael@0: 
michael@0: void SkCanvasStack::onClipPath(const SkPath& p, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
michael@0:     this->INHERITED::onClipPath(p, op, edgeStyle);
michael@0:     this->clipToZOrderedBounds();
michael@0: }
michael@0: 
michael@0: void SkCanvasStack::onClipRegion(const SkRegion& deviceRgn, SkRegion::Op op) {
michael@0:     SkASSERT(fList.count() == fCanvasData.count());
michael@0:     for (int i = 0; i < fList.count(); ++i) {
michael@0:         SkRegion tempRegion;
michael@0:         deviceRgn.translate(-fCanvasData[i].origin.x(),
michael@0:                             -fCanvasData[i].origin.y(), &tempRegion);
michael@0:         tempRegion.op(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op);
michael@0:         fList[i]->clipRegion(tempRegion, op);
michael@0:     }
michael@0:     this->SkCanvas::onClipRegion(deviceRgn, op);
michael@0: }