1 2/* 3 * Copyright 2013 Google Inc. 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8#include "SkCanvasStack.h" 9 10SkCanvasStack::SkCanvasStack(int width, int height) 11 : INHERITED(width, height) {} 12 13SkCanvasStack::~SkCanvasStack() { 14 this->removeAll(); 15} 16 17void SkCanvasStack::pushCanvas(SkCanvas* canvas, const SkIPoint& origin) { 18 if (canvas) { 19 // compute the bounds of this canvas 20 const SkIRect canvasBounds = SkIRect::MakeSize(canvas->getDeviceSize()); 21 22 // push the canvas onto the stack 23 this->INHERITED::addCanvas(canvas); 24 25 // push the canvas data onto the stack 26 CanvasData* data = &fCanvasData.push_back(); 27 data->origin = origin; 28 data->requiredClip.setRect(canvasBounds); 29 30 // subtract this region from the canvas objects already on the stack. 31 // This ensures they do not draw into the space occupied by the layers 32 // above them. 33 for (int i = fList.count() - 1; i > 0; --i) { 34 SkIRect localBounds = canvasBounds; 35 localBounds.offset(origin - fCanvasData[i-1].origin); 36 37 fCanvasData[i-1].requiredClip.op(localBounds, SkRegion::kDifference_Op); 38 fList[i-1]->clipRegion(fCanvasData[i-1].requiredClip); 39 } 40 } 41 SkASSERT(fList.count() == fCanvasData.count()); 42} 43 44void SkCanvasStack::removeAll() { 45 fCanvasData.reset(); 46 this->INHERITED::removeAll(); 47} 48 49/** 50 * Traverse all canvases (e.g. layers) the stack and ensure that they are clipped 51 * to their bounds and that the area covered by any canvas higher in the stack is 52 * also clipped out. 53 */ 54void SkCanvasStack::clipToZOrderedBounds() { 55 SkASSERT(fList.count() == fCanvasData.count()); 56 for (int i = 0; i < fList.count(); ++i) { 57 fList[i]->clipRegion(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op); 58 } 59} 60 61//////////////////////////////////////////////////////////////////////////////// 62 63/** 64 * We need to handle setMatrix specially as it overwrites the matrix in each 65 * canvas unlike all other matrix operations (i.e. translate, scale, etc) which 66 * just pre-concatenate with the existing matrix. 67 */ 68void SkCanvasStack::setMatrix(const SkMatrix& matrix) { 69 SkASSERT(fList.count() == fCanvasData.count()); 70 for (int i = 0; i < fList.count(); ++i) { 71 72 SkMatrix tempMatrix = matrix; 73 tempMatrix.postTranslate(SkIntToScalar(-fCanvasData[i].origin.x()), 74 SkIntToScalar(-fCanvasData[i].origin.y())); 75 fList[i]->setMatrix(tempMatrix); 76 } 77 this->SkCanvas::setMatrix(matrix); 78} 79 80bool SkCanvasStack::clipRect(const SkRect& r, SkRegion::Op op, bool aa) { 81 bool result = this->INHERITED::clipRect(r, op, aa); 82 this->clipToZOrderedBounds(); 83 return result; 84} 85 86bool SkCanvasStack::clipRRect(const SkRRect& rr, SkRegion::Op op, bool aa) { 87 bool result = this->INHERITED::clipRRect(rr, op, aa); 88 this->clipToZOrderedBounds(); 89 return result; 90} 91 92bool SkCanvasStack::clipPath(const SkPath& p, SkRegion::Op op, bool aa) { 93 bool result = this->INHERITED::clipPath(p, op, aa); 94 this->clipToZOrderedBounds(); 95 return result; 96} 97 98bool SkCanvasStack::clipRegion(const SkRegion& deviceRgn, SkRegion::Op op) { 99 SkASSERT(fList.count() == fCanvasData.count()); 100 for (int i = 0; i < fList.count(); ++i) { 101 SkRegion tempRegion; 102 deviceRgn.translate(-fCanvasData[i].origin.x(), 103 -fCanvasData[i].origin.y(), &tempRegion); 104 tempRegion.op(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op); 105 fList[i]->clipRegion(tempRegion, op); 106 } 107 return this->SkCanvas::clipRegion(deviceRgn, op); 108} 109