1 /*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "src/utils/SkCanvasStack.h"
9
10 #include "include/core/SkRect.h"
11 #include "include/core/SkScalar.h"
12 #include "include/core/SkShader.h"
13 #include "include/private/base/SkTDArray.h"
14 #include <utility>
15
16 class SkPath;
17 class SkRRect;
18
SkCanvasStack(int width,int height)19 SkCanvasStack::SkCanvasStack(int width, int height)
20 : INHERITED(width, height) {}
21
~SkCanvasStack()22 SkCanvasStack::~SkCanvasStack() {
23 this->removeAll();
24 }
25
pushCanvas(std::unique_ptr<SkCanvas> canvas,const SkIPoint & origin)26 void SkCanvasStack::pushCanvas(std::unique_ptr<SkCanvas> canvas, const SkIPoint& origin) {
27 if (canvas) {
28 // compute the bounds of this canvas
29 const SkIRect canvasBounds = SkIRect::MakeSize(canvas->getBaseLayerSize());
30
31 // push the canvas onto the stack
32 this->INHERITED::addCanvas(canvas.get());
33
34 // push the canvas data onto the stack
35 CanvasData* data = &fCanvasData.push_back();
36 data->origin = origin;
37 data->requiredClip.setRect(canvasBounds);
38 data->ownedCanvas = std::move(canvas);
39
40 // subtract this region from the canvas objects already on the stack.
41 // This ensures they do not draw into the space occupied by the layers
42 // above them.
43 for (int i = fList.size() - 1; i > 0; --i) {
44 SkIRect localBounds = canvasBounds;
45 localBounds.offset(origin - fCanvasData[i-1].origin);
46
47 fCanvasData[i-1].requiredClip.op(localBounds, SkRegion::kDifference_Op);
48 fList[i-1]->clipRegion(fCanvasData[i-1].requiredClip);
49 }
50 }
51 SkASSERT(fList.size() == fCanvasData.size());
52 }
53
removeAll()54 void SkCanvasStack::removeAll() {
55 this->INHERITED::removeAll(); // call the baseclass *before* we actually delete the canvases
56 fCanvasData.clear();
57 }
58
59 /**
60 * Traverse all canvases (e.g. layers) the stack and ensure that they are clipped
61 * to their bounds and that the area covered by any canvas higher in the stack is
62 * also clipped out.
63 */
clipToZOrderedBounds()64 void SkCanvasStack::clipToZOrderedBounds() {
65 SkASSERT(fList.size() == fCanvasData.size());
66 for (int i = 0; i < fList.size(); ++i) {
67 fList[i]->clipRegion(fCanvasData[i].requiredClip);
68 }
69 }
70
71 ////////////////////////////////////////////////////////////////////////////////
72
73 /**
74 * We need to handle setMatrix specially as it overwrites the matrix in each
75 * canvas unlike all other matrix operations (i.e. translate, scale, etc) which
76 * just pre-concatenate with the existing matrix.
77 */
didSetM44(const SkM44 & mx)78 void SkCanvasStack::didSetM44(const SkM44& mx) {
79 SkASSERT(fList.size() == fCanvasData.size());
80 for (int i = 0; i < fList.size(); ++i) {
81 fList[i]->setMatrix(SkM44::Translate(SkIntToScalar(-fCanvasData[i].origin.x()),
82 SkIntToScalar(-fCanvasData[i].origin.y())) * mx);
83 }
84 this->SkCanvas::didSetM44(mx);
85 }
86
onClipRect(const SkRect & r,SkClipOp op,ClipEdgeStyle edgeStyle)87 void SkCanvasStack::onClipRect(const SkRect& r, SkClipOp op, ClipEdgeStyle edgeStyle) {
88 this->INHERITED::onClipRect(r, op, edgeStyle);
89 this->clipToZOrderedBounds();
90 }
91
onClipRRect(const SkRRect & rr,SkClipOp op,ClipEdgeStyle edgeStyle)92 void SkCanvasStack::onClipRRect(const SkRRect& rr, SkClipOp op, ClipEdgeStyle edgeStyle) {
93 this->INHERITED::onClipRRect(rr, op, edgeStyle);
94 this->clipToZOrderedBounds();
95 }
96
onClipPath(const SkPath & p,SkClipOp op,ClipEdgeStyle edgeStyle)97 void SkCanvasStack::onClipPath(const SkPath& p, SkClipOp op, ClipEdgeStyle edgeStyle) {
98 this->INHERITED::onClipPath(p, op, edgeStyle);
99 this->clipToZOrderedBounds();
100 }
101
onClipShader(sk_sp<SkShader> cs,SkClipOp op)102 void SkCanvasStack::onClipShader(sk_sp<SkShader> cs, SkClipOp op) {
103 this->INHERITED::onClipShader(std::move(cs), op);
104 // we don't change the "bounds" of the clip, so we don't need to update zorder
105 }
106
onClipRegion(const SkRegion & deviceRgn,SkClipOp op)107 void SkCanvasStack::onClipRegion(const SkRegion& deviceRgn, SkClipOp op) {
108 SkASSERT(fList.size() == fCanvasData.size());
109 for (int i = 0; i < fList.size(); ++i) {
110 SkRegion tempRegion;
111 deviceRgn.translate(-fCanvasData[i].origin.x(),
112 -fCanvasData[i].origin.y(), &tempRegion);
113 tempRegion.op(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op);
114 fList[i]->clipRegion(tempRegion, op);
115 }
116 this->SkCanvas::onClipRegion(deviceRgn, op);
117 }
118