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Diffstat (limited to 'src/utils/SkCanvasStack.cpp')
-rw-r--r-- | src/utils/SkCanvasStack.cpp | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/src/utils/SkCanvasStack.cpp b/src/utils/SkCanvasStack.cpp new file mode 100644 index 0000000000..db5a8b2740 --- /dev/null +++ b/src/utils/SkCanvasStack.cpp @@ -0,0 +1,108 @@ + +/* + * Copyright 2013 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ +#include "SkCanvasStack.h" + +SkCanvasStack::SkCanvasStack(int width, int height) + : INHERITED(width, height) {} + +SkCanvasStack::~SkCanvasStack() { + this->removeAll(); +} + +void SkCanvasStack::pushCanvas(SkCanvas* canvas, const SkIPoint& origin) { + if (canvas) { + // compute the bounds of this canvas + const SkIRect canvasBounds = SkIRect::MakeSize(canvas->getDeviceSize()); + + // push the canvas onto the stack + this->INHERITED::addCanvas(canvas); + + // push the canvas data onto the stack + CanvasData* data = &fCanvasData.push_back(); + data->origin = origin; + data->requiredClip.setRect(canvasBounds); + + // subtract this region from the canvas objects already on the stack. + // This ensures they do not draw into the space occupied by the layers + // above them. + for (int i = fList.count() - 1; i > 0; --i) { + SkIRect localBounds = canvasBounds; + localBounds.offset(origin - fCanvasData[i-1].origin); + + fCanvasData[i-1].requiredClip.op(localBounds, SkRegion::kDifference_Op); + fList[i-i]->clipRegion(fCanvasData[i-1].requiredClip); + } + } + SkASSERT(fList.count() == fCanvasData.count()); +} + +void SkCanvasStack::removeAll() { + fCanvasData.reset(); + this->INHERITED::removeAll(); +} + +/** + * Traverse all canvases (e.g. layers) the stack and ensure that they are clipped + * to their bounds and that the area covered by any canvas higher in the stack is + * also clipped out. + */ +void SkCanvasStack::clipToZOrderedBounds() { + SkASSERT(fList.count() == fCanvasData.count()); + for (int i = 0; i < fList.count(); ++i) { + fList[i]->clipRegion(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op); + } +} + +//////////////////////////////////////////////////////////////////////////////// + +/** + * We need to handle setMatrix specially as it overwrites the matrix in each + * canvas unlike all other matrix operations (i.e. translate, scale, etc) which + * just pre-concatenate with the existing matrix. + */ +void SkCanvasStack::setMatrix(const SkMatrix& matrix) { + SkASSERT(fList.count() == fCanvasData.count()); + for (int i = 0; i < fList.count(); ++i) { + + SkMatrix tempMatrix = matrix; + tempMatrix.postTranslate(SkIntToScalar(-fCanvasData[i].origin.x()), + SkIntToScalar(-fCanvasData[i].origin.y())); + fList[i]->setMatrix(tempMatrix); + } + this->SkCanvas::setMatrix(matrix); +} + +bool SkCanvasStack::clipRect(const SkRect& r, SkRegion::Op op, bool aa) { + bool result = this->INHERITED::clipRect(r, op, aa); + this->clipToZOrderedBounds(); + return result; +} + +bool SkCanvasStack::clipRRect(const SkRRect& rr, SkRegion::Op op, bool aa) { + bool result = this->INHERITED::clipRRect(rr, op, aa); + this->clipToZOrderedBounds(); + return result; +} + +bool SkCanvasStack::clipPath(const SkPath& p, SkRegion::Op op, bool aa) { + bool result = this->INHERITED::clipPath(p, op, aa); + this->clipToZOrderedBounds(); + return result; +} + +bool SkCanvasStack::clipRegion(const SkRegion& deviceRgn, SkRegion::Op op) { + SkASSERT(fList.count() == fCanvasData.count()); + for (int i = 0; i < fList.count(); ++i) { + SkRegion tempRegion; + deviceRgn.translate(-fCanvasData[i].origin.x(), + -fCanvasData[i].origin.y(), &tempRegion); + tempRegion.op(fCanvasData[i].requiredClip, SkRegion::kIntersect_Op); + fList[i]->clipRegion(tempRegion, op); + } + return this->SkCanvas::clipRegion(deviceRgn, op); +} |