1 /* 2 * Copyright 2018 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 "SkSGOpacityEffect.h" 9 10 #include "SkCanvas.h" 11 12 #include <math.h> 13 14 namespace sksg { 15 16 OpacityEffect::OpacityEffect(sk_sp<RenderNode> child, float opacity) 17 : INHERITED(std::move(child)) 18 , fOpacity(opacity) {} 19 20 void OpacityEffect::onRender(SkCanvas* canvas) const { 21 // opacity <= 0 disables rendering 22 if (fOpacity <= 0) 23 return; 24 25 // TODO: we could avoid savelayer if there is no more than one drawing primitive 26 // in the sub-DAG. 27 SkAutoCanvasRestore acr(canvas, false); 28 if (fOpacity < 1) { 29 canvas->saveLayerAlpha(&this->bounds(), roundf(fOpacity * 255)); 30 } 31 32 this->INHERITED::onRender(canvas); 33 } 34 35 SkRect OpacityEffect::onRevalidate(InvalidationController* ic, const SkMatrix& ctm) { 36 SkASSERT(this->hasInval()); 37 38 // opacity <= 0 disables rendering AND revalidation for the sub-DAG 39 return fOpacity > 0 ? this->INHERITED::onRevalidate(ic, ctm) : SkRect::MakeEmpty(); 40 } 41 42 } // namespace sksg 43
