SkSGOpacityEffect.cpp

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/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#include "include/private/base/SkAssert.h"
#include "modules/sksg/include/SkSGOpacityEffect.h"
 
class SkCanvas;
class SkMatrix;
struct SkPoint;
 
namespace sksg {
class InvalidationController;
 
OpacityEffect::OpacityEffect(sk_sp<RenderNode> child, float opacity)
    : INHERITED(std::move(child))
    , fOpacity(opacity) {}
 
void OpacityEffect::onRender(SkCanvas* canvas, const RenderContext* ctx) const {
    // opacity <= 0 disables rendering
    if (fOpacity <= 0)
        return;
 
    // opacity >= 1 has no effect
    if (fOpacity >= 1) {
        this->INHERITED::onRender(canvas, ctx);
        return;
    }
 
    const auto local_context = ScopedRenderContext(canvas, ctx).modulateOpacity(fOpacity);
 
    this->INHERITED::onRender(canvas, local_context);
}
 
const RenderNode* OpacityEffect::onNodeAt(const SkPoint& p) const {
    return (fOpacity > 0) ? this->INHERITED::onNodeAt(p) : nullptr;
}
 
SkRect OpacityEffect::onRevalidate(InvalidationController* ic, const SkMatrix& ctm) {
    SkASSERT(this->hasInval());
 
    // opacity <= 0 disables rendering AND revalidation for the sub-DAG
    return fOpacity > 0 ? this->INHERITED::onRevalidate(ic, ctm) : SkRect::MakeEmpty();
}
 
} // namespace sksg