Source/WebCore/platform/graphics/filters/FEGaussianBlur.h

/*
 * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
 * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2021-2022 Apple Inc.  All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#pragma once

#include "FEConvolveMatrix.h"
#include "FilterEffect.h"

namespace WebCore {

class FEGaussianBlur : public FilterEffect {
public:
    WEBCORE_EXPORT static Ref<FEGaussianBlur> create(float x, float y, EdgeModeType);

    float stdDeviationX() const { return m_stdX; }
    bool setStdDeviationX(float);

    float stdDeviationY() const { return m_stdY; }
    bool setStdDeviationY(float);

    EdgeModeType edgeMode() const { return m_edgeMode; }
    bool setEdgeMode(EdgeModeType);

    static IntSize calculateKernelSize(const Filter&, FloatSize stdDeviation);
    static IntSize calculateUnscaledKernelSize(FloatSize stdDeviation);
    static IntSize calculateOutsetSize(FloatSize stdDeviation);

    static IntOutsets calculateOutsets(const FloatSize& stdDeviation);

    template<class Encoder> void encode(Encoder&) const;
    template<class Decoder> static std::optional<Ref<FEGaussianBlur>> decode(Decoder&);

private:
    FEGaussianBlur(float x, float y, EdgeModeType);

    FloatRect calculateImageRect(const Filter&, const FilterImageVector& inputs, const FloatRect& primitiveSubregion) const override;

    bool resultIsAlphaImage(const FilterImageVector& inputs) const override;

    std::unique_ptr<FilterEffectApplier> createSoftwareApplier() const override;

    WTF::TextStream& externalRepresentation(WTF::TextStream&, FilterRepresentation) const override;

    float m_stdX;
    float m_stdY;
    EdgeModeType m_edgeMode;
};

template<class Encoder>
void FEGaussianBlur::encode(Encoder& encoder) const
{
    encoder << m_stdX;
    encoder << m_stdY;
    encoder << m_edgeMode;
}

template<class Decoder>
std::optional<Ref<FEGaussianBlur>> FEGaussianBlur::decode(Decoder& decoder)
{
    std::optional<float> stdX;
    decoder >> stdX;
    if (!stdX)
        return std::nullopt;

    std::optional<float> stdY;
    decoder >> stdY;
    if (!stdY)
        return std::nullopt;

    std::optional<EdgeModeType> edgeMode;
    decoder >> edgeMode;
    if (!edgeMode)
        return std::nullopt;

    return FEGaussianBlur::create(*stdX, *stdY, *edgeMode);
}

} // namespace WebCore

SPECIALIZE_TYPE_TRAITS_FILTER_EFFECT(FEGaussianBlur)