Source/WebCore/platform/graphics/filters/FEComponentTransfer.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 "FilterEffect.h"
#include <wtf/Vector.h>

namespace WebCore {

enum ComponentTransferType {
    FECOMPONENTTRANSFER_TYPE_UNKNOWN  = 0,
    FECOMPONENTTRANSFER_TYPE_IDENTITY = 1,
    FECOMPONENTTRANSFER_TYPE_TABLE    = 2,
    FECOMPONENTTRANSFER_TYPE_DISCRETE = 3,
    FECOMPONENTTRANSFER_TYPE_LINEAR   = 4,
    FECOMPONENTTRANSFER_TYPE_GAMMA    = 5
};

struct ComponentTransferFunction {
    ComponentTransferType type { FECOMPONENTTRANSFER_TYPE_UNKNOWN };

    float slope { 0 };
    float intercept { 0 };
    float amplitude { 0 };
    float exponent { 0 };
    float offset { 0 };

    Vector<float> tableValues;

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

class FEComponentTransfer : public FilterEffect {
public:
    WEBCORE_EXPORT static Ref<FEComponentTransfer> create(const ComponentTransferFunction& redFunc, const ComponentTransferFunction& greenFunc, const ComponentTransferFunction& blueFunc, const ComponentTransferFunction& alphaFunc);

    ComponentTransferFunction redFunction() const { return m_redFunction; }
    ComponentTransferFunction greenFunction() const { return m_greenFunction; }
    ComponentTransferFunction blueFunction() const { return m_blueFunction; }
    ComponentTransferFunction alphaFunction() const { return m_alphaFunction; }

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

private:
    FEComponentTransfer(const ComponentTransferFunction& redFunc, const ComponentTransferFunction& greenFunc, const ComponentTransferFunction& blueFunc, const ComponentTransferFunction& alphaFunc);

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

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

    ComponentTransferFunction m_redFunction;
    ComponentTransferFunction m_greenFunction;
    ComponentTransferFunction m_blueFunction;
    ComponentTransferFunction m_alphaFunction;
};

template<class Encoder>
void ComponentTransferFunction::encode(Encoder& encoder) const
{
    encoder << type;
    encoder << slope;
    encoder << intercept;
    encoder << amplitude;
    encoder << exponent;
    encoder << offset;
    encoder << tableValues;
}

template<class Decoder>
std::optional<ComponentTransferFunction> ComponentTransferFunction::decode(Decoder& decoder)
{
    std::optional<ComponentTransferType> type;
    decoder >> type;
    if (!type)
        return std::nullopt;

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

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

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

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

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

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

    return { { *type, *slope, *intercept, *amplitude, *exponent, *offset, WTFMove(*tableValues) } };
}

template<class Encoder>
void FEComponentTransfer::encode(Encoder& encoder) const
{
    encoder << m_redFunction;
    encoder << m_greenFunction;
    encoder << m_blueFunction;
    encoder << m_alphaFunction;
}

template<class Decoder>
std::optional<Ref<FEComponentTransfer>> FEComponentTransfer::decode(Decoder& decoder)
{
    std::optional<ComponentTransferFunction> redFunction;
    decoder >> redFunction;
    if (!redFunction)
        return std::nullopt;

    std::optional<ComponentTransferFunction> greenFunction;
    decoder >> greenFunction;
    if (!greenFunction)
        return std::nullopt;

    std::optional<ComponentTransferFunction> blueFunction;
    decoder >> blueFunction;
    if (!blueFunction)
        return std::nullopt;

    std::optional<ComponentTransferFunction> alphaFunction;
    decoder >> alphaFunction;
    if (!alphaFunction)
        return std::nullopt;

    return FEComponentTransfer::create(*redFunction, *greenFunction, *blueFunction, *alphaFunction);
}

} // namespace WebCore

namespace WTF {

template<> struct EnumTraits<WebCore::ComponentTransferType> {
    using values = EnumValues<
        WebCore::ComponentTransferType,

        WebCore::FECOMPONENTTRANSFER_TYPE_UNKNOWN,
        WebCore::FECOMPONENTTRANSFER_TYPE_IDENTITY,
        WebCore::FECOMPONENTTRANSFER_TYPE_TABLE,
        WebCore::FECOMPONENTTRANSFER_TYPE_DISCRETE,
        WebCore::FECOMPONENTTRANSFER_TYPE_LINEAR,
        WebCore::FECOMPONENTTRANSFER_TYPE_GAMMA
    >;
};

} // namespace WTF

SPECIALIZE_TYPE_TRAITS_FILTER_EFFECT(FEComponentTransfer)