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// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
#ifndef QLOTTIEGRADIENTHOLDER_P_H
#define QLOTTIEGRADIENTHOLDER_P_H
//
// W A R N I N G
// -------------
//
// This file is not part of the Qt API. It exists purely as an
// implementation detail. This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
#include <QtLottie/private/qlottiespatialproperty_p.h>
#include <QtLottie/private/qlottiestroke_p.h>
QT_BEGIN_NAMESPACE
class Q_LOTTIE_EXPORT QLottieGradientHolderContent
{
public:
QGradient *value() const;
QGradient::Type gradientType() const;
QPointF startPoint() const;
QPointF endPoint() const;
qreal highlightLength() const;
qreal highlightAngle() const;
protected:
void setGradient(qreal opacity);
void updateGradientProperties(int frame);
QGradient *m_gradient = nullptr;
QLottieSpatialProperty m_startPoint;
QLottieSpatialProperty m_endPoint;
QLottieProperty<qreal> m_highlightLength;
QLottieProperty<qreal> m_highlightAngle;
QHash<qreal, QLottieProperty4D<QVector4D>> m_colors;
};
template <typename T>
class QLottieGradientHolder: public T, public QLottieGradientHolderContent
{
public:
QLottieGradientHolder(QLottieBase *parent);
QLottieGradientHolder(const QLottieGradientHolder<T> &other);
~QLottieGradientHolder() override;
protected:
bool parseGradientProperties(const QJsonObject &definition);
};
template <typename T>
QLottieGradientHolder<T>::QLottieGradientHolder(QLottieBase *parent)
{
T::setParent(parent);
}
template <typename T>
QLottieGradientHolder<T>::QLottieGradientHolder(const QLottieGradientHolder<T> &other)
: T(other)
{
if (T::m_hidden)
return;
m_startPoint = other.m_startPoint;
m_endPoint = other.m_endPoint;
m_highlightLength = other.m_highlightLength;
m_highlightAngle = other.m_highlightAngle;
m_colors = other.m_colors;
if (other.gradientType() == QGradient::LinearGradient)
m_gradient = new QLinearGradient;
else if (other.gradientType() == QGradient::RadialGradient)
m_gradient = new QRadialGradient;
else
Q_UNREACHABLE();
}
template <typename T>
QLottieGradientHolder<T>::~QLottieGradientHolder()
{
delete m_gradient;
}
template <typename T>
bool QLottieGradientHolder<T>::parseGradientProperties(const QJsonObject &definition)
{
if (!T::checkRequiredKeys(definition, "Gradient"_L1, { "s"_L1, "e"_L1, "g"_L1, "t"_L1 }, T::m_name))
return false;
int type = definition.value("t"_L1).toVariant().toInt();
switch (type) {
case 1:
m_gradient = new QLinearGradient;
break;
case 2:
m_gradient = new QRadialGradient;
break;
default:
qCWarning(lcLottieQtLottieParser) << "Unknown gradient fill type";
}
QJsonObject color = definition.value("g"_L1).toObject();
if (!T::checkRequiredKeys(color, "Gradient"_L1, { "p"_L1, "k"_L1 }, T::m_name))
return false;
int elementCount = color.value("p"_L1).toInt();
if (elementCount <= 0) {
qCInfo(lcLottieQtLottieParser) << "Empty gradient enountered";
return true;
}
QJsonObject stops = color.value("k"_L1).toObject();
bool isAnimated = stops.value("a"_L1).toVariant().toBool();
if (!T::checkRequiredKeys(stops, "Gradient"_L1, { "a"_L1, "k"_L1 }, T::m_name))
return false;
if (!isAnimated) {
QMap<qreal, QVector4D> colorStops;
QJsonArray colorArr = stops.value("k"_L1).toArray();
if (colorArr.size() < elementCount * 4) {
qCWarning(lcLottieQtLottieParser) << "Gradient color array too short";
return false;
}
for (int i = 0; i < (elementCount * 4); i += 4) {
// p denotes the color stop percentage
QVector4D colorVec;
colorVec[0] = colorArr.at(i + 1).toVariant().toFloat();
colorVec[1] = colorArr.at(i + 2).toVariant().toFloat();
colorVec[2] = colorArr.at(i + 3).toVariant().toFloat();
colorVec[3] = 1.0f;
QLottieProperty4D<QVector4D> colorPos;
colorPos.setValue(colorVec);
// The stop position is found in the first element of the vector
qreal pos = colorArr.at(i + 0).toVariant().toFloat();
m_colors[pos] = colorPos;
colorStops.insert(pos, colorVec);
}
if (colorArr.size() > (elementCount * 4)) {
// The gradient has opacity stops; handle them
QMap<qreal, qreal> opacityStops;
for (int i = (elementCount * 4); i < colorArr.size(); i += 2) {
qreal pos = colorArr.at(i).toVariant().toFloat();
qreal opacity = colorArr.at(i + 1).toVariant().toFloat();
opacityStops.insert(pos, opacity);
}
QMap<qreal, qreal> uniqueOpacityStops(opacityStops);
// First: add opacity to all existing color stops
for (auto [pos, color] : colorStops.asKeyValueRange()) {
qreal opacity = 1.0;
if (pos <= opacityStops.firstKey() || opacityStops.size() == 1) {
opacity = opacityStops.first();
} else if (pos >= opacityStops.lastKey()) {
opacity = opacityStops.last();
} else {
auto it2 = opacityStops.lowerBound(pos);
Q_ASSERT(it2 != opacityStops.cbegin());
auto it1(it2);
it1--;
qreal ratio = (pos - it1.key()) / (it2.key() - it1.key());
opacity = it1.value() + ratio * (it2.value() - it1.value());
}
color[3] = opacity;
m_colors[pos].setValue(color);
uniqueOpacityStops.remove(pos); // will remove if position present, otherwise noop
}
// Second: add new color stops for any unique opacity stop positions
for (auto [pos, opacity] : uniqueOpacityStops.asKeyValueRange()) {
QVector4D color;
if (pos <= colorStops.firstKey() || colorStops.size() == 1) {
color = colorStops.first();
} else if (pos >= colorStops.lastKey()) {
color = colorStops.last();
} else {
auto it2 = colorStops.lowerBound(pos);
Q_ASSERT(it2 != colorStops.cbegin());
auto it1(it2);
it1--;
qreal ratio = (pos - it1.key()) / (it2.key() - it1.key());
color = it1.value() + ratio * (it2.value() - it1.value());
}
color[3] = opacity;
m_colors[pos].setValue(color);
}
}
} else {
qCInfo(lcLottieQtLottieParser) << "Animated gradient is not supported";
}
QJsonObject startPoint = definition.value("s"_L1).toObject();
startPoint = T::resolveExpression(startPoint);
m_startPoint.construct(startPoint);
QJsonObject endPoint = definition.value("e"_L1).toObject();
endPoint = T::resolveExpression(endPoint);
m_endPoint.construct(endPoint);
QJsonObject highlight = definition.value("h"_L1).toObject();
m_highlightLength.construct(highlight);
QJsonObject angle = definition.value("a"_L1).toObject();
angle = T::resolveExpression(angle);
m_highlightAngle.construct(angle);
return true;
}
QT_END_NAMESPACE
#endif // QLOTTIEGRADIENTHOLDER_P_H