Method updateShader

snap_drawing/src/snap_drawing/cpp/Drawing/RadialGradient.cpp:40–80

}

void RadialGradient::updateShader(const Rect& bounds) {
    if (isEmpty()) {
        _shader = nullptr;
    } else {
        auto width = bounds.width();
        auto height = bounds.height();
        auto radius = std::min(width / 2, height / 2);

        const auto* colorsData = reinterpret_cast<const SkColor*>(_colors.data());

        SkMatrix localMatrix;
        if (width != height) {
            localMatrix.postScale(width / height, 1);
        }
        localMatrix.postTranslate(bounds.x() + (width / 2), bounds.y() + (height / 2));

        sk_sp<SkShader> shader;
        if (_colors.size() == _locations.size()) {
            // User provided color distribution

            _shader = SkGradientShader::MakeRadial(Point::make(0, 0).getSkValue(),
                                                   radius,
                                                   colorsData,
                                                   _locations.data(),
                                                   static_cast<int>(_colors.size()),
                                                   SkTileMode::kClamp,
                                                   0,
                                                   &localMatrix);
        } else {
            // Distribute colors evenly
            _shader = SkGradientShader::MakeRadial(Point::make(0, 0).getSkValue(),
                                                   radius,
                                                   colorsData,
                                                   nullptr,
                                                   static_cast<int>(_colors.size()),
                                                   SkTileMode::kClamp,
                                                   0,
                                                   &localMatrix);
        }
    }
}

void RadialGradient::applyToPaint(Paint& paint) const {
    paint.getSkValue().setShader(_shader);