Function clipRenderTarget

src/OpenLoco/src/Graphics/RenderTarget.cpp:21–37

0x004CEC50

    // 0x004CEC50
    std::optional<RenderTarget> clipRenderTarget(const RenderTarget& src, const Ui::Rect& newRect)
    {
        const Ui::Rect oldRect = src.getUiRect();
        Ui::Rect intersect = oldRect.intersection(newRect);
        const auto stride = oldRect.size.width + src.pitch;
        const int16_t newPitch = stride - intersect.size.width;
        auto* newBits = src.bits + (stride * (intersect.origin.y - oldRect.origin.y) + (intersect.origin.x - oldRect.origin.x));
        intersect.origin.x = std::max(0, oldRect.origin.x - newRect.origin.x);
        intersect.origin.y = std::max(0, oldRect.origin.y - newRect.origin.y);
        RenderTarget newRT{ newBits, static_cast<int16_t>(intersect.origin.x), static_cast<int16_t>(intersect.origin.y), static_cast<int16_t>(intersect.size.width), static_cast<int16_t>(intersect.size.height), newPitch, 0 };

        if (newRT.width <= 0 || newRT.height <= 0)
        {
            return {};
        }
        return { newRT };
    }
}