Method Render

core/graphics/guide/Image.cpp:16–49

using namespace xg;

void guide::Image::Render(XChart &chart, shape::Group *container, canvas::CanvasContext &context, const std::vector<util::Rect> &dangerRects) {
    const std::string &xField = chart.GetXScaleField();
    std::vector<std::string> yFields = chart.getYScaleFields();
    const std::string &yField = yFields[0];

    util::Point position = this->GetPosition(chart, json::GetArray(this->config_, "position"), xField, yField);
    const nlohmann::json &margin = config_["margin"];
    std::array<float, 2> _margin = margin;
    
    double width = json::GetNumber(config_, "width", 12) * context.GetDevicePixelRatio();
    double height = json::GetNumber(config_, "height", 12) * context.GetDevicePixelRatio();
    if (width <= 0 || height <= 0) {
        return;
    }
    const std::string &src = json::GetString(config_, "src");
    if (src.empty()) {
        return;
    }
    float  marginLeft = _margin[0] * context.GetDevicePixelRatio();
    float  marginTop = _margin[1] * context.GetDevicePixelRatio();
    // 显示image的位置点的上方居中，因此x偏移x/2，y偏移y
    position.x = position.x - width / 2 - marginLeft;
    position.y = position.y - height - marginTop;
    auto image = xg::make_unique<shape::Image>(src, position, util::Size {width, height});
    
    //上屏
    image->OnLoad([&] () {
        func::Command *cmd = func::CreateCommand([this]() -> void {});
        //立刻上屏
        chart.RequestAnimationFrame(cmd, 0);
    });
    container->AddElement(std::move(image));

}