Method alpha

source/matplot/core/line_spec.cpp:282–282

    const std::array<float, 4> &line_spec::color() const { return color_; }

    float line_spec::alpha() const { return color_[0]; }

    void line_spec::color(const std::array<float, 3> &color) {
        color_ = {0, color[0], color[1], color[2]};