Method getRect

CvPlot/examples/examples_gui.cpp:179–183

        cv::Vec2d _dragOffset;
        const double _size = 30;
        cv::Rect2d getRect(const Projection &projection) {
            auto p = projection.project(_point);
            cv::Point2d diag2(_size / 2, _size / 2);
            return cv::Rect2d(p - diag2, p + diag2);
        }
        void render(RenderTarget &renderTarget) override {
            cv::rectangle(renderTarget.innerMat(), getRect(renderTarget), cv::Scalar::all(0), cv::FILLED);
        }