#include <opencv2/v4d/v4d.hpp>
#include <opencv2/v4d/nvg.hpp>

int main(int argc, char** argv) {
    using namespace cv;
    using namespace cv::viz;

	Ptr<V4D> v4d = V4D::make(Size(1280, 720), "Vector Graphics");
	//Creates a NanoVG context and draws a cross-hair on the framebuffer
	v4d->nvg([](const Size& sz) {
		//Calls from this namespace may only be used inside a nvg context
		using namespace cv::viz::nvg;

		//Draws a cross hair
		beginPath();
		strokeWidth(3.0);
		strokeColor(Scalar(0,0,255,255)); //BGRA
		moveTo(sz.width/2.0, 0);
		lineTo(sz.width/2.0, sz.height);
		moveTo(0, sz.height/2.0);
		lineTo(sz.width, sz.height/2.0);
		stroke();
	});

    //Display the framebuffer in the native window in an endless loop
    v4d->run([=](){ return v4d->display(); });
}