Vector drawing

openMVG considers that visualizing data is important. OpenMVG provides a class that help to perform vector graphics (SVG) drawing in order to have the best possible visualization of his algorithm output. Vector graphics allows keeping details when you zoom what is not done when you use raster graphics. (SVG files are supported by web navigator and the Inkscape software).

.. code-block:: c++

// Draw a cardiod curve with the svg polyline
// http://en.wikipedia.org/wiki/Cardioid
{ // Pre-compute (x, y ) curve points
	size_t nbPoints = 120 ;
	std::vector<float> vec_x ( nbPoints, 0.f ), vec_y ( nbPoints, 0.f );
	doubleS = 20.;
	for ( size_t i = 0; i < nbPoints; ++i ) {
		const double theta = i*2*M_PI/nbPoints;
		//-- Cardioid equation
		vec_x[i] = (3*S+S*(2.*sin(theta)-(sin(2.*theta))));
		vec_y[i] = (2*S-S*(2.*cos(theta)-(cos(2.*theta))));
	}
	// Create a svg surface and add the cardiod polyline
	svgDrawer svgSurface (6 *S, 6 *S); //Create a svg object
	svgSurface << drawPolyline (
		vec_x.cbegin() , vec_x.cend(),
		vec_y.cbegin() , vec_y.cend(),
		svgAttributes().stroke( "blue", 2));

	//Export the SVG stream to a file
	std::string sFileName = "ThirdExample.svg";
	std::ofstream svgFile ( sFileName.c_str() );
	svgFile << svgSurface.closeSvgFile().str();
	svgFile.close();
}

Here the result exported vector graphic:

.. figure:: vectorGraphic.png :align: center :alt: alternate text :figclass: align-center