I'd like to draw a white filled polygon, with arbitrary angle, in a black IplImage. I know there exists function such as createCircle, but I can't find something similar for polygons. I found this , but the use of it is awful, I mean I shouldn't have to go into this just to draw one simple white polygon on a black background...!
The example I found on the OpenCV documentation:
void MyPolygon( Mat img )
{
int lineType = 8;
/** Create some points */
Point rook_points[1][20];
rook_points[0][0] = Point( w/4.0, 7*w/8.0 );
rook_points[0][1] = Point( 3*w/4.0, 7*w/8.0 );
rook_points[0][2] = Point( 3*w/4.0, 13*w/16.0 );
rook_poi /*** blablabla **/
rook_points[0][19] = Point( w/4.0, 13*w/16.0) ;
const Point* ppt[1] = { rook_points[0] };
int npt[] = { 20 };
fillPoly( img,
ppt,
npt,
1,
Scalar( 255, 255, 255 ),
lineType );
}
Basically, my question is, how do I put a CvBox2D into fillPoly, to get a mask out of it and finally set the "ROI with angle" that I need?
Like this:
#include <cv.h>
void drawBox( CvArr* img, CvBox2D box, CvScalar color )
{
CvPoint2D32f pointsf[4];
cvBoxPoints( box , pointsf );
CvPoint pointsi[4];
for(int i=0;i<4;i++)
{
pointsi[i]=cvPointFrom32f(pointsf[i]);
}
CvPoint* countours[1]={
pointsi,
};
int countours_n[1]={
4,
};
cvFillPoly( img, countours, countours_n, 1, color );
}