# Perspective change of vector

Hi!

say I have a source image than I transform to a dst image using getPerspectiveTransform and cv::warpPerspective. after that I have special vector of points in my source image, and I want to get or rather draw them in my dst image , I thought it'll obvious, but I don't this done , to better explain the problem I have a sample with a chessboard:

.................................
cv::warpPerspective(src, dst, transformationMatrix, dst.size()/,CV_INTER_LINEAR,cv::BORDER_ISOLATED);


this work fine so Now I've changed the perspective of my src frame. to transform my Points and theen put them in the dst I wrote this small function

std::vector<cv::Point2f> warpStuff(std::vector<cv::Point2f> inputVector , cv::Mat transformationMatrix){
cv::Matx33f warp = transformationMatrix;
cv::Point3f homogenous;
std::vector<cv::Point2f> result;

for (int k  =0;  k < inputVector.size()-1; k++ ){
homogenous = warp* inputVector[k];
result.push_back(cv::Point2f(homogenous.x,homogenous.y));
}

return result;
}


when try to draw the result vector in dst I don't get the points in their position ?

here's my source image

and after the transformation, when draw result here' a what I get :

I think the problem is that cv::warpPerspective is using in addition to the transformation matrix the size of the dst image, I tried to debugg the stuff but I really didn't understand what does it do with this size so I can add this to my function !

any suggestion ?

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