color replacement in image for iphone application

Question

Basically i want to implement color replacement feature for my paint application. Below are original and expected output

Original:

Answer 1

I know this answer will be useful to someone someday. try this out in your view viewdidLoad() override method for iOS. image in the code snippet below should be from your UIImageView seed also is fixed.you can make it dynamic based on user tap event.

 cv::Mat mask = cv::Mat::zeros(image.rows + 2, image.cols + 2, CV_8U);
 imageView.image = [self UIImageFromCVMat:image];
 cv::cvtColor(image, image, cv::COLOR_BGR2RGB);

  try {
    if(seed.x > 0 && seed.y > 0){
        cv::floodFill(image, mask, seed, cv::Scalar(50, 155, 20) ,0,        cv::Scalar(2,2, 2), cv::Scalar(2,2, 2), 8);
        cv::floodFill(image, mask, seed2, cv::Scalar(50, 155, 20) ,0, cv::Scalar(2,2, 2), cv::Scalar(2,2, 2), 8);
        cv::floodFill(image, mask, seed3, cv::Scalar(50, 155, 0) ,0, cv::Scalar(2,2, 2), cv::Scalar(2,2, 2), 8);

    }
} catch (Exception ex) {

}
cv::cvtColor(image, image, cv::COLOR_RGB2BGR);

self.imageView.contentMode = UIViewContentModeScaleAspectFill;
self.imageView.image = [self UIImageFromCVMat:image];