#import <opencv2/opencv.hpp>#import <opencv2/imgcodecs/ios.h>#import <opencv2/imgproc/types_c.h>@implementation OpenCVHelper+(UIImage *)getImageOutLine:(UIImage *)iputimg{    cv::Mat cvImage;    UIImageToMat(iputimg, cvImage);    cv::Mat gray;    // Convert the image to grayscale;    cv::cvtColor(cvImage, gray, CV_RGBA2GRAY);    // Apply Gaussian filter to remove small edges    cv::GaussianBlur(gray, gray, cv::Size(5,5), 1.2,1.2);    // Calculate edges with Canny    cv::Mat edges;    cv::Canny(gray, edges, 0, 60);    // Fill image with white color    //cvImage.setTo(cv::Scalar(255,255,255,1));    // Change color on edges    // cvImage.setTo(cv::Scalar(0,128,255,255),edges);        cv::Mat cvOutImage= cv::Mat::zeros(cvImage.size(), cvImage.type());    cvOutImage.setTo(cv::Scalar(255,255,255,0));    cvOutImage.setTo(cv::Scalar(0,139,139,1),edges);    return MatToUIImage(cvOutImage);}@end

-(UIImage *)transparentImage:(UIImage *)image{        // Create a pixel buffer in an easy to use format    CGImageRef imageRef = [image CGImage];    NSUInteger width = CGImageGetWidth(imageRef);    NSUInteger height = CGImageGetHeight(imageRef);    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();        UInt8 * m_PixelBuf = malloc(sizeof(UInt8) * height * width * 4);        NSUInteger bytesPerPixel = 4;    NSUInteger bytesPerRow = bytesPerPixel * width;    NSUInteger bitsPerComponent = 8;    CGContextRef context = CGBitmapContextCreate(m_PixelBuf, width, height,                                                 bitsPerComponent, bytesPerRow, colorSpace,                                                 kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);        CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);    CGContextRelease(context);        //alter the alpha    int length = height * width * 4;    for (int i=0; i<length; i+=4)    {        if (m_PixelBuf[i+0] ==255) {            m_PixelBuf[i+0] =0;            m_PixelBuf[i+1] =0;            m_PixelBuf[i+2] =0;            m_PixelBuf[i+3] =0;        }     }            //create a new image    CGContextRef ctx = CGBitmapContextCreate(m_PixelBuf, width, height,                                             bitsPerComponent, bytesPerRow, colorSpace,                                             kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);        CGImageRef newImgRef = CGBitmapContextCreateImage(ctx);    CGColorSpaceRelease(colorSpace);    CGContextRelease(ctx);     free(m_PixelBuf);        UIImage *finalImage = [UIImage imageWithCGImage:newImgRef];    CGImageRelease(newImgRef);         return finalImage;}