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- (UIImage *)convertImageToGrayScale:(UIImage *)image { // Create image rectangle with current image width/height CGRect imageRect = CGRectMake(0, 0, image.size.width, image.size.height); // Grayscale color space CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray(); // Create bitmap content with current image size and grayscale colorspace CGContextRef context = CGBitmapContextCreate(nil, image.size.width, image.size.height, 8, 0, colorSpace, kCGImageAlphaNone); // Draw image into current context, with specified rectangle // using previously defined context (with grayscale colorspace) CGContextDrawImage(context, imageRect, [image CGImage]); // Create bitmap image info from pixel data in current context CGImageRef imageRef = CGBitmapContextCreateImage(context); // Create a new UIImage object UIImage *newImage = [UIImage imageWithCGImage:imageRef]; // Release colorspace, context and bitmap information CGColorSpaceRelease(colorSpace); CGContextRelease(context); CFRelease(imageRef); // Return the new grayscale image return newImage; } |