Question

I developing the simple UIApplication in which i want to crop the UIImage (in .jpg format) with help of CGContext. The developed code till now as follows,

CGImageRef graphicOriginalImage = [originalImage.image CGImage];

UIGraphicsBeginImageContext(originalImage.image.size);

CGContextRef ctx = UIGraphicsGetCurrentContext();
CGBitmapContextCreateImage(graphicOriginalImage);

CGFloat fltW = originalImage.image.size.width;
CGFloat fltH = originalImage.image.size.height;
CGFloat X = round(fltW/4); 
CGFloat Y =round(fltH/4);
CGFloat width = round(X + (fltW/2));
CGFloat height = round(Y + (fltH/2));   

CGContextTranslateCTM(ctx, 0, image.size.height);
CGContextScaleCTM(ctx, 1.0, -1.0);
CGRect rect = CGRectMake(X,Y ,width ,height); 
CGContextDrawImage(ctx, rect, graphicOriginalImage);

croppedImage = UIGraphicsGetImageFromCurrentImageContext();

return croppedImage;

}
The above code is worked fine but it can’t crop image.
The original image memory and cropped image memory i will got same(equal to original image memory).
The above code is right for cropping the image??????????????????

Answer 1

The context you create to draw the image has the same size that the original image. That’s why they have the same size.

If you don’t want to re-invent the wheel, take a look at the TouchCode project on Google Code. You will find UIImage categories that do the job (see UIImage_ThumbnailExtensions.m).