Image cropping issue in iOS - ios

Question

I am creating an iPhone app which has image cropping feature. In this, I am getting the photos from the UIImagePickerController and passing it for cropping. There it has a scrollview and the selected image will be added as a subview to the scrollview. And I am using a UIButton for selecting the area for cropping. User can move the button over the imageview and place it anywhere, and when click on CROP button, the area similar to the frame size of the button should be cropped from the imageview.
I used the following code, but it is not returning the actual image.
CGRect clippedRect = CGRectMake(self.scrollView.frame.origin.x+90, self.scrollView.frame.origin.y, self.scrollView.frame.size.width-180, self.scrollView.frame.size.height-220);
CGImageRef imageRef = CGImageCreateWithImageInRect([self.myPhoto CGImage], clippedRect);
UIImage *newImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
self.imageView.image = newImage;
also used
- (UIImage *)cropImage:(UIImage *)oldImage {
CGSize imageSize = self.cropFrame.frame.size;
UIGraphicsBeginImageContextWithOptions( CGSizeMake( imageSize.width, imageSize.height), NO, 0.);
[oldImage drawAtPoint:CGPointMake( xPosition, yPosition)
blendMode:kCGBlendModeCopy
alpha:1.];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}
but the result image is not the exact image as per the button frame. I am getting the image from another area.
Updated code
- (void)loadPhoto{
CGFloat w = self.myPhoto.size.width;
CGFloat h = self.myPhoto.size.height;
CGRect imageViewFrame = CGRectMake(0.0f, 0.0f, roundf(w / 2.0f), roundf(h / 2.0f));
self.scrollView.contentSize = imageViewFrame.size;
UIImageView *iv = [[UIImageView alloc] initWithFrame:imageViewFrame];
iv.contentMode = UIViewContentModeScaleAspectFit;
iv.image = self.myPhoto;
[self.view addSubview:iv];
self.imageView = iv;
[iv release];
}
CGRect crop;//= CGRectMake(10, 10, 360, 360);
crop.origin.x = self.cropFrame.frame.origin.x;
crop.origin.y = self.cropFrame.frame.origin.y;
crop.size.width = roundf(self.cropFrame.frame.size.width * 2.0f); //self.cropFrame.frame.size.width * 2;
crop.size.height = roundf(self.cropFrame.frame.size.height * 2.0f); //self.cropFrame.frame.size.height * 2;
NSLog(#"Rect: %#", NSStringFromCGRect(crop));
self.imageView.image = [self croppedImage:crop];
- (UIImage *)croppedImage:(CGRect)bounds {
CGImageRef imageRef = CGImageCreateWithImageInRect([self.imageView.image CGImage], bounds);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef scale:1.0 orientation:self.myPhoto.imageOrientation];
CGImageRelease(imageRef);
return croppedImage;
}
Please help to find a solution.

Answer 1

The iOS has a default feature for cropping images.Try this code.
picker.allowsEditing = YES;
and also check this controller for cropping..this is exactly the one you are looking for I think https://github.com/barrettj/BJImageCropper .Hope this helps you..

Answer 2

Since you are using a scrollView that allows the image to be scrolled, you need to adjust your crop rect to the scrollView's position:
float zoomScale = self.scrollView.zoomScale;
int cropX = (self.scrollView.contentOffset.x-imageView.frame.origin.x)/zoomScale;
int cropY = (self.scrollView.contentOffset.y-imageView.frame.origin.y)/zoomScale;

Answer 3

You could use this crop tool that I made. It essentially gives you an interface to allow the user to select the crop area. I think it is in line with that you are looking for.
https://github.com/nicholjs/BFCropInterface

Answer 4

Believing you have solve this problem. Me too had this when tried cropping functionality
Set image.size as the imageView.size & scrollView.contentSize. Below code will give the rect to crop
cropRect.origin = scrollView.contentOffset;
cropRect.size = scrollView.bounds.size;
cropRect.origin.x /= scrollView.zoomScale;
cropRect.origin.y /= scrollView.zoomScale;
cropRect.size.width /= scrollView.zoomScale;
cropRect.size.height /= scrollView.zoomScale;
If planning to show the full image first on visible rect. Setting the imageView.size & scrollView.contentSize to visible view size will give crop image of some other area. Instead try finding the zoom scale by
CGFloat dxWidth = viewCrop.frame.size.width / imageView.image.size.width;
CGFloat dxHeight = viewCrop.frame.size.height / imageView.image.size.height;
CGFloat zoomScale = fmaxf(dWidth, dHeight)
and apply (if by adding subView then after addSubView)
scrollView.minimumZoomScale = zoomScale; // to disable further zoom-out
[scrollView setZoomScale: zoomScale];