Resizing UIimages pulled from the Camera also ROTATES the UIimage? - iphone

Question

I am getting UIimages from the camera and assigning them to UIImageViews to be displayed. When I do this the camera gives me a 1200 x 1600 pixel image which I then assign to a UIImageView in my Application. The image is displayed as expected in the image view under this condition. However, when I attempt to RESIZE the retrieved UIImage before assigning it to the UIImageView, the image is resizing as expected but there IS a problem in that somewhere (in the RESIZING code?) my UIImage is getting ROTATED... As a result, when I assign the resized UIImage to a UIImageView the image is rotated 90 degrees and appears stretched as the aspect ratio (1200 x 1600 pixels) was unchanged...
I am using this to get a UIImage from the Camera:
- (void) imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary*)info
{
myImg = [info objectForKey:#"UIImagePickerControllerOriginalImage"];
myResizedImg = [self resizeImage:myImg width:400 height:533];
[myImageView setImage:myResizedImg];
}
I am using this to resize it:
-(UIImage *)resizeImage:(UIImage *)anImage width:(int)width height:(int)height
{
CGImageRef imageRef = [anImage CGImage];
CGImageAlphaInfo alphaInfo = CGImageGetAlphaInfo(imageRef);
if (alphaInfo == kCGImageAlphaNone)
alphaInfo = kCGImageAlphaNoneSkipLast;
CGContextRef bitmap = CGBitmapContextCreate(NULL, width, height, CGImageGetBitsPerComponent(imageRef), 4 * width, CGImageGetColorSpace(imageRef), alphaInfo);
CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage *result = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap);
CGImageRelease(ref);
return result;
}
QUESTION: How do I RESIZE a UIImage pulled from the Camera WITHOUT rotating the pixels?

Answer 1

The reason your code doesn't work is because the imageOrientation on the code that you have is not being taken into account. Specifically, if the imageOrientation is right/left, then you need to both rotate the image and swap width/height. Here is some code to do this:
-(UIImage*)imageByScalingToSize:(CGSize)targetSize
{
UIImage* sourceImage = self;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGImageRef imageRef = [sourceImage CGImage];
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef);
if (bitmapInfo == kCGImageAlphaNone) {
bitmapInfo = kCGImageAlphaNoneSkipLast;
}
CGContextRef bitmap;
if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) {
bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
} else {
bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
}
if (sourceImage.imageOrientation == UIImageOrientationLeft) {
CGContextRotateCTM (bitmap, radians(90));
CGContextTranslateCTM (bitmap, 0, -targetHeight);
} else if (sourceImage.imageOrientation == UIImageOrientationRight) {
CGContextRotateCTM (bitmap, radians(-90));
CGContextTranslateCTM (bitmap, -targetWidth, 0);
} else if (sourceImage.imageOrientation == UIImageOrientationUp) {
// NOTHING
} else if (sourceImage.imageOrientation == UIImageOrientationDown) {
CGContextTranslateCTM (bitmap, targetWidth, targetHeight);
CGContextRotateCTM (bitmap, radians(-180.));
}
CGContextDrawImage(bitmap, CGRectMake(0, 0, targetWidth, targetHeight), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage* newImage = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap);
CGImageRelease(ref);
return newImage;
}
This will resize your image and rotate it to the correct orientation. If you need the definition for radians, it is:
static inline double radians (double degrees) {return degrees * M_PI/180;}
The answer Daniel gave is also correct, but it suffers from the problem that it is not thread-safe, since you're using UIGraphicsBeginImageContext(). Since the above code only uses CG functions, you're all set. I also have a similar function to resize and do proper aspect fill on images - let me know if that's what you're looking for.
Note: I got the original function from this post, and did some modifications to make it work on JPEGs.

Answer 2

I had this problem too with some of the code out there, i found this code that works, check it out, let me know what you find
+ (UIImage*)imageWithImage:(UIImage*)image
scaledToSize:(CGSize)newSize;
{
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}

Answer 3

Swift 3
I add this to didFinishPickingMediaWithInfo method and then use image without worrying for its rotation.
var image = info[UIImagePickerControllerOriginalImage] as! UIImage
if (image.imageOrientation != .up) {
UIGraphicsBeginImageContextWithOptions(image.size, false, image.scale)
image.draw(in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
image = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
}

Answer 4

If you want to make a square image from a rectangle image (no matter horizontal or vertical) by cropping it by width or height in both sides, use my code. The difference is that I don't stretch, but I crop. I made it from the top code by modification:
//Cropping _image to fit it to the square by height or width
CGFloat a = _image.size.height;
CGFloat b = _image.size.width;
CGRect cropRect;
if (!(a==b)) {
if (a<b) {
cropRect = CGRectMake((b-a)/2.0, 0, a, a);
b = a;
}
else if (b<a) {
cropRect = CGRectMake(0, (a-b)/2.0, b, b);
a = b;
}
CGImageRef imageRef = CGImageCreateWithImageInRect([_image CGImage], cropRect);
UIImage* sourceImage = _image;
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef);
CGContextRef bitmap;
if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) {
bitmap = CGBitmapContextCreate(NULL, a, a, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
} else {
bitmap = CGBitmapContextCreate(NULL, a, a, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
}
if (sourceImage.imageOrientation == UIImageOrientationLeft) {
CGContextRotateCTM (bitmap, radians(90));
CGContextTranslateCTM (bitmap, 0, -a);
} else if (sourceImage.imageOrientation == UIImageOrientationRight) {
CGContextRotateCTM (bitmap, radians(-90));
CGContextTranslateCTM (bitmap, -a, 0);
} else if (sourceImage.imageOrientation == UIImageOrientationUp) {
// NOTHING
} else if (sourceImage.imageOrientation == UIImageOrientationDown) {
CGContextTranslateCTM (bitmap, a, a);
CGContextRotateCTM (bitmap, radians(-180.));
}
CGContextDrawImage(bitmap, CGRectMake(0, 0, a, a), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
_image = [UIImage imageWithCGImage:ref];
CGImageRelease(imageRef);
}