How to Crop a UiImage to specific Size? - ios

Question

Hi I am working with the UIimage, I need to crop my image to specific size, Suppose my specific size width is equal to device width and height is fixed 200.
I tried in Google lot of examples but non of those not working for me, I tried below samples
-(UIImage *)resizeImage:(UIImage *)image
{
float h=200;
float w=400;
float actualHeight = image.size.height;
float actualWidth = image.size.width;
float maxHeight = h;
float maxWidth = w;
float imgRatio = actualWidth/actualHeight;
float maxRatio = maxWidth/maxHeight;
float compressionQuality = 0.8;//50 percent compression
if (actualHeight > maxHeight || actualWidth > maxWidth)
{
if(imgRatio < maxRatio)
{
//adjust width according to maxHeight
imgRatio = maxHeight / actualHeight;
actualWidth = imgRatio * actualWidth;
actualHeight = maxHeight;
}
else if(imgRatio > maxRatio)
{
//adjust height according to maxWidth
imgRatio = maxWidth / actualWidth;
actualHeight = imgRatio * actualHeight;
actualWidth = maxWidth;
}
else
{
actualHeight = maxHeight;
actualWidth = maxWidth;
}
}
CGRect rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight);
UIGraphicsBeginImageContext(rect.size);
//UIGraphicsBeginImageContextWithOptions(rect.size,NO,0.0);
[image drawInRect:rect];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
NSData *imageData = UIImageJPEGRepresentation(img, compressionQuality);
UIGraphicsEndImageContext();
return [UIImage imageWithData:imageData];
}
Below is my actual image
After cropping I am getting like below
All of my examples are stretching the image But i want with out stretching need to scale the image.Where i am missing?Please help me.

Answer 1

The code you are using will resize your image, We use it for image compression or image resizing.
If you want to crop an Image there are two way.
1)Allow user to edit when image is selected.
You can achieve this by adding allowEditing property to picker like,
pickerView.allowEditing = true
This will give you rectangle to crop image, you can retrieve edited image from didFinish method of picker view
2)Programatically
To crop image programatically you need to pass frame for cropping.
Here is the function i am using
func croppImage(originalImage:UIImage, toRect rect:CGRect) -> UIImage{
var imageRef:CGImageRef = CGImageCreateWithImageInRect(originalImage.CGImage, rect)
var croppedimage:UIImage = UIImage(CGImage:imageRef)
return croppedimage
}
The above code will return you cropped image.

Answer 2

These will crop your image into size you required.
- (CGImageRef)newTransformedImage:(CGAffineTransform)transform
sourceImage:(CGImageRef)sourceImage
sourceSize:(CGSize)sourceSize
sourceOrientation:(UIImageOrientation)sourceOrientation
outputWidth:(CGFloat)outputWidth
cropSize:(CGSize)cropSize
imageViewSize:(CGSize)imageViewSize
{
CGImageRef source = [self newScaledImage:sourceImage
withOrientation:sourceOrientation
toSize:sourceSize
withQuality:kCGInterpolationNone];
CGFloat aspect = cropSize.height/cropSize.width;
CGSize outputSize = CGSizeMake(outputWidth, outputWidth*aspect);
CGContextRef context = CGBitmapContextCreate(NULL,
outputSize.width,
outputSize.height,
CGImageGetBitsPerComponent(source),
0,
CGImageGetColorSpace(source),
CGImageGetBitmapInfo(source));
CGContextSetFillColorWithColor(context, [[UIColor clearColor] CGColor]);
CGContextFillRect(context, CGRectMake(0, 0, outputSize.width, outputSize.height));
CGAffineTransform uiCoords = CGAffineTransformMakeScale(outputSize.width / cropSize.width,
outputSize.height / cropSize.height);
uiCoords = CGAffineTransformTranslate(uiCoords, cropSize.width/2.0, cropSize.height / 2.0);
uiCoords = CGAffineTransformScale(uiCoords, 1.0, -1.0);
CGContextConcatCTM(context, uiCoords);
CGContextConcatCTM(context, transform);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextDrawImage(context, CGRectMake(-imageViewSize.width/2.0,
-imageViewSize.height/2.0,
imageViewSize.width,
imageViewSize.height)
, source);
CGImageRef resultRef = CGBitmapContextCreateImage(context);
CGContextRelease(context);
CGImageRelease(source);
return resultRef;
}
- (CGImageRef)newScaledImage:(CGImageRef)source withOrientation:(UIImageOrientation)orientation toSize:(CGSize)size withQuality:(CGInterpolationQuality)quality
{
CGSize srcSize = size;
CGFloat rotation = 0.0;
switch(orientation)
{
case UIImageOrientationUp: {
rotation = 0;
} break;
case UIImageOrientationDown: {
rotation = M_PI;
} break;
case UIImageOrientationLeft:{
rotation = M_PI_2;
srcSize = CGSizeMake(size.height, size.width);
} break;
case UIImageOrientationRight: {
rotation = -M_PI_2;
srcSize = CGSizeMake(size.height, size.width);
} break;
default:
break;
}
CGContextRef context = CGBitmapContextCreate(NULL,
size.width,
size.height,
8, //CGImageGetBitsPerComponent(source),
0,
CGImageGetColorSpace(source),
(CGBitmapInfo)kCGImageAlphaNoneSkipFirst //CGImageGetBitmapInfo(source)
);
CGContextSetInterpolationQuality(context, quality);
CGContextTranslateCTM(context, size.width/2, size.height/2);
CGContextRotateCTM(context,rotation);
CGContextDrawImage(context, CGRectMake(-srcSize.width/2 ,
-srcSize.height/2,
srcSize.width,
srcSize.height),
source);
CGImageRef resultRef = CGBitmapContextCreateImage(context);
CGContextRelease(context);
return resultRef;
}
///where you want to crop.
CGImageRef imageRef = [self newTransformedImage:transform
sourceImage:self.image.CGImage
sourceSize:self.image.size
sourceOrientation:self.image.imageOrientation
outputWidth:self.image.size.width
cropSize:self.photoView.cropView.frame.size
imageViewSize:self.photoView.photoContentView.bounds.size];
UIImage *image = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
Thank you. Enjoy Coding :)