iOS Taglia un'immagine in un cerchio - Obiettivo C

Esempio

import #include <math.h>

Il codice in viewDidLoad o loadView dovrebbe apparire qualcosa di simile a questo

- (void)loadView
{
[super loadView];
UIImageView *imageView=[[UIImageView alloc]initWithFrame:CGRectMake(0, 50, 320, 320)];
[self.view addSubview:imageView];
UIImage *image=[UIImage imageNamed:@"Dubai-Photos-Images-Travel-Tourist-Images-Pictures-800x600.jpg"];
imageView.image=[self circularScaleAndCropImage:[UIImage imageNamed:@"Dubai-Photos-Images-Travel-Tourist-Images-Pictures-800x600.jpg"] frame:CGRectMake(0, 0, 320, 320)];
}

Infine la funzione che fa il sollevamento pesante circularScaleAndCropImage è come definito di seguito

- (UIImage*)circularScaleAndCropImage:(UIImage*)image frame:(CGRect)frame {
    // This function returns a newImage, based on image, that has been:
    // - scaled to fit in (CGRect) rect
    // - and cropped within a circle of radius: rectWidth/2
    
    //Create the bitmap graphics context
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(frame.size.width, frame.size.height), NO, 0.0);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    //Get the width and heights
    CGFloat imageWidth = image.size.width;
    CGFloat imageHeight = image.size.height;
    CGFloat rectWidth = frame.size.width;
    CGFloat rectHeight = frame.size.height;
    
    //Calculate the scale factor
    CGFloat scaleFactorX = rectWidth/imageWidth;
    CGFloat scaleFactorY = rectHeight/imageHeight;
    
    //Calculate the centre of the circle
    CGFloat imageCentreX = rectWidth/2;
    CGFloat imageCentreY = rectHeight/2;
    
    // Create and CLIP to a CIRCULAR Path
    // (This could be replaced with any closed path if you want a different shaped clip)
    CGFloat radius = rectWidth/2;
    CGContextBeginPath (context);
    CGContextAddArc (context, imageCentreX, imageCentreY, radius, 0, 2*M_PI, 0);
    CGContextClosePath (context);
    CGContextClip (context);
    
    //Set the SCALE factor for the graphics context
    //All future draw calls will be scaled by this factor
    CGContextScaleCTM (context, scaleFactorX, scaleFactorY);
    
    // Draw the IMAGE
    CGRect myRect = CGRectMake(0, 0, imageWidth, imageHeight);
    [image drawInRect:myRect];
    
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return newImage;
}