/*

     File: UIImage+Resize.m

 Abstract: Category methods to resize an image to fit or fill a given rect.

  Version: 1.0

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 */

#import "UIImage+Resize.h"

@implementation UIImage (Resize)

+ (UIImage *)imageWithImage:(UIImage *)image

              scaledToSize:(CGSize)newSize

                     inRect:(CGRect)rect

{

    //Determine whether the screen is retina

    if ([[UIScreen mainScreen] scale] == 2.0) {

        UIGraphicsBeginImageContextWithOptions(newSize, YES, 2.0);

    }

    else

    {

        UIGraphicsBeginImageContext(newSize);

    }

    //Draw image in provided rect

    [image drawInRect:rect];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    //Pop this context

    UIGraphicsEndImageContext();

    return newImage;

}

+ (UIImage *)imageWithImage:(UIImage *)image

          scaledToFitToSize:(CGSize)newSize

{

    //Only scale images down

    if (image.size.width < newSize.width && image.size.height < newSize.height) {

        return [image copy];

    }

    //Determine the scale factors

    CGFloat widthScale = newSize.width/image.size.width;

    CGFloat heightScale = newSize.height/image.size.height;

    CGFloat scaleFactor;

    //The smaller scale factor will scale more (0 < scaleFactor < 1) leaving the other dimension inside the newSize rect

    widthScale < heightScale ? (scaleFactor = widthScale) : (scaleFactor = heightScale);

    CGSize scaledSize = CGSizeMake(image.size.width * scaleFactor, image.size.height * scaleFactor);

    //Scale the image

    return [UIImage imageWithImage:image scaledToSize:scaledSize inRect:CGRectMake(0.0, 0.0, scaledSize.width, scaledSize.height)];

}

+ (UIImage *)imageWithImage:(UIImage *)image

          scaledToFillToSize:(CGSize)newSize

{

    //Only scale images down

    if (image.size.width < newSize.width && image.size.height < newSize.height) {

        return [image copy];

    }

    //Determine the scale factors

    CGFloat widthScale = newSize.width/image.size.width;

    CGFloat heightScale = newSize.height/image.size.height;

    CGFloat scaleFactor;

    //The larger scale factor will scale less (0 < scaleFactor < 1) leaving the other dimension hanging outside the newSize rect

    widthScale > heightScale ? (scaleFactor = widthScale) : (scaleFactor = heightScale);

    CGSize scaledSize = CGSizeMake(image.size.width * scaleFactor, image.size.height * scaleFactor);

    //Create origin point so that the center of the image falls into the drawing context rect (the origin will have negative component).

    CGPoint imageDrawOrigin = CGPointMake(0, 0);

    widthScale > heightScale ?  (imageDrawOrigin.y = (newSize.height - scaledSize.height) * 0.5) :

                                (imageDrawOrigin.x = (newSize.width - scaledSize.width) * 0.5);

    //Create rect where the image will draw

    CGRect imageDrawRect = CGRectMake(imageDrawOrigin.x, imageDrawOrigin.y, scaledSize.width, scaledSize.height);

    //The imageDrawRect is larger than the newSize rect, where the imageDraw origin is located defines what part of

    //the image will fall into the newSize rect.

    return [UIImage imageWithImage:image scaledToSize:newSize inRect:imageDrawRect];

}

@end