AirDropSample/UIImage+Resize.m
/* |
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 |
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