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JPImagePickerController/Classes/UIImageResizing.m
2009-11-14 20:51:10 +01:00

150 lines
3.8 KiB
Objective-C

//
// UIImageResizing.m
// JPImagePickerController
//
// Created by Jeena on 07.11.09.
// Copyright 2009 Jeena Paradies.
// Licence: MIT-Licence
//
#import "UIImageResizing.h"
@implementation UIImage (Resizing)
+ (UIImage *)image:(UIImage *)sourceImage scaleAndCroppForSize:(CGSize)targetSize {
UIImage *newImage = nil;
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor >= heightFactor) {
scaleFactor = widthFactor; // scale to fit height
} else {
scaleFactor = heightFactor; // scale to fit width
}
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the image
if (widthFactor >= heightFactor) {
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
} else if (widthFactor < heightFactor) {
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
NSLog(@"could not scale image");
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}
- (UIImage *)scaleAndCropToSize:(CGSize)targetSize {
return [UIImage image:self scaleAndCroppForSize:(CGSize)targetSize];
}
- (UIImage *)scaleAndCropToSize:(CGSize)targetSize onlyIfNeeded:(BOOL)onlyIfNeeded {
UIImage *image;
if (!onlyIfNeeded || [self needsToScale:targetSize]) {
image = [self scaleAndCropToSize:targetSize];
} else {
image = self;
}
return image;
}
+ (UIImage *)image:(UIImage *)sourceImage scaleToSize:(CGSize)targetSize {
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetSize.width;
CGFloat scaledHeight = targetSize.height;
CGFloat widthFactor = targetSize.width / sourceImage.size.width;
CGFloat heightFactor = targetSize.height / sourceImage.size.height;
if (widthFactor < heightFactor) {
scaleFactor = widthFactor; // scale to fit height
} else {
scaleFactor = heightFactor; // scale to fit width
}
scaledWidth = sourceImage.size.width * scaleFactor;
scaledHeight = sourceImage.size.height * scaleFactor;
CGSize propperSize = CGSizeMake(scaledWidth, scaledHeight);
UIGraphicsBeginImageContext( propperSize );
[sourceImage drawInRect:CGRectMake(0, 0, propperSize.width, propperSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}
- (UIImage *)scaleToSize:(CGSize)newSize {
return [UIImage image:self scaleToSize:newSize];
}
- (UIImage *)scaleToSize:(CGSize)targetSize onlyIfNeeded:(BOOL)onlyIfNeeded {
UIImage *image;
if (!onlyIfNeeded || [self needsToScale:targetSize]) {
image = [self scaleToSize:targetSize];
} else {
image = self;
}
return image;
}
+ (BOOL)image:(UIImage *)sourceImage needsToScale:(CGSize)targetSize {
BOOL needsToScale = NO;
if (sourceImage.size.width > targetSize.width) {
needsToScale = YES;
}
if (sourceImage.size.height > targetSize.height) {
needsToScale = YES;
}
return needsToScale;
}
- (BOOL)needsToScale:(CGSize)targetSize {
return [UIImage image:self needsToScale:targetSize];
}
@end