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//
// GTMUIImage+Resize.m
//
// Copyright 2009 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy
// of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
//
#import "GTMUIImage+Resize.h"
@implementation UIImage (GTMUIImageResizeAdditions)
- (UIImage *)gtm_imageByResizingToSize:(CGSize)targetSize
preserveAspectRatio:(BOOL)preserveAspectRatio
trimToFit:(BOOL)trimToFit {
CGSize imageSize = [self size];
if (imageSize.height < 1 || imageSize.width < 1) {
return nil;
}
if (targetSize.height < 1 || targetSize.width < 1) {
return nil;
}
CGFloat aspectRatio = imageSize.width / imageSize.height;
CGFloat targetAspectRatio = targetSize.width / targetSize.height;
CGRect projectTo = CGRectZero;
if (preserveAspectRatio) {
if (trimToFit) {
// Scale and clip image so that the aspect ratio is preserved and the
// target size is filled.
if (targetAspectRatio < aspectRatio) {
// clip the x-axis.
projectTo.size.width = targetSize.height * aspectRatio;
projectTo.size.height = targetSize.height;
projectTo.origin.x = (targetSize.width - projectTo.size.width) / 2;
projectTo.origin.y = 0;
} else {
// clip the y-axis.
projectTo.size.width = targetSize.width;
projectTo.size.height = targetSize.width / aspectRatio;
projectTo.origin.x = 0;
projectTo.origin.y = (targetSize.height - projectTo.size.height) / 2;
}
} else {
// Scale image to ensure it fits inside the specified targetSize.
if (targetAspectRatio < aspectRatio) {
// target is less wide than the original.
projectTo.size.width = targetSize.width;
projectTo.size.height = projectTo.size.width / aspectRatio;
targetSize = projectTo.size;
} else {
// target is wider than the original.
projectTo.size.height = targetSize.height;
projectTo.size.width = projectTo.size.height * aspectRatio;
targetSize = projectTo.size;
}
} // if (clip)
} else {
// Don't preserve the aspect ratio.
projectTo.size = targetSize;
}
projectTo = CGRectIntegral(projectTo);
// There's no CGSizeIntegral, so we fake our own.
CGRect integralRect = CGRectZero;
integralRect.size = targetSize;
targetSize = CGRectIntegral(integralRect).size;
// iPhone recommended settings.
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = (kCGBitmapByteOrder32Little |
kCGImageAlphaPremultipliedFirst);
CGContextRef context = CGBitmapContextCreate(nil, // data
targetSize.width,
targetSize.height,
8, // bitsPerPixel
0, // bytesPerRow
colorSpace,
bitmapInfo);
CGColorSpaceRelease(colorSpace);
// Produce the image
CGContextDrawImage(context, projectTo, [self CGImage]);
CGImageRef resizedRef = CGBitmapContextCreateImage(context);
CGContextRelease(context);
UIImage *resized = [UIImage imageWithCGImage:resizedRef];
CGImageRelease(resizedRef);
return resized;
}
@end
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