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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"
#import "GTMDefines.h"
GTM_INLINE CGSize swapWidthAndHeight(CGSize size) {
CGFloat tempWidth = size.width;
size.width = size.height;
size.height = tempWidth;
return size;
}
@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;
// Resize photo. Use UIImage drawing methods because they respect
// UIImageOrientation as opposed to CGContextDrawImage().
UIGraphicsBeginImageContext(targetSize);
[self drawInRect:projectTo];
UIImage* resizedPhoto = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resizedPhoto;
}
// Based on code by Trevor Harmon:
// http://vocaro.com/trevor/blog/wp-content/uploads/2009/10/UIImage+Resize.h
// http://vocaro.com/trevor/blog/wp-content/uploads/2009/10/UIImage+Resize.m
- (UIImage *)gtm_imageByRotating:(UIImageOrientation)orientation {
CGRect bounds = CGRectZero;
CGRect rect = CGRectZero;
CGAffineTransform transform = CGAffineTransformIdentity;
bounds.size = [self size];
rect.size = [self size];
switch (orientation) {
case UIImageOrientationUp:
return [UIImage imageWithCGImage:[self CGImage]];
case UIImageOrientationUpMirrored:
transform = CGAffineTransformMakeTranslation(rect.size.width, 0.0);
transform = CGAffineTransformScale(transform, -1.0, 1.0);
break;
case UIImageOrientationDown:
transform = CGAffineTransformMakeTranslation(rect.size.width,
rect.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationDownMirrored:
transform = CGAffineTransformMakeTranslation(0.0, rect.size.height);
transform = CGAffineTransformScale(transform, 1.0, -1.0);
break;
case UIImageOrientationLeft:
bounds.size = swapWidthAndHeight(bounds.size);
transform = CGAffineTransformMakeTranslation(0.0, rect.size.width);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
case UIImageOrientationLeftMirrored:
bounds.size = swapWidthAndHeight(bounds.size);
transform = CGAffineTransformMakeTranslation(rect.size.height,
rect.size.width);
transform = CGAffineTransformScale(transform, -1.0, 1.0);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
case UIImageOrientationRight:
bounds.size = swapWidthAndHeight(bounds.size);
transform = CGAffineTransformMakeTranslation(rect.size.height, 0.0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
case UIImageOrientationRightMirrored:
bounds.size = swapWidthAndHeight(bounds.size);
transform = CGAffineTransformMakeScale(-1.0, 1.0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
default:
_GTMDevAssert(false, @"Invalid orientation %ld", (long)orientation);
return nil;
}
UIGraphicsBeginImageContextWithOptions(bounds.size, NO, self.scale);
CGContextRef context = UIGraphicsGetCurrentContext();
switch (orientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
CGContextScaleCTM(context, -1.0, 1.0);
CGContextTranslateCTM(context, -rect.size.height, 0.0);
break;
default:
CGContextScaleCTM(context, 1.0, -1.0);
CGContextTranslateCTM(context, 0.0, -rect.size.height);
break;
}
CGContextConcatCTM(context, transform);
CGContextDrawImage(context, rect, [self CGImage]);
UIImage *rotatedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return rotatedImage;
}
@end
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