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Objective-Cで画像のリサイズ系
#import "ImageUtil.h"
@implementation ImageUtil
// 幅を元に、リサイズ画像の幅・高さを算出する
+ (CGSize)resizeFromWidth:(CGFloat)width imageSize:(CGSize)imageSize {
CGFloat s_x = imageSize.width / width;
CGFloat s_y = imageSize.height / (imageSize.height / s_x);
CGFloat scale = MAX(s_x, s_y);
if (scale > 1) {
CGFloat new_x = imageSize.width / scale;
CGFloat new_y = imageSize.height / scale;
return CGSizeMake(new_x, new_y);
}
return imageSize;
}
// 幅を元に、UIImageのリサイズした場合のサイズを返す
+ (CGSize)resizeFromWidth:(CGFloat)width image:(UIImage *)image {
return [self resizeFromWidth:width imageSize:CGSizeMake(image.size.width, image.size.height)];
}
// 幅を元に、UIImageをリサイズし、UIImageを返す
+ (UIImage *)resizeImageFromWidth:(CGFloat)width image:(UIImage *)image {
CGSize resizedSize = [self resizeFromWidth:width image:image];
UIGraphicsBeginImageContext(resizedSize);
[image drawInRect:CGRectMake(0, 0, resizedSize.width, resizedSize.height)];
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resizedImage;
}
// 幅・高さを元に、リサイズ画像の幅・高さを算出する
+ (CGSize)resizeFromSize:(CGSize)size imageSize:(CGSize)imageSize {
CGFloat widthRatio = imageSize.width / size.width;
CGFloat heightRatio = imageSize.height / size.height;
CGFloat ratio = (widthRatio < heightRatio) ? widthRatio : heightRatio;
CGSize resizedSize = CGSizeMake(size.width * ratio, size.height * ratio);
return resizedSize;
}
// 幅・高さを元に、UIImageをリサイズして、CGSizeを返す
+ (CGSize)resizeFromSize:(CGSize)size image:(UIImage *)image {
CGFloat widthRatio = size.width / image.size.width;
CGFloat heightRatio = size.height / image.size.height;
CGFloat ratio = (widthRatio < heightRatio) ? widthRatio : heightRatio;
CGSize resizedSize = CGSizeMake(image.size.width * ratio, image.size.height * ratio);
return resizedSize;
}
// 幅・高さを元に、UIImageをリサイズして、UIImageを返す
+ (UIImage *)resizeImageFromSize:(CGSize)size image:(UIImage *)image {
CGSize resizedSize = [self resizeFromSize:(CGSize) size image:image];
UIGraphicsBeginImageContext(resizedSize);
[image drawInRect:CGRectMake(0, 0, resizedSize.width, resizedSize.height)];
UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return resizedImage;
}
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