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<span style="font-size: 15px;">@implementation ImageSizeManager#define iphoneSize [[UIScreen mainScreen] bounds]#define newSizeWidth [[UIScreen mainScreen] bounds].size.width * 2.0#define newSizeHeight [[UIScreen mainScreen] bounds].size.height * 2.0//转换成大图片+(UIImage*)getMaxImageWithOldImage:(UIImage*)oldImage{ CGSize newSize = [self changeImage:oldImage.size andScale:2]; UIImage *newImage = [self imageWithImageSimple:oldImage scaledToSize:newSize]; return
newImage;}//转换中图片+(UIImage*)getMidImageWithOldImage:(UIImage*)oldImage{ CGSize newSize = [self changeImage:oldImage.size andScale:4]; UIImage *newImage = [self imageWithImageSimple:oldImage scaledToSize:newSize]; return
newImage;}//转换成小图片+(UIImage*)getSmallImageWithOldImage:(UIImage*)oldImage{ CGSize newSize = [self changeImage:oldImage.size andScale:8]; UIImage *newImage = [self imageWithImageSimple:oldImage scaledToSize:newSize]; return
newImage;}+(CGSize)changeImage:(CGSize)size andScale:(float)scale{ float
newWidth = newSizeWidth/scale; float
newHeight = newSizeHeight/scale; CGSize newSize; if
(size.width <=newWidth && size.height <=newHeight) { return
size; } if
(size.width>newWidth || size.height >newHeight) { if
(size.width > size.height) { //如果宽大，就把宽度缩小到,高按同比例缩放 newSize.width = newWidth; newSize.height = (int) ((newWidth/size.width) * size.height); } else
if(size.width < size.height) { newSize.height = newHeight; newSize.width =(int) ((newHeight/size.height) * size.width); }else//宽高相同 { newSize.width = newWidth; newSize.height = newWidth; } } return
newSize;}+ (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize{ UIGraphicsBeginImageContext(newSize); [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); NSData *data = UIImageJPEGRepresentation(newImage, 1.0); DLog(@"长度:%d ",data.length); DLog(@"长:%f 宽:%f",newImage.size.height,newImage.size.width); return
newImage;} </span> |
原文：http://www.cnblogs.com/zhangsongbai/p/3580301.html