压缩图片至指定大小

//循环实现该方法

-(UIImage *)CutImage:(UIImage *)image ToTargetsize:(float)size{

UIImage *img1 = [Tools imageCompressForWidth:image targetWidth:image.size.width/2];

NSData *data = UIImageJPEGRepresentation(img1, 0.5);

if(data.length >= size) {

[self CutImage:img1 ToTargetsize:size];

}

UIImage *img = [UIImage imageWithData:data];

return img;

}

+(UIImage *) imageCompressForWidth:(UIImage *)sourceImage targetWidth:(CGFloat)defineWidth

{

CGSize imageSize = sourceImage.size;

CGFloat width = imageSize.width;

CGFloat height = imageSize.height;

CGFloat targetWidth = defineWidth;

CGFloat targetHeight = (targetWidth / width) * height;

UIGraphicsBeginImageContext(CGSizeMake(targetWidth, targetHeight));

[sourceImage drawInRect:CGRectMake(0,0,targetWidth, targetHeight)];

UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return newImage;

}