IOS 压缩图片到指定大小kb

#import <UIKit/UIKit.h>

@interface UIImage (WLTScaleImage)
+(UIImage *)scaleImage:(UIImage *)image toKb:(NSInteger)kb;

@end

#import "UIImage+WLTScaleImage.h"

@implementation UIImage (WLTScaleImage)

+(UIImage *)scaleImage:(UIImage *)image toKb:(NSInteger)kb{

if (!image) {
return image;
}
if (kb<1) {
return image;
}

kb*=1024;

CGFloat compression = 0.9f;
CGFloat maxCompression = 0.1f;
NSData *imageData = UIImageJPEGRepresentation(image, compression);
while ([imageData length] > kb && compression > maxCompression) {
compression -= 0.1;
imageData = UIImageJPEGRepresentation(image, compression);
}
NSLog(@"当前大小:%fkb",(float)[imageData length]/1024.0f);
UIImage *compressedImage = [UIImage imageWithData:imageData];
return compressedImage;

}
@end