压缩图片

//对图片尺寸进行压缩--

+ (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize

{

    // Create a graphics image context

    UIGraphicsBeginImageContext(newSize);

    

    // Tell the old image to draw in this new context, with the desired

    // new size

    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

    

    // Get the new image from the context

    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

    

    // End the context

    UIGraphicsEndImageContext();

    

    // Return the new image.

    return newImage;

}

// 对图片大小进行压缩，压缩到不大于size（字节）

+ (UIImage *)imageWithImage:(UIImage *)image scaledToFileSize:(CGFloat)size{

    NSData *imageData = UIImageJPEGRepresentation(image, 1.0);

    if (size < imageData.length) {

        CGFloat compressionQuality = size / imageData.length;

        NSData *newImageData = UIImageJPEGRepresentation(image, compressionQuality);

        UIImage *newImage = [UIImage imageWithData:newImageData];

        return newImage;

    }

    return image;

}