Convert UIImage to Base64 and vice versa

Code used to convert an image to base64 or an UIImage to base64 NSString

- (void)viewDidLoad

{

// Do any additional setup after loading the view, typically from a nib.

    /*

     CONVERT BASE64 TO IMAGE

     */

    //Base64 image URL as string

    NSString *base64Url = @"https://dl.dropbox.com/u/37581115/base64image";

    //convert base64 url string to NSURL object

    NSURL *url = [NSURL URLWithString:base64Url];

    //fetch data from url in case if image is in utf8 format

    NSString *base64Image = [NSString stringWithContentsOfURL:url];

    

    //convert base64image to NSURL object

    url = [NSURL URLWithString:base64Image];

    

    //convert it to NSData object

    NSData *rawImageData = [NSData dataWithContentsOfURL:url];

    /*

    //SAVE TO DISK

    NSString  *jpgPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/Test.png"]; // identity the home directory and file name

    [rawImageData writeToFile:jpgPath atomically:YES];

    */

    /*

     CHECK DATA TYPE OF IMAGE FILE FROM NSData

     NSString * imageExt = [self contentTypeForImageData:rawImageData];

     */

    //convert NSData to UIImage object

    UIImage *image = [UIImage imageWithData:rawImageData];

    //Set image to uiview

    imageView.image = image;

    /*

     CONVERT IMAGE TO BASE64

     */

    //Reconvert UIImage to NSData

    NSData *imageData = UIImageJPEGRepresentation(image, 1.0);

    //And then apply Base64 encoding to convert it into a base-64 encoded string:

    NSString *encodedString = [self base64forData:imageData];

    //NSLog(@"encodedString is %@",encodedString);

    //Show in UITextView

    textView.text = encodedString;

}

- (NSString *)contentTypeForImageData:(NSData *)data {

    uint8_t c;

    [data getBytes:&c length:1];

    

    switch (c) {

        case 0xFF:

            return @"image/jpeg";

        case 0x89:

            return @"image/png";

        case 0x47:

            return @"image/gif";

        case 0x49:

        case 0x4D:

            return @"image/tiff";

    }

    return nil;

}

- (NSString*)base64forData:(NSData*)theData {

    

    const uint8_t* input = (const uint8_t*)[theData bytes];

    NSInteger length = [theData length];

    

    static char table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

    

    NSMutableData* data = [NSMutableData dataWithLength:((length + 2) / 3) * 4];

    uint8_t* output = (uint8_t*)data.mutableBytes;

    

    NSInteger i;

    for (i=0; i < length; i += 3) {

        NSInteger value = 0;

        NSInteger j;

        for (j = i; j < (i + 3); j++) {

            value <<= 8;

            

            if (j < length) {

                value |= (0xFF & input[j]);

            }

        }

        

        NSInteger theIndex = (i / 3) * 4;

        output[theIndex + 0] =                    table[(value >> 18) & 0x3F];

        output[theIndex + 1] =                    table[(value >> 12) & 0x3F];

        output[theIndex + 2] = (i + 1) < length ? table[(value >> 6)  & 0x3F] : '=';

        output[theIndex + 3] = (i + 2) < length ? table[(value >> 0)  & 0x3F] : '=';

    }

    

    return [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];

}