I'm creating an app that uploads an image to a server. It must send the byte array on a XML. How do I get the byte array into a NSString?
Thanks!
3 Answers
You can convert the UIImage to a NSData object and then extract the byte array from there. Here is some sample code:
UIImage *image = [UIImage imageNamed:@"image.png"]; NSString *byteArray = [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength]; If you are using a PNG Image you can use the UIImagePNGRepresentation function as shown above or if you are using a JPEG Image, you can use the UIImageJPEGRepresentation function. Documentation is available on the UIImage Class Reference
1 Comment
Patricia
This was very helpful to me. Thank you, Suhail, for your post.
Here is a simple function for iOS to convert from UIImage to unsigned char* byte array -->
+ (unsigned char*)UIImageToByteArray:(UIImage*)image; { unsigned char *imageData = (unsigned char*)(malloc( 4*image.size.width*image.size.height)); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); CGImageRef imageRef = [image CGImage]; CGContextRef bitmap = CGBitmapContextCreate( imageData, image.size.width, image.size.height, 8, image.size.width*4, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst); CGContextDrawImage( bitmap, CGRectMake(0, 0, image.size.width, image.size.height), imageRef); CGContextRelease( bitmap); CGColorSpaceRelease( colorSpace); return imageData; } 
Comments
using NSData *data = UIImagePNGRepresentation(image); you can convert image into data , now convert dat to bytes by using getBytes:length: or getBytes:range:
