How to convert UIImage into byte array in objective-c

Question

I am converting UIImageinto byte like this

NSUInteger len = [imageData length];
Byte *byteData= (Byte*)malloc(len);
memcpy(byteData, [imageData bytes], len);

when I print this byteData in log I see a value like this.

(lldb) po byteData
"\377\330\377\340

But how can I make a byte array from this? Please help me. Thanks

UPDATE

this is how our web application pass data to the same service.

byte[] fileContent; 
using (var inputStream = file.InputStream)
 { var memoryStream = inputStream as MemoryStream;
   if (memoryStream == null) { memoryStream = new MemoryStream();
   inputStream.CopyTo(memoryStream); } fileContent = memoryStream.ToArray(); 
 }

So I want to do the same in my iOS application.

I want to send it to my web service and it takes a byte array — Irrd, Aug 30 '16 at 09:01
@Irrd Have you find the solution of converting UIImage into byte array. — shashi Gupta, May 05 '19 at 09:24

score 0 · Answer 1 · edited Jul 22 '22 at 04:15

0

You have to convert your UIImage into NSData like this......

UIImage *imgObj = [UIImage imageNamed:@"image.jpg"];

NSData *imgData = UIImageJPEGRepresentation(imgObj, 0.9);

edited Jul 22 '22 at 04:15

Community

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answered Aug 30 '16 at 09:06

Abha

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score 0 · Answer 2 · edited Feb 08 '17 at 08:19

0

May be below code could help:

@try {
    NSData *data = UIImagePNGRepresentation(img);
    NSUInteger len = data.length;
    uint8_t bytes = (uint8_t )[data bytes];
    NSMutableString *result = [NSMutableString stringWithCapacity:len];
    for (NSUInteger i = 0; i < len; i++) {
        if (i) {
            [result appendString:@","];
        }
        [result appendFormat:@"%d",bytes];
    }
    return result;
} @catch (NSException * e) {
    NSLog(@"Exception: %@", e);
}
@finally {
    NSLog(@"finally");
}

edited Feb 08 '17 at 08:19

Muhammad Zeshan Mazhar

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answered Aug 30 '16 at 09:09

Ronak Chaniyara

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why string capacity is len*3? – Irrd Aug 30 '16 at 09:23
you can simply define it as `NSMutableString`@Irrd – Ronak Chaniyara Aug 30 '16 at 09:47

score 0 · Answer 3 · edited Aug 30 '16 at 10:12

0

This is the simplest way...

UIImage *img =  [UIImage imageNamed:@"yourimage.png"];

NSData *imageData = UIImagePNGRepresentation(img);

or

UIImage *img =  [UIImage imageNamed:@"yourimage.jpg"];

CGFloat quality = 0.80;

NSData *imageData = UIImageJPEGRepresentation(img,quality);

edited Aug 30 '16 at 10:12

milos.ai

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answered Aug 30 '16 at 09:30

Manas Mahala

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How to convert UIImage into byte array in objective-c

3 Answers3