Objective-c Base64 encoding

Question

NSString *base64String = [UIImagePNGRepresentation(myimage) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];

I am trying to convert uiimage to base64 string. But i think it gives wrong result. It gives this string:

iVBORw0KGgoAAAANSUhEUgAAABgAAAAYCAYAAADgdz34AAAAAXNSR0IArs4c6QAA\r\nABxpRE9UAAAAAgAAAAAAAAAMAAAAKAAAAAwAAAAMAAAAnHRoHj4AAABoSURBVEgN\r\nYvj//z8DLTFNDQc5fNQCgiHAcJSBxekYA+MmIN5PZbwJZDbDMQam+0D8n0b4PtAC\r\nxnU0MhzoaMZ1QAsYhIAWnKOBJUAzGYTAkUQDS8CGo+QDKloCNxzFAhCHCpagGA4y\r\nEwAAAP//PscxrwAAAGxJREFU7ZJBCsAgDASX/qB+22cVPPZLafZQsGDM2rOHhZDE\r\nGQjCzNCnAaXhuD22GH+D0rNYf+Dv8IdkCA8FHCxIQvhUIEqm8FSQSFK4JAgkElwW\r\ncPECTv9VlWHNnhJpSQFFO1uQXiBdiG6r9h9C14aGNgNBwQAAAABJRU5ErkJggg==

But this is an empty image. What is wrong?

can you check you version and check this it will help you http://stackoverflow.com/questions/11251340/convert-between-uiimage-and-base64-string — HariKrishnan.P, Jun 27 '16 at 11:23
Why you are converting image base64 string ? is it only for uploading image to sever? explain your flow what you are trying to achieve — Pawan Rai, Jun 27 '16 at 12:27
What does "empty image" mean? The object reference is `nil` or it's an image of all white or something? — Droppy, Jun 27 '16 at 14:19

KDeogharkar · Answer 1 · 2016-06-27T11:02:45.847

0

Change:

NSString *base64String = [UIImagePNGRepresentation(myimage) base64EncodedStringWithOptions:NSDataBase64DecodingIgnoreUnknownCharacters];

To:

NSString *base64String = [UIImagePNGRepresentation(myimage) base64EncodedStringWithOptions:NSDataBase64EncodingEndLineWithLineFeed];

types of encoding:

   NSDataBase64Encoding64CharacterLineLength     
   NSDataBase64Encoding76CharacterLineLength     
   NSDataBase64EncodingEndLineWithCarriageReturn     
   NSDataBase64EncodingEndLineWithLineFeed

types of decoding:

NSDataBase64DecodingIgnoreUnknownCharacters

you are using type of decoding while encoding image

edited Jun 27 '16 at 11:02

answered Jun 27 '16 at 10:55

KDeogharkar

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Please add an explanation of why this fixes the problem. – Avi Jun 27 '16 at 10:56
i tried all encoding types but it didn't work. It gives same result. – user Jun 27 '16 at 11:31

HariKrishnan.P · Answer 2 · 2016-06-27T11:59:23.017

In the post data your base64 "+" character was translate to " " character.

So you have got the invalid base64 string.

UIImage *img = [UIImage imageNamed:@"white.jpeg"];
NSData *imageData = UIImagePNGRepresentation(img);
NSString *imageString = [imageData base64EncodedStringWithOptions:0]; // type one

NSString *imageString = [imageData base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
//type two 
NSString *str = [imageString stringByReplacingOccurrencesOfString:@"+" withString:@" "];

Hope this will help you. Any one type to achieve the encode string

score 0 · Answer 3 · answered Jun 27 '16 at 13:09

Generally when we convert image into Base64 Encoding,we need to convert Decoding the image.You encoded the image only.After that you must convert into decoded format.

Encoding

UIImage *imageEncode = [UIImage imageNamed:@"yourImage.png"];  // or yourImage.jpeg
NSData *dataImageEncode = UIImageJPEGRepresentation(imageEncode, 1.0);
           //OR
NSData *dataImage = UIImagePNGRepresentation(image);
NSString *strEncodedBase64 = [dataImageEncode base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];

Decoding

NSData *dataImageDecode = [[NSData alloc]initWithBase64EncodedString:strEncodedBase64 options:NSDataBase64DecodingIgnoreUnknownCharacters];
UIImage *imageDecode  = [UIImage imageWithData:dataImageDecode];

score 0 · Answer 4 · answered Jun 28 '16 at 07:53

I have made one method in which you just need to pass uiimage and it will return a base64 string.

    - (NSString *)encodeToBase64String:(UIImage *)image {
    return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}

Objective-c Base64 encoding

4 Answers4