Converting UIImage to Byte Array

Question

I need to convert a UIImage to a byte array. I am using Xamarin's Visual Studio plugin to produce an iOS application.

The bit of code below gets the image, but I need to send it across a Service Stack as a byte array instead of a UIImage.

        var signatureView = new SignaturePad.SignaturePadView(new RectangleF(10, 660, 300, 150));
        signatureView.BackgroundColor = UIColor.White;
        this.View.AddSubview(signatureView);
        UIImage signatureImage = signatureView.GetImage();

score 32 · Accepted Answer · answered Jun 14 '13 at 20:55

32

Shamelessly stolen from ChrisNTR

using (NSData imageData = image.AsPNG()) {
  Byte[] myByteArray = new Byte[imageData.Length];
  System.Runtime.InteropServices.Marshal.Copy(imageData.Bytes, myByteArray, 0, Convert.ToInt32(imageData.Length));
}

answered Jun 14 '13 at 20:55

Jason

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score 17 · Answer 2 · answered Jun 14 '13 at 23:10

17

It's been a long time since I checked the ServiceStack API but, if possible, try to avoid byte[] since it will need to create another copy of the same data. It does not matter in many cases but images are often huge.

E.g. if there's an overload that accept a System.IO.Stream then use image.AsPNG ().AsStream () and avoid the overhead :-)

answered Jun 14 '13 at 23:10

poupou

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Using image.AsPNG() does not keep the orientation flag, so it seems better to use image.AsJPEG() to get the stream. That took me two hours ;-). – asp_net Feb 24 '14 at 16:36

score 14 · Answer 3 · answered Feb 21 '14 at 22:50

14

Stream pst =   img.AsPNG().AsStream();

answered Feb 21 '14 at 22:50

Hâluk Yilmaz

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You could also use .ToArray(); – Csharpest Feb 08 '18 at 15:24

Converting UIImage to Byte Array

3 Answers3

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