Converting bitmap to byteArray android

Question

I have a bitmap that I want to send to the server by encoding it to base64 but I do not want to compress the image in either png or jpeg.

Now what I was previously doing was.

ByteArrayOutputStream byteArrayBitmapStream = new ByteArrayOutputStream();
bitmapPicture.compress(Bitmap.CompressFormat.PNG, COMPRESSION_QUALITY, byteArrayBitmapStream);
byte[] b = byteArrayBitmapStream.toByteArray();
//then simple encoding to base64 and off to server
encodedImage = Base64.encodeToString(b, Base64.NO_WRAP);

Now I just dont want to use any compression nor any format plain simple byte[] from bitmap that I can encode and send to the server.

Any pointers?

score 138 · Accepted Answer · edited May 24 '13 at 12:53

138

You can use copyPixelsToBuffer() to move the pixel data to a Buffer, or you can use getPixels() and then convert the integers to bytes with bit-shifting.

copyPixelsToBuffer() is probably what you'll want to use, so here is an example on how you can use it:

//b is the Bitmap

//calculate how many bytes our image consists of.
int bytes = b.getByteCount();
//or we can calculate bytes this way. Use a different value than 4 if you don't use 32bit images.
//int bytes = b.getWidth()*b.getHeight()*4; 

ByteBuffer buffer = ByteBuffer.allocate(bytes); //Create a new buffer
b.copyPixelsToBuffer(buffer); //Move the byte data to the buffer

byte[] array = buffer.array(); //Get the underlying array containing the data.

edited May 24 '13 at 12:53

petrnohejl

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answered Apr 17 '12 at 13:21

Jave

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byte[] b ; ByteBuffer byteBuffer = ByteBuffer.allocate(bitmapPicture.getByteCount()); bitmapPicture.copyPixelsToBuffer(byteBuffer); b = byteBuffer.array(); ??? – Asad Khan Apr 17 '12 at 13:22
@AsadKhan I added an example. – Jave Apr 17 '12 at 13:33
Thank you I will check it out – Asad Khan Apr 17 '12 at 13:34
@AsadKhan whats the bitmapPicture in your comment. I do not find any method as getByteCount() in bitmap object. – Shail Adi Apr 04 '13 at 09:41
Hey @Jave, so even if you convert bitmap to a byte array you can't necessarily tell whether mBuffer was null or not. – Etienne Lawlor Aug 15 '13 at 18:38
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@ShailAdi to call getByteCount() you will nedd API level 12. – Alfredo Cavalcanti Nov 20 '13 at 15:40
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If you look at the getByteCount() impl it's simply getRowBytes() * getHeight(), do the math yourself if you're targeting < API 12. – Anthony Chuinard Jan 02 '14 at 01:27
This doesn't work, it is better to get byte array using bitmap.compress(...) – Demigod Jul 06 '15 at 14:52
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@iDemigod The OP explicitly did not want to use Bitmap.Compress(). – Jave Jul 06 '15 at 18:49

score 9 · Answer 2 · edited Oct 06 '16 at 21:40

instead of the following line in @jave answer:

int bytes = b.getByteCount();

Use the following line and function:

int bytes = byteSizeOf(b);

protected int byteSizeOf(Bitmap data) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB_MR1) {
    return data.getRowBytes() * data.getHeight();
} else if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
    return data.getByteCount();
} else {
      return data.getAllocationByteCount();
}

score 6 · Answer 3 · answered Apr 21 '17 at 16:11

6

BitmapCompat.getAllocationByteCount(bitmap);

is helpful to find the required size of the ByteBuffer

answered Apr 21 '17 at 16:11

Jobin Jacob Kavalam

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Converting bitmap to byteArray android

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