Render a byte[] as Bitmap in Android

Question

I'm getting a byte array from a JNI call, and trying to construct a Bitmap object with it.

My problem is, the following code, returns null.

    byte[] image = services.getImageBuffer(1024, 600);
    Bitmap bmp = BitmapFactory.decodeByteArray(image, 0, image.length);

Any tips about it?

PS: The pixel layout is BGR, not a RGB.

Have you tested that the image byte array contains the correct content? Otherwise your code looks ok to me. — mreichelt, Jan 13 '11 at 18:51
Yes, I did. The content is correct, the decodeByteArray that doesn't understood that. — Marcos Vasconcelos, Jan 14 '11 at 18:49

score 4 · Answer 1 · answered Jan 13 '11 at 19:15

4

The doc says the method returns "null if the image could not be decode." You can try:

byte[] image = services.getImageBuffer(1024, 600);
InputStream is = new ByteArrayInputStream(image);
Bitmap bmp = BitmapFactory.decodeStream(is);

Even if I don't think it's going to change anything though.. Try to have a look at android.graphics.BitmapFactory.Options as well

answered Jan 13 '11 at 19:15

CodegistCRest

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Same error. And the Options doens't care about the pixel format. – Marcos Vasconcelos Jan 13 '11 at 19:52

score 1 · Accepted Answer · edited Aug 30 '11 at 03:48

The decodeByteArray really doens't works with this format. I change from BGR to RGB manually.

    byte[] image = services.getImageBuffer(1024, 600);

    Bitmap bmp = Bitmap.createBitmap(1024, 600, Bitmap.Config.RGB_565);
    int row = 0, col = 0;
    for (int i = 0; i < image.length; i += 3) {
        bmp.setPixel(col++, row, image[i + 2] & image[i + 1] & image[i]);

        if (col == 1024) {
            col = 0;
            row++;
        }

However,

for (i < image.length) 。。。bmp.setPixel(image[i + 2] & image[i + 1] & image[i]);

can cause:

08-29 14:34:23.460: ERROR/AndroidRuntime(8638): java.lang.ArrayIndexOutOfBoundsException

Render a byte[] as Bitmap in Android

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