CODEWITHSUNDEEP
androidimage
Jesus Lorca Luque
Jesus Lorca Luque

Reputation: 11

display a matrix of double values which represents a gray scale image

My issue is: I have a byte array which must be display with ImageView. This is my code:

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ImageView imageView = (ImageView)findViewById(R.id.show_image);
    byte[] arrayBytes = ...; // It's initialized
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSample = 4;
    imageView.setImageBitmap(BitmapFactory.decodeByteArray(arrayBytes,0,arrayBytes.length,options));
  }

Each byte stores in byte array is an element of double[][] but in byte format. Android by default, uses ARGB_8888 format.

I don't know which is the best format for displaying a gray scale matrix.

Any suggestion?

//EDIT The problem in this code is that image is not display. I think the conversion I have done is wrong:

byte[] byteArray = new byte[SIZE];
int k = 0;

for(...i) {
    for(...j) {
        byteArray[k] = Double.valueOf(matrix[i][j]).byteValue();
        k++;
    }
}

var matrix is double[][] and it represents grayscale image. Each pixel is transform to byte using byteValue method of Double class.

I think it's wrong because format I'm using (ARGB_8888 or RGB_565) needs more than one byte for each pixel.

So, I don't know how to transform it

Upvotes: 0

Views: 753

Answers (1)

Suneel Prakash
Suneel Prakash

Reputation: 389

If you have minimum number of images to be displayed, you can go ahead using ARGB_8888 It enhances the image clarity and its colors Here Each pixel is stored on 4 bytes.

If you are using more number of images, use RGB_565

Here Each pixel is stored on 2 bytes and only the RGB channels are encoded.

Any have you want it in grey scale so you can go ahead with RGB_565 which consumes less RAM.

  @Override
  protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  ImageView imageView = (ImageView)findViewById(R.id.show_image);
  byte[] arrayBytes = ...; // It's initialized
  BitmapFactory.Options options = new BitmapFactory.Options();
  options.inSample = 4;

  // Add this line in your code
  options.inPreferredConfig = Bitmap.Config.RGB_565; 


  imageView.setImageBitmap(BitmapFactory.decodeByteArray(arrayBytes,0,arrayBytes.length,options));
  }

Upvotes: 1

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