Android : Converting color image to grayscale [duplicate]

Question

I am trying to convert color image into grayscale using the average of red, green, blue. But it comes out with errors.

Here is my code

imgWidth = myBitmap.getWidth(); imgHeight = myBitmap.getHeight();                      for(int i =0;i<imgWidth;i++) {     for(int j=0;j<imgHeight;j++) {      int s = myBitmap.getPixel(i, j)/3;      myBitmap.setPixel(i, j, s);     } }                      ImageView img = (ImageView)findViewById(R.id.image1); img.setImageBitmap(myBitmap); 

But when I run my application on Emulator, it's force close. Any idea?

I have solved my problem use the following code:

for(int x = 0; x < width; ++x) {             for(int y = 0; y < height; ++y) {                 // get one pixel color                 pixel = src.getPixel(x, y);                 // retrieve color of all channels                 A = Color.alpha(pixel);                 R = Color.red(pixel);                 G = Color.green(pixel);                 B = Color.blue(pixel);                 // take conversion up to one single value                 R = G = B = (int)(0.299 * R + 0.587 * G + 0.114 * B);                 // set new pixel color to output bitmap                 bmOut.setPixel(x, y, Color.argb(A, R, G, B));             }         } 

Answer 1

You can do this too :

    ColorMatrix matrix = new ColorMatrix();     matrix.setSaturation(0);      imageview.setColorFilter(new ColorMatrixColorFilter(matrix)); 

Answer 2

Try the solution from this previous answer by leparlon:

public Bitmap toGrayscale(Bitmap bmpOriginal)     {                 int width, height;         height = bmpOriginal.getHeight();         width = bmpOriginal.getWidth();              Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);         Canvas c = new Canvas(bmpGrayscale);         Paint paint = new Paint();         ColorMatrix cm = new ColorMatrix();         cm.setSaturation(0);         ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);         paint.setColorFilter(f);         c.drawBitmap(bmpOriginal, 0, 0, paint);         return bmpGrayscale;     }