title: How to set color to certain pixels of an image
body: <p>I have an image in an ImageView. I would like to set certain pixels to red. I have made some progress, but the created image has lost its colour. </p>
  
  <pre><code> iv.setImageBitmap(processingBitmap(bitmap));
  
    private Bitmap processingBitmap(Bitmap src){
  
          Bitmap dest = Bitmap.createBitmap(src.getWidth(), src.getHeight(), src.getConfig());
  
          for(int x = 0; x &lt; src.getWidth(); x++){
           for(int y = 0; y &lt; src.getHeight(); y++){
            int pixelColor = src.getPixel(x, y);
            int newPixel= Color.rgb(pixelColor, pixelColor, pixelColor);
            dest.setPixel(x, y, newPixel);
           }
          }
  
          for (int i=5; i&lt;50; i++)
          {
          dest.setPixel(i, i, Color.rgb(255, 0, 0));
          }
  
          return dest;
         }
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/r0QAr.png" alt="enter image description here"></p>
  
  <p>If I use  <code>Bitmap dest = src.copy(src.getConfig(), src.isMutable());</code> instead of  <code>Bitmap dest = Bitmap.createBitmap(src.getWidth(), src.getHeight(), src.getConfig());</code> I get an error to the  <code>iv.setImageBitmap(processingBitmap(bitmap));</code> line:</p>
  
  <blockquote>
    <p>09-06 18:03:37.226: E/AndroidRuntime(811): Caused by:
    java.lang.IllegalStateException 09-06 18:03:37.226:
    E/AndroidRuntime(811):    at
    android.graphics.Bitmap.setPixel(Bitmap.java:847)</p>
  </blockquote>
  
  <p>I also don't know why do I have to copy-paste all the pixels and after then set those pixels to red I want. If I use only </p>
  
  <pre><code> for (int i=5; i&lt;50; i++)
          {
          dest.setPixel(i, i, Color.rgb(255, 0, 0));
          }
  </code></pre>
  
  <p>I get a black image with the red line.</p>
  
  <p>Any help is appreciated!</p>