combining two png files in android

Question

I have two png image files that I would like my android app to combine programmatically into one png image file and am wondering if it is possible to do so? if so, what I w

Answer 1

I use this code

private class PhotoComposition extends AsyncTask {
    private String pathSave;//path save combined images

    @Override
    protected Boolean doInBackground(Object... objects) {

      List images = (List) objects[0]; //lsit of path iamges
      pathSave = (String) objects[1];//path save combined images
      if (images.size() == 0) {
        return false;
      }
      List bitmaps = new ArrayList<>();
      for (int i = 0; i < images.size(); i++) {
        bitmaps.add(BitmapFactory.decodeFile( images.get(i)));
      }
      int width = findWidth(bitmaps);//Find the width of the composite image
      int height = findMaxHeight(bitmaps);//Find the height of the composite image

      Bitmap combineBitmap  = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);//create bitmap of composite image

      combineBitmap.eraseColor(Color.parseColor("#00000000")); //bcakgraound color of composite image

      Bitmap mutableCombineBitmap = combineBitmap.copy(Bitmap.Config.ARGB_8888, true);//create mutable bitmap to create canvas

      Canvas canvas = new Canvas(mutableCombineBitmap);// create canvas to add bitmaps

      float left = 0f;

      for (int i = 0; i < bitmaps.size(); i++) {
        canvas.drawBitmap(bitmaps.get(i), left, 0f, null);//Taking photos horizontally

        left += bitmaps.get(i).getWidth();//Take right to the size of the previous photo
      }

      OutputStream outputStream = null;
      try {
        outputStream = new FileOutputStream(pathSave);//path of save composite image
        mutableCombineBitmap.compress(Bitmap.CompressFormat.PNG, 80, outputStream);
      } catch (IOException e) {
        e.printStackTrace();
        return false;
      }
      return true;
    }


    @Override
    protected void onPostExecute(Boolean isSave) {
      if (isSave) {
        //iamge save on pathSave
        Log.i("PhotoComposition", "onPostExecute: " + pathSave);
      }
      super.onPostExecute(isSave);
    }

    private int findMaxHeight(List bitmaps) {
      int maxHeight = Integer.MIN_VALUE;
      for (int i = 0; i < bitmaps.size(); i++) {
        if (bitmaps.get(i).getHeight() > maxHeight) {
          maxHeight = bitmaps.get(i).getHeight();
        }
      }
      return maxHeight;
    }

    private int findWidth(List bitmaps) {
      int width = 0;
      for (int i = 0; i < bitmaps.size(); i++) {
        width += bitmaps.get(i).getWidth();
      }
      return width;
    }

USAGE

List images = new ArrayList<>();
    images.add("/storage/emulated/0/imageOne.png");//path of image in storage
    images.add("/storage/emulated/0/imageTwo.png");
//   images.add("/storage/emulated/0/imageThree");
//   ... //add more images
    String pathSaveCombinedImage = "/storage/emulated/0/CombinedImage.png";//path save result image
  new PhotoComposition().execute(images, pathSaveCombinedImage);

And the result of using the above code will be as follows