android_crop_example_crop_algo1.java

/*
 * This method gets the image inside the template area and returns that bitmap.
 * Process of how this method works:
 *     1) Combine img and templateImage together with templateImage being on the top.
 *     2) Create a new blank bitmap using the given width and height, which is the 
 *        size of the template on the screen.
 *     3) Starting in the center go through the image quadrant by quadrant copying 
 *        the pixel value onto the new blank bitmap.
 *     4) Once it hits the pixel colour values of the template lines, then set the pixel
 *        values from that point on transparent.
 *     5) Return the cropped bitmap.
 */
public static Bitmap cropImage(Bitmap img, Bitmap templateImage, int width, int height) {
    // Merge two images together.
    Bitmap bm = Bitmap.createBitmap(img.getWidth(), img.getHeight(), Bitmap.Config.ARGB_8888);
    Canvas combineImg = new Canvas(bm);
    combineImg.drawBitmap(img, 0f, 0f, null);
    combineImg.drawBitmap(templateImage, 0f, 0f, null);
    
    // Create new blank ARGB bitmap.
    Bitmap finalBm = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    
    // Get the coordinates for the middle of combineImg.
    int hMid = bm.getHeight() / 2;
    int wMid = bm.getWidth() / 2;
    int hfMid = finalBm.getHeight() / 2;
    int wfMid = finalBm.getWidth() / 2;
  
    int y2 = hfMid;
    int x2 = wfMid;
    
    // Top half of the template.
    for (int y = hMid; y >= 0; y--) {
        boolean template = false;
        // Check Upper-left section of combineImg.
        for (int x = wMid; x >= 0; x--) {
            if (x2 < 0) {
                break;
            }
  
            int px = bm.getPixel(x, y);
            if (Color.red(px) == 234 && Color.green(px) == 157 && Color.blue(px) == 33) {
                template = true;
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else if (template) {
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else {
                finalBm.setPixel(x2, y2, px);
            }
            x2--;
        }
      
        // Check upper-right section of combineImage.
        x2 = wfMid;
        template = false;
        for (int x = wMid; x < bm.getWidth(); x++) {
            if (x2 >= finalBm.getWidth()) {
                break;  
            }
    
            int px = bm.getPixel(x, y);
            if (Color.red(px) == 234 && Color.green(px) == 157 && Color.blue(px) == 33) {
                template = true;
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else if (template) {
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else {
                finalBm.setPixel(x2, y2, px);
            }
            x2++;
        }
  
        // Once we reach the top-most part on the template line, set pixel value transparent
        // from that point on.
        int px = bm.getPixel(wMid, y);
        if (Color.red(px) == 234 && Color.green(px) == 157 && Color.blue(px) == 33) {
            for (int y3 = y2; y3 >= 0; y3--) {
                for (int x3 = 0; x3 < finalBm.getWidth(); x3++) {
                    finalBm.setPixel(x3, y3, Color.TRANSPARENT);
                }
            }
            break;
        }
        x2 = wfMid;
        y2--;
    }
  
    x2 = wfMid;
    y2 = hfMid;
    // Bottom half of the template.
    for (int y = hMid; y <= bm.getHeight(); y++) {
        boolean template = false;
        // Check bottom-left section of combineImage.
        for (int x = wMid; x >= 0; x--) {
            if (x2 < 0) {
                break;
            }

            int px = bm.getPixel(x, y);
            if (Color.red(px) == 234 && Color.green(px) == 157 && Color.blue(px) == 33) {
                template = true;
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else if (template) {
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else {
                finalBm.setPixel(x2, y2, px);
            }
            x2--;
        }

        // Check bottom-right section of combineImage.
        x2 = wfMid;
        template = false;
        for (int x = wMid; x < bm.getWidth(); x++) {
            if (x2 >= finalBm.getWidth()) {
                break;
            }
  
            int px = bm.getPixel(x, y);
            if (Color.red(px) == 234 && Color.green(px) == 157 && Color.blue(px) == 33) {
                template = true;
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else if (template) {
                finalBm.setPixel(x2, y2, Color.TRANSPARENT);
            } else {
                finalBm.setPixel(x2, y2, px);
            }
            x2++;
        }

      // Once we reach the bottom-most part on the template line, set pixel value transparent
      // from that point on.
      int px = bm.getPixel(wMid, y);
      if (Color.red(px) == 234 && Color.green(px) == 157 && Color.blue(px) == 33) {
          for (int y3 = y2; y3 < finalBm.getHeight(); y3++) {
              for (int x3 = 0; x3 < finalBm.getWidth(); x3++) {
                  finalBm.setPixel(x3, y3, Color.TRANSPARENT);
              }
          }
          break;
      }

      x2 = wfMid;
      y2++;
  }
  return finalBm;
}