code: public void update() {
          if (settings != null && getWidth() > 0 && getHeight() > 0) {
              // Updating finder area rectangle
              GravityUtils.getMovementAreaPosition(settings, tmpRect);
              rect.set(tmpRect);
              rect.offset(getPaddingLeft(), getPaddingTop());
  
              // We want to stroke outside of finder rectangle, while by default stroke is centered
              strokeRect.set(rect);
              float halfStroke = 0.5f * paintStroke.getStrokeWidth();
              strokeRect.inset(-halfStroke, -halfStroke);
  
              invalidate();
          }
      }
docs: Updates finder area size and position. Should be called whenever
  corresponding settings are changed, see {@link #setSettings(Settings)}