private void init() {
    polygonView = this;
    pointer1 = getImageView(0, 0);
    pointer2 = getImageView(getWidth(), 0);
    pointer3 = getImageView(0, getHeight());
    pointer4 = getImageView(getWidth(), getHeight());
    midPointer13 = getImageView(0, getHeight() / 2);
    midPointer13.setOnTouchListener(new MidPointTouchListenerImpl(pointer1, pointer3));
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P)
        magnifier = new Magnifier(polygonView);
    midPointer12 = getImageView(0, getWidth() / 2);
    midPointer12.setOnTouchListener(new MidPointTouchListenerImpl(pointer1, pointer2));

    midPointer34 = getImageView(0, getHeight() / 2);
    midPointer34.setOnTouchListener(new MidPointTouchListenerImpl(pointer3, pointer4));

    midPointer24 = getImageView(0, getHeight() / 2);
    midPointer24.setOnTouchListener(new MidPointTouchListenerImpl(pointer2, pointer4));

    addView(pointer1);
    addView(pointer2);
    addView(midPointer13);
    addView(midPointer12);
    addView(midPointer34);
    addView(midPointer24);
    addView(pointer3);
    addView(pointer4);
    initPaint();
}