void updateScrollBars() {
		if (horizScroll == null || vertScroll == null
		 || horizScroll.getValueIsAdjusting() || vertScroll.getValueIsAdjusting() ) {
			return;
		}
		
		if (img == null) {
			horizScroll.setEnabled(false);
			vertScroll.setEnabled(false);
		}
		
		Rectangle visibleRect = getRefreshArea(new CPRect(img.getWidth(null), img.getHeight(null)));
		updateScrollBar(horizScroll, visibleRect.x, visibleRect.width, getWidth(), -getOffset().x);
		updateScrollBar(vertScroll, visibleRect.y, visibleRect.height, getHeight(), -getOffset().y);
	}