// set idCanvas bufferedImage to null
// to prevent drawing old image
FontMetrics fm = getFontMetrics(av.getFont());
+
+ // update the flag controlling whether the grid is too small to render the font
+ av.validCharWidth = fm.charWidth('M') <= av.getCharWidth();
scalePanelHolder.setPreferredSize(
new Dimension(10, av.getCharHeight() + fm.getDescent()));