How to get FontMetrics without use Graphics ? I want to get FontMetrics in constructor, now I do this way:
BufferedImage bi = new BufferedImage(5, 5, BufferedImage.TYPE_INT_RGB);
FontMetrics fm = bi.getGraphics().getFontMetrics(font);
int width = fm.stringWidth(pattern);
int height = fm.getHeight();
Hmm... It is quite logical that you need graphics to get FontMetrics. Font height, width etc. can differ on various displays.
If you have some Component, you can use it for getting FontMetrics:
component.getFontMetrics(font);
No you do not necessarily need to get/use the graphics object:
Font font = new Font("Helvetica",Font.PLAIN,12);
Canvas c = new Canvas();
FontMetrics fm = c.getFontMetrics(font);
If you now call c.getGraphics() it will return null. This (canvas) will also work in headless mode.
来源：https://stackoverflow.com/questions/2843601/java-fontmetrics-without-graphics