Java - FontMetrics without Graphics

Question

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();

Smallscale

Why do you want to do this without graphics? – Achelous

I create my own control, and I want to set preffred size in constructor – Smallscale

This is useful for getting font metrics when in a headless mode, i.e. a command line tool that processes fonts to bitmaps. – Grafting

Answer 1

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);

Fetter

@Fetter Are you sure that font width and height depend on display while I have specified the font-size? – Anastaciaanastas

Answer 2

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 would now call c.getGraphics() it would return null. The canvas solution on the other hand will also work in headless mode.

Mechanize

If I may expand ever so slightly on this - if you're reading a font from a file, remember to "derive" a font with a viable size (failing to remember to do so will result in values such as getMaxAscent/Descent returning 1): Font sourceFont = Font.createFont(Font.TRUETYPE_FONT, fontStream); Font awtFont = sourceFont.deriveFont(72.0f); Canvas canvas = new Canvas(); FontMetrics metrics = canvas.getFontMetrics(awtFont); – Infective