How to calculate the font's width?

Question

I am using java to draw some text, but it is hard for me to calculate the string\'s width. for example: zheng中国... How long will this string occupy?

Answer 1

For a single string, you can obtain the metrics for the given drawing font, and use that to calculate the string size. For example:

String      message = new String("Hello, StackOverflow!");
Font        defaultFont = new Font("Helvetica", Font.PLAIN, 12);
FontMetrics fontMetrics = new FontMetrics(defaultFont);
//...
int width = fontMetrics.stringWidth(message);

If you have more complex text layout requirements, such as flowing a paragraph of text within a given width, you can create a java.awt.font.TextLayout object, such as this example (from the docs):

Graphics2D g = ...;
Point2D loc = ...;
Font font = Font.getFont("Helvetica-bold-italic");
FontRenderContext frc = g.getFontRenderContext();
TextLayout layout = new TextLayout("This is a string", font, frc);
layout.draw(g, (float)loc.getX(), (float)loc.getY());

Rectangle2D bounds = layout.getBounds();
bounds.setRect(bounds.getX()+loc.getX(),
              bounds.getY()+loc.getY(),
              bounds.getWidth(),
              bounds.getHeight());
g.draw(bounds);