如何消除大尺寸的Java Swing标签中的间隙

JDigit

may give you some
ideas:

• It override’s

  paintComponent()

  to down-sample a high-resolution

  BufferedImage

  and control the geometry.

• It uses

  setBorderPainted(false)

  to set the

  borderPainted

  property.

• It uses a

  FocusHandler

  for custom highlighting.

Addendum: As noted here, the
underlying problem is the font’s leading , defined in

FontMetrics

as being included in the font’s height. As suggested in a comment by
@Guillaume Polet, you can render the text wherever you want in your own

JComponent

.

TextLayout

, discussed here can be used to calculate
the bounds, as shown below.

Pros:

• Absolute control over placement.

• Geometry of

  TexteLayout

  bounds based on

  FontMetrics

  .

Cons:

• No

  Icon

  support.

• No HTML support.

Note that the

JComponent

authors “recommend that you put the component in a

JPanel

and set the border on the

JPanel

.”

import java.awt.Dimension;import java.awt.EventQueue;import java.awt.Font;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Rectangle;import java.awt.font.FontRenderContext;import java.awt.font.TextLayout;import javax.swing.BorderFactory;import javax.swing.JComponent;import javax.swing.Jframe;import javax.swing.JPanel;public class UnleadedTest {    private static class Unleaded extends JComponent {        private Font font = new Font("Verdana", Font.PLAIN, 144);        private FontRenderContext frc = new FontRenderContext(null, true, true);        private String text;        private TextLayout layout;        private Rectangle r;        public Unleaded(String text) { this.text = text; calcBounds();        }        @Override        public Dimension getPreferredSize() { return new Dimension(r.width, r.height);        }        @Override        protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2d = (Graphics2D) g; calcBounds(); layout.draw(g2d, -r.x, -r.y);        }        private void calcBounds() { layout = new TextLayout(text, font, frc); r = layout.getPixelBounds(null, 0, 0);        }    }    private void display() {        Jframe f = new Jframe("Unleaded");        f.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE);        Unleaded label = new Unleaded("Unleaded");        JPanel panel = new JPanel();        panel.setBorder(BorderFactory.createTitledBorder("Title"));        panel.add(label);        f.add(panel);        f.pack();        f.setLocationRelativeTo(null);        f.setVisible(true);    }    public static void main(String[] args) {        EventQueue.invokeLater(new Runnable() { @Override public void run() {     new UnleadedTest().display(); }        });    }}