linenumber.java

模仿WINDOWS的WINZIP的一款软件

package org.jr.jzj.editor;
/**
 * <p>Copyright: Copyright (c) 2002-2003</p>
 * <p>Company: JavaResearch(http://www.javaresearch.org)</p>
 * <p>最后更新日期:2003年3月20日
 * @author Barney,Cherami,Brain
 * @version 0.8
 */

import java.awt.*;
import javax.swing.*;

public class LineNumber
    extends JComponent {
  private final static Color DEFAULT_BACKGROUND = Color.white;
  private final static Color DEFAULT_FOREGROUND = new Color(153, 153, 204);
  private final static Color DEFAULT_LINECLR = new Color(192, 192, 192);
  private final static Font DEFAULT_FONT = new Font("SansSerif", Font.PLAIN, 12);
  //private final static
  private final static int HEIGHT = Integer.MAX_VALUE - 1000000;
  private final static int MARGIN = 5;
  private FontMetrics fontMetrics;
  private int lineHeight;
  private int currentRowWidth;
  private JComponent component;
  private int componentFontHeight;
  private int componentFontAscent;

  public LineNumber(JComponent component) {
    if (component == null) {
      setBackground(DEFAULT_BACKGROUND);
      setForeground(DEFAULT_FOREGROUND);
      setFont(DEFAULT_FONT);
      this.component = this;
    }
    else {
      setBackground(DEFAULT_BACKGROUND);
      setForeground(component.getForeground());
      setFont(component.getFont());
      this.component = component;
    }
    componentFontHeight = component.getFontMetrics(component.getFont()).
        getHeight();
    componentFontAscent = component.getFontMetrics(component.getFont()).
        getAscent();
    setPreferredWidth(9999);

    this.setBorder(BorderFactory.createLineBorder(DEFAULT_LINECLR, 1));
  }

  public void setPreferredWidth(int row) {
    int width = fontMetrics.stringWidth(String.valueOf(row));
    if (currentRowWidth < width) {
      currentRowWidth = width;
      setPreferredSize(new Dimension(2 * MARGIN + width, HEIGHT));
    }
  }

  public void setFont(Font font) {
    super.setFont(font);
    fontMetrics = getFontMetrics(getFont());
  }

  public int getLineHeight() {
    if (lineHeight == 0) {
      return componentFontHeight;
    }
    else {
      return lineHeight;
    }
  }

  public void setLineHeight(int lineHeight) {
    if (lineHeight > 0) {
      this.lineHeight = lineHeight;
    }
  }

  public int getStartOffset() {
    return component.getInsets().top + componentFontAscent;
  }

  public void paintComponent(Graphics g) {

    int lineHeight = getLineHeight();
    int startOffset = getStartOffset();
    Rectangle drawHere = g.getClipBounds();
    g.setColor(getBackground());
    g.fillRect(drawHere.x, drawHere.y, drawHere.width, drawHere.height);
    g.setColor(getForeground());
    int startLineNumber = (drawHere.y / lineHeight) + 1;
    int endLineNumber = startLineNumber + (drawHere.height / lineHeight);
    int start = (drawHere.y / lineHeight) * lineHeight + startOffset;
    for (int i = startLineNumber; i <= endLineNumber; i++) {
      String lineNumber = String.valueOf(i);
      int width = fontMetrics.stringWidth(lineNumber);
      g.drawString(lineNumber, MARGIN + currentRowWidth - width, start);
      start += lineHeight;
    }
    setPreferredWidth(endLineNumber);

    //draw line
//                g.setColor(DEFAULT_LINECLR);
//                g.drawLine(this.getWidth(),0,this.getWidth(),this.getHeight());

  }
}