spider/spider-web/MultiLineLabel.java

import java.awt.*;
import java.util.*;

public class MultiLineLabel extends Canvas {
	public static final int LEFT = 0;
	public static final int CENTER = 1;
	public static final int RIGHT = 2;
	protected String[] lines;
	protected int num_lines;
	protected int margin_width;
	protected int margin_height;
	protected int line_height;
	protected int line_ascent;
	protected int[] line_widths;
	protected int max_width;
	protected int alignment = LEFT;
	
	protected void newLabel(String label) {
		StringTokenizer t = new StringTokenizer(label,"\n");
		num_lines = t.countTokens();
		lines = new String[num_lines];
		line_widths = new int[num_lines];
		for(int i = 0; i < num_lines; i++) lines[i] = t.nextToken();
	}
	
	protected void measure() {
		FontMetrics fm = this.getFontMetrics(this.getFont());
		if (fm == null) return;
		
		line_height = fm.getHeight();
		line_ascent = fm.getAscent();
		max_width = 0;
		for(int i = 0; i < num_lines; i++) {
			line_widths[i] = fm.stringWidth(lines[i]);
			if (line_widths[i] > max_width) max_width = line_widths[i];	
		}
	}
	
	public MultiLineLabel(String label, int margin_width, 
	       int margin_height, int alignment) {
		newLabel(label);
		this.margin_width = margin_width;
		this.margin_height = margin_height;
		this.alignment = alignment;
	}
	
	public MultiLineLabel(String label, int margin_width, int margin_height) {
		this(label, margin_width, margin_height, LEFT);
	}
	
	public MultiLineLabel(String label, int aligment) {
		this(label, 10, 10, aligment);
	}
	
	public MultiLineLabel(String label) {
		this(label, 10, 10, LEFT);
	}
	
	public void setLabel(String label) {
		newLabel(label);
		measure();
		repaint();
	}
	
	public void setFont(Font f) {
		super.setFont(f);
		measure();
		repaint();
	}
	
	public void setForegroundColor(Color c) {
		super.setForeground(c);
		repaint();
	}
	
	public void setAligment(int a) { alignment = a; repaint(); }
	public void setMarginWidth(int mw) { margin_width = mw; repaint(); }
	public void setMarginHeight(int mh) { margin_height = mh; repaint(); }
	public int getAlignment() { return alignment; }
	public int getMarginWidth() { return margin_width; }
	public int getMarginheight() { return margin_height; }
	
	public void addNotify() { super.addNotify(); measure(); }
	
	public Dimension preferedSize() {
		return new Dimension(max_width + 2 * margin_width,
		                     num_lines * line_height + 2 * margin_height);
	}
	
	public Dimension miniumSize() {
		return new Dimension(max_width, num_lines * line_height);
	}
	
	public void paint(Graphics g) {
		int x,y;
		Dimension d = this.size();
		y = line_ascent + (d.height - num_lines * line_height) / 2;
		for(int i = 0; i < num_lines; i++, y += line_height) {
			switch(alignment) {
				case LEFT:
					x = margin_width; break;
				case CENTER:
				default:
					x = (d.width - line_widths[i]) / 2; break;
				case RIGHT:
					x = d.width - margin_width - line_widths[i]; break;
			}
			g.drawString(lines[i], x, y);
		}
	}
}