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Java/media/LineBreaker.java

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+/*   
+LineBreaker.java
+ *    
+ *    Copyright (c) 2000, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Tuomas Lukka
+ */
+package org.gzigzag;
+import java.awt.FontMetrics;
+import java.lang.reflect.*;
+import java.util.*;
+
+/** An interface to line breaking algorithms
+ * This class knows absolutely nothing about characters, words, or so on.
+ * It handles abstract tokens given by integers and asks the related
+ * class LineInfo about the goodness of fitting a particular line
+ * at a particular point.
+ * <p>
+ * Specific attention is paid to the billowing problem where
+ * we have to render a paragraph so that the cursor is at the line with
+ * the first line of the paragraph starts from the beginning of a line.
+ * This is achieved by specifying the cursor position (from where the lines
+ * should be counted) and the desired line number for that position.
+ * This can also be used to render the paragraph starting from the end.
+ */
+
+public abstract class LineBreaker {
+String rcsid = "$Id: LineBreaker.java,v 1.8.10.1 2001/08/16 13:50:01 bfallenstein Exp $";
+    static private void pa(String s) { System.out.println(s); }
+    /** Break the lines between the given addresses.
+     * @return An array: the first element is the line index the rendering
+     * starts on, and from the second element onwards the end points of the
+     * lines are given.
+     */
+    public abstract int[] breakLines(LineInfo li);
+
+    static private void test(LineBreaker b, String str, int cursor,
+				    SimpleLineInfo.Layout l) {
+	SimpleLineInfo inf = new SimpleLineInfo(str, cursor, l);
+	int[] foo = b.breakLines(inf);
+	pa("Tested '"+str+"'");
+	for(int i=0; i<foo.length; i++)
+	    pa(""+foo[i]);
+    }
+
+    /** Doesn't compile with Kaffe's classes.
+    static private class FixFM extends FontMetrics {
+	  FixFM() { super(null); }
+	  public int getAscent()  { return 0; }
+	  public int getDescent()  { return 0; }
+	  public int getLeading()  { return 0; }
+	  public int getMaxAdvance()  { return 10; }
+	  public int charWidth(char ch)  { return 10; }
+	  public int charsWidth(char data[], int off, int len) {
+	    return 10 * len;
+	  }
+    }
+    **/
+
+    /** A test routine. Provide name of the class to test first.
+     * The class to test must have a public constructor.
+     */
+    /** FixFM doesn't compile with Kaffe's classes.
+    static public void main(String[] argv) {
+      try {
+	Class cls = Class.forName("org.gzigzag."+argv[0]);
+	Constructor ctr = cls.getConstructor(new Class[] {});
+	LineBreaker b = (LineBreaker)ctr.newInstance(new Object[] {});
+
+	Vector db = new Vector();
+	for(int i=0; i<argv.length; i++)
+	    Main.debugClass(argv[i], db);
+
+	final FontMetrics fixwd = new FixFM();
+
+	// Test 1: fixed-width lines, 10 chars each.
+	SimpleLineInfo.Layout lay = new SimpleLineInfo.Layout() {
+	    public FontMetrics getFontMetrics(int line) {
+		return fixwd; 
+	    }
+	    public int getWidth(int line) {
+		return 100;
+	    }
+	    public int getCenterLine() { return 0; }
+	};
+
+	test(b, "", 0, lay);
+	test(b, "A", 0, lay);
+	test(b, "A B C D E F G H I J K L M N O P Q", 0, lay);
+
+      } catch(Exception e) {
+	e.printStackTrace();
+	pa(""+e);
+      }
+    }
+    **/
+}