textutilities.java

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/* ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it 
 * under the terms of the GNU Lesser General Public License as published by 
 * the Free Software Foundation; either version 2.1 of the License, or 
 * (at your option) any later version.
 *
 * This library 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 GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License 
 * along with this library; if not, write to the Free Software Foundation, 
 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 * 
 * ------------------
 * TextUtilities.java
 * ------------------
 * (C) Copyright 2004, 2005, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: TextUtilities.java,v 1.11 2005/06/01 14:12:29 taqua Exp $
 *
 * Changes
 * -------
 * 07-Jan-2004 : Version 1 (DG);
 * 24-Mar-2004 : Added 'paint' argument to createTextBlock() method (DG);
 * 07-Apr-2004 : Added getTextBounds() method and useFontMetricsGetStringBounds
 *               flag (DG);
 * 08-Apr-2004 : Changed word break iterator to line break iterator in the 
 *               createTextBlock() method - see bug report 926074 (DG);
 * 03-Sep-2004 : Updated createTextBlock() method to add ellipses when limit 
 *               is reached (DG);
 * 30-Sep-2004 : Modified bounds returned by drawAlignedString() method (DG);
 * 10-Nov-2004 : Added new createTextBlock() method that works with 
 *               newlines (DG);
 * 19-Apr-2005 : Changed default value of useFontMetricsGetStringBounds (DG);
 * 17-May-2005 : createTextBlock() now recognises '\n' (DG);
 * 
 */

package org.jfree.text;

import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.font.FontRenderContext;
import java.awt.font.LineMetrics;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.text.BreakIterator;

import org.jfree.ui.TextAnchor;
import org.jfree.util.Log;
import org.jfree.util.LogContext;

/**
 * Some utility methods for working with text.
 *
 * @author David Gilbert
 */
public class TextUtilities {

    /** Access to logging facilities. */
    protected static final LogContext logger 
        = Log.createContext(TextUtilities.class);

    /**
     * Private constructor prevents object creation.
     */
    private TextUtilities() {
    }

    /**
     * Creates a {@link TextBlock} from a <code>String</code>.  Line breaks 
     * are added where the <code>String</code> contains '\n' characters.
     * 
     * @param text  the text.
     * @param font  the font.
     * @param paint  the paint.
     * 
     * @return A text block.
     */
    public static TextBlock createTextBlock(final String text, 
                                            final Font font, 
                                            final Paint paint) {
        if (text == null) {
            throw new IllegalArgumentException("Null 'text' argument.");
        }
        final TextBlock result = new TextBlock();
        String input = text;
        boolean moreInputToProcess = (text.length() > 0);
        final int start = 0;
        while (moreInputToProcess) {
            final int index = input.indexOf("\n");
            if (index > start) {
                final String line = input.substring(start, index);
                if (index < input.length() - 1) {
                    result.addLine(line, font, paint);
                    input = input.substring(index + 1);
                }
                else {
                    moreInputToProcess = false;
                }
            }
            else if (index == start) {
                if (index < input.length() - 1) {
                    input = input.substring(index + 1);
                }
                else {
                    moreInputToProcess = false;
                }
            }
            else {
                result.addLine(input, font, paint);
                moreInputToProcess = false;
            }
        }
        return result;
    }
    
    /**
     * Creates a new text block from the given string, breaking the
     * text into lines so that the <code>maxWidth</code> value is
     * respected.
     * 
     * @param text  the text.
     * @param font  the font.
     * @param paint  the paint.
     * @param maxWidth  the maximum width for each line.
     * @param measurer  the text measurer.
     * 
     * @return A text block.
     */
    public static TextBlock createTextBlock(final String text,
                                            final Font font,
                                            final Paint paint,
                                            final float maxWidth,
                                            final TextMeasurer measurer) {
        return createTextBlock(
            text, font, paint, maxWidth, Integer.MAX_VALUE, measurer
        );
    }
    
    /**
     * Creates a new text block from the given string, breaking the
     * text into lines so that the <code>maxWidth</code> value is
     * respected.
     * 
     * @param text  the text.
     * @param font  the font.
     * @param paint  the paint.
     * @param maxWidth  the maximum width for each line.
     * @param maxLines  the maximum number of lines.
     * @param measurer  the text measurer.
     * 
     * @return A text block.
     */
    public static TextBlock createTextBlock(final String text,
                                            final Font font,
                                            final Paint paint,
                                            final float maxWidth,
                                            final int maxLines,
                                            final TextMeasurer measurer) {
        final TextBlock result = new TextBlock();
        final BreakIterator iterator = BreakIterator.getLineInstance();
        iterator.setText(text);
        int current = 0;
        int lines = 0;
        final int length = text.length();
        while (current < length && lines < maxLines) {
            final int next = nextLineBreak(
                text, current, maxWidth, iterator, measurer
            );
            if (next == BreakIterator.DONE) {
                result.addLine(text.substring(current), font, paint); 
                return result;
            }
            result.addLine(text.substring(current, next), font, paint);
            lines++;
            current = next;
            while (text.charAt(current) == '\n' && current < text.length()) {
                current++;
            }
        }
        if (current < length) {
            final TextLine lastLine = result.getLastLine();
            final TextFragment lastFragment = lastLine.getLastTextFragment();
            final String oldStr = lastFragment.getText();
            String newStr = "...";
            if (oldStr.length() > 3) {
                newStr = oldStr.substring(0, oldStr.length() - 3) + "...";
            }
            
            lastLine.removeFragment(lastFragment);
            final TextFragment newFragment = new TextFragment(
                newStr, lastFragment.getFont(), lastFragment.getPaint()
            );
            lastLine.addFragment(newFragment);
        }
        return result;
    }
    
    /**
     * Returns the character index of the next line break.
     * 
     * @param text  the text.
     * @param start  the start index.
     * @param width  the target display width.
     * @param iterator  the word break iterator.
     * @param measurer  the text measurer.
     * 
     * @return The index of the next line break.
     */
    private static int nextLineBreak(final String text, final int start, 
                                     final float width,
                                     final BreakIterator iterator, 
                                     final TextMeasurer measurer) {
        // this method is (loosely) based on code in JFreeReport's 
        // TextParagraph class
        int current = start;
        int end;
        float x = 0.0f;
        boolean firstWord = true;
        int newline = text.indexOf('\n', start);
        if (newline < 0) {
            newline = Integer.MAX_VALUE;   
        }
        while (((end = iterator.next()) != BreakIterator.DONE)) {
            if (end > newline) {
                return newline;
            }
            x += measurer.getStringWidth(text, current, end);  
            if (x > width) {
                if (firstWord) {
                    while (measurer.getStringWidth(text, start, end) > width) {
                        end--;
                        if (end <= start) {
                            return end;   
                        }
                    }
                    return end;
                }
                else {
                    end = iterator.previous();
                    return end;
                }
            }
            // we found at least one word that fits ...
            firstWord = false;
            current = end;
        }
        return BreakIterator.DONE;
    }
    
    /**
     * Returns the bounds for the specified text.
     * 
     * @param text  the text (<code>null</code> permitted).
     * @param g2  the graphics context (not <code>null</code>).
     * @param fm  the font metrics (not <code>null</code>).
     * 
     * @return The text bounds (<code>null</code> if the <code>text</code> 
     *         argument is <code>null</code>).
     */
    public static Rectangle2D getTextBounds(final String text,
                                            final Graphics2D g2, 
                                            final FontMetrics fm) {
        final Rectangle2D bounds;
        if (TextUtilities.useFontMetricsGetStringBounds) {
            bounds = fm.getStringBounds(text, g2);
        }
        else {
            final double width = fm.stringWidth(text);
            final double height = fm.getHeight();
            if (logger.isDebugEnabled()) {
                logger.debug("Height = " + height);   
            }
            bounds = new Rectangle2D.Double(
                0.0, -fm.getAscent(), width, height