com.openhtmltopdf.layout.Breaker Maven / Gradle / Ivy

Go to download
/*
 * Breaker.java
 * Copyright (c) 2004, 2005 Torbjoern Gannholm,
 * Copyright (c) 2005 Wisconsin Court System
 *
 * This program 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 program 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 program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
package com.openhtmltopdf.layout;

import java.text.BreakIterator;

import com.openhtmltopdf.css.constants.IdentValue;
import com.openhtmltopdf.css.style.CalculatedStyle;
import com.openhtmltopdf.render.FSFont;

/**
 * A utility class that scans the text of a single inline box, looking for the
 * next break point.
 * @author Torbjoern Gannholm
 */
public class Breaker {

    public static void breakFirstLetter(LayoutContext c, LineBreakContext context,
            int avail, CalculatedStyle style) {
        FSFont font = style.getFSFont(c);
        context.setEnd(getFirstLetterEnd(context.getMaster(), context.getStart()));
        context.setWidth(c.getTextRenderer().getWidth(
                c.getFontContext(), font, context.getCalculatedSubstring()));

        if (context.getWidth() > avail) {
            context.setNeedsNewLine(true);
            context.setUnbreakable(true);
        }
    }

    private static int getFirstLetterEnd(String text, int start) {
        boolean letterFound = false;
        int end = text.length();
        char currentChar;
        for ( int i = start; i < end; i++ ) {
            currentChar = text.charAt(i);
            if (!TextUtil.isFirstLetterSeparatorChar(currentChar)) {
                if (letterFound) {
                    return i;
                } else {
                    letterFound = true;
                }
            }
        }
        return end;
    }

    public static void breakText(LayoutContext c,
            LineBreakContext context, int avail, CalculatedStyle style) {
        FSFont font = style.getFSFont(c);
        IdentValue whitespace = style.getWhitespace();

        // ====== handle nowrap
        if (whitespace == IdentValue.NOWRAP) {
        	context.setEnd(context.getLast());
        	context.setWidth(c.getTextRenderer().getWidth(
                    c.getFontContext(), font, context.getCalculatedSubstring()));
            return;
        }

        //check if we should break on the next newline
        if (whitespace == IdentValue.PRE ||
                whitespace == IdentValue.PRE_WRAP ||
                whitespace == IdentValue.PRE_LINE) {
            int n = context.getStartSubstring().indexOf(WhitespaceStripper.EOL);
            if (n > -1) {
                context.setEnd(context.getStart() + n + 1);
                context.setWidth(c.getTextRenderer().getWidth(
                        c.getFontContext(), font, context.getCalculatedSubstring()));
                context.setNeedsNewLine(true);
                context.setEndsOnNL(true);
            } else if (whitespace == IdentValue.PRE) {
            	context.setEnd(context.getLast());
                context.setWidth(c.getTextRenderer().getWidth(
                        c.getFontContext(), font, context.getCalculatedSubstring()));
            }
        }

        //check if we may wrap
        if (whitespace == IdentValue.PRE ||
                (context.isNeedsNewLine() && context.getWidth() <= avail)) {
            return;
        }

        context.setEndsOnNL(false);
        doBreakText(c, context, avail, style, false);
    }

    private static void doBreakText(LayoutContext c,
            LineBreakContext context, int avail, CalculatedStyle style,
            boolean tryToBreakAnywhere) {
        FSFont font = style.getFSFont(c);
        String currentString = context.getStartSubstring();
        BreakIterator iterator = getWordStream(currentString);
        int left = 0;
        int right = tryToBreakAnywhere ? 1 : iterator.next();
        int lastWrap = 0;
        int graphicsLength = 0;
        int lastGraphicsLength = 0;

        while (right > 0 && graphicsLength <= avail) {
            lastGraphicsLength = graphicsLength;
            graphicsLength += c.getTextRenderer().getWidth(
                    c.getFontContext(), font, currentString.substring(left, right));
            lastWrap = left;
            left = right;
            if ( tryToBreakAnywhere ) {
                right = ( right + 1 ) % currentString.length();
            }
            else { // break relies on BreakIterator
                right = iterator.next();
            }
        }

        if (graphicsLength <= avail) {
            //try for the last bit too!
            lastWrap = left;
            lastGraphicsLength = graphicsLength;
            graphicsLength += c.getTextRenderer().getWidth(
                    c.getFontContext(), font, currentString.substring(left));
        }

        if (graphicsLength <= avail) {
            context.setWidth(graphicsLength);
            context.setEnd(context.getMaster().length());
            //It fit!
            return;
        }

        context.setNeedsNewLine(true);
        if ( lastWrap == 0 && style.getWordWrap() == IdentValue.BREAK_WORD ) {
            if ( ! tryToBreakAnywhere ) {
                doBreakText(c, context, avail, style, true);
                return;
            }
        }

        if (lastWrap != 0) {//found a place to wrap
            context.setEnd(context.getStart() + lastWrap);
            context.setWidth(lastGraphicsLength);
        } else {//unbreakable string
            if (left == 0) {
                left = currentString.length();
            }

            context.setEnd(context.getStart() + left);
            context.setUnbreakable(true);

            if (left == currentString.length()) {
                context.setWidth(c.getTextRenderer().getWidth(
                        c.getFontContext(), font, context.getCalculatedSubstring()));
            } else {
                context.setWidth(graphicsLength);
            }
        }
        return;
    }

	public static BreakIterator getWordStream(String s) {
		BreakIterator i = new UrlAwareLineBreakIterator();
		i.setText(s);
		return i;
	}

}