TextLimiter.java

/*
Android Rivers is an app to read and discover news using RiverJs, RSS and OPML format.
Copyright (C) 2012 Dody Gunawinata (dodyg@silverkeytech.com)

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>
*/

package com.silverkeytech.android_rivers;

//http://stackoverflow.com/questions/3597550/ideal-method-to-truncate-a-string-with-ellipsis
public class TextLimiter {
    private final static String NON_THIN = "[^iIl1\\.,']";

    private static int textWidth(String str) {
        return (int) (str.length() - str.replaceAll(NON_THIN, "").length() / 2);
    }

    public static String ellipsize(String text, int max) {

        if (textWidth(text) <= max)
            return text;

        // Start by chopping off at the word before max
        // This is an over-approximation due to thin-characters...
        int end = text.lastIndexOf(' ', max - 3);

        // Just one long word. Chop it off.
        if (end == -1)
            return text.substring(0, max - 3) + "...";

        // Step forward as long as textWidth allows.
        int newEnd = end;
        do {
            end = newEnd;
            newEnd = text.indexOf(' ', end + 1);

            // No more spaces.
            if (newEnd == -1)
                newEnd = text.length();

        } while (textWidth(text.substring(0, newEnd) + "...") < max);

        return text.substring(0, end) + "...";
    }
}