TextUtils.java

/*******************************************************************************
 * Copyright (c) 2006 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    chris.gross@us.ibm.com - initial API and implementation
 *******************************************************************************/ 
package org.eclipse.nebula.widgets.grid.internal;

import org.eclipse.swt.graphics.GC;

/**
 * Utility class to provide common operations on strings not supported by the
 * base java API.
 * 
 * @author chris.gross@us.ibm.com
 * @since 2.0.0
 */
public class TextUtils
{

    /**
     * Shortens a supplied string so that it fits within the area specified by
     * the width argument. Strings that have been shorted have an "..." attached
     * to the end of the string. The width is computed using the
     * {@link GC#textExtent(String)}.
     * 
     * @param gc GC used to perform calculation.
     * @param t text to modify.
     * @param width Pixels to display.
     * @return shortened string that fits in area specified.
     */
    public static String getShortText(GC gc, String t, int width)
    {
        if (t == null)
        {
            return null;
        }

        if (t.equals(""))
        {
            return "";
        }

        if (width >= gc.textExtent(t).x)
        {
            return t;
        }

        int w = gc.textExtent("...").x;
        String text = t;
        int l = text.length();
        int pivot = l / 2;
        int s = pivot;
        int e = pivot + 1;

        while (s >= 0 && e < l)
        {
            String s1 = text.substring(0, s);
            String s2 = text.substring(e, l);
            int l1 = gc.textExtent(s1).x;
            int l2 = gc.textExtent(s2).x;
            if (l1 + w + l2 < width)
            {
                text = s1 + "..." + s2;
                break;
            }
            s--;
            e++;
        }

        if (s == 0 || e == l)
        {
            text = text.substring(0, 1) + "..." + text.substring(l - 1, l);
        }

        return text;
    }

    /**
     * Shortens a supplied string so that it fits within the area specified by
     * the width argument. Strings that have been shorted have an "..." attached
     * to the end of the string. The width is computed using the
     * {@link GC#stringExtent(String)}.
     * 
     * @param gc GC used to perform calculation.
     * @param t text to modify.
     * @param width Pixels to display.
     * @return shortened string that fits in area specified.
     */
    public static String getShortString(GC gc, String t, int width)
    {

        if (t == null)
        {
            return null;
        }

        if (t.equals(""))
        {
            return "";
        }

        if (width >= gc.stringExtent(t).x)
        {
            return t;
        }

        int w = gc.stringExtent("...").x;
        String text = t;
        int l = text.length();
        int pivot = l / 2;
        int s = pivot;
        int e = pivot + 1;
        while (s >= 0 && e < l)
        {
            String s1 = text.substring(0, s);
            String s2 = text.substring(e, l);
            int l1 = gc.stringExtent(s1).x;
            int l2 = gc.stringExtent(s2).x;
            if (l1 + w + l2 < width)
            {
                text = s1 + "..." + s2;
                break;
            }
            s--;
            e++;
        }

        if (s == 0 || e == l)
        {
            text = text.substring(0, 1) + "..." + text.substring(l - 1, l);
        }

        return text;
    }

    /**
     * Protected constructor to prevent instantiation.
     */
    protected TextUtils()
    {
    }
}