jdk/src/share/classes/javax/swing/text/TabableView.java

/*
 * Copyright 1998-2000 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
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 */
package javax.swing.text;


/**
 * Interface for <code>View</code>s that have size dependent upon tabs.
 *
 * @author  Timothy Prinzing
 * @author  Scott Violet
 * @see TabExpander
 * @see LabelView
 * @see ParagraphView
 */
public interface TabableView {

    /**
     * Determines the desired span when using the given
     * tab expansion implementation.  If a container
     * calls this method, it will do so prior to the
     * normal layout which would call getPreferredSpan.
     * A view implementing this should give the same
     * result in any subsequent calls to getPreferredSpan
     * along the axis of tab expansion.
     *
     * @param x the position the view would be located
     *  at for the purpose of tab expansion >= 0.
     * @param e how to expand the tabs when encountered.
     * @return the desired span >= 0
     */
    float getTabbedSpan(float x, TabExpander e);

    /**
     * Determines the span along the same axis as tab
     * expansion for a portion of the view.  This is
     * intended for use by the TabExpander for cases
     * where the tab expansion involves aligning the
     * portion of text that doesn't have whitespace
     * relative to the tab stop.  There is therefore
     * an assumption that the range given does not
     * contain tabs.
     *
     * @param p0 the starting location in the text document >= 0
     * @param p1 the ending location in the text document >= p0
     * @return the span >= 0
     */
    float getPartialSpan(int p0, int p1);
}