/*

 * Copyright 1998-2003 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

 * have any questions.

 */

package java.awt.font;

/**

* The <code>LineMetrics</code> class allows access to the

* metrics needed to layout characters along a line

* and to layout of a set of lines.  A <code>LineMetrics</code>

* object encapsulates the measurement information associated

* with a run of text.

* <p>

* Fonts can have different metrics for different ranges of

* characters.  The <code>getLineMetrics</code> methods of

* {@link java.awt.Font Font} take some text as an argument

* and return a <code>LineMetrics</code> object describing the

* metrics of the initial number of characters in that text, as

* returned by {@link #getNumChars}.

*/

public abstract class LineMetrics {

    /**

     * Returns the number of characters (<code>char</code> values) in the text whose

     * metrics are encapsulated by this <code>LineMetrics</code>

     * object.

     * @return the number of characters (<code>char</code> values) in the text with which

     *         this <code>LineMetrics</code> was created.

     */

    public abstract int getNumChars();

    /**

     * Returns the ascent of the text.  The ascent

     * is the distance from the baseline

     * to the ascender line.  The ascent usually represents the

     * the height of the capital letters of the text.  Some characters

     * can extend above the ascender line.

     * @return the ascent of the text.

     */

    public abstract float getAscent();

    /**

     * Returns the descent of the text.  The descent

     * is the distance from the baseline

     * to the descender line.  The descent usually represents

     * the distance to the bottom of lower case letters like

     * 'p'.  Some characters can extend below the descender

     * line.

     * @return the descent of the text.

     */

    public abstract float getDescent();

    /**

     * Returns the leading of the text. The

     * leading is the recommended

     * distance from the bottom of the descender line to the

     * top of the next line.

     * @return the leading of the text.

     */

    public abstract float getLeading();

    /**

     * Returns the height of the text.  The

     * height is equal to the sum of the ascent, the

     * descent and the leading.

     * @return the height of the text.

     */

    public abstract float getHeight();

    /**

     * Returns the baseline index of the text.

     * The index is one of

     * {@link java.awt.Font#ROMAN_BASELINE ROMAN_BASELINE},

     * {@link java.awt.Font#CENTER_BASELINE CENTER_BASELINE},

     * {@link java.awt.Font#HANGING_BASELINE HANGING_BASELINE}.

     * @return the baseline of the text.

     */

    public abstract int getBaselineIndex();

    /**

     * Returns the baseline offsets of the text,

     * relative to the baseline of the text.  The

     * offsets are indexed by baseline index.  For

     * example, if the baseline index is

     * <code>CENTER_BASELINE</code> then

     * <code>offsets[HANGING_BASELINE]</code> is usually

     * negative, <code>offsets[CENTER_BASELINE]</code>

     * is zero, and <code>offsets[ROMAN_BASELINE]</code>

     * is usually positive.

     * @return the baseline offsets of the text.

     */

    public abstract float[] getBaselineOffsets();

    /**

     * Returns the position of the strike-through line

     * relative to the baseline.

     * @return the position of the strike-through line.

     */

    public abstract float getStrikethroughOffset();

    /**

     * Returns the thickness of the strike-through line.

     * @return the thickness of the strike-through line.

     */

    public abstract float getStrikethroughThickness();

    /**

     * Returns the position of the underline relative to

     * the baseline.

     * @return the position of the underline.

     */

    public abstract float getUnderlineOffset();

    /**

     * Returns the thickness of the underline.

     * @return the thickness of the underline.

     */

    public abstract float getUnderlineThickness();

}