350 lines
8.4 KiB
Java
350 lines
8.4 KiB
Java
/* FontMetrics.java -- Information about about a fonts display characteristics
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Copyright (C) 1999, 2002 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt;
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// FIXME: I leave many methods basically unimplemented. This
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// should be reviewed.
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/**
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* This class returns information about the display characteristics of
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* a font. It is abstract, and concrete subclasses should implement at
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* least the following methods:
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* <p>
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* <ul>
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* <li>getAscent
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* <li>getDescent
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* <li>getLeading()
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* <li>getMaxAdvance()
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* <li>charWidth(char)
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* <li>charsWidth(char[], int, int)
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* </ul>
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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*/
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public abstract class FontMetrics implements java.io.Serializable
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{
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/*
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* Static Variables
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*/
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// Serialization constant
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private static final long serialVersionUID = 1681126225205050147L;
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/*************************************************************************/
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/*
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* Instance Variables
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*/
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/**
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* This is the font for which metrics will be returned.
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*/
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protected Font font;
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/*************************************************************************/
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/*
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* Constructors
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*/
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/**
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* Initializes a new instance of <code>FontMetrics</code> for the
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* specified font.
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*
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* @param font The font to return metric information for.
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*/
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protected
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FontMetrics(Font font)
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{
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this.font = font;
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}
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/*************************************************************************/
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/*
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* Instance Methods
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*/
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/**
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* Returns the font that this object is creating metric information fo.
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*
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* @return The font for this object.
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*/
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public Font
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getFont()
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{
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return(font);
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}
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/*************************************************************************/
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/**
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* Returns the leading, or spacing between lines, for this font.
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*
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* @return The font leading.
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*/
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public int
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getLeading()
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{
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return(0);
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}
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/*************************************************************************/
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/**
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* Returns the ascent of the font, which is the distance from the base
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* to the top of the majority of characters in the set. Some characters
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* can exceed this value however.
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*
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* @return The font ascent.
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*/
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public int
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getAscent()
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{
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return(1);
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}
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/*************************************************************************/
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/**
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* Returns the descent of the font, which is the distance from the base
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* to the bottom of the majority of characters in the set. Some characters
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* can exceed this value however.
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*
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* @return The font descent.
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*/
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public int
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getDescent()
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{
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return(1);
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}
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/*************************************************************************/
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/**
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* Returns the height of a line in this font. This will be the sum
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* of the leading, the ascent, and the descent.
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*
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* @return The height of the font.
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*/
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public int
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getHeight()
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{
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return(getAscent() + getDescent() + getLeading());
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}
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/*************************************************************************/
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/**
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* Returns the maximum ascent value. This is the maximum distance any
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* character in the font rised above the baseline.
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*
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* @return The maximum ascent for this font.
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*/
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public int
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getMaxAscent()
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{
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return(getAscent());
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}
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/*************************************************************************/
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/**
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* Returns the maximum descent value. This is the maximum distance any
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* character in the font extends below the baseline.
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*
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* @return The maximum descent for this font.
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*/
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public int
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getMaxDescent()
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{
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return(getDescent());
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}
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/*************************************************************************/
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/**
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* Returns the maximum descent value. This is the maximum distance any
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* character in the font extends below the baseline.
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*
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* @return The maximum descent for this font.
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*
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* @deprecated This method is deprecated in favor of
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* <code>getMaxDescent()</code>.
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*/
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public int
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getMaxDecent()
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{
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return(getMaxDescent());
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}
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/*************************************************************************/
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/**
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* Returns the width of the widest character in the font.
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*
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* @return The width of the widest character in the font.
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*/
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public int
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getMaxAdvance()
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{
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return(-1);
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}
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/*************************************************************************/
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/**
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* Returns the width of the specified character.
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*
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* @param ch The character to return the width of.
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*
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* @return The width of the specified character.
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*/
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public int
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charWidth(int ch)
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{
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return(charWidth((char)ch));
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}
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/*************************************************************************/
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/**
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* Returns the width of the specified character.
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*
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* @param ch The character to return the width of.
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*
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* @return The width of the specified character.
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*/
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public int
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charWidth(char ch)
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{
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return(1);
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}
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/*************************************************************************/
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/**
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* Returns the total width of the specified string
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*
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* @param str The string to return the width of.
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*
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* @return The width of the string.
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*/
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public int
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stringWidth(String str)
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{
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char[] buf = new char[str.length()];
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str.getChars(0, str.length(), buf, 0);
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return(charsWidth(buf, 0, buf.length));
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}
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/*************************************************************************/
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/**
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* Returns the total width of the specified character array.
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*
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* @param buf The character array containing the data.
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* @param offset The offset into the array to start calculating from.
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* @param len The total number of bytes to process.
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*
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* @return The width of the requested characters.
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*/
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public int
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charsWidth(char buf[], int offset, int len)
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{
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int total_width = 0;
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for (int i = offset; i < len; i++)
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total_width = charWidth(buf[i]);
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return(total_width);
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}
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/*************************************************************************/
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/**
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* Returns the total width of the specified byte array.
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*
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* @param buf The byte array containing the data.
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* @param offset The offset into the array to start calculating from.
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* @param len The total number of bytes to process.
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*
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* @return The width of the requested characters.
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*/
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public int
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bytesWidth(byte buf[], int offset, int len)
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{
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int total_width = 0;
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for (int i = offset; i < len; i++)
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total_width = charWidth((char)buf[i]);
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return(total_width);
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}
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/*************************************************************************/
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/**
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* Returns the widths of the first 256 characters in the font.
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*
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* @return The widths of the first 256 characters in the font.
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*/
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public int[]
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getWidths()
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{
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return(new int[256]);
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}
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/*************************************************************************/
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/**
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* Returns a string representation of this object.
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*
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* @return A string representation of this object.
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*/
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public String
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toString()
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{
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return (this.getClass() + "[font=" + font + ",ascent=" + getAscent()
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+ ",descent=" + getDescent() + ",height=" + getHeight() + "]");
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}
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} // class FontMetrics
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