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package org.eclipse.swt.graphics;
/*
* Copyright (c) 2000, 2002 IBM Corp. All rights reserved.
* This file is made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
*/
import org.eclipse.swt.internal.gtk.*;
/**
* Instances of this class provide measurement information
* about fonts including ascent, descent, height, leading
* space between rows, and average character width.
* <code>FontMetrics</code> are obtained from <code>GC</code>s
* using the <code>getFontMetrics()</code> method.
*
* @see GC#getFontMetrics
*/
public final class FontMetrics {
int ascent, descent, averageCharWidth, leading, height;
FontMetrics() {
}
/**
* Compares the argument to the receiver, and returns true
* if they represent the <em>same</em> object using a class
* specific comparison.
*
* @param object the object to compare with this object
* @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise
*
* @see #hashCode
*/
public boolean equals (Object object) {
if (object == this) return true;
if (!(object instanceof FontMetrics)) return false;
FontMetrics metrics = (FontMetrics)object;
return ascent == metrics.ascent && descent == metrics.descent &&
averageCharWidth == metrics.averageCharWidth && leading == metrics.leading &&
height == metrics.height;
}
/**
* Returns the ascent of the font described by the receiver. A
* font's <em>ascent</em> is the distance from the baseline to the
* top of actual characters, not including any of the leading area,
* measured in pixels.
*
* @return the ascent of the font
*/
public int getAscent() {
return ascent;
}
/**
* Returns the average character width, measured in pixels,
* of the font described by the receiver.
*
* @return the average character width of the font
*/
public int getAverageCharWidth() {
return averageCharWidth;
}
/**
* Returns the descent of the font described by the receiver. A
* font's <em>descent</em> is the distance from the baseline to the
* bottom of actual characters, not including any of the leading area,
* measured in pixels.
*
* @return the descent of the font
*/
public int getDescent() {
return descent;
}
/**
* Returns the height of the font described by the receiver,
* measured in pixels. A font's <em>height</em> is the sum of
* its ascent, descent and leading area.
*
* @return the height of the font
*
* @see #getAscent
* @see #getDescent
* @see #getLeading
*/
public int getHeight() {
return height;
}
/**
* Returns the leading area of the font described by the
* receiver. A font's <em>leading area</em> is the space
* above its ascent which may include accents or other marks.
*
* @return the leading space of the font
*/
public int getLeading() {
return leading;
}
public static FontMetrics gtk_new(int fontHandle) {
GdkFont f = new GdkFont();
OS.memmove (f, fontHandle, GdkFont.sizeof);
FontMetrics fontMetrics = new FontMetrics();
fontMetrics.ascent = f.ascent;
fontMetrics.descent = f.descent;
fontMetrics.averageCharWidth = OS.gdk_char_width(fontHandle, (byte)'a');
fontMetrics.leading = 3;
fontMetrics.height = fontMetrics.ascent+fontMetrics.descent+3;
return fontMetrics;
}
/**
* Returns an integer hash code for the receiver. Any two
* objects which return <code>true</code> when passed to
* <code>equals</code> must return the same value for this
* method.
*
* @return the receiver's hash
*
* @see #equals
*/
public int hashCode() {
return ascent ^ descent ^ averageCharWidth ^ leading ^ height;
}
}
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