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/*******************************************************************************
* Copyright (c) 2000, 2008 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:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.graphics;
import org.eclipse.swt.internal.photon.*;
/**
* 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
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*/
public final class FontMetrics {
/**
* On Windows, handle is a Win32 TEXTMETRIC struct
* On Photon, handle is a Photon FontQueryInfo struct
* (Warning: This field is platform dependent)
* <p>
* <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT
* public API. It is marked public only so that it can be shared
* within the packages provided by SWT. It is not available on all
* platforms and should never be accessed from application code.
* </p>
*/
public FontQueryInfo handle;
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;
FontQueryInfo info = ((FontMetrics)object).handle;
if (info == handle) return true;
if (info == null || handle == null) return false;
if (handle.size == info.size &&
handle.style == info.style &&
handle.ascender == info.ascender &&
handle.descender == info.descender &&
handle.width == info.width &&
handle.lochar == info.lochar &&
handle.hichar == info.hichar &&
handle.desc.length == info.desc.length &&
handle.font.length == info.font.length)
{
for (int i = handle.desc.length - 1; i >= 0; i--) {
if (handle.desc[i] != info.desc[i]) return false;
}
for (int i = handle.font.length - 1; i >= 0; i--) {
if (handle.font[i] != info.font[i]) return false;
}
return true;
}
return false;
}
/**
* 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 -handle.ascender;
}
/**
* 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() {
if ((handle.style & OS.PHFONT_INFO_FIXED) != 0) return handle.width;
return handle.width / 3;
}
/**
* 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 handle.descender;
}
/**
* 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 -handle.ascender + handle.descender;
}
/**
* 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 0;
}
/**
* Returns an integer hash code for the receiver. Any two
* objects that 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() {
if (handle == null) return 0;
return handle.size ^ handle.style ^ handle.ascender ^
handle.descender ^ handle.width ^
handle.lochar ^ handle.hichar ^ handle.font.hashCode() ^
handle.desc.hashCode();
}
public static FontMetrics internal_new(int ascent, int descent, int aveCharWidth, int leading, int height) {
FontQueryInfo info = new FontQueryInfo();
info.ascender = (short)-ascent;
info.descender = (short)descent;
info.style = OS.PHFONT_INFO_FIXED;
info.width = (short)aveCharWidth;
return photon_new(info);
}
public static FontMetrics photon_new(FontQueryInfo handle) {
FontMetrics fontMetrics = new FontMetrics();
fontMetrics.handle = handle;
return fontMetrics;
}
}
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