org.eclipse.swt.graphics.FontMetrics Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of org.eclipse.swt.win32.win32.x86 Show documentation
SWT is an open source widget toolkit for Java designed to provide efficient, portable access to the user-interface facilities of the operating systems on which it is implemented.
The newest version!
/*******************************************************************************
 * Copyright (c) 2000, 2011 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.win32.*;

/**
 * Instances of this class provide measurement information
 * about fonts including ascent, descent, height, leading
 * space between rows, and average character width.
 * FontMetrics are obtained from GCs
 * using the getFontMetrics() method.
 *
 * @see GC#getFontMetrics
 * @see Sample code and further information
 */
 
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)
	 * 
	 * IMPORTANT: This field is not 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.
	 * 
	 * 
	 * @noreference This field is not intended to be referenced by clients.
	 */
	public TEXTMETRIC handle;
	
/**
 * Prevents instances from being created outside the package.
 */
FontMetrics() {
}

/**
 * Compares the argument to the receiver, and returns true
 * if they represent the same object using a class
 * specific comparison.
 *
 * @param object the object to compare with this object
 * @return true if the object is the same as this object and false otherwise
 *
 * @see #hashCode
 */
public boolean equals (Object object) {
	if (object == this) return true;
	if (!(object instanceof FontMetrics)) return false;
	TEXTMETRIC metric = ((FontMetrics)object).handle;
	return handle.tmHeight == metric.tmHeight &&
		handle.tmAscent == metric.tmAscent &&
		handle.tmDescent == metric.tmDescent &&
		handle.tmInternalLeading == metric.tmInternalLeading &&
		handle.tmExternalLeading == metric.tmExternalLeading &&
		handle.tmAveCharWidth == metric.tmAveCharWidth &&
		handle.tmMaxCharWidth == metric.tmMaxCharWidth &&
		handle.tmWeight == metric.tmWeight &&
		handle.tmOverhang == metric.tmOverhang &&
		handle.tmDigitizedAspectX == metric.tmDigitizedAspectX &&
		handle.tmDigitizedAspectY == metric.tmDigitizedAspectY &&
//		handle.tmFirstChar == metric.tmFirstChar &&
//		handle.tmLastChar == metric.tmLastChar &&
//		handle.tmDefaultChar == metric.tmDefaultChar &&
//		handle.tmBreakChar == metric.tmBreakChar &&
		handle.tmItalic == metric.tmItalic &&
		handle.tmUnderlined == metric.tmUnderlined &&
		handle.tmStruckOut == metric.tmStruckOut &&
		handle.tmPitchAndFamily == metric.tmPitchAndFamily &&
		handle.tmCharSet == metric.tmCharSet;
}

/**
 * Returns the ascent of the font described by the receiver. A
 * font's ascent 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.tmAscent - handle.tmInternalLeading;
}

/**
 * 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 handle.tmAveCharWidth;
}

/**
 * Returns the descent of the font described by the receiver. A
 * font's descent 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.tmDescent;
}

/**
 * Returns the height of the font described by the receiver, 
 * measured in pixels. A font's height 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.tmHeight;
}

/**
 * Returns the leading area of the font described by the
 * receiver. A font's leading area is the space
 * above its ascent which may include accents or other marks.
 *
 * @return the leading space of the font
 */
public int getLeading() {
	return handle.tmInternalLeading;
}

/**
 * Returns an integer hash code for the receiver. Any two 
 * objects that return true when passed to 
 * equals must return the same value for this
 * method.
 *
 * @return the receiver's hash
 *
 * @see #equals
 */
public int hashCode() {
	return handle.tmHeight ^ handle.tmAscent ^ handle.tmDescent ^
		handle.tmInternalLeading ^ handle.tmExternalLeading ^
		handle.tmAveCharWidth ^ handle.tmMaxCharWidth ^ handle.tmWeight ^
		handle.tmOverhang ^ handle.tmDigitizedAspectX ^ handle.tmDigitizedAspectY ^
//		handle.tmFirstChar ^ handle.tmLastChar ^ handle.tmDefaultChar ^ handle.tmBreakChar ^
		handle.tmItalic ^ handle.tmUnderlined ^ handle.tmStruckOut ^
		handle.tmPitchAndFamily ^ handle.tmCharSet;
}

/**	 
 * Invokes platform specific functionality to allocate a new font metrics.
 * 
 * IMPORTANT: This method is not part of the public
 * API for FontMetrics. 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 called from
 * application code.
 * 
 *
 * @param handle the TEXTMETRIC containing information about a font
 * @return a new font metrics object containing the specified TEXTMETRIC
 * 
 * @noreference This method is not intended to be referenced by clients.
 */
public static FontMetrics win32_new(TEXTMETRIC handle) {
	FontMetrics fontMetrics = new FontMetrics();
	fontMetrics.handle = handle;
	return fontMetrics;
}

}