org.eclipse.swt.graphics.FontMetrics.java Source code

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Here is the source code for org.eclipse.swt.graphics.FontMetrics.java

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/*******************************************************************************
 * Copyright (c) 2010, 2013 EclipseSource 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:
 *    EclipseSource - initial API and implementation
 ******************************************************************************/
package org.eclipse.swt.graphics;

import org.eclipse.rap.rwt.internal.textsize.TextSizeUtil;

/**
 * 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
 * @since 1.3
 */
public final class FontMetrics {

    private Font font;

    /**
     * Prevents instances from being created outside the package.
     */
    FontMetrics(Font font) {
        this.font = font;
    }

    /**
     * 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 (int) TextSizeUtil.getAvgCharWidth(font);
    }

    /**
     * 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
     */
    public int getHeight() {
        return TextSizeUtil.getCharHeight(font);
    }

    /**
     * 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
     */
    @Override
    public boolean equals(Object object) {
        boolean result = false;
        if (object == this) {
            result = true;
        } else if (object instanceof FontMetrics) {
            FontMetrics other = (FontMetrics) object;
            result = font.equals(other.font);
        }
        return result;
    }

    /**
     * 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
     */
    @Override
    public int hashCode() {
        return font.hashCode();
    }
}