Java Programmer's Toolkit/Java Programmer's Toolkit.iso/solaris2/jdk/src/java/awt/fontmetr.jav

Text File | 1995-10-30 | 5.3 KB | 197 lines

/*
 * @(#)FontMetrics.java    1.7 95/08/17 Jim Graham
 *
 * Copyright (c) 1994-1995 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

package java.awt;

/**
 * A font metrics object. Note that the implementations of these
 * methods are inefficient, they are usually overridden with more
 * efficient toolkit specific implementations.
 *
 * @version     1.7 08/17/95
 * @author     Jim Graham
 */
public abstract class FontMetrics {
    /**
     * The actual font.
     * @see #getFont
     */
    protected Font font;

    /**
     * Creates a new FontMetrics object with the specified font.
     * @param font the font
     * @see Font
     */
    protected FontMetrics(Font font) {
    this.font = font;
    }

    /**
     * Gets the font.
     */
    public Font getFont() {
    return font;
    }

    /**
     * Gets the standard leading, or line spacing, for the font.
     * This is the logical amount of space to be reserved between the
     * descent of one line of text and the ascent of the next line.
     * The height metric is calculated to include this extra space.
     */
    public int getLeading() {
    return 0;
    }

    /**
     * Gets the font ascent. The font ascent is the distance from the
     * base line to the top of the characters.
     * @see #getMaxAscent
     */
    public int getAscent() {
    return font.getSize();
    }

    /**
     * Gets the font descent. The font descent is the distance from the
     * base line to the bottom of the characters.
     * @see #getMaxDescent
     */
    public int getDescent() {
    return 0;
    }

    /**
     * Gets the total height of the font.  This is the distance between
     * the baseline of adjacent lines of text.  It is the sum of the
     * leading + ascent + descent.
     *
     */
    public int getHeight() {
    return getLeading() + getAscent() + getDescent();
    }

    /**
     * Gets the maximum ascent of all characters in this Font.
     * No character will extend further above the baseline than this
     * metric.
     * @see #getAscent
     */
    public int getMaxAscent() {
    return getAscent();
    }

    /**
     * Gets the maximum descent of all characters.
     * No character will descend futher below the baseline than this
     * metric.
     * @see #getDescent
     */
    public int getMaxDecent() {
    return getDescent();
    }

    /**
     * Gets the maximum advance width of any character in this Font.
     * @return -1 if the max advance is not known.
     */
    public int getMaxAdvance() {
    return -1;
    }

    /**
     * Returns the width of the specified character in this Font.
     * @param ch the specified font
     * @see #stringWidth
     */
    public int charWidth(int ch) {
    return charWidth((char)ch);
    }

    /**
     * Returns the width of the specified character in this Font.
     * @param ch the specified font
     * @see #stringWidth
     */
    public int charWidth(char ch) {
    if (ch < 256) {
        return getWidths()[ch];
    }
    char data[] = {ch};
    return charsWidth(data, 0, 1);
    }

    /**
     * Returns the width of the specified String in this Font.
     * @param str the String to be checked
     * @see #charsWidth
     * @see #bytesWidth
     */
    public int stringWidth(String str) {
    int len = str.length();
    char data[] = new char[len];
    str.getChars(0, len, data, 0);
    return charsWidth(data, 0, len);
    }

    /**
     * Returns the width of the specified character array in this Font.
     * @param data the data to be checked
     * @param off the start offset of the data
     * @param len the maximum number of bytes checked
     * @see #stringWidth
     * @see #bytesWidth
     */
    public int charsWidth(char data[], int off, int len) {
    return stringWidth(new String(data, off, len));
    }

    /**
     * Returns the width of the specified array of bytes in this Font.
     * @param data the data to be checked
     * @param off the start offset of the data
     * @param len the maximum number of bytes checked
     * @see #stringWidth
     * @see #charsWidth
     */
    public int bytesWidth(byte data[], int off, int len) {
    return stringWidth(new String(data, 0, off, len));
    }

    /**
     * Gets the widths of the first 256 characters in the Font.
     */
    public int[] getWidths() {
    int widths[] = new int[256];
    for (char ch = 0 ; ch < 256 ; ch++) {
        widths[ch] = charWidth(ch);
    }
    return widths;
    }

    /**
     * Returns the String representation of this FontMetric's values.
     */
    public String toString() {
    return getClass().getName() + "[font=" + getFont() + "ascent=" +
        getAscent() + ", descent=" + getDescent() + ", height=" + getHeight() + "]";
    }
}