FontEmbedder.java

// Copyright 2001-2005 freehep
package org.xmind.org.freehep.graphicsio.font;

import java.awt.Font;
import java.awt.Shape;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphMetrics;
import java.awt.font.GlyphVector;
import java.awt.geom.GeneralPath;
import java.awt.geom.Rectangle2D;
import java.io.IOException;

import org.xmind.org.freehep.graphics2d.font.CharTable;

/**
 * A FontIncluder that also embeds all glyphs. Subclasses must implement the
 * <tt>writeGlyph</tt> method which is called for all defined (up to 256)
 * characters and the notdefined character. These method calls are bracketed by
 * <tt>openGlyphs()</tt> and <tt>closeGlyph()</tt>. All invocations of methods
 * that are abstract in this class succeed the method calls of the superclass
 * <tt>FontIncluder</tt> (especially <tt>closeIncludeFont()</tt>!) All of these
 * calls are again succeeded by <tt>closeEmbedFont</tt>. <br>
 * The abstract methods are called in the following order:
 * <ul>
 * <li><tt>openIncludeFont</tt>
 * <li><tt>writeEncoding</tt>
 * <li><tt>closeIncludeFont</tt>
 * <li><tt>writeWidths</tt>
 * <li><tt>openGlyphs</tt>
 * <li>loop over all glyphs: <tt>openGlyphs</tt>
 * <li><tt>closeGlyphs</tt>
 * <li><tt>closeEmbedFont</tt>
 * </ul>
 *
 * @author Simon Fischer
 * @author Jason Wong
 */
public abstract class FontEmbedder extends FontIncluder {

    public static final String NOTDEF = ".notdef"; //$NON-NLS-1$

    /**
     * Writes a single glyph to the file. A null value for <tt>glyphMetrics</tt>
     * indicates the undefined character. In this case the value of
     * <tt>unicodeName</tt> equals the value of <tt>NOTDEF</TT> (=
     * <tt>.notdef</tt>).
     *
     * @param unicodeName
     *            the character's name according to the unicode standard
     * @param glyph
     *            the shape that represents this glyph
     * @param glyphMetrics
     *            the metrics of this glyph
     */
    protected abstract void writeGlyph(String unicodeName, Shape glyph,
            GlyphMetrics glyphMetrics) throws IOException;

    /** Writes the character widths to the file. */
    protected abstract void writeWidths(double[] widths) throws IOException;

    /**
     * Called before the glyph loop starts. Does nothing by default but can be
     * implemented.
     */
    protected void openGlyphs() throws IOException {
    }

    /**
     * Called after the glyph loop ends. Does nothing by default but can be
     * implemented.
     */
    protected void closeGlyphs() throws IOException {
    }

    protected abstract void closeEmbedFont() throws IOException;

    private double[] widths;

    private GlyphVector glyphs;

    private Font font; // FONTHACK

    public FontEmbedder(FontRenderContext context) {
        super(context);
    }

    protected double[] getAdvanceWidths() {
        if (widths == null) {
            // figure out the widths of the characters if not yet done
            widths = new double[256];
            for (int i = 0; i < widths.length; i++) {
                widths[i] = glyphs.getGlyphMetrics(i).getAdvance();
                // in case of undefined character set to width of undefined
                // symbol
                if (getCharName(i) == null) {
                    widths[i] = getUndefinedWidth();
                }
            }
        }
        return widths;
    }

    protected double getAdvanceWidth(int character) {
        return getAdvanceWidths()[character];
    }

    protected Shape getGlyph(int i) {
        // This one-line implementation produces different results under JDK 1.3
        // and 1.4
        // return glyphs.getGlyphOutline(i);

        // The substitute code attempts to work around this by using defensive
        // programming
        // See code marked FONTHACK elsewhere in this file
        // Create a GlyphVector for this single character.
        FontRenderContext orig = getContext();
        FontRenderContext frc = new FontRenderContext(null,
                orig.isAntiAliased(), orig.usesFractionalMetrics());
        Shape shape = font.createGlyphVector(frc, new char[] { getUnicode(i) })
                .getGlyphOutline(0);
        return orig.getTransform().createTransformedShape(shape);
    }

    protected GlyphMetrics getGlyphMetrics(int i) {
        return glyphs.getGlyphMetrics(i);
    }

    public void includeFont(Font font, CharTable charTable, String name)
            throws IOException {

        glyphs = null;
        widths = null;
        // FONTHACK: Needed by hacked version of getGlyph()
        this.font = font;

        super.includeFont(font, charTable, name);

        this.glyphs = font.createGlyphVector(getContext(), getUnicode());

        writeWidths(getAdvanceWidths());

        try {

            openGlyphs();

            // write the glyphs
            for (int i = 0; i < 256; i++) {
                if (getCharName(i) != null) {
                    writeGlyph(getCharName(i), getGlyph(i), getGlyphMetrics(i));
                }
            }
            writeGlyph(NOTDEF, createUndefined(), null);

            closeGlyphs();
            closeEmbedFont();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private Shape createUndefined() {
        GeneralPath ud = new GeneralPath(GeneralPath.WIND_EVEN_ODD, 10);
        ud.append(new Rectangle2D.Double(0, 0, FONT_SIZE, FONT_SIZE), false);
        ud.append(new Rectangle2D.Double(FONT_SIZE / 20, FONT_SIZE / 20,
                18 * FONT_SIZE / 20, 18 * FONT_SIZE / 20), false);
        return ud;
    }
}