// Copyright 2001 freehep
package org.freehep.graphicsio.font;

import java.io.IOException;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.font.GlyphVector;
import java.awt.font.GlyphMetrics;
import java.awt.geom.Rectangle2D;
import java.awt.Shape;
import java.awt.geom.GeneralPath;

import org.freehep.graphicsio.font.encoding.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
 *  @version $Id: FontEmbedder.java,v 1.2 2002/08/24 00:04:13 duns Exp $
 */
public abstract class FontEmbedder extends FontIncluder {

    public static final String NOTDEF = ".notdef";

    /** 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;
    }
}