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

import java.awt.Shape;
import java.io.IOException;
import java.io.OutputStream;

import org.freehep.graphicsio.QuadToCubicPathConstructor;

/**
 * Encoder to encode "CharStrings" used in PostScript and Type 1 Fonts.
 * 
 * @author Simon Fischer
 * @version $Id: freehep-graphicsio/src/main/java/org/freehep/graphicsio/font/CharstringEncoder.java 5641ca92a537 2005/11/26 00:15:35 duns $
 */
public class CharstringEncoder extends QuadToCubicPathConstructor {

    private static final int LAST_POINT = 0;

    private static final int HORIZONTAL = 1;

    private static final int VERTICAL = 2;

    private static final int BOTH = 3;

    private OutputStream out;

    private int currentX, currentY;

    public CharstringEncoder(OutputStream out) {
        this.out = out;
        currentX = currentY = 0;
    }

    private int writeNumber(double v) throws IOException {
        int round = (int) Math.round(v);
        writeNumber(round);
        return round;
    }

    private void writeNumber(int v) throws IOException {
        if ((v >= -107) && (v <= 107)) {
            out.write(v + 139);
        } else if ((v >= 108) && (v <= 1131)) {
            int highByte = (v - 108) / 256;
            out.write(highByte + 247);
            out.write(v - 108 - 256 * highByte);
        } else if ((v >= -1131) && (v <= -108)) {
            int highByte = (v + 108) / 256;
            out.write(-highByte + 251);
            out.write(-(v + 108 - 256 * highByte));
        } else {
            out.write(255);
            // copied from DataOutputStream correct? '>>>'?
            out.write((v >>> 24) & 0xFF);
            out.write((v >>> 16) & 0xFF);
            out.write((v >>> 8) & 0xFF);
            out.write((v >>> 0) & 0xFF);
        }
    }

    protected void writeCommand(int com) throws IOException {
        if (com >= 31)
            throw new IOException("Charstring command out of range: " + com);
        out.write(com);
    }

    protected void writeExtCommand(int com) throws IOException {
        out.write(12);
        out.write(com);
    }

    // -------------------- PATH CONSTRUCTION --------------------

    private void writePoint(double x, double y) throws IOException {
        currentX += writeNumber(x - currentX);
        currentY += writeNumber(y - currentY);
    }

    private void writeX(double x) throws IOException {
        currentX += writeNumber(x - currentX);
    }

    private void writeY(double y) throws IOException {
        currentY += writeNumber(y - currentY);
    }

    // -------------------- start/end --------------------

    public void startChar(double sidebearing, double width) throws IOException {
        currentX = writeNumber(sidebearing);
        writeNumber(width);
        writeCommand(13);
    }

    public void endchar() throws IOException {
        writeCommand(14);
    }

    // -------------------- path construction --------------------

    private int to(double x, double y) throws IOException {
        // writePoint(x, y);
        // return BOTH;

        int rx = (int) Math.round(x);
        int ry = (int) Math.round(y);

        if (rx == currentX) {
            if (ry == currentY) {
                return LAST_POINT;
            } else {
                writeY(y);
                return VERTICAL;
            }
        } else if (ry == currentY) {
            writeX(x);
            return HORIZONTAL;
        } else {
            writePoint(x, y);
            return BOTH;
        }
    }

    public void move(double x, double y) throws IOException {
        switch (to(x, y)) {
        case BOTH:
            writeCommand(21);
            break;
        case HORIZONTAL:
            writeCommand(22);
            break;
        case VERTICAL:
            writeCommand(4);
            break;
        case LAST_POINT:
            break;
        }
        super.move(x, y);
    }

    public void line(double x, double y) throws IOException {
        switch (to(x, y)) {
        case BOTH:
            writeCommand(5);
            break;
        case HORIZONTAL:
            writeCommand(6);
            break;
        case VERTICAL:
            writeCommand(7);
            break;
        case LAST_POINT:
            break;
        }
        super.line(x, y);
    }

    public void cubic(double x1, double y1, double x2, double y2, double x3,
            double y3) throws IOException {
        writePoint(x1, y1);
        writePoint(x2, y2);
        writePoint(x3, y3);
        writeCommand(8);
        super.cubic(x1, y1, x2, y2, x3, y3);
    }

    public void closePath(double x0, double y0) throws IOException {
        writeCommand(9);
        super.closePath(x0, y0);
    }

    public void drawPath(Shape s) throws IOException {
        addPath(s);
    }

}