package org.ibex.graphics;
import java.io.*;
import java.util.*;

public class PCX {

    public static void main(String[] s) throws Exception {
        FileOutputStream fos = new FileOutputStream("out.pcx");
        int[] data = new int[104 * 104];
        for(int i=0; i<104; i++) data[i*104+i] = 1;
        for(int i=0; i<104; i++) data[i*104+(104-i)] = 1;
        //for(int i=0; i<104*104; i++) data[i] = i%2==0?1:0;
        dump(104, 104, data, new DataOutputStream(fos));
    }

    public static void writeLittleShort(DataOutputStream out, int i) throws IOException {
        short s = (short)i;
        out.writeByte(s & 0xff);
        out.writeByte((s & 0xff00) << 8);
    }

    public static void dump(int width, int height, int[] data, DataOutputStream out) throws IOException {
        out.writeByte(0x0A);             // PCX ID
        out.writeByte(0);                // Version
        out.writeByte(1);                // Encoding = RLE
        out.writeByte(1);                // 1bpp
        writeLittleShort(out, 0);        // XStart
        writeLittleShort(out, 0);        // YStart
        //writeLittleShort(out, 203);      // HDPI
        //writeLittleShort(out, 203);      // VDPI
        writeLittleShort(out, width-1);    // XEnd
        writeLittleShort(out, height-1);   // YEnd
        writeLittleShort(out, width-1);    // XEnd
        writeLittleShort(out, height-1);   // YEnd
        for(int i=0; i<48; i++)
            out.writeByte(0);            // Pallette
        out.writeByte(0);                // Reserved
        out.writeByte(1);                // NumBitPlanes
        writeLittleShort(out, (int)Math.ceil(((float)width)/8));  // bytes per line
        writeLittleShort(out, 1); // PalleteType=Mono
        writeLittleShort(out, 0); // HorizScreenSize (FIXME: maybe omit?)
        writeLittleShort(out, 0); // VertScreenSize (FIXME: maybe omit?)
        for(int i=0; i<54; i++)
            out.writeByte(0);            // Reserved
        
        byte dat = 0;
        int count = 0;
        for(int y=0; y<height; y++) {
            for(int x=0; x<width; x+=8) {
                int i = y * width + x;
                byte b = 0;
                for(int j=i; j<Math.min(data.length, i+8); j++)
                    b |= (data[j]==0?0:1) << (7-(j-i));
                if (dat==b && count < 63) count++;
                else {
                    if (count > 0) {
                        out.writeByte(count | 0xc0);
                        out.writeByte(dat);
                    }
                    dat = b;
                    count = 1;
                }
            }
            if (count > 0) {
                out.writeByte(count | 0xc0);
                out.writeByte(dat);
                count = 0;
                dat = 0;
            }
        }
        out.flush();
        out.close();
    }

}