/*
 *  bm2ecsp -- 画像ファイルをESC/P形式に変換
 *
 *  revision history:
 *	0.0: Sep. 14, 2004 by Dai ISHIJIMA
 *	0.1: Sep. 16, 2004 BMPファイル対応 (FS誤差拡散など)
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#define EOS '\0'

/* 量子化法 (BMPを変換するとき) */
#define FLOYD_STEINBERG 'f'
#define RANDOM_DITHER   'r'

/* デバッグ */
#define PBM_OUTPUT 1

/* ファイル識別 */
#define MAGIC_LENGTH 3
#define MAGIC_PBM "P4\n"
#define MAGIC_BMP "BM6"

/* なんとBMP形式は寸法その他を決め打ちだ! (苦笑) */
#define BMPWIDTH  480
#define BMPHEIGHT 640
#define BMPFILSIZ 921654
#define BMPSKIP   (BMPFILSIZ - 3 * BMPWIDTH * BMPHEIGHT - MAGIC_LENGTH)
#define BMPMAXVAL 255

/* プリンタの縦ドット数 */
#define NBITS 24

/* プリンタ初期化 */
#define PINIT  "\x1b@\x1bx1\x1b\x33\x18"	/* ESC @  ESC x 1  ESC 3 24 */
#define BITIMG "\x1b*\x27"	/* ビットイメージモード */


char *prog;
#define shift --argc; ++argv


/* PBMファイルを一度に印刷する分だけ読む */
int fillpbm(FILE *fp, unsigned char *canvas, int xbytes, int height)
{
    bzero(canvas, xbytes * height);
    return(fread(canvas, xbytes, height, fp));
}


/* PBM形式データをESC/P形式に変換して出力 (1行分) */
void putpbm(unsigned char *canvas, int width, int height)
{
    int xbytes;
    int x, y;
    int xmask, ymask;
    int bits;

    xbytes = (width + 7) / 8;
    printf("%s%c%c", BITIMG, width & 255, width / 256);
    xmask = 0x80;
    for (x = 0; x < width; x++) {
	bits = 0;
	ymask = 0x80;
	for (y = 0; y < height; y++) {
	    if (canvas[y * xbytes + x / 8] & xmask) {
		bits |= ymask;
	    }
	    ymask >>= 1;
	    if (ymask == 0) {
		putc(bits, stdout);
		ymask = 0x80;
		bits = 0;
	    }
	}
	xmask >>= 1;
	if (xmask == 0) {
	    xmask = 0x80;
	}
    }
    printf("\r\n");
}


/* デバッグ用 (量子化の確認など) にPBM形式データをそのまま出力 */
void debug_putpbm(unsigned char *canvas, int width, int height)
{
    fwrite(canvas, (width + 7) / 8, height, stdout);
}


/* PBMファイルを読んで、ESC/P形式に変換 */
void pbmtoescp(FILE *fp, int debug)
{
    char s[BUFSIZ];
    int width, height;
    int xbytes;
    int y;
    unsigned char *canvas;
    
    fgets(s, BUFSIZ, fp);
    if (sscanf(s, "%d %d", &width, &height) != 2) {
	fprintf(stderr, "%s: can't get image size\n", prog);
	exit(1);
    }
    xbytes = (width + 7) / 8;
    canvas = (unsigned char *)calloc(xbytes, NBITS);
    if (debug & PBM_OUTPUT) {
	printf("P4\n%d %d\n", width, height);
    }
    else {
	printf(PINIT);
    }
    for (y = 0; y < height; y += NBITS) {
	if (fillpbm(fp, canvas, xbytes, NBITS) <= 0) {
	    break;
	}
	if (debug & PBM_OUTPUT) {
	    debug_putpbm(canvas, width, NBITS);
	}
	else {
	    putpbm(canvas, width, NBITS);
	}
    }
    free(canvas);
}


/* RGBをグレースケールに変換 */
#define rgb2gray(r,g,b) ((  (double)(r) * 0.30 \
			  + (double)(g) * 0.59 \
			  + (double)(b) * 0.11) / (double)BMPMAXVAL)


/* BMP用のバッファをクリアする */
void clearbmp(float *grayscale, int width, int height)
{
    int x, y;

    for (y = 0; y < height; y++) {
	for (x = 0; x < width; x++) {
	    grayscale[width * y + x] = 0.0;
	}
    }
}


/* 一度に印刷する分だけBMPファイルを読んで、グレースケールに変換 */
int fillbmp(FILE *fp, float *grayscale, int width, int height)
{
    int x, y;
    int r, g, b;
    int n;

    n = 0;
    for (y = 0; y < height; y++) {
	for (x = 0; x < width; x++) {
	    if ((r = getc(fp)) != EOF) {	/* エエ加減なチェック (^^; */
		++n;
		g = getc(fp);
		b = getc(fp);
		/* 左右を反転して格納する */
		grayscale[width * y + (width - x - 1)] += rgb2gray(r, g, b);
	    }
	    else {
		/* データがないときは「白」にしておく */
		grayscale[width * y + (width - x - 1)] = 1.0;
	    }
	}
    }
    return(n);
}


/* 誤差拡散法 (Floyd-Steinberg) で二値化してPBM形式に変換 */
void fs_bmp2pbm(float *bmp, unsigned char *pbm, int width, int height)
{
    int xbytes;
    int x, y;
    float val, error;
    int bit;
    
    xbytes = (width + 7) / 8;
    bzero(pbm, xbytes * height);
    for (y = 0; y < height; y++) {
	bit = 0x80;
	for (x = 0; x < width; x++) {
	    if (bmp[y * width + x] > 0.5) {
		val = 1.0;
	    }
	    else {
		val = 0.0;
		pbm[xbytes * y + (x / 8)] |= bit;
	    }
	    bit >>= 1;
	    if (bit <= 0) {
		bit = 0x80;
	    }
	    error = bmp[y * width + x] - val;
	    if (x < width - 1) {
		bmp[y * width + x + 1] += error * 7.0 / 16.0;
		bmp[(y + 1) * width + x + 1] += error * 1.0 / 16.0;
	    }
	    if (x > 0) {
		bmp[(y + 1) * width + x - 1] += error * 3.0 / 16.0;
	    }
	    bmp[(y + 1) * width + x] += error * 5.0 / 16.0;
	    bmp[y * width + x] = 0.0;
	}
    }
    /* 最終列の誤差を次のところにコピー */
    for (x = 0; x < width; x++) {
	bmp[x] = bmp[height * width + x];
	bmp[height * width + x] = 0.0;
    }
}


/* ランダムディザ法で二値化してPBM形式に変換 */
void rd_bmp2pbm(float *bmp, unsigned char *pbm, int width, int height)
{
    int xbytes;
    int x, y;
    int bit;
    float val;
    
    xbytes = (width + 7) / 8;
    bzero(pbm, xbytes * height);
    for (y = 0; y < height; y++) {
	bit = 0x80;
	for (x = 0; x < width; x++) {
	    val = (double)random() / (double)RAND_MAX;
	    if (bmp[y * width + x] < val) {
		pbm[xbytes * y + (x / 8)] |= bit;
	    }
	    bit >>= 1;
	    if (bit <= 0) {
		bit = 0x80;
	    }
	    bmp[y * width + x] = 0.0;
	}
    }
}


/* BMPファイルを二値化してESC/P形式に変換 */
void bmptoescp(FILE *fp, int q, int debug)
{
    float *bmpcanvas;
    unsigned char *canvas;
    int width, height;
    int y;
    int xbytes;

    /* 寸法決め打ち (^^; */
    width = BMPWIDTH;
    height = BMPHEIGHT;
    fseek(fp, BMPSKIP, SEEK_CUR);
    bmpcanvas = (float *)calloc(width * (NBITS + 1), sizeof(float));
    clearbmp(bmpcanvas, width, NBITS + 1);
    xbytes = (width + 7) / 8;
    canvas = (unsigned char *)calloc(xbytes, NBITS);
    if (debug & PBM_OUTPUT) {
	printf("P4\n%d %d\n", width, height);
    }
    else {
	printf(PINIT);
    }
    for (y = 0; y < height; y += NBITS) {
	if (fillbmp(fp, bmpcanvas, width, NBITS) <= 0) {
	    break;
	}
	if (q == RANDOM_DITHER) {
	    rd_bmp2pbm(bmpcanvas, canvas, width, NBITS);
	}
	else {
	    fs_bmp2pbm(bmpcanvas, canvas, width, NBITS);
	}
	if (debug & PBM_OUTPUT) {
	    debug_putpbm(canvas, width, NBITS);
	}
	else {
	    putpbm(canvas, width, NBITS);
	}
    }
    free(canvas);
    free(bmpcanvas);
}


void convert(FILE *fp, int q, int debug)
{
    char magic[MAGIC_LENGTH];

    if (fread(magic, 1, MAGIC_LENGTH, fp) != MAGIC_LENGTH) {
	fprintf(stderr, "%s: can't read magic\n", prog);
	exit(1);
    }
    if (strncmp(magic, MAGIC_PBM, MAGIC_LENGTH) == 0) {		/* PBM */
	pbmtoescp(fp, debug);
    }
    else if (strncmp(magic, MAGIC_BMP, MAGIC_LENGTH) == 0) {	/* BMP */
	bmptoescp(fp, q, debug);
    }
    else {
	fprintf(stderr, "%s: unknown file format\n", prog);
	exit(1);
    }
    exit(0);
}


void usage()
{
    fprintf(stderr, "Usage: %s [-d] [-f] [-r] [file]...\n", prog);
}


int main(int argc, char *argv[])
{
    int q;
    int debug;
    FILE *fp;

    prog = *argv;
    shift;
    debug = 0;
    q = FLOYD_STEINBERG;
    while ((argc > 0) && (argv[0][0] == '-') && (argv[0][1] != EOS)) {
	if (argv[0][1] == 'f') {
	    q = FLOYD_STEINBERG;
	}
	else if (argv[0][1] == 'r') {
	    q = RANDOM_DITHER;
	}
	else if (argv[0][1] == 'd') {
	    debug |= PBM_OUTPUT;
	}
	else {
	    usage();
	    exit(1);
	}
	shift;
    }
    if (argc > 0) {
	while (argc > 0) {
	    if (argv[0][0] == '-') {
		fp = stdin;
	    }
	    else if ((fp = fopen(*argv, "r")) == NULL) {
		fprintf(stderr, "%s: can't open %s\n", prog, *argv);
		exit(1);
	    }
	    convert(fp, q, debug);
	    if (argv[0][0] != '-') {
		fclose(fp);
	    }
	}
    }
    else {
	convert(stdin, q, debug);
    }
    exit(0);
}
	
/* Local Variables: */
/* compile-command:"gcc -Wall -o bm2escp bm2escp.c" */
/* End: */