path: root/gs/src/gdevpcl.c

/* Copyright (C) 1992, 1994, 1999 Aladdin Enterprises.  All rights reserved.

   This software is licensed to a single customer by Artifex Software Inc.
   under the terms of a specific OEM agreement.
 */

/*$RCSfile$ $Revision$ */
/* Utilities for PCL printers */
#include "gdevprn.h"
#include "gdevpcl.h"

/* ------ Get paper size ------ */

/* Get the paper size code, based on width and height. */
int
gdev_pcl_paper_size(gx_device * dev)
{
    float height_inches = dev->height / dev->y_pixels_per_inch;

    return
	(height_inches >= 44.4 ? PAPER_SIZE_A0 :
	 height_inches >= 32.0 ? PAPER_SIZE_A1 :
	 height_inches >= 22.2 ? PAPER_SIZE_A2 :
	 height_inches >= 15.9 ? PAPER_SIZE_A3 :
	 height_inches >= 11.8 ? PAPER_SIZE_LEGAL :
	 height_inches >= 11.1 ? PAPER_SIZE_A4 :
	 PAPER_SIZE_LETTER);
}

/* ------ Color mapping ------ */

/* The PaintJet and DeskJet 500C use additive colors in separate planes. */
/* We only keep one bit of color, with 1 = R, 2 = G, 4 = B. */
/* Because the buffering routines assume 0 = white, */
/* we complement all the color components. */
#define cv_shift (sizeof(gx_color_value) * 8 - 1)

/* Map an RGB color to a printer color. */
gx_color_index
gdev_pcl_3bit_map_rgb_color(gx_device * dev,
		       gx_color_value r, gx_color_value g, gx_color_value b)
{
    return (((b >> cv_shift) << 2) + ((g >> cv_shift) << 1) + (r >> cv_shift)) ^ 7;
}

/* Map the printer color back to RGB. */
int
gdev_pcl_3bit_map_color_rgb(gx_device * dev, gx_color_index color,
			    gx_color_value prgb[3])
{
    ushort cc = (ushort) color ^ 7;

    prgb[0] = -(cc & 1);
    prgb[1] = -((cc >> 1) & 1);
    prgb[2] = -(cc >> 2);
    return 0;
}

/* ------ Compression ------ */

/*
 * Mode 2 Row compression routine for the HP DeskJet & LaserJet IIp.
 * Compresses data from row up to end_row, storing the result
 * starting at compressed.  Returns the number of bytes stored.
 * Runs of K<=127 literal bytes are encoded as K-1 followed by
 * the bytes; runs of 2<=K<=127 identical bytes are encoded as
 * 257-K followed by the byte.
 * In the worst case, the result is N+(N/127)+1 bytes long,
 * where N is the original byte count (end_row - row).
 * To speed up the search, we examine an entire word at a time.
 * We will miss a few blocks of identical bytes; tant pis.
 */
int
gdev_pcl_mode2compress_padded(const word * row, const word * end_row,
			      byte * compressed, bool pad)
{
    register const word *exam = row;	/* word being examined in the row to compress */
    register byte *cptr = compressed;	/* output pointer into compressed bytes */

    while (exam < end_row) {	/* Search ahead in the input looking for a run */
	/* of at least 4 identical bytes. */
	const byte *compr = (const byte *)exam;
	const byte *end_dis;
	const word *next;
	register word test = *exam;

	while (((test << 8) ^ test) > 0xff) {
	    if (++exam >= end_row)
		break;
	    test = *exam;
	}

	/* Find out how long the run is */
	end_dis = (const byte *)exam;
	if (exam == end_row) {	/* no run */
	    /* See if any of the last 3 "dissimilar" bytes are 0. */
	    if (!pad && end_dis > compr && end_dis[-1] == 0) {
		if (end_dis[-2] != 0)
		    end_dis--;
		else if (end_dis[-3] != 0)
		    end_dis -= 2;
		else
		    end_dis -= 3;
	    }
	    next = --end_row;
	} else {
	    next = exam + 1;
	    while (next < end_row && *next == test)
		next++;
	    /* See if any of the last 3 "dissimilar" bytes */
	    /* are the same as the repeated byte. */
	    if (end_dis > compr && end_dis[-1] == (byte) test) {
		if (end_dis[-2] != (byte) test)
		    end_dis--;
		else if (end_dis[-3] != (byte) test)
		    end_dis -= 2;
		else
		    end_dis -= 3;
	    }
	}

	/* Now [compr..end_dis) should be encoded as dissimilar, */
	/* and [end_dis..next) should be encoded as similar. */
	/* Note that either of these ranges may be empty. */

	for (;;) {		/* Encode up to 127 dissimilar bytes */
	    uint count = end_dis - compr;	/* uint for faster switch */

	    switch (count) {	/* Use memcpy only if it's worthwhile. */
		case 6:
		    cptr[6] = compr[5];
		case 5:
		    cptr[5] = compr[4];
		case 4:
		    cptr[4] = compr[3];
		case 3:
		    cptr[3] = compr[2];
		case 2:
		    cptr[2] = compr[1];
		case 1:
		    cptr[1] = compr[0];
		    *cptr = count - 1;
		    cptr += count + 1;
		case 0:	/* all done */
		    break;
		default:
		    if (count > 127)
			count = 127;
		    *cptr++ = count - 1;
		    memcpy(cptr, compr, count);
		    cptr += count, compr += count;
		    continue;
	    }
	    break;
	}

	{			/* Encode up to 127 similar bytes. */
	    /* Note that count may be <0 at end of row. */
	    int count = (const byte *)next - end_dis;

	    while (count > 0) {
		int this = (count > 127 ? 127 : count);

		*cptr++ = 257 - this;
		*cptr++ = (byte) test;
		count -= this;
	    }
	    exam = next;
	}
    }
    return (cptr - compressed);
}
int
gdev_pcl_mode2compress(const word * row, const word * end_row,
		       byte * compressed)
{
    return gdev_pcl_mode2compress_padded(row, end_row, compressed, false);
}

/*
 * Mode 3 compression routine for the HP LaserJet III family.
 * Compresses bytecount bytes starting at current, storing the result
 * in compressed, comparing against and updating previous.
 * Returns the number of bytes stored.  In the worst case,
 * the number of bytes is bytecount+(bytecount/8)+1.
 */
int
gdev_pcl_mode3compress(int bytecount, const byte * current, byte * previous, byte * compressed)
{
    register const byte *cur = current;
    register byte *prev = previous;
    register byte *out = compressed;
    const byte *end = current + bytecount;

    while (cur < end) {		/* Detect a maximum run of unchanged bytes. */
	const byte *run = cur;
	register const byte *diff;
	const byte *stop;
	int offset, cbyte;

	while (cur < end && *cur == *prev) {
	    cur++, prev++;
	}
	if (cur == end)
	    break;		/* rest of row is unchanged */
	/* Detect a run of up to 8 changed bytes. */
	/* We know that *cur != *prev. */
	diff = cur;
	stop = (end - cur > 8 ? cur + 8 : end);
	do {
	    *prev++ = *cur++;
	}
	while (cur < stop && *cur != *prev);
	/* Now [run..diff) are unchanged, and */
	/* [diff..cur) are changed. */
	/* Generate the command byte(s). */
	offset = diff - run;
	cbyte = (cur - diff - 1) << 5;
	if (offset < 31)
	    *out++ = cbyte + offset;
	else {
	    *out++ = cbyte + 31;
	    offset -= 31;
	    while (offset >= 255)
		*out++ = 255, offset -= 255;
	    *out++ = offset;
	}
	/* Copy the changed data. */
	while (diff < cur)
	    *out++ = *diff++;
    }
    return out - compressed;
}

/*
 * Mode 9 2D compression for the HP DeskJets . This mode can give
 * very good compression ratios, especially if there are areas of flat
 * colour (or blank areas), and so is 'highly recommended' for colour
 * printing in particular because of the very large amounts of data which
 * can be generated
 */
int
gdev_pcl_mode9compress(int bytecount, const byte *current,
		       const byte *previous, byte *compressed)
{
    register const byte *cur = current;
    register const byte *prev = previous;
    register byte *out = compressed;
    const byte *end = current + bytecount;

    while (cur < end) {		/* Detect a run of unchanged bytes. */
	const byte *run = cur;
	register const byte *diff;
	int offset;

	while (cur < end && *cur == *prev) {
	    cur++, prev++;
	}
	if (cur == end)
	    break;		/* rest of row is unchanged */
	/* Detect a run of changed bytes. */
	/* We know that *cur != *prev. */
	diff = cur;
	do {
	    prev++;
	    cur++;
	}
	while (cur < end && *cur != *prev);
	/* Now [run..diff) are unchanged, and */
	/* [diff..cur) are changed. */
	offset = diff - run;
	{
	    const byte *stop_test = cur - 4;
	    int dissimilar, similar;

	    while (diff < cur) {
		const byte *compr = diff;
		const byte *next;	/* end of run */
		byte value = 0;

		while (diff <= stop_test &&
		       ((value = *diff) != diff[1] ||
			value != diff[2] ||
			value != diff[3]))
		    diff++;

		/* Find out how long the run is */
		if (diff > stop_test)	/* no run */
		    next = diff = cur;
		else {
		    next = diff + 4;
		    while (next < cur && *next == value)
			next++;
		}

#define MAXOFFSETU 15
#define MAXCOUNTU 7
		/* output 'dissimilar' bytes, uncompressed */
		if ((dissimilar = diff - compr)) {
		    int temp, i;

		    if ((temp = --dissimilar) > MAXCOUNTU)
			temp = MAXCOUNTU;
		    if (offset < MAXOFFSETU)
			*out++ = (offset << 3) | (byte) temp;
		    else {
			*out++ = (MAXOFFSETU << 3) | (byte) temp;
			offset -= MAXOFFSETU;
			while (offset >= 255) {
			    *out++ = 255;
			    offset -= 255;
			}
			*out++ = offset;
		    }
		    if (temp == MAXCOUNTU) {
			temp = dissimilar - MAXCOUNTU;
			while (temp >= 255) {
			    *out++ = 255;
			    temp -= 255;
			}
			*out++ = (byte) temp;
		    }
		    for (i = 0; i <= dissimilar; i++)
			*out++ = *compr++;
		    offset = 0;
		}		/* end uncompressed */
#undef MAXOFFSETU
#undef MAXCOUNTU

#define MAXOFFSETC 3
#define MAXCOUNTC 31
		/* output 'similar' bytes, run-length encoded */
		if ((similar = next - diff)) {
		    int temp;

		    if ((temp = (similar -= 2)) > MAXCOUNTC)
			temp = MAXCOUNTC;
		    if (offset < MAXOFFSETC)
			*out++ = 0x80 | (offset << 5) | (byte) temp;
		    else {
			*out++ = 0x80 | (MAXOFFSETC << 5) | (byte) temp;
			offset -= MAXOFFSETC;
			while (offset >= 255) {
			    *out++ = 255;
			    offset -= 255;
			}
			*out++ = offset;
		    }
		    if (temp == MAXCOUNTC) {
			temp = similar - MAXCOUNTC;
			while (temp >= 255) {
			    *out++ = 255;
			    temp -= 255;
			}
			*out++ = (byte) temp;
		    }
		    *out++ = value;
		    offset = 0;
		}		/* end compressed */
#undef MAXOFFSETC
#undef MAXCOUNTC

		diff = next;
	    }
	}
    }
    return out - compressed;
}