/* Copyright (C) 1989, 1995, 1996, 1997, 1998, 2000 artofcode LLC.  All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.

*/

/*$Id: gximono.c,v 1.2.6.1.2.1 2003/01/17 00:49:04 giles Exp $ */
/* General mono-component image rendering */
#include "gx.h"
#include "memory_.h"
#include "gpcheck.h"
#include "gserrors.h"
#include "gxfixed.h"
#include "gxarith.h"
#include "gxmatrix.h"
#include "gsccolor.h"
#include "gspaint.h"
#include "gsutil.h"
#include "gxdevice.h"
#include "gxcmap.h"
#include "gxdcolor.h"
#include "gxistate.h"
#include "gxdevmem.h"
#include "gdevmem.h"		/* for mem_mono_device */
#include "gxcpath.h"
#include "gximage.h"
#include "gzht.h"

/* ------ Strategy procedure ------ */

/* Check the prototype. */
iclass_proc(gs_image_class_3_mono);

private irender_proc(image_render_mono);
irender_proc_t
gs_image_class_3_mono(gx_image_enum * penum)
{
    if (penum->spp == 1) {
	/*
	 * Use the slow loop for imagemask with a halftone or a non-default
	 * logical operation.
	 */
	penum->slow_loop =
	    (penum->masked && !color_is_pure(&penum->icolor1)) ||
	    penum->use_rop;
	/* We can bypass X clipping for portrait mono-component images. */
	if (!(penum->slow_loop || penum->posture != image_portrait))
	    penum->clip_image &= ~(image_clip_xmin | image_clip_xmax);
	if_debug0('b', "[b]render=mono\n");
	/* Precompute values needed for rasterizing. */
	penum->dxx =
	    float2fixed(penum->matrix.xx + fixed2float(fixed_epsilon) / 2);
	/*
	 * Scale the mask colors to match the scaling of each sample to a
	 * full byte.  Also, if black or white is transparent, reset icolor0
	 * or icolor1, which are used directly in the fast case loop.
	 */
	if (penum->use_mask_color) {
	    gx_image_scale_mask_colors(penum, 0);
	    if (penum->mask_color.values[0] <= 0)
		color_set_null(&penum->icolor0);
	    if (penum->mask_color.values[1] >= 255)
		color_set_null(&penum->icolor1);
	}
	return image_render_mono;
    }
    return 0;
}

/* ------ Rendering procedure ------ */

/* Provide a fake map_gray procedure for the DevicePixel color space. */
private void
no_map_gray(frac pixel, gx_device_color * pdc, const gs_imager_state * pis,
	    gx_device * dev, gs_color_select_t select)
{
    color_set_pure(pdc, frac2byte(pixel));
}

/*
 * Rendering procedure for general mono-component images, dealing with
 * multiple bit-per-sample images, general transformations, arbitrary
 * single-component color spaces (DeviceGray, DevicePixel, CIEBasedA,
 * Separation, Indexed), and color masking. This procedure handles a
 * single scan line.
 */
private int
image_render_mono(gx_image_enum * penum, const byte * buffer, int data_x,
		  uint w, int h, gx_device * dev)
{
    const gs_imager_state *pis = penum->pis;
    gs_logical_operation_t lop = penum->log_op;
    const bool masked = penum->masked;
    const gs_color_space *pcs;	/* only set for non-masks */
    cmap_proc_gray((*map_gray));	/* ditto */
    cs_proc_remap_color((*remap_color));	/* ditto */
    gs_client_color cc;
    gx_device_color *pdevc = &penum->icolor1;	/* color for masking */
    /*
     * Make sure the cache setup matches the graphics state.  Also determine
     * whether all tiles fit in the cache.  We may bypass the latter check
     * for masked images with a pure color.
     */
    bool tiles_fit =
	(pis && penum->device_color ? gx_check_tile_cache(pis) : false);
    uint mask_base = penum->mask_color.values[0];
    uint mask_limit =
	(penum->use_mask_color ?
	 penum->mask_color.values[1] - mask_base + 1 : 0);
/*
 * Free variables of IMAGE_SET_GRAY:
 *   Read: penum, pis, dev, tiles_fit, mask_base, mask_limit
 *   Set: pdevc, code, cc
 */
#define IMAGE_SET_GRAY(sample_value)\
  BEGIN\
    pdevc = &penum->clues[sample_value].dev_color;\
    if (!color_is_set(pdevc)) {\
	if ((uint)(sample_value - mask_base) < mask_limit)\
	    color_set_null(pdevc);\
	else if (penum->device_color)\
	    (*map_gray)(byte2frac(sample_value), pdevc, pis, dev, gs_color_select_source);\
	else {\
	    decode_sample(sample_value, cc, 0);\
	    code = (*remap_color)(&cc, pcs, pdevc, pis, dev, gs_color_select_source);\
	    if (code < 0)\
		goto err;\
	}\
    } else if (!color_is_pure(pdevc)) {\
	if (!tiles_fit) {\
	    code = gx_color_load_select(pdevc, pis, dev, gs_color_select_source);\
	    if (code < 0)\
		goto err;\
	}\
    }\
  END
    gx_dda_fixed_point next;	/* (y not used in fast loop) */
    gx_dda_step_fixed dxx2, dxx3, dxx4;		/* (not used in all loops) */
    const byte *psrc_initial = buffer + data_x;
    const byte *psrc = psrc_initial;
    const byte *rsrc = psrc;	/* psrc at start of run */
    const byte *endp = psrc + w;
    const byte *stop = endp;
    fixed xrun;			/* x at start of run */
    byte run;		/* run value */
    int htrun = (masked ? 255 : -2);		/* halftone run value */
    int code = 0;

    if (h == 0)
	return 0;
    next = penum->dda.pixel0;
    xrun = dda_current(next.x);
    if (!masked) {
	pcs = penum->pcs;	/* (may not be set for masks) */
	if (penum->device_color)
	    map_gray =
		(gs_color_space_get_index(pcs) ==
		 gs_color_space_index_DeviceGray ?
		 gx_get_cmap_procs(pis, dev)->map_gray :
		 no_map_gray /*DevicePixel */ );
	else
	    remap_color = pcs->type->remap_color;
    }
    run = *psrc;
    /* Find the last transition in the input. */
    {
	byte last = stop[-1];

	while (stop > psrc && stop[-1] == last)
	    --stop;
    }
    if (penum->slow_loop || penum->posture != image_portrait) {

	/**************************************************************
	 * Slow case (skewed, rotated, or imagemask with a halftone). *
	 **************************************************************/

	fixed yrun;
	const fixed pdyx = dda_current(penum->dda.row.x) - penum->cur.x;
	const fixed pdyy = dda_current(penum->dda.row.y) - penum->cur.y;
	dev_proc_fill_parallelogram((*fill_pgram)) =
	    dev_proc(dev, fill_parallelogram);

#define xl dda_current(next.x)
#define ytf dda_current(next.y)
	yrun = ytf;
	if (masked) {

	    /**********************
	     * Slow case, masked. *
	     **********************/

	    pdevc = &penum->icolor1;
	    code = gx_color_load(pdevc, pis, dev);
	    if (code < 0)
		return code;
	    if (stop <= psrc)
		goto last;
	    if (penum->posture == image_portrait) {

		/********************************
		 * Slow case, masked, portrait. *
		 ********************************/

		/*
		 * We don't have to worry about the Y DDA, and the fill
		 * regions are rectangles.  Calculate multiples of the DDA
		 * step.
		 */
		fixed ax =
		    (penum->matrix.xx < 0 ? -penum->adjust : penum->adjust);
		fixed ay =
		    (pdyy < 0 ? -penum->adjust : penum->adjust);
		fixed dyy = pdyy + (ay << 1);

		yrun -= ay;
		dda_translate(next.x, -ax);
		ax <<= 1;
		dxx2 = next.x.step;
		dda_step_add(dxx2, next.x.step);
		dxx3 = dxx2;
		dda_step_add(dxx3, next.x.step);
		dxx4 = dxx3;
		dda_step_add(dxx4, next.x.step);
		for (;;) {	/* Skip a run of zeros. */
		    while (!psrc[0])
			if (!psrc[1]) {
			    if (!psrc[2]) {
				if (!psrc[3]) {
				    psrc += 4;
				    dda_state_next(next.x.state, dxx4);
				    continue;
				}
				psrc += 3;
				dda_state_next(next.x.state, dxx3);
				break;
			    }
			    psrc += 2;
			    dda_state_next(next.x.state, dxx2);
			    break;
			} else {
			    ++psrc;
			    dda_next(next.x);
			    break;
			}
		    xrun = xl;
		    if (psrc >= stop)
			break;
		    for (; *psrc; ++psrc)
			dda_next(next.x);
		    code = (*fill_pgram)(dev, xrun, yrun,
					 xl - xrun + ax, fixed_0, fixed_0, dyy,
					 pdevc, lop);
		    if (code < 0)
			goto err;
		    rsrc = psrc;
		    if (psrc >= stop)
			break;
		}

	    } else if (penum->posture == image_landscape) {

		/*********************************
		 * Slow case, masked, landscape. *
		 *********************************/

		/*
		 * We don't have to worry about the X DDA.  However, we do
		 * have to take adjustment into account.  We don't bother to
		 * optimize this as heavily as the portrait case.
		 */
		fixed ax =
		    (pdyx < 0 ? -penum->adjust : penum->adjust);
		fixed dyx = pdyx + (ax << 1);
		fixed ay =
		    (penum->matrix.xy < 0 ? -penum->adjust : penum->adjust);

		xrun -= ax;
		dda_translate(next.y, -ay);
		ay <<= 1;
		for (;;) {
		    for (; !*psrc; ++psrc)
			dda_next(next.y);
		    yrun = ytf;
		    if (psrc >= stop)
			break;
		    for (; *psrc; ++psrc)
			dda_next(next.y);
		    code = (*fill_pgram)(dev, xrun, yrun, fixed_0,
					 ytf - yrun + ay, dyx, fixed_0,
					 pdevc, lop);
		    if (code < 0)
			goto err;
		    rsrc = psrc;
		    if (psrc >= stop)
			break;
		}

	    } else {

		/**************************************
		 * Slow case, masked, not orthogonal. *
		 **************************************/

		for (;;) {
		    for (; !*psrc; ++psrc) {
			dda_next(next.x);
			dda_next(next.y);
		    }
		    yrun = ytf;
		    xrun = xl;
		    if (psrc >= stop)
			break;
		    for (; *psrc; ++psrc) {
			dda_next(next.x);
			dda_next(next.y);
		    }
		    code = (*fill_pgram)(dev, xrun, yrun, xl - xrun,
					 ytf - yrun, pdyx, pdyy, pdevc, lop);
		    if (code < 0)
			goto err;
		    rsrc = psrc;
		    if (psrc >= stop)
			break;
		}

	    }

	} else if (penum->posture == image_portrait ||
		   penum->posture == image_landscape
	    ) {

	    /**************************************
	     * Slow case, not masked, orthogonal. *
	     **************************************/

	    /* In this case, we can fill runs quickly. */
	    /****** DOESN'T DO ADJUSTMENT ******/
	    if (stop <= psrc)
		goto last;
	    for (;;) {
		if (*psrc != run) {
		    if (run != htrun) {
			htrun = run;
			IMAGE_SET_GRAY(run);
		    }
		    code = (*fill_pgram)(dev, xrun, yrun, xl - xrun,
					 ytf - yrun, pdyx, pdyy,
					 pdevc, lop);
		    if (code < 0)
			goto err;
		    yrun = ytf;
		    xrun = xl;
		    rsrc = psrc;
		    if (psrc >= stop)
			break;
		    run = *psrc;
		}
		psrc++;
		dda_next(next.x);
		dda_next(next.y);
	    }
	} else {

	    /******************************************
	     * Slow case, not masked, not orthogonal. *
	     ******************************************/

	    /*
	     * Since we have to check for the end after every pixel
	     * anyway, we may as well avoid the last-run code.
	     */
	    stop = endp;
	    for (;;) {
		/* We can't skip large constant regions quickly, */
		/* because this leads to rounding errors. */
		/* Just fill the region between xrun and xl. */
		if (run != htrun) {
		    htrun = run;
		    IMAGE_SET_GRAY(run);
		}
		code = (*fill_pgram) (dev, xrun, yrun, xl - xrun,
				      ytf - yrun, pdyx, pdyy, pdevc, lop);
		if (code < 0)
		    goto err;
		yrun = ytf;
		xrun = xl;
		rsrc = psrc;
		if (psrc >= stop)
		    break;
		run = *psrc++;
		dda_next(next.x);
		dda_next(next.y);	/* harmless if no skew */
	    }

	}
	/* Fill the last run. */
      last:if (stop < endp && (*stop || !masked)) {
	    if (!masked) {
		IMAGE_SET_GRAY(*stop);
	    }
	    dda_advance(next.x, endp - stop);
	    dda_advance(next.y, endp - stop);
	    code = (*fill_pgram) (dev, xrun, yrun, xl - xrun,
				  ytf - yrun, pdyx, pdyy, pdevc, lop);
	}
#undef xl
#undef ytf

    } else {

	/**********************************************************
	 * Fast case: no skew, and not imagemask with a halftone. *
	 **********************************************************/

	const fixed adjust = penum->adjust;
	const fixed dxx = penum->dxx;
	fixed xa = (dxx >= 0 ? adjust : -adjust);
	const int yt = penum->yci, iht = penum->hci;

	dev_proc_fill_rectangle((*fill_proc)) =
	    dev_proc(dev, fill_rectangle);
	dev_proc_strip_tile_rectangle((*tile_proc)) =
	    dev_proc(dev, strip_tile_rectangle);
	dev_proc_copy_mono((*copy_mono_proc)) =
	    dev_proc(dev, copy_mono);
	/*
	 * If each pixel is likely to fit in a single halftone tile,
	 * determine that now (tile_offset = offset of row within tile).
	 * Don't do this for band devices; they handle halftone fills
	 * more efficiently than copy_mono.
	 */
	int bstart;
	int phase_x;
	int tile_offset =
	    (pis && penum->device_color &&
	     (*dev_proc(dev, get_band)) (dev, yt, &bstart) == 0 ?
	     gx_check_tile_size(pis,
				fixed2int_ceiling(any_abs(dxx) + (xa << 1)),
				yt, iht, gs_color_select_source, &phase_x) :
	     -1);
	int xmin = fixed2int_pixround(penum->clip_outer.p.x);
	int xmax = fixed2int_pixround(penum->clip_outer.q.x);

#define xl dda_current(next.x)
	/* Fold the adjustment into xrun and xl, */
	/* including the +0.5-epsilon for rounding. */
	xrun = xrun - xa + (fixed_half - fixed_epsilon);
	dda_translate(next.x, xa + (fixed_half - fixed_epsilon));
	xa <<= 1;
	/* Calculate multiples of the DDA step. */
	dxx2 = next.x.step;
	dda_step_add(dxx2, next.x.step);
	dxx3 = dxx2;
	dda_step_add(dxx3, next.x.step);
	dxx4 = dxx3;
	dda_step_add(dxx4, next.x.step);
	if (stop > psrc)
	    for (;;) {		/* Skip large constant regions quickly, */
		/* but don't slow down transitions too much. */
	      skf:if (psrc[0] == run) {
		    if (psrc[1] == run) {
			if (psrc[2] == run) {
			    if (psrc[3] == run) {
				psrc += 4;
				dda_state_next(next.x.state, dxx4);
				goto skf;
			    } else {
				psrc += 4;
				dda_state_next(next.x.state, dxx3);
			    }
			} else {
			    psrc += 3;
			    dda_state_next(next.x.state, dxx2);
			}
		    } else {
			psrc += 2;
			dda_next(next.x);
		    }
		} else
		    psrc++;
		{		/* Now fill the region between xrun and xl. */
		    int xi = fixed2int_var(xrun);
		    int wi = fixed2int_var(xl) - xi;
		    int xei, tsx;
		    const gx_strip_bitmap *tile;

		    if (wi <= 0) {
			if (wi == 0)
			    goto mt;
			xi += wi, wi = -wi;
		    }
		    if ((xei = xi + wi) > xmax || xi < xmin) {	/* Do X clipping */
			if (xi < xmin)
			    wi -= xmin - xi, xi = xmin;
			if (xei > xmax)
			    wi -= xei - xmax;
			if (wi <= 0)
			    goto mt;
		    }
		    switch (run) {
			case 0:
			    if (masked)
				goto mt;
			    if (!color_is_pure(&penum->icolor0))
				goto ht;
			    code = (*fill_proc) (dev, xi, yt, wi, iht,
						 penum->icolor0.colors.pure);
			    break;
			case 255:	/* just for speed */
			    if (!color_is_pure(&penum->icolor1))
				goto ht;
			    code = (*fill_proc) (dev, xi, yt, wi, iht,
						 penum->icolor1.colors.pure);
			    break;
			default:
			  ht:	/* Use halftone if needed */
			    if (run != htrun) {
				IMAGE_SET_GRAY(run);
				htrun = run;
			    }
			    /* We open-code gx_fill_rectangle, */
			    /* because we've done some of the work for */
			    /* halftone tiles in advance. */
			    if (color_is_pure(pdevc)) {
				code = (*fill_proc) (dev, xi, yt, wi, iht,
						     pdevc->colors.pure);
			    } else if (!color_is_binary_halftone(pdevc)) {
				code =
				    gx_fill_rectangle_device_rop(xi, yt, wi, iht,
							   pdevc, dev, lop);
			    } else if (tile_offset >= 0 &&
				(tile = &pdevc->colors.binary.b_tile->tiles,
				 (tsx = (xi + phase_x) % tile->rep_width) + wi <= tile->size.x)
				) {	/* The pixel(s) fit(s) in a single (binary) tile. */
				byte *row = tile->data + tile_offset;

				code = (*copy_mono_proc)
				    (dev, row, tsx, tile->raster, gx_no_bitmap_id,
				     xi, yt, wi, iht,
				     pdevc->colors.binary.color[0],
				     pdevc->colors.binary.color[1]);
			    } else {
				code = (*tile_proc) (dev,
					&pdevc->colors.binary.b_tile->tiles,
						     xi, yt, wi, iht,
					      pdevc->colors.binary.color[0],
					      pdevc->colors.binary.color[1],
					    pdevc->phase.x, pdevc->phase.y);
			    }
		    }
		    if (code < 0)
			goto err;
		  mt:xrun = xl - xa;	/* original xa << 1 */
		    rsrc = psrc - 1;
		    if (psrc > stop) {
			--psrc;
			break;
		    }
		    run = psrc[-1];
		}
		dda_next(next.x);
	    }
	/* Fill the last run. */
	if (*stop != 0 || !masked) {
	    int xi = fixed2int_var(xrun);
	    int wi, xei;

	    dda_advance(next.x, endp - stop);
	    wi = fixed2int_var(xl) - xi;
	    if (wi <= 0) {
		if (wi == 0)
		    goto lmt;
		xi += wi, wi = -wi;
	    }
	    if ((xei = xi + wi) > xmax || xi < xmin) {	/* Do X clipping */
		if (xi < xmin)
		    wi -= xmin - xi, xi = xmin;
		if (xei > xmax)
		    wi -= xei - xmax;
		if (wi <= 0)
		    goto lmt;
	    }
	    IMAGE_SET_GRAY(*stop);
	    code = gx_fill_rectangle_device_rop(xi, yt, wi, iht,
						pdevc, dev, lop);
	  lmt:;
	}

    }
#undef xl
    if (code >= 0)
	return 1;
    /* Save position if error, in case we resume. */
err:
    penum->used.x = rsrc - psrc_initial;
    penum->used.y = 0;
    return code;
}