/* Copyright (C) 1989, 1995, 1996, 1997, 1998, 2000 Aladdin Enterprises.  All rights reserved.
  
  This software is provided AS-IS with no warranty, either express or
  implied.
  
  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: gximono.c,v 1.10.2.1 2003/12/12 22:08:04 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 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 = NULL;	/* only set for non-masks */
    cs_proc_remap_color((*remap_color)) = NULL;	/* ditto */
    gs_client_color cc;
    gx_device_color *pdevc = &penum->icolor1;	/* color for masking */
    bool tiles_fit;
    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 {\
	    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;
    /*
     * 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.
     */

    /* TO_DO_DEVICEN - The gx_check_tile_cache_current() routine is bogus */

    if (pis == 0 || !gx_check_tile_cache_current(pis)) {
        image_init_clues(penum, penum->bps, penum->spp);
    }
    tiles_fit = (pis && penum->device_color ? gx_check_tile_cache(pis) : false);
    next = penum->dda.pixel0;
    xrun = dda_current(next.x);
    if (!masked) {
	pcs = penum->pcs;	/* (may not be set for masks) */
        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);
	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;

		    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;
			    }
                            code = gx_fill_rectangle_device_rop(xi, yt, wi, iht,
                                                                 pdevc, dev, lop);

		    }
		    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;
}
