/* Copyright (C) 1997, 1998, 1999 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: gxclrect.c,v 1.2.6.1.2.1 2003/01/17 00:49:03 giles Exp $ */
/* Rectangle-oriented command writing for command list */
#include "gx.h"
#include "gserrors.h"
#include "gsutil.h"		/* for gs_next_ids */
#include "gxdevice.h"
#include "gxdevmem.h"		/* must precede gxcldev.h */
#include "gxcldev.h"

/* ---------------- Writing utilities ---------------- */

#define cmd_set_rect(rect)\
  ((rect).x = x, (rect).y = y,\
   (rect).width = width, (rect).height = height)

/* Write a rectangle. */
private int
cmd_size_rect(register const gx_cmd_rect * prect)
{
    return
	cmd_sizew(prect->x) + cmd_sizew(prect->y) +
	cmd_sizew(prect->width) + cmd_sizew(prect->height);
}
private byte *
cmd_put_rect(register const gx_cmd_rect * prect, register byte * dp)
{
    cmd_putw(prect->x, dp);
    cmd_putw(prect->y, dp);
    cmd_putw(prect->width, dp);
    cmd_putw(prect->height, dp);
    return dp;
}

int
cmd_write_rect_cmd(gx_device_clist_writer * cldev, gx_clist_state * pcls,
		   int op, int x, int y, int width, int height)
{
    int dx = x - pcls->rect.x;
    int dy = y - pcls->rect.y;
    int dwidth = width - pcls->rect.width;
    int dheight = height - pcls->rect.height;
    byte *dp;
    int code;

#define check_range_xy(rmin, rmax)\
  ((unsigned)(dx - rmin) <= (rmax - rmin) &&\
   (unsigned)(dy - rmin) <= (rmax - rmin))
#define check_range_w(rmin, rmax)\
  ((unsigned)(dwidth - rmin) <= (rmax - rmin))
#define check_ranges(rmin, rmax)\
  (check_range_xy(rmin, rmax) && check_range_w(rmin, rmax) &&\
   (unsigned)(dheight - rmin) <= (rmax - rmin))
    cmd_set_rect(pcls->rect);
    if (dheight == 0 && check_range_w(cmd_min_dw_tiny, cmd_max_dw_tiny) &&
	check_range_xy(cmd_min_dxy_tiny, cmd_max_dxy_tiny)
	) {
	byte op_tiny = op + 0x20 + dwidth - cmd_min_dw_tiny;

	if (dx == width - dwidth && dy == 0) {
	    code = set_cmd_put_op(dp, cldev, pcls, op_tiny + 8, 1);
	    if (code < 0)
		return code;
	} else {
	    code = set_cmd_put_op(dp, cldev, pcls, op_tiny, 2);
	    if (code < 0)
		return code;
	    dp[1] = (dx << 4) + dy - (cmd_min_dxy_tiny * 0x11);
	}
    }
#define rmin cmd_min_short
#define rmax cmd_max_short
    else if (check_ranges(rmin, rmax)) {
	int dh = dheight - cmd_min_dxy_tiny;

	if ((unsigned)dh <= cmd_max_dxy_tiny - cmd_min_dxy_tiny &&
	    dh != 0 && dy == 0
	    ) {
	    op += dh;
	    code = set_cmd_put_op(dp, cldev, pcls, op + 0x10, 3);
	    if (code < 0)
		return code;
	    if_debug3('L', "    rs2:%d,%d,0,%d\n",
		      dx, dwidth, dheight);
	} else {
	    code = set_cmd_put_op(dp, cldev, pcls, op + 0x10, 5);
	    if (code < 0)
		return code;
	    if_debug4('L', "    rs4:%d,%d,%d,%d\n",
		      dx, dwidth, dy, dheight);
	    dp[3] = dy - rmin;
	    dp[4] = dheight - rmin;
	}
	dp[1] = dx - rmin;
	dp[2] = dwidth - rmin;
    }
#undef rmin
#undef rmax
    else if (dy >= -2 && dy <= 1 && dheight >= -2 && dheight <= 1 &&
	     (dy + dheight) != -4
	) {
	int rcsize = 1 + cmd_sizew(x) + cmd_sizew(width);

	code = set_cmd_put_op(dp, cldev, pcls,
			      op + ((dy + 2) << 2) + dheight + 2, rcsize);
	if (code < 0)
	    return code;
	++dp;
	cmd_put2w(x, width, dp);
    } else {
	int rcsize = 1 + cmd_size_rect(&pcls->rect);

	code = set_cmd_put_op(dp, cldev, pcls, op, rcsize);
	if (code < 0)
	    return code;
	if_debug5('L', "    r%d:%d,%d,%d,%d\n",
		  rcsize - 1, dx, dwidth, dy, dheight);
	cmd_put_rect(&pcls->rect, dp + 1);
    }
    return 0;
}

/* ---------------- Driver procedures ---------------- */

int
clist_fill_rectangle(gx_device * dev, int x, int y, int width, int height,
		     gx_color_index color)
{
    gx_device_clist_writer * const cdev =
	&((gx_device_clist *)dev)->writer;
    int code;

    fit_fill(dev, x, y, width, height);
    FOR_RECTS {
	pcls->colors_used.or |= color;
	TRY_RECT {
	    code = cmd_disable_lop(cdev, pcls);
	    if (code >= 0 && color != pcls->colors[1])
		code = cmd_put_color(cdev, pcls, &clist_select_color1,
				     color, &pcls->colors[1]);
	    if (code >= 0)
		code = cmd_write_rect_cmd(cdev, pcls, cmd_op_fill_rect, x, y,
					  width, height);
	} HANDLE_RECT(code);
    } END_RECTS;
    return 0;
}

int
clist_strip_tile_rectangle(gx_device * dev, const gx_strip_bitmap * tile,
			   int x, int y, int width, int height,
	       gx_color_index color0, gx_color_index color1, int px, int py)
{
    gx_device_clist_writer * const cdev =
	&((gx_device_clist *)dev)->writer;
    int depth =
	(color1 == gx_no_color_index && color0 == gx_no_color_index ?
	 dev->color_info.depth : 1);
    gx_color_index colors_used =
	(color1 == gx_no_color_index && color0 == gx_no_color_index ?
	 /* We can't know what colors will be used: assume the worst. */
	 ((gx_color_index)1 << depth) - 1 :
	 (color0 == gx_no_color_index ? 0 : color0) |
	 (color1 == gx_no_color_index ? 0 : color1));
    int code;

    fit_fill(dev, x, y, width, height);
    FOR_RECTS {
	ulong offset_temp;

	pcls->colors_used.or |= colors_used;
	TRY_RECT {
	    code = cmd_disable_lop(cdev, pcls);
	} HANDLE_RECT(code);
	if (!cls_has_tile_id(cdev, pcls, tile->id, offset_temp)) {
	    code = 0;
	    if (tile->id != gx_no_bitmap_id) {
		TRY_RECT {
		    code = clist_change_tile(cdev, pcls, tile, depth);
		} HANDLE_RECT_UNLESS(code,
		    (code != gs_error_VMerror || !cdev->error_is_retryable));
	    }
	    if (code < 0) {
		/* ok if gx_default... does retries internally: */
		/* it's self-sufficient */
		code = gx_default_strip_tile_rectangle(dev, tile,
						       x, y, width, height,
						       color0, color1,
						       px, py);
		if (code < 0)
		    ERROR_RECT(code);
		goto endr;
	    }
	}
	TRY_RECT {
	    code = 0;
	    if (color0 != pcls->tile_colors[0] || color1 != pcls->tile_colors[1])
		code = cmd_set_tile_colors(cdev, pcls, color0, color1);
	    if (px != pcls->tile_phase.x || py != pcls->tile_phase.y) {
		if (code >= 0)
		    code = cmd_set_tile_phase(cdev, pcls, px, py);
	    }
	    if (code >= 0)
		code = cmd_write_rect_cmd(cdev, pcls, cmd_op_tile_rect, x, y,
					  width, height);
	} HANDLE_RECT(code);
endr:;
    } END_RECTS;
    return 0;
}

int
clist_copy_mono(gx_device * dev,
		const byte * data, int data_x, int raster, gx_bitmap_id id,
		int x, int y, int width, int height,
		gx_color_index color0, gx_color_index color1)
{
    gx_device_clist_writer * const cdev =
	&((gx_device_clist *)dev)->writer;
    int y0;
    gx_bitmap_id orig_id = id;
    gx_color_index colors_used =
	(color0 == gx_no_color_index ? 0 : color0) |
	(color1 == gx_no_color_index ? 0 : color1);

    fit_copy(dev, data, data_x, raster, id, x, y, width, height);
    y0 = y;
    FOR_RECTS {
	int dx = data_x & 7;
	int w1 = dx + width;
	const byte *row = data + (y - y0) * raster + (data_x >> 3);
	int code;

	pcls->colors_used.or |= colors_used;
	TRY_RECT {
	    code = cmd_disable_lop(cdev, pcls);
	    if (code >= 0)
		code = cmd_disable_clip(cdev, pcls);
	    if (color0 != pcls->colors[0] && code >= 0)
		code = cmd_set_color0(cdev, pcls, color0);
	    if (color1 != pcls->colors[1] && code >= 0)
		code = cmd_set_color1(cdev, pcls, color1);
	} HANDLE_RECT(code);
	/* Don't bother to check for a possible cache hit: */
	/* tile_rectangle and fill_mask handle those cases. */
copy:{
	gx_cmd_rect rect;
	int rsize;
	byte op = (byte) cmd_op_copy_mono;
	byte *dp;
	uint csize;
	uint compress;
	int code;

	rect.x = x, rect.y = y;
	rect.width = w1, rect.height = height;
	rsize = (dx ? 3 : 1) + cmd_size_rect(&rect);
	TRY_RECT {
	    code = cmd_put_bits(cdev, pcls, row, w1, height, raster,
				rsize, (orig_id == gx_no_bitmap_id ?
					1 << cmd_compress_rle :
					cmd_mask_compress_any),
				&dp, &csize);
	} HANDLE_RECT_UNLESS(code, code == gs_error_limitcheck);
	compress = (uint)code;
	if (code < 0) {
	    /* The bitmap was too large; split up the transfer. */
	    if (height > 1) {
		/*
		 * Split the transfer by reducing the height.
		 * See the comment above FOR_RECTS in gxcldev.h.
		 */
		height >>= 1;
		goto copy;
	    } else {
		/* Split a single (very long) row. */
		int w2 = w1 >> 1;

		NEST_RECT {
		    code = clist_copy_mono(dev, row, dx,
					   raster, gx_no_bitmap_id, x, y,
					   w2, 1, color0, color1);
		    if (code >= 0)
			code = clist_copy_mono(dev, row, dx + w2,
					       raster, gx_no_bitmap_id,
					       x + w2, y,
					       w1 - w2, 1, color0, color1);
		} UNNEST_RECT;
		if (code < 0)
		    ERROR_RECT(code);
		continue;
	    }
	}
	op += compress;
	if (dx) {
	    *dp++ = cmd_count_op(cmd_opv_set_misc, 2);
	    *dp++ = cmd_set_misc_data_x + dx;
	}
	*dp++ = cmd_count_op(op, csize);
	cmd_put2w(x, y, dp);
	cmd_put2w(w1, height, dp);
	pcls->rect = rect;
	}
    } END_RECTS;
    return 0;
}

int
clist_copy_color(gx_device * dev,
		 const byte * data, int data_x, int raster, gx_bitmap_id id,
		 int x, int y, int width, int height)
{
    gx_device_clist_writer * const cdev =
	&((gx_device_clist *)dev)->writer;
    int depth = dev->color_info.depth;
    int y0;
    int data_x_bit;
    /* We can't know what colors will be used: assume the worst. */
    gx_color_index colors_used = ((gx_color_index)1 << depth) - 1;

    fit_copy(dev, data, data_x, raster, id, x, y, width, height);
    y0 = y;
    data_x_bit = data_x * depth;
    FOR_RECTS {
	int dx = (data_x_bit & 7) / depth;
	int w1 = dx + width;
	const byte *row = data + (y - y0) * raster + (data_x_bit >> 3);
	int code;

	pcls->colors_used.or |= colors_used;
	TRY_RECT {
	    code = cmd_disable_lop(cdev, pcls);
	    if (code >= 0)
		code = cmd_disable_clip(cdev, pcls);
	} HANDLE_RECT(code);
	if (pcls->color_is_alpha) {
	    byte *dp;

	    TRY_RECT {
		code =
		    set_cmd_put_op(dp, cdev, pcls, cmd_opv_set_copy_color, 1);
	    } HANDLE_RECT(code);
	    pcls->color_is_alpha = 0;
	}
copy:{
	    gx_cmd_rect rect;
	    int rsize;
	    byte op = (byte) cmd_op_copy_color_alpha;
	    byte *dp;
	    uint csize;
	    uint compress;

	    rect.x = x, rect.y = y;
	    rect.width = w1, rect.height = height;
	    rsize = (dx ? 3 : 1) + cmd_size_rect(&rect);
	    TRY_RECT {
		code = cmd_put_bits(cdev, pcls, row, w1 * depth,
				    height, raster, rsize,
				    1 << cmd_compress_rle, &dp, &csize);
	    } HANDLE_RECT_UNLESS(code, code == gs_error_limitcheck);
	    compress = (uint)code;
	    if (code < 0) {
		/* The bitmap was too large; split up the transfer. */
		if (height > 1) {
		    /* Split the transfer by reducing the height.
		     * See the comment above FOR_RECTS in gxcldev.h.
		     */
		    height >>= 1;
		    goto copy;
		} else {
		    /* Split a single (very long) row. */
		    int w2 = w1 >> 1;

		    NEST_RECT {
			code = clist_copy_color(dev, row, dx,
						raster, gx_no_bitmap_id,
						x, y, w2, 1);
			if (code >= 0)
			    code = clist_copy_color(dev, row, dx + w2,
						    raster, gx_no_bitmap_id,
						    x + w2, y, w1 - w2, 1);
		    } UNNEST_RECT;
		    if (code < 0)
			ERROR_RECT(code);
		    continue;
		}
	    }
	    op += compress;
	    if (dx) {
		*dp++ = cmd_count_op(cmd_opv_set_misc, 2);
		*dp++ = cmd_set_misc_data_x + dx;
	    }
	    *dp++ = cmd_count_op(op, csize);
	    cmd_put2w(x, y, dp);
	    cmd_put2w(w1, height, dp);
	    pcls->rect = rect;
	}
    } END_RECTS;
    return 0;
}

int
clist_copy_alpha(gx_device * dev, const byte * data, int data_x,
	   int raster, gx_bitmap_id id, int x, int y, int width, int height,
		 gx_color_index color, int depth)
{
    gx_device_clist_writer * const cdev =
	&((gx_device_clist *)dev)->writer;
    /* I don't like copying the entire body of clist_copy_color */
    /* just to change 2 arguments and 1 opcode, */
    /* but I don't see any alternative that doesn't require */
    /* another level of procedure call even in the common case. */
    int log2_depth = ilog2(depth);
    int y0;
    int data_x_bit;

    fit_copy(dev, data, data_x, raster, id, x, y, width, height);
    y0 = y;
    data_x_bit = data_x << log2_depth;
    FOR_RECTS {
	int dx = (data_x_bit & 7) >> log2_depth;
	int w1 = dx + width;
	const byte *row = data + (y - y0) * raster + (data_x_bit >> 3);
	int code;

	pcls->colors_used.or |= color;
	TRY_RECT {
	    code = cmd_disable_lop(cdev, pcls);
	    if (code >= 0)
		code = cmd_disable_clip(cdev, pcls);
	} HANDLE_RECT(code);
	if (!pcls->color_is_alpha) {
	    byte *dp;

	    TRY_RECT {
		code =
		    set_cmd_put_op(dp, cdev, pcls, cmd_opv_set_copy_alpha, 1);
	    } HANDLE_RECT(code);
	    pcls->color_is_alpha = 1;
	}
	if (color != pcls->colors[1]) {
	    TRY_RECT {
		code = cmd_set_color1(cdev, pcls, color);
	    } HANDLE_RECT(code);
	}
copy:{
	    gx_cmd_rect rect;
	    int rsize;
	    byte op = (byte) cmd_op_copy_color_alpha;
	    byte *dp;
	    uint csize;
	    uint compress;

	    rect.x = x, rect.y = y;
	    rect.width = w1, rect.height = height;
	    rsize = (dx ? 4 : 2) + cmd_size_rect(&rect);
	    TRY_RECT {
		code = cmd_put_bits(cdev, pcls, row, w1 << log2_depth,
				    height, raster, rsize,
				    1 << cmd_compress_rle, &dp, &csize);
	    } HANDLE_RECT_UNLESS(code, code == gs_error_limitcheck);
	    compress = (uint)code;
	    if (code < 0) {
		/* The bitmap was too large; split up the transfer. */
		if (height > 1) {
		    /* Split the transfer by reducing the height.
		     * See the comment above FOR_RECTS in gxcldev.h.
		     */
		    height >>= 1;
		    goto copy;
		} else {
		    /* Split a single (very long) row. */
		    int w2 = w1 >> 1;

		    NEST_RECT {
			code = clist_copy_alpha(dev, row, dx,
						raster, gx_no_bitmap_id, x, y,
						w2, 1, color, depth);
			if (code >= 0)
			    code = clist_copy_alpha(dev, row, dx + w2,
						    raster, gx_no_bitmap_id,
						    x + w2, y, w1 - w2, 1,
						    color, depth);
		    } UNNEST_RECT;
		    if (code < 0)
			ERROR_RECT(code);
		    continue;
		}
	    }
	    op += compress;
	    if (dx) {
		*dp++ = cmd_count_op(cmd_opv_set_misc, 2);
		*dp++ = cmd_set_misc_data_x + dx;
	    }
	    *dp++ = cmd_count_op(op, csize);
	    *dp++ = depth;
	    cmd_put2w(x, y, dp);
	    cmd_put2w(w1, height, dp);
	    pcls->rect = rect;
	}
    } END_RECTS;
    return 0;
}

int
clist_strip_copy_rop(gx_device * dev,
	     const byte * sdata, int sourcex, uint sraster, gx_bitmap_id id,
		     const gx_color_index * scolors,
	   const gx_strip_bitmap * textures, const gx_color_index * tcolors,
		     int x, int y, int width, int height,
		     int phase_x, int phase_y, gs_logical_operation_t lop)
{
    gx_device_clist_writer * const cdev =
	&((gx_device_clist *)dev)->writer;
    gs_rop3_t rop = lop_rop(lop);
    gx_strip_bitmap tile_with_id;
    const gx_strip_bitmap *tiles = textures;
    int y0;
    /* Compute the set of possible colors that this operation can generate. */
    gx_color_index all = ((gx_color_index)1 << dev->color_info.depth) - 1;
    bool subtractive = dev->color_info.num_components == 4; /****** HACK ******/
    gx_color_index S =
	(scolors ? scolors[0] | scolors[1] : sdata ? all : 0);
    gx_color_index T =
	(tcolors ? tcolors[0] | tcolors[1] : textures ? all : 0);
    gs_rop3_t color_rop =
	(subtractive ? byte_reverse_bits[rop ^ 0xff] : rop);
    bool slow_rop;

    if (scolors != 0 && scolors[0] != scolors[1]) {
	fit_fill(dev, x, y, width, height);
    } else {
	fit_copy(dev, sdata, sourcex, sraster, id, x, y, width, height);
    }
    /*
     * On CMYK devices, RasterOps must be executed with complete pixels
     * if the operation involves the destination.
     * This is because the black plane interacts with the other planes
     * in the conversion between RGB and CMYK.  Check for this now.
     */
    {
	gs_rop3_t rop_used = rop;

	if (scolors && (scolors[0] == scolors[1]))
	    rop_used = (scolors[0] == gx_device_black(dev) ?
			rop3_know_S_0(rop_used) :
			scolors[0] == gx_device_white(dev) ?
			rop3_know_S_1(rop_used) : rop_used);
	if (tcolors && (tcolors[0] == tcolors[1]))
	    rop_used = (tcolors[0] == gx_device_black(dev) ?
			rop3_know_T_0(rop_used) :
			tcolors[0] == gx_device_white(dev) ?
			rop3_know_T_1(rop_used) : rop_used);
	slow_rop = !(rop == rop3_0 || rop == rop3_1 ||
		     rop == rop3_D || rop == rop3_S || rop == rop3_T);
    }
    y0 = y;
    /*
     * We shouldn't need to put the logic below inside FOR/END_RECTS,
     * but the lop_enabled flags are per-band.
     */
    FOR_RECTS {
	const byte *row = sdata + (y - y0) * sraster;
	gx_color_index D = pcls->colors_used.or;
	int code;

	pcls->colors_used.or =
	    ((rop_proc_table[color_rop])(D, S, T) & all) | D;
	pcls->colors_used.slow_rop |= slow_rop;
	if (rop3_uses_T(rop)) {
	    if (tcolors == 0 || tcolors[0] != tcolors[1]) {
		ulong offset_temp;

		if (!cls_has_tile_id(cdev, pcls, tiles->id, offset_temp)) {
		    /* Change tile.  If there is no id, generate one. */
		    if (tiles->id == gx_no_bitmap_id) {
			tile_with_id = *tiles;
			tile_with_id.id = gs_next_ids(1);
			tiles = &tile_with_id;
		    }
		    TRY_RECT {
			code = clist_change_tile(cdev, pcls, tiles,
						 (tcolors != 0 ? 1 :
						  dev->color_info.depth));
		    } HANDLE_RECT_UNLESS(code, code == gs_error_limitcheck);
		    if (code < 0) {
			/*
			 * The error is a limitcheck: we have a tile that
			 * is too big to fit in the command reading buffer.
			 * For now, just divide up the transfer into scan
			 * lines.  (If a single scan line won't fit, punt.)
			 * Eventually, we'll need a way to transfer the tile
			 * in pieces.
			 */
			uint rep_height = tiles->rep_height;
			gs_id ids;
			gx_strip_bitmap line_tile;
			int iy;

			if (rep_height == 1 ||
			    /****** CAN'T HANDLE SHIFT YET ******/
			    tiles->rep_shift != 0
			    )
			    return code;
			/*
			 * Allocate enough fake IDs, since the inner call on
			 * clist_strip_copy_rop will need them anyway.
			 */
			ids = gs_next_ids(min(height, rep_height));
			line_tile = *tiles;
			line_tile.size.y = 1;
			line_tile.rep_height = 1;
			for (iy = 0; iy < height; ++iy) {
			    line_tile.data = tiles->data + line_tile.raster *
				((y + iy + phase_y) % rep_height);
			    line_tile.id = ids + (iy % rep_height);
			    /*
			     * Note that since we're only transferring
			     * a single scan line, phase_y is irrelevant;
			     * we may as well use the current tile phase
			     * so we don't have to write extra commands.
			     */
			    NEST_RECT {
				code = clist_strip_copy_rop(dev,
					(sdata == 0 ? 0 : row + iy * sraster),
					sourcex, sraster,
					gx_no_bitmap_id, scolors,
					&line_tile, tcolors,
					x, y + iy, width, 1,
					phase_x, pcls->tile_phase.y, lop);
			    } UNNEST_RECT;
			    if (code < 0)
				ERROR_RECT(code);
			}
			continue;
		    }
		    if (phase_x != pcls->tile_phase.x ||
			phase_y != pcls->tile_phase.y
			) {
			TRY_RECT {
			    code = cmd_set_tile_phase(cdev, pcls, phase_x,
						      phase_y);
			} HANDLE_RECT(code);
		    }
		}
	    }
	    /* Set the tile colors. */
	    TRY_RECT {
		code =
		    (tcolors != 0 ?
		     cmd_set_tile_colors(cdev, pcls, tcolors[0], tcolors[1]) :
		     cmd_set_tile_colors(cdev, pcls, gx_no_color_index,
					 gx_no_color_index));
	    } HANDLE_RECT(code);
	}
	TRY_RECT {
	    code = 0;
	    if (lop != pcls->lop)
		code = cmd_set_lop(cdev, pcls, lop);
	    if (code >= 0)
		code = cmd_enable_lop(cdev, pcls);
	} HANDLE_RECT(code);

	/* Set lop_enabled to -1 so that fill_rectangle / copy_* */
	/* won't attempt to set it to 0. */
	pcls->lop_enabled = -1;
	NEST_RECT {
	    if (scolors != 0) {
		if (scolors[0] == scolors[1])
		    code = clist_fill_rectangle(dev, x, y, width, height,
						scolors[1]);
		else
		    code = clist_copy_mono(dev, row, sourcex, sraster, id,
					   x, y, width, height,
					   scolors[0], scolors[1]);
	    } else
		code = clist_copy_color(dev, row, sourcex, sraster, id,
					x, y, width, height);
	} UNNEST_RECT;
	pcls->lop_enabled = 1;
	if (code < 0)
	    ERROR_RECT(code);
    } END_RECTS;
    return 0;
}