ghostscript-7.07/src/gdevht.c

/* Copyright (C) 1995, 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: gdevht.c,v 1.3.6.1.2.1 2003/01/17 00:49:00 giles Exp $ */
/* Halftoning device implementation */
#include "gx.h"
#include "gserrors.h"
#include "gxdevice.h"
#include "gdevht.h"
#include "gxdcolor.h"
#include "gxdcconv.h"
#include "gxdither.h"

/* The device procedures */
private dev_proc_open_device(ht_open);
private dev_proc_map_rgb_color(ht_map_rgb_color);
private dev_proc_map_color_rgb(ht_map_color_rgb);
private dev_proc_fill_rectangle(ht_fill_rectangle);
private dev_proc_map_cmyk_color(ht_map_cmyk_color);
private dev_proc_map_rgb_alpha_color(ht_map_rgb_alpha_color);
private dev_proc_fill_path(ht_fill_path);
private dev_proc_stroke_path(ht_stroke_path);
private dev_proc_fill_mask(ht_fill_mask);
private dev_proc_fill_trapezoid(ht_fill_trapezoid);
private dev_proc_fill_parallelogram(ht_fill_parallelogram);
private dev_proc_fill_triangle(ht_fill_triangle);
private dev_proc_draw_thin_line(ht_draw_thin_line);
private const gx_device_ht gs_ht_device =
{std_device_dci_body(gx_device_ht, 0, "halftoner",
		     0, 0, 1, 1,
		     1, 8, 255, 0, 0, 0),
 {ht_open,
  gx_forward_get_initial_matrix,
  gx_forward_sync_output,
  gx_forward_output_page,
  gx_default_close_device,
  ht_map_rgb_color,
  ht_map_color_rgb,
  ht_fill_rectangle,
  gx_default_tile_rectangle,
  gx_default_copy_mono,
  gx_default_copy_color,
  gx_default_draw_line,
  gx_default_get_bits,
  gx_forward_get_params,
  gx_forward_put_params,
  ht_map_cmyk_color,
  gx_forward_get_xfont_procs,
  gx_forward_get_xfont_device,
  ht_map_rgb_alpha_color,
  gx_forward_get_page_device,
  gx_forward_get_alpha_bits,
  gx_default_copy_alpha,
  gx_forward_get_band,
  gx_default_copy_rop,
  ht_fill_path,
  ht_stroke_path,
  ht_fill_mask,
  ht_fill_trapezoid,
  ht_fill_parallelogram,
  ht_fill_triangle,
  ht_draw_thin_line,
  gx_default_begin_image,
  gx_default_image_data,
  gx_default_end_image,
  gx_default_strip_tile_rectangle,
  gx_default_strip_copy_rop,
  gx_forward_get_clipping_box,
  gx_default_begin_typed_image,
  gx_no_get_bits_rectangle,
  gx_default_map_color_rgb_alpha,
  gx_no_create_compositor,
  gx_forward_get_hardware_params,
  gx_default_text_begin,
  gx_default_finish_copydevice
 }
};

/*
 * Define the packing of two target colors and a halftone level into
 * a gx_color_index.  Since C doesn't let us cast between a structure
 * and a scalar, we have to use explicit shifting and masking.
 */
#define cx_color0(color) ((color) & htdev->color_mask)
#define cx_color1(color) (((color) >> htdev->color_shift) & htdev->color_mask)
#define cx_level(color) ((color) >> htdev->level_shift)
#define cx_values(c0, c1, lev)\
  ( ((lev) << htdev->level_shift) + ((c1) << htdev->color_shift) + (c0) )

/* ---------------- Non-drawing procedures ---------------- */

/* Open the device.  Right now we just make some error checks. */
private int
ht_open(gx_device * dev)
{
    gx_device_ht *htdev = (gx_device_ht *) dev;
    const gx_device *target = htdev->target;
    const gx_device_halftone *pdht = htdev->dev_ht;
    int target_depth;
    uint num_levels;

    if (target == 0 || pdht == 0 || pdht->num_comp != 0)
	return_error(gs_error_rangecheck);
    /*
     * Make sure we can fit a halftone level and two target colors
     * into a gx_color_index.  If we're lucky, we can pack them into
     * even less space.
     */
    target_depth = target->color_info.depth;
    num_levels = pdht->order.num_levels;
    {
	int depth = target_depth * 2 + num_levels;

	if (depth > sizeof(gx_color_index) * 8)
	    return_error(gs_error_rangecheck);
	/*
	 * If there are too few halftone levels (fewer than 32),
	 * we can't treat this device as contone.
	 */
	if (num_levels < 32)
	    return_error(gs_error_rangecheck);
	/* Set up color information. */
	htdev->color_info.num_components = target->color_info.num_components;
	htdev->color_info.depth = depth;
	htdev->color_info.max_gray = num_levels - 1;
	htdev->color_info.max_color = num_levels - 1;
	htdev->color_info.dither_grays = num_levels;
	htdev->color_info.dither_colors = num_levels;
    }
    htdev->color_shift = target_depth;
    htdev->level_shift = target_depth * 2;
    htdev->color_mask = ((gx_color_index) 1 << target_depth) - 1;
    htdev->phase.x = imod(-htdev->ht_phase.x, pdht->lcm_width);
    htdev->phase.y = imod(-htdev->ht_phase.y, pdht->lcm_height);
    return 0;
}

/* Map from RGB or CMYK colors to the packed representation. */
private gx_color_index
ht_finish_map_color(const gx_device_ht * htdev, int code,
		    const gx_device_color * pdevc)
{
    if (code < 0)
	return gx_no_color_index;
    if (gx_dc_is_pure(pdevc))
	return cx_values(pdevc->colors.pure, 0, 0);
    if (gx_dc_is_binary_halftone(pdevc))
	return cx_values(pdevc->colors.binary.color[0],
			 pdevc->colors.binary.color[1],
			 pdevc->colors.binary.b_level);
    lprintf("bad type in ht color mapping!");
    return gx_no_color_index;
}
private gx_color_index
ht_map_rgb_color(gx_device * dev, gx_color_value r, gx_color_value g,
		 gx_color_value b)
{
    return ht_map_rgb_alpha_color(dev, r, g, b, gx_max_color_value);
}
private gx_color_index
ht_map_cmyk_color(gx_device * dev, gx_color_value c, gx_color_value m,
		  gx_color_value y, gx_color_value k)
{
    gx_device_ht *htdev = (gx_device_ht *) dev;
    gx_device_color devc;
    frac fc = cv2frac(k);
    frac fk = cv2frac(k);
    int code =
    (c == m && m == y ?
     gx_render_device_gray(color_cmyk_to_gray(fc, fc, fc, fk, NULL),
			   gx_max_color_value,
			   &devc, htdev->target, htdev->dev_ht,
			   &htdev->ht_phase) :
     gx_render_device_color(fc, cv2frac(m), cv2frac(y),
			    fk, false, gx_max_color_value,
			    &devc, htdev->target, htdev->dev_ht,
			    &htdev->ht_phase));

    return ht_finish_map_color(htdev, code, &devc);
}
private gx_color_index
ht_map_rgb_alpha_color(gx_device * dev, gx_color_value r,
		   gx_color_value g, gx_color_value b, gx_color_value alpha)
{
    gx_device_ht *htdev = (gx_device_ht *) dev;
    gx_device_color devc;
    int code =
    (r == g && g == b ?
     gx_render_device_gray(cv2frac(r), alpha,
			   &devc, htdev->target, htdev->dev_ht,
			   &htdev->ht_phase) :
     gx_render_device_color(cv2frac(r), cv2frac(g), cv2frac(b),
			    frac_0, false, alpha,
			    &devc, htdev->target, htdev->dev_ht,
			    &htdev->ht_phase));

    return ht_finish_map_color(htdev, code, &devc);
}

/* Map back to an RGB color. */
private int
ht_map_color_rgb(gx_device * dev, gx_color_index color,
		 gx_color_value prgb[3])
{
    gx_device_ht *htdev = (gx_device_ht *) dev;
    gx_device *tdev = htdev->target;
    gx_color_index color0 = cx_color0(color);
    uint level = cx_level(color);

    dev_proc_map_color_rgb((*map)) = dev_proc(tdev, map_color_rgb);

    if (level == 0)
	return (*map) (tdev, color0, prgb);
    {
	gx_color_index color1 = cx_color1(color);
	gx_color_value rgb0[3], rgb1[3];
	uint num_levels = htdev->dev_ht->order.num_levels;
	int i;

	(*map) (tdev, color0, rgb0);
	(*map) (tdev, color1, rgb1);
	for (i = 0; i < 3; ++i)
	    prgb[i] = rgb0[i] +
		(rgb1[i] - rgb0[i]) * (ulong) level / num_levels;
	return 0;
    }
}

/* ---------------- Drawing procedures ---------------- */

/*
 * Map a (pure) contone color into a gx_device_color, either pure or
 * halftoned.  Return 0 if pure, 1 if halftoned, <0 if the original color
 * wasn't pure.  (This is not a driver procedure.)
 */
private int
ht_map_device_color(const gx_device_ht * htdev, gx_device_color * pdevc,
		    const gx_device_color * pcdevc)
{
    if (!gx_dc_is_pure(pcdevc))
	return -1;
    {
	gx_color_index color = pcdevc->colors.pure;
	gx_color_index color0 = cx_color0(color);
	uint level = cx_level(color);

	if (level == 0) {
	    color_set_pure(pdevc, color0);
	    return 0;
	} else {
	    color_set_binary_halftone(pdevc, htdev->dev_ht, color0,
				      cx_color1(color), level);
	    color_set_phase(pdevc, htdev->phase.x, htdev->phase.y);
	    return 1;
	}
    }
}

/* Fill a rectangle by tiling with a halftone. */
private int
ht_fill_rectangle(gx_device * dev, int x, int y, int w, int h,
		  gx_color_index color)
{
    gx_device_ht *htdev = (gx_device_ht *) dev;
    gx_device *tdev = htdev->target;
    gx_color_index color0 = cx_color0(color);
    uint level = cx_level(color);

    if (level == 0)
	return (*dev_proc(tdev, fill_rectangle))
	    (tdev, x, y, w, h, color0);
    {
	const gx_ht_order *porder = &htdev->dev_ht->order;
	gx_ht_cache *pcache = porder->cache;
	gx_ht_tile *tile;

	/* Ensure that the tile cache is current. */
	if (pcache->order.bits != porder->bits)
	    gx_ht_init_cache(pcache, porder);
	/* Ensure that the tile we want is cached. */
	tile = gx_render_ht(pcache, level);
	if (tile == 0)
	    return_error(gs_error_Fatal);
	/* Fill the rectangle with the tile. */
	return (*dev_proc(tdev, strip_tile_rectangle))
	    (tdev, &tile->tiles, x, y, w, h, color0, cx_color1(color),
	     htdev->phase.x, htdev->phase.y);
    }
}

/*
 * Create a halftoned color if necessary for the high-level drawing
 * operations.
 */

#define MAP_DRAWING_COLOR(proc, default_proc)\
	gx_device_ht *htdev = (gx_device_ht *)dev;\
	gx_device_color dcolor;\
	gx_device *tdev;\
	const gx_device_color *tdcolor;\
\
	if ( ht_map_device_color(htdev, &dcolor, pdcolor) < 0 )\
	  tdev = dev, tdcolor = pdcolor, proc = default_proc;\
	else\
	  tdev = htdev->target, tdcolor = &dcolor,\
	    proc = dev_proc(tdev, proc)

private int
ht_fill_path(gx_device * dev,
	     const gs_imager_state * pis, gx_path * ppath,
	     const gx_fill_params * params,
	     const gx_drawing_color * pdcolor, const gx_clip_path * pcpath)
{
    dev_proc_fill_path((*fill_path));
    MAP_DRAWING_COLOR(fill_path, gx_default_fill_path);
    return (*fill_path) (tdev, pis, ppath, params, tdcolor, pcpath);
}

private int
ht_stroke_path(gx_device * dev,
	       const gs_imager_state * pis, gx_path * ppath,
	       const gx_stroke_params * params,
	       const gx_drawing_color * pdcolor, const gx_clip_path * pcpath)
{
    dev_proc_stroke_path((*stroke_path));
    MAP_DRAWING_COLOR(stroke_path, gx_default_stroke_path);
    return (*stroke_path) (tdev, pis, ppath, params, tdcolor, pcpath);
}

private int
ht_fill_mask(gx_device * dev,
	     const byte * data, int data_x, int raster, gx_bitmap_id id,
	     int x, int y, int width, int height,
	     const gx_drawing_color * pdcolor, int depth,
	     gs_logical_operation_t lop, const gx_clip_path * pcpath)
{
    dev_proc_fill_mask((*fill_mask));
    MAP_DRAWING_COLOR(fill_mask, gx_default_fill_mask);
    return (*fill_mask) (tdev, data, data_x, raster, id, x, y,
			 width, height, tdcolor, depth, lop, pcpath);
}

private int
ht_fill_trapezoid(gx_device * dev,
		  const gs_fixed_edge * left, const gs_fixed_edge * right,
		  fixed ybot, fixed ytop, bool swap_axes,
	       const gx_drawing_color * pdcolor, gs_logical_operation_t lop)
{
    dev_proc_fill_trapezoid((*fill_trapezoid));
    MAP_DRAWING_COLOR(fill_trapezoid, gx_default_fill_trapezoid);
    return (*fill_trapezoid) (tdev, left, right, ybot, ytop, swap_axes,
			      tdcolor, lop);
}

private int
ht_fill_parallelogram(gx_device * dev,
		 fixed px, fixed py, fixed ax, fixed ay, fixed bx, fixed by,
	       const gx_drawing_color * pdcolor, gs_logical_operation_t lop)
{
    dev_proc_fill_parallelogram((*fill_parallelogram));
    MAP_DRAWING_COLOR(fill_parallelogram, gx_default_fill_parallelogram);
    return (*fill_parallelogram) (tdev, px, py, ax, ay, bx, by,
				  tdcolor, lop);
}

private int
ht_fill_triangle(gx_device * dev,
		 fixed px, fixed py, fixed ax, fixed ay, fixed bx, fixed by,
	       const gx_drawing_color * pdcolor, gs_logical_operation_t lop)
{
    dev_proc_fill_triangle((*fill_triangle));
    MAP_DRAWING_COLOR(fill_triangle, gx_default_fill_triangle);
    return (*fill_triangle) (tdev, px, py, ax, ay, bx, by,
			     tdcolor, lop);
}

private int
ht_draw_thin_line(gx_device * dev,
		  fixed fx0, fixed fy0, fixed fx1, fixed fy1,
	       const gx_drawing_color * pdcolor, gs_logical_operation_t lop)
{
    dev_proc_draw_thin_line((*draw_thin_line));
    MAP_DRAWING_COLOR(draw_thin_line, gx_default_draw_thin_line);
    return (*draw_thin_line) (tdev, fx0, fy0, fx1, fy1, tdcolor, lop);
}