/* Copyright (C) 1994, 1996, 1998, 1999 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
  to anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given
  to you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
*/

/*$RCSfile: gdevm16.c,v $ $Revision: 1.2.2.1 $ */
/* 16-bit-per-pixel "memory" (stored bitmap) device */
#include "memory_.h"
#include "gx.h"
#include "gxdevice.h"
#include "gxdevmem.h"		/* semi-public definitions */
#include "gdevmem.h"		/* private definitions */

#undef chunk
#define chunk byte

/* The 16 bits are divided 5 for red, 6 for green, and 5 for blue. */
/* Note that the bits must always be kept in big-endian order. */

/* Procedures */
declare_mem_map_procs(mem_true16_map_rgb_color, mem_true16_map_color_rgb);
declare_mem_procs(mem_true16_copy_mono, mem_true16_copy_color, mem_true16_fill_rectangle);

/* The device descriptor. */
const gx_device_memory mem_true16_device =
    mem_device("image16", 16, 0,
	       mem_true16_map_rgb_color, mem_true16_map_color_rgb,
	       mem_true16_copy_mono, mem_true16_copy_color,
	       mem_true16_fill_rectangle, mem_default_strip_copy_rop);

/* Map a r-g-b color to a color index. */
private gx_color_index
mem_true16_map_rgb_color(gx_device * dev, gx_color_value r, gx_color_value g,
			 gx_color_value b)
{
    return ((r >> (gx_color_value_bits - 5)) << 11) +
	((g >> (gx_color_value_bits - 6)) << 5) +
	(b >> (gx_color_value_bits - 5));
}

/* Map a color index to a r-g-b color. */
private int
mem_true16_map_color_rgb(gx_device * dev, gx_color_index color,
			 gx_color_value prgb[3])
{
    ushort value = color >> 11;

    prgb[0] = ((value << 11) + (value << 6) + (value << 1) + (value >> 4))
		      >> (16 - gx_color_value_bits);
    value = (color >> 5) & 0x3f;
    prgb[1] = ((value << 10) + (value << 4) + (value >> 2))
		      >> (16 - gx_color_value_bits);
    value = color & 0x1f;
    prgb[2] = ((value << 11) + (value << 6) + (value << 1) + (value >> 4))
		      >> (16 - gx_color_value_bits);
    return 0;
}

/* Convert x coordinate to byte offset in scan line. */
#undef x_to_byte
#define x_to_byte(x) ((x) << 1)

/* Fill a rectangle with a color. */
private int
mem_true16_fill_rectangle(gx_device * dev,
			  int x, int y, int w, int h, gx_color_index color)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;
#if arch_is_big_endian
    const ushort color16 = (ushort)color;
#else
    const ushort color16 = (ushort)((color << 8) | (color >> 8));
#endif
    declare_scan_ptr(dest);

    fit_fill(dev, x, y, w, h);
    setup_rect(dest);
    if (w == 1) {
	while (h-- > 0) {
	    *(ushort *)dest = color16;
	    inc_ptr(dest, draster);
	}
    } else if ((color16 >> 8) == (color16 & 0xff)) {
	bytes_fill_rectangle(scan_line_base(mdev, y) + (x << 1), draster,
			     (byte)color, w << 1, h);
    } else {
	while (h-- > 0) {
	    ushort *pptr = (ushort *) dest;
	    int cnt = w;

	    for (; cnt >= 4; pptr += 4, cnt -= 4)
		pptr[3] = pptr[2] = pptr[1] = pptr[0] = color16;
	    switch (cnt) {
	    case 3: pptr[2] = color16;
	    case 2: pptr[1] = color16;
	    case 1: pptr[0] = color16;
	    case 0: DO_NOTHING;
	    }
	    inc_ptr(dest, draster);
	}
    }
    return 0;
}

/* Copy a monochrome bitmap. */
private int
mem_true16_copy_mono(gx_device * dev,
		     const byte * base, int sourcex, int sraster,
		     gx_bitmap_id id, int x, int y, int w, int h,
		     gx_color_index zero, gx_color_index one)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;
#if arch_is_big_endian
    const ushort zero16 = (ushort)zero;
    const ushort one16 = (ushort)one;
#else
    ushort zero16 = ((uint) (byte) zero << 8) + ((ushort) zero >> 8);
    ushort one16 = ((uint) (byte) one << 8) + ((ushort) one >> 8);
#endif
    const byte *line;
    int first_bit;

    declare_scan_ptr(dest);
    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    setup_rect(dest);
    line = base + (sourcex >> 3);
    first_bit = 0x80 >> (sourcex & 7);
    while (h-- > 0) {
	register ushort *pptr = (ushort *) dest;
	const byte *sptr = line;
	register int sbyte = *sptr++;
	register int bit = first_bit;
	int count = w;

	do {
	    if (sbyte & bit) {
		if (one != gx_no_color_index)
		    *pptr = one16;
	    } else {
		if (zero != gx_no_color_index)
		    *pptr = zero16;
	    }
	    if ((bit >>= 1) == 0)
		bit = 0x80, sbyte = *sptr++;
	    pptr++;
	}
	while (--count > 0);
	line += sraster;
	inc_ptr(dest, draster);
    }
    return 0;
}

/* Copy a color bitmap. */
private int
mem_true16_copy_color(gx_device * dev,
	       const byte * base, int sourcex, int sraster, gx_bitmap_id id,
		      int x, int y, int w, int h)
{
    gx_device_memory * const mdev = (gx_device_memory *)dev;

    fit_copy(dev, base, sourcex, sraster, id, x, y, w, h);
    mem_copy_byte_rect(mdev, base, sourcex, sraster, x, y, w, h);
    return 0;
}
