/* Copyright (C) 1998 Aladdin Enterprises.  All rights reserved.

   This file is part of Aladdin Ghostscript.

   Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
   or distributor accepts any responsibility for the consequences of using it,
   or for whether it serves any particular purpose or works at all, unless he
   or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
   License (the "License") for full details.

   Every copy of Aladdin Ghostscript must include a copy of the License,
   normally in a plain ASCII text file named PUBLIC.  The License grants you
   the right to copy, modify and redistribute Aladdin Ghostscript, but only
   under certain conditions described in the License.  Among other things, the
   License requires that the copyright notice and this notice be preserved on
   all copies.
 */

/*$Id: gdevbmpc.c $ */
/* .BMP file format driver utilities */
#include "gdevprn.h"
#include "gdevbmp.h"

/*
 * Define BMP file format structures.
 * All multi-byte quantities are stored LSB-first!
 */

typedef ushort word;
#if arch_sizeof_int == 4
typedef uint dword;
#else
#  if arch_sizeof_long == 4
typedef ulong dword;
#  endif
#endif
#if arch_is_big_endian
#  define BMP_ASSIGN_WORD(a,v) a = ((v) >> 8) + ((v) << 8)
#  define BMP_ASSIGN_DWORD(a,v)\
     a = ((v) >> 24) + (((v) >> 8) & 0xff00L) +\
	 (((dword)(v) << 8) & 0xff0000L) + ((dword)(v) << 24)
#else
#  define BMP_ASSIGN_WORD(a,v) a = (v)
#  define BMP_ASSIGN_DWORD(a,v) a = (v)
#endif

typedef struct bmp_file_header_s {

    /* BITMAPFILEHEADER */

    /*
     * This structure actually begins with two bytes
     * containing the characters 'BM', but we must omit them,
     * because some compilers would insert padding to force
     * the size member to a 32- or 64-bit boundary.
     */

    /*byte  typeB, typeM; *//* always 'BM' */
    dword size;			/* total size of file */
    word reserved1;
    word reserved2;
    dword offBits;		/* offset of bits from start of file */

} bmp_file_header;

#define sizeof_bmp_file_header (2 + sizeof(bmp_file_header))

typedef struct bmp_info_header_s {

    /* BITMAPINFOHEADER */

    dword size;			/* size of info header in bytes */
    dword width;		/* width in pixels */
    dword height;		/* height in pixels */
    word planes;		/* # of planes, always 1 */
    word bitCount;		/* bits per pixel */
    dword compression;		/* compression scheme, always 0 */
    dword sizeImage;		/* size of bits */
    dword xPelsPerMeter;	/* X pixels per meter */
    dword yPelsPerMeter;	/* Y pixels per meter */
    dword clrUsed;		/* # of colors used */
    dword clrImportant;		/* # of important colors */

    /* This is followed by (1 << bitCount) bmp_quad structures, */
    /* unless bitCount == 24. */

} bmp_info_header;

typedef struct bmp_quad_s {

    /* RGBQUAD */

    byte blue, green, red, reserved;

} bmp_quad;

/* Write the BMP file header. */
int
write_bmp_header(gx_device_printer *pdev, FILE *file)
{
    int raster = gdev_prn_raster(pdev);
    /* BMP scan lines are padded to 32 bits. */
    ulong bmp_raster = raster + (-raster & 3);
    int height = pdev->height;
    int depth = pdev->color_info.depth;
    int quads = (depth <= 8 ? sizeof(bmp_quad) << depth : 0);

    /* Write the file header. */

    fputc('B', file);
    fputc('M', file);
    {
	bmp_file_header fhdr;

	BMP_ASSIGN_DWORD(fhdr.size,
		     sizeof_bmp_file_header +
		     sizeof(bmp_info_header) + quads +
		     bmp_raster * height);
	BMP_ASSIGN_WORD(fhdr.reserved1, 0);
	BMP_ASSIGN_WORD(fhdr.reserved2, 0);
	BMP_ASSIGN_DWORD(fhdr.offBits,
		     sizeof_bmp_file_header +
		     sizeof(bmp_info_header) + quads);
	if (fwrite((const char *)&fhdr, 1, sizeof(fhdr), file) != sizeof(fhdr))
	    return_error(gs_error_ioerror);
    }

    /* Write the info header. */

    {
	bmp_info_header ihdr;

	BMP_ASSIGN_DWORD(ihdr.size, sizeof(ihdr));
	BMP_ASSIGN_DWORD(ihdr.width, pdev->width);
	BMP_ASSIGN_DWORD(ihdr.height, height);
	BMP_ASSIGN_WORD(ihdr.planes, 1);
	BMP_ASSIGN_WORD(ihdr.bitCount, depth);
	BMP_ASSIGN_DWORD(ihdr.compression, 0);
	BMP_ASSIGN_DWORD(ihdr.sizeImage, bmp_raster * height);
	/* Even though we could compute the resolution correctly, */
	/* the convention seems to be to leave it unspecified. */
	BMP_ASSIGN_DWORD(ihdr.xPelsPerMeter, 0);
	    /*(dword)(pdev->x_pixels_per_inch * (1000.0 / 30.48))); */
	BMP_ASSIGN_DWORD(ihdr.yPelsPerMeter, 0);
	    /*(dword)(pdev->y_pixels_per_inch * (1000.0 / 30.48))); */
	BMP_ASSIGN_DWORD(ihdr.clrUsed, 0);
	BMP_ASSIGN_DWORD(ihdr.clrImportant, 0);
	if (fwrite((const char *)&ihdr, 1, sizeof(ihdr), file) != sizeof(ihdr))
	    return_error(gs_error_ioerror);
    }

    /* Write the palette. */

    if (depth <= 8) {
	int i;
	gx_color_value rgb[3];
	bmp_quad q;

	q.reserved = 0;
	for (i = 0; i != 1 << depth; i++) {
	    (*dev_proc(pdev, map_color_rgb))((gx_device *)pdev,
					     (gx_color_index)i, rgb);
	    q.red = gx_color_value_to_byte(rgb[0]);
	    q.green = gx_color_value_to_byte(rgb[1]);
	    q.blue = gx_color_value_to_byte(rgb[2]);
	    fwrite((const char *)&q, sizeof(q), 1, file);
	}
    }

    return 0;
}

/* 24-bit color mappers (taken from gdevmem2.c). */
/* Note that Windows expects RGB values in the order B,G,R. */

/* Map a r-g-b color to a color index. */
gx_color_index
bmp_map_16m_rgb_color(gx_device * dev, gx_color_value r, gx_color_value g,
		  gx_color_value b)
{
    return gx_color_value_to_byte(r) +
	((uint) gx_color_value_to_byte(g) << 8) +
	((ulong) gx_color_value_to_byte(b) << 16);
}

/* Map a color index to a r-g-b color. */
int
bmp_map_16m_color_rgb(gx_device * dev, gx_color_index color,
		  gx_color_value prgb[3])
{
    prgb[2] = gx_color_value_from_byte(color >> 16);
    prgb[1] = gx_color_value_from_byte((color >> 8) & 0xff);
    prgb[0] = gx_color_value_from_byte(color & 0xff);
    return 0;
}
