bmp_cod.h

/*
 * Copyright (c) 1999-2000 Image Power, Inc. and the University of
 *   British Columbia.
 * Copyright (c) 2001-2002 Michael David Adams.
 * All rights reserved.
 */

/* __START_OF_JASPER_LICENSE__
 * 
 * JasPer License Version 2.0
 * 
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person (the
 * "User") obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 * 
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 * 
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 * 
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
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 * __END_OF_JASPER_LICENSE__
 */

/*
 * Windows Bitmap File Library
 *
 * $Id$
 */

#ifndef BMP_COD_H
#define BMP_COD_H

/******************************************************************************\
* Includes.
\******************************************************************************/

#include "jasper/jas_types.h"

/******************************************************************************\
* Constants and macros.
\******************************************************************************/

#define BMP_MAGIC       0x4d42
/* The signature for a BMP file. */

#define BMP_HDRLEN      14
/* The nominal header length. */

#define BMP_INFOLEN     40
/* The nominal info length. */

#define BMP_PALLEN(info)        ((info)->numcolors * 4)
/* The length of the palette. */

#define BMP_HASPAL(info)        ((info)->numcolors > 0)
/* Is this a palettized image? */

/* Encoding types. */
#define BMP_ENC_RGB             0 /* No special encoding. */
#define BMP_ENC_RLE8    1 /* Run length encoding. */
#define BMP_ENC_RLE4    2 /* Run length encoding. */

/******************************************************************************\
* Types.
\******************************************************************************/

/* BMP header. */
typedef struct {

        int_fast16_t magic;
        /* The signature (a.k.a. the magic number). */

        int_fast32_t siz;
        /* The size of the file in 32-bit words. */

        int_fast16_t reserved1;
        /* Ask Bill Gates what this is all about. */

        int_fast16_t reserved2;
        /* Ditto. */

        int_fast32_t off;
        /* The offset of the bitmap data from the bitmap file header in bytes. */

} bmp_hdr_t;

/* Palette entry. */
typedef struct {

        int_fast16_t red;
        /* The red component. */

        int_fast16_t grn;
        /* The green component. */

        int_fast16_t blu;
        /* The blue component. */

        int_fast16_t res;
        /* Reserved. */

} bmp_palent_t;

/* BMP info. */
typedef struct {

        int_fast32_t len;
        /* The length of the bitmap information header in bytes. */

        int_fast32_t width;
        /* The width of the bitmap in pixels. */

        int_fast32_t height;
        /* The height of the bitmap in pixels. */

        int_fast8_t topdown;
        /* The bitmap data is specified in top-down order. */

        int_fast16_t numplanes;
        /* The number of planes.  This must be set to a value of one. */

        int_fast16_t depth;
        /* The number of bits per pixel. */

        int_fast32_t enctype;
        /* The type of compression used. */

        int_fast32_t siz;
        /* The size of the image in bytes. */

        int_fast32_t hres;
        /* The horizontal resolution in pixels/metre. */

        int_fast32_t vres;
        /* The vertical resolution in pixels/metre. */

        int_fast32_t numcolors;
        /* The number of color indices used by the bitmap. */

        int_fast32_t mincolors;
        /* The number of color indices important for displaying the bitmap. */

        bmp_palent_t *palents;
        /* The colors should be listed in order of importance. */

} bmp_info_t;

/******************************************************************************\
* Functions and macros.
\******************************************************************************/

#define bmp_issupported(hdr, info) \
        ((hdr)->magic == BMP_MAGIC && !(hdr)->reserved1 && \
          !(hdr)->reserved2 && (info)->numplanes == 1 && \
          ((info)->depth == 8 || (info)->depth == 24) && \
          (info)->enctype == BMP_ENC_RGB)
/* Is this type of BMP file supported? */

#define bmp_haspal(info) \
        ((info)->depth == 8)
/* Is there a palette? */

int bmp_numcmpts(bmp_info_t *info);
/* Get the number of components. */

bmp_info_t *bmp_info_create(void);
/* Create BMP information. */

void bmp_info_destroy(bmp_info_t *info);
/* Destroy BMP information. */

int bmp_isgrayscalepal(bmp_palent_t *palents, int numpalents);
/* Does the specified palette correspond to a grayscale image? */

#endif