sma_bmp.c

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/***********************************************************************
 * $Workfile:   SMA_bmp.c  $
 * $Revision:   1.0  $
 * $Author:   WellsK  $
 * $Date:   Aug 27 2002 08:37:34  $
 *
 * Project: BMP file structures
 *
 * Description:
 *  See the bmp.h header file for a description of this package.
 *
 *  This package uses *malloc*. If you want to use this package, you
 *  should replace malloc with your own dynamic allocation call if
 *  malloc is an invalid function.
 *
 * Revision History:
 * $Log:   //smaicnt2/pvcs/VM/CHIPS/archives/SOC/Source/Graphics/Utilities/BMP conversion/SMA_bmp.c-arc  $
 * 
 *    Rev 1.0   Aug 27 2002 08:37:34   WellsK
 * Initial revision.
 * 
 *
 * SHARP MICROELECTRONICS OF THE AMERICAS MAKES NO REPRESENTATION
 * OR WARRANTIES WITH RESPECT TO THE PERFORMANCE OF THIS SOFTWARE,
 * AND SPECIFICALLY DISCLAIMS ANY RESPONSIBILITY FOR ANY DAMAGES, 
 * SPECIAL OR CONSEQUENTIAL, CONNECTED WITH THE USE OF THIS SOFTWARE.
 *
 * SHARP MICROELECTRONICS OF THE AMERICAS PROVIDES THIS SOFTWARE SOLELY 
 * FOR THE PURPOSE OF SOFTWARE DEVELOPMENT INCORPORATING THE USE OF A 
 * SHARP MICROCONTROLLER OR SYSTEM-ON-CHIP PRODUCT. USE OF THIS SOURCE
 * FILE IMPLIES ACCEPTANCE OF THESE CONDITIONS.
 *
 * COPYRIGHT (C) 2002 SHARP MICROELECTRONICS OF THE AMERICAS, INC.
 *     CAMAS, WA
 **********************************************************************/
#include "SMA_bmp.h"
#include <stdlib.h>

//**********************************************************************
// Functions
//**********************************************************************

/***********************************************************************
 *
 * Function: bmp_is_header_valid
 *
 * Purpose:
 *  Determine if the structure is a BMP structure
 *
 * Processing:
 *  The header type (bftype) is examined to match 'BM'. If it matches
 *  and the file type is uncompressed, then the color depth is examined
 *  and the return value set to the appropriate color depth enumeration.
 *  If an unsupported type is found, type INVALID_BMP will be returned.
 *
 * Parameters:
 *  bmp_data : Pointer to a BMP data structure.
 *
 * Outputs:
 *  None
 *
 * Returns:
 *  Enumeration that defines the BMP color depth, or INVALID_BMP if
 *  the BMP type is unsupported.
 *
 * Notes:
 *  None
 *
 **********************************************************************/
bmp_storage_type bmp_is_header_valid (bmp_type *bmp_data)
{
    bmp_storage_type retval = INVALID_BMP;

    // Does the structure have the bitmap identifier?
    if ((bmp_data->bftype [0] == BMP_ID0) &&
        (bmp_data->bftype [1] == BMP_ID1))
    {
        // Compression field must be empty!
        if ((bmp_data->bicompressn == BI_RGB) ||
            (bmp_data->bicompressn == BI_RGBA))
        {
            switch (bmp_data->bibitcount)
            {
                case 1:
                    // 1 bit per pixel
                    retval = BPP1;
                    break;

                case 4:
                    // 4 bits per pixel
                    retval = BPP4;
                    break;

                case 8:
                    // 8 bits per pixel
                    retval = BPP8;
                    break;

                case 24:
                    // 24 bits per pixel
                    retval = BPP24;
                    break;

                default:
                    // No other modes are valid, keep invalid flag
                    break;
            }
        }
    }

    return retval;
}

/***********************************************************************
 *
 * Function: bmp_get_color_table
 *
 * Purpose:
 *  Returns a pointer to the color table (or NULL if it doesn't exist).
 *
 * Processing:
 *  A call to bmp_is_header_valid is performed to determine the BMP
 *  file type. If the BMP file type is BPP1, BPP4, or BPP8, then the
 *  color table is assigned a pointer after the BMP header information.
 *
 * Parameters:
 *  bmp_data : Pointer to a BMP data structure.
 *
 * Outputs:
 *  Nothing
 *
 * Returns:
 *  A pointer to the color table, or NULL if one does not exist.
 *
 * Notes:
 *  1, 4, and 8 bit per pixel BMP images have color tables.
 *
 **********************************************************************/
bmp_color_table_type *bmp_get_color_table (bmp_type *bmp_data)
{
    bmp_storage_type bmp_colors;
    bmp_color_table_type *table_ptr = (bmp_color_table_type *) NULL;

    // Get BMP structure type
    bmp_colors = bmp_is_header_valid (bmp_data);

    // Does a color table exist?
    if ((bmp_colors >= BPP1) && (bmp_colors <= BPP8))
    {
        // Color table exists, return pointer
        table_ptr = (bmp_color_table_type *) &bmp_data->ct_data;
    }

    return table_ptr;
}

/***********************************************************************
 *
 * Function: bmp_get_image_data
 *
 * Purpose:
 *  Returns a pointer to the BMP image data.
 *
 * Processing:
 *  A call to bmp_is_header_valid is performed to determine the BMP
 *  file type. Based on the BMP file type, the number of entries in
 *  the color table is computed. The pointer to the image data is
 *  computed at the end of the header plus an offset for the color
 *  table.
 *
 * Parameters:
 *  bmp_data : Pointer to a BMP data structure.
 *
 * Outputs:
 *  Nothing
 *
 * Returns:
 *  A pointer to the BMP image data.
 *
 * Notes:
 *  None
 *
 **********************************************************************/
void *bmp_get_image_data (bmp_type *bmp_data)
{
    INT_32 ctsize;

    // Skip past color table
    switch (bmp_is_header_valid (bmp_data))
    {
        case BPP1:
            // Color table size is 2 entries
            ctsize = 2;
            break;

        case BPP4:
            // Color table size is 16 entries
            ctsize = 16;
            break;

        case BPP8:
            // Color table size is 256 entries
            ctsize = 256;
            break;

        default:
            // No color table
            ctsize = 0;
    }

    return (void *) ((UNS_32) &bmp_data->ct_data +
        ctsize * sizeof (bmp_color_table_type));
}

/***********************************************************************
 *
 * Function: bmp_convert_color
 *
 * Purpose:
 *  Converts a BMP color table entry to a color_type color.
 *
 * Processing:
 *  A color table entry (or raw 24-bit entry) is converted into the
 *  native (compiled) color type by masking and shifting the red,
 *  green, and blue components of color and computing the closest color
 *  in the native format (either 233, 555, or 565).
 *
 * Parameters: 
 *  color_entry : Color table entry pointer
 *
 * Outputs:
 *  None
 *
 * Returns:
 *  A converted color_type entry from the color data.
 *
 * Notes:
 *  Not valid for 16-bit or 32-bit color formats.
 *
 **********************************************************************/
color_type bmp_convert_color (bmp_color_table_type *color_entry)
{
    color_type cv_color, r, g, b;

    // Scale colors to color_type color
    r = (color_type)
        ((UNS_32) color_entry->red * (REDMASK >> REDSHIFT) / 256);
    g = (color_type)
        ((UNS_32) color_entry->green * (GREENMASK >> GREENSHIFT) / 256);
    b = (color_type)
        ((UNS_32) color_entry->blue * (BLUEMASK >> BLUESHIFT) / 256);
    cv_color = (b << BLUESHIFT) + (g << GREENSHIFT) + (r << REDSHIFT);

    return cv_color;
}

/***********************************************************************
 *
 * Function: bmp_render_w_palette
 *
 * Purpose:
 *  Converts a pelletized (color table) BMP image into a color_type
 *  image in raw format.
 *
 * Processing:
 *  See function.
 *
 * Parameters: 
 *  bmp_data : pointer to BMP data structure
 *  buf      : pointer of where to place converted image
 *  pmask    : Color table entry mask
 *  md_shift : incremental mask shift value
 *  pshift   : initial mask shift value
 *
 * Outputs:
 *  The buffer 'buf' will be updated with the raw image data in the
 *  native color format.
 *
 * Returns:
 *  Nothing
 *
 * Notes:
 *  This function is private to this module.
 *
 **********************************************************************/
void bmp_render_w_palette (bmp_type *bmp_data, color_type *buf,
    UNS_8 pmask, UNS_8 md_shift, UNS_8 pshift)
{
    bmp_color_table_type *color_table;
    UNS_8 *image_data;
    INT_32 x, xdif, y;
    UNS_8 pixel_data, pixel_mask, pixel_shift;
    INT_32 table_index, image_start;
    UNS_8 mask_shift;
    color_type *fbuf;