chromium/third_party/libjpeg_turbo/wrbmp.c

/*
 * wrbmp.c
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * libjpeg-turbo Modifications:
 * Copyright (C) 2013, Linaro Limited.
 * Copyright (C) 2014-2015, 2017, 2019, 2022, D. R. Commander.
 * For conditions of distribution and use, see the accompanying README.ijg
 * file.
 *
 * This file contains routines to write output images in Microsoft "BMP"
 * format (MS Windows 3.x and OS/2 1.x flavors).
 * Either 8-bit colormapped or 24-bit full-color format can be written.
 * No compression is supported.
 *
 * These routines may need modification for non-Unix environments or
 * specialized applications.  As they stand, they assume output to
 * an ordinary stdio stream.
 *
 * This code contributed by James Arthur Boucher.
 */

#include "cmyk.h"
#include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
#include "jconfigint.h"

#ifdef BMP_SUPPORTED


/*
 * To support 12-bit JPEG data, we'd have to scale output down to 8 bits.
 * This is not yet implemented.
 */

#if BITS_IN_JSAMPLE != 8
  Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
#endif

/*
 * Since BMP stores scanlines bottom-to-top, we have to invert the image
 * from JPEG's top-to-bottom order.  To do this, we save the outgoing data
 * in a virtual array during put_pixel_row calls, then actually emit the
 * BMP file during finish_output.  The virtual array contains one JSAMPLE per
 * pixel if the output is grayscale or colormapped, three if it is full color.
 */

/* Private version of data destination object */

bmp_dest_struct;

bmp_dest_ptr;


/* Forward declarations */
LOCAL(void) write_colormap(j_decompress_ptr cinfo, bmp_dest_ptr dest,
                           int map_colors, int map_entry_size);


static INLINE boolean is_big_endian(void)
{ … }


/*
 * Write some pixel data.
 * In this module rows_supplied will always be 1.
 */

METHODDEF(void)
put_pixel_rows(j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
               JDIMENSION rows_supplied)
/* This version is for writing 24-bit pixels */
{ … }

METHODDEF(void)
put_gray_rows(j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
              JDIMENSION rows_supplied)
/* This version is for grayscale OR quantized color output */
{ … }


/*
 * Finish up at the end of the file.
 *
 * Here is where we really output the BMP file.
 *
 * First, routines to write the Windows and OS/2 variants of the file header.
 */

LOCAL(void)
write_bmp_header(j_decompress_ptr cinfo, bmp_dest_ptr dest)
/* Write a Windows-style BMP file header, including colormap if needed */
{ … }


LOCAL(void)
write_os2_header(j_decompress_ptr cinfo, bmp_dest_ptr dest)
/* Write an OS2-style BMP file header, including colormap if needed */
{ … }


/*
 * Write the colormap.
 * Windows uses BGR0 map entries; OS/2 uses BGR entries.
 */

LOCAL(void)
write_colormap(j_decompress_ptr cinfo, bmp_dest_ptr dest, int map_colors,
               int map_entry_size)
{ … }


/*
 * Startup: write the file header unless the inversion array is being used.
 */

METHODDEF(void)
start_output_bmp(j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{ … }


METHODDEF(void)
finish_output_bmp(j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{ … }


/*
 * The module selection routine for BMP format output.
 */

GLOBAL(djpeg_dest_ptr)
jinit_write_bmp(j_decompress_ptr cinfo, boolean is_os2,
                boolean use_inversion_array)
{ … }

#endif /* BMP_SUPPORTED */