view release on metacpan or  search on metacpan

src/Source/LibJPEG/wrbmp.c  view on Meta::CPAN

/*
 * wrbmp.c
 *
 * Copyright (C) 1994-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README 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 "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */

#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 */

typedef struct {
  struct djpeg_dest_struct pub;	/* public fields */

  boolean is_os2;		/* saves the OS2 format request flag */

  jvirt_sarray_ptr whole_image;	/* needed to reverse row order */
  JDIMENSION data_width;	/* JSAMPLEs per row */
  JDIMENSION row_width;		/* physical width of one row in the BMP file */
  int pad_bytes;		/* number of padding bytes needed per row */
  JDIMENSION cur_output_row;	/* next row# to write to virtual array */
} bmp_dest_struct;

typedef bmp_dest_struct * bmp_dest_ptr;


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


/*
 * 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 */