/*
* 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 */
{
bmp_dest_ptr dest = (bmp_dest_ptr) dinfo;
JSAMPARRAY image_ptr;
register JSAMPROW inptr, outptr;
register JDIMENSION col;
int pad;
/* Access next row in virtual array */
image_ptr = (*cinfo->mem->access_virt_sarray)
((j_common_ptr) cinfo, dest->whole_image,
dest->cur_output_row, (JDIMENSION) 1, TRUE);
dest->cur_output_row++;
/* Transfer data. Note destination values must be in BGR order
* (even though Microsoft's own documents say the opposite).
*/
inptr = dest->pub.buffer[0];
outptr = image_ptr[0];
for (col = cinfo->output_width; col > 0; col--) {
outptr[2] = *inptr++; /* can omit GETJSAMPLE() safely */
outptr[1] = *inptr++;
outptr[0] = *inptr++;
outptr += 3;
}
/* Zero out the pad bytes. */
pad = dest->pad_bytes;
while (--pad >= 0)
*outptr++ = 0;
}
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 */
{
bmp_dest_ptr dest = (bmp_dest_ptr) dinfo;
JSAMPARRAY image_ptr;
register JSAMPROW inptr, outptr;
register JDIMENSION col;
int pad;
/* Access next row in virtual array */
image_ptr = (*cinfo->mem->access_virt_sarray)
((j_common_ptr) cinfo, dest->whole_image,
dest->cur_output_row, (JDIMENSION) 1, TRUE);
dest->cur_output_row++;
/* Transfer data. */
inptr = dest->pub.buffer[0];
outptr = image_ptr[0];
for (col = cinfo->output_width; col > 0; col--) {
*outptr++ = *inptr++; /* can omit GETJSAMPLE() safely */
}
/* Zero out the pad bytes. */
pad = dest->pad_bytes;
while (--pad >= 0)
*outptr++ = 0;
}
/*
* Startup: normally writes the file header.
* In this module we may as well postpone everything until finish_output.
*/
METHODDEF(void)
start_output_bmp (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
/* no work here */
}
/*
* 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 */
{
char bmpfileheader[14];
char bmpinfoheader[40];
#define PUT_2B(array,offset,value) \
(array[offset] = (char) ((value) & 0xFF), \
array[offset+1] = (char) (((value) >> 8) & 0xFF))
#define PUT_4B(array,offset,value) \
(array[offset] = (char) ((value) & 0xFF), \
array[offset+1] = (char) (((value) >> 8) & 0xFF), \
array[offset+2] = (char) (((value) >> 16) & 0xFF), \
array[offset+3] = (char) (((value) >> 24) & 0xFF))
INT32 headersize, bfSize;
int bits_per_pixel, cmap_entries;
/* Compute colormap size and total file size */
if (cinfo->out_color_space == JCS_RGB) {
if (cinfo->quantize_colors) {
/* Colormapped RGB */
bits_per_pixel = 8;
cmap_entries = 256;
} else {
/* Unquantized, full color RGB */
bits_per_pixel = 24;
cmap_entries = 0;
}
} else {
/* Grayscale output. We need to fake a 256-entry colormap. */
bits_per_pixel = 8;
cmap_entries = 256;
}
/* File size */
headersize = 14 + 40 + cmap_entries * 4; /* Header and colormap */
bfSize = headersize + (INT32) dest->row_width * (INT32) cinfo->output_height;
/* Set unused fields of header to 0 */
MEMZERO(bmpfileheader, SIZEOF(bmpfileheader));
MEMZERO(bmpinfoheader, SIZEOF(bmpinfoheader));
/* Fill the file header */
bmpfileheader[0] = 0x42; /* first 2 bytes are ASCII 'B', 'M' */
bmpfileheader[1] = 0x4D;
PUT_4B(bmpfileheader, 2, bfSize); /* bfSize */
/* we leave bfReserved1 & bfReserved2 = 0 */
PUT_4B(bmpfileheader, 10, headersize); /* bfOffBits */
/* Fill the info header (Microsoft calls this a BITMAPINFOHEADER) */
PUT_2B(bmpinfoheader, 0, 40); /* biSize */
PUT_4B(bmpinfoheader, 4, cinfo->output_width); /* biWidth */
PUT_4B(bmpinfoheader, 8, cinfo->output_height); /* biHeight */
PUT_2B(bmpinfoheader, 12, 1); /* biPlanes - must be 1 */
PUT_2B(bmpinfoheader, 14, bits_per_pixel); /* biBitCount */
/* we leave biCompression = 0, for none */
/* we leave biSizeImage = 0; this is correct for uncompressed data */
if (cinfo->density_unit == 2) { /* if have density in dots/cm, then */
PUT_4B(bmpinfoheader, 24, (INT32) (cinfo->X_density*100)); /* XPels/M */
PUT_4B(bmpinfoheader, 28, (INT32) (cinfo->Y_density*100)); /* XPels/M */
}
PUT_2B(bmpinfoheader, 32, cmap_entries); /* biClrUsed */
/* we leave biClrImportant = 0 */
if (JFWRITE(dest->pub.output_file, bmpfileheader, 14) != (size_t) 14)
ERREXIT(cinfo, JERR_FILE_WRITE);
if (JFWRITE(dest->pub.output_file, bmpinfoheader, 40) != (size_t) 40)
ERREXIT(cinfo, JERR_FILE_WRITE);
if (cmap_entries > 0)
write_colormap(cinfo, dest, cmap_entries, 4);
}
LOCAL(void)
write_os2_header (j_decompress_ptr cinfo, bmp_dest_ptr dest)
/* Write an OS2-style BMP file header, including colormap if needed */
{
char bmpfileheader[14];
char bmpcoreheader[12];
INT32 headersize, bfSize;
int bits_per_pixel, cmap_entries;
/* Compute colormap size and total file size */
if (cinfo->out_color_space == JCS_RGB) {
if (cinfo->quantize_colors) {
/* Colormapped RGB */
bits_per_pixel = 8;
cmap_entries = 256;
} else {
/* Unquantized, full color RGB */
bits_per_pixel = 24;
cmap_entries = 0;
}
} else {
/* Grayscale output. We need to fake a 256-entry colormap. */
bits_per_pixel = 8;
cmap_entries = 256;
}
/* File size */
headersize = 14 + 12 + cmap_entries * 3; /* Header and colormap */
bfSize = headersize + (INT32) dest
