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/*
* wrppm.c
*
* Copyright (C) 1991-1996, 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 PPM/PGM format.
* The extended 2-byte-per-sample raw PPM/PGM formats are supported.
* The PBMPLUS library is NOT required to compile this software
* (but it is highly useful as a set of PPM image manipulation programs).
*
* These routines may need modification for non-Unix environments or
* specialized applications. As they stand, they assume output to
* an ordinary stdio stream.
*/
#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
#ifdef PPM_SUPPORTED
/*
* For 12-bit JPEG data, we either downscale the values to 8 bits
* (to write standard byte-per-sample PPM/PGM files), or output
* nonstandard word-per-sample PPM/PGM files. Downscaling is done
* if PPM_NORAWWORD is defined (this can be done in the Makefile
* or in jconfig.h).
* (When the core library supports data precision reduction, a cleaner
* implementation will be to ask for that instead.)
*/
#if BITS_IN_JSAMPLE == 8
#define PUTPPMSAMPLE(ptr,v) *ptr++ = (char) (v)
#define BYTESPERSAMPLE 1
#define PPM_MAXVAL 255
#else
#ifdef PPM_NORAWWORD
#define PUTPPMSAMPLE(ptr,v) *ptr++ = (char) ((v) >> (BITS_IN_JSAMPLE-8))
#define BYTESPERSAMPLE 1
#define PPM_MAXVAL 255
#else
/* The word-per-sample format always puts the LSB first. */
#define PUTPPMSAMPLE(ptr,v) \
{ register int val_ = v; \
*ptr++ = (char) (val_ & 0xFF); \
*ptr++ = (char) ((val_ >> 8) & 0xFF); \
}
#define BYTESPERSAMPLE 2
#define PPM_MAXVAL ((1<<BITS_IN_JSAMPLE)-1)
#endif
#endif
/*
* When JSAMPLE is the same size as char, we can just fwrite() the
* decompressed data to the PPM or PGM file. On PCs, in order to make this
* work the output buffer must be allocated in near data space, because we are
* assuming small-data memory model wherein fwrite() can't reach far memory.
* If you need to process very wide images on a PC, you might have to compile
* in large-memory model, or else replace fwrite() with a putc() loop ---
* which will be much slower.
*/
/* Private version of data destination object */
typedef struct {
struct djpeg_dest_struct pub
; /* public fields */
/* Usually these two pointers point to the same place: */
char *iobuffer
; /* fwrite's I/O buffer */
JSAMPROW pixrow
; /* decompressor output buffer */
size_t buffer_width
; /* width of I/O buffer */
JDIMENSION samples_per_row
; /* JSAMPLEs per output row */
} ppm_dest_struct
;
typedef ppm_dest_struct
* ppm_dest_ptr
;
/*
* Write some pixel data.
* In this module rows_supplied will always be 1.
*
* put_pixel_rows handles the "normal" 8-bit case where the decompressor
* output buffer is physically the same as the fwrite buffer.
*/
METHODDEF
(void)
put_pixel_rows
(j_decompress_ptr cinfo
, djpeg_dest_ptr dinfo
,
JDIMENSION rows_supplied
)
{
ppm_dest_ptr dest
= (ppm_dest_ptr
) dinfo
;
(void) JFWRITE
(dest
->pub.
output_file, dest
->iobuffer
, dest
->buffer_width
);
}
/*
* This code is used when we have to copy the data and apply a pixel
* format translation. Typically this only happens in 12-bit mode.
*/
METHODDEF
(void)
copy_pixel_rows
(j_decompress_ptr cinfo
, djpeg_dest_ptr dinfo
,
JDIMENSION rows_supplied
)
{
ppm_dest_ptr dest
= (ppm_dest_ptr
) dinfo
;
register char * bufferptr
;
register JSAMPROW ptr
;
register JDIMENSION col
;
ptr
= dest
->pub.
buffer[0];
bufferptr
= dest
->iobuffer
;
for (col
= dest
->samples_per_row
; col
> 0; col
--) {
PUTPPMSAMPLE
(bufferptr
, GETJSAMPLE
(*ptr
++));
}
(void) JFWRITE
(dest
->pub.
output_file, dest
->iobuffer
, dest
->buffer_width
);
}
/*
* Write some pixel data when color quantization is in effect.
* We have to demap the color index values to straight data.
*/
METHODDEF
(void)
put_demapped_rgb
(j_decompress_ptr cinfo
, djpeg_dest_ptr dinfo
,
JDIMENSION rows_supplied
)
{
ppm_dest_ptr dest
= (ppm_dest_ptr
) dinfo
;
register char * bufferptr
;
register int pixval
;
register JSAMPROW ptr
;
register JSAMPROW color_map0
= cinfo
->colormap
[0];
register JSAMPROW color_map1
= cinfo
->colormap
[1];
register JSAMPROW color_map2
= cinfo
->colormap
[2];
register JDIMENSION col
;
ptr
= dest
->pub.
buffer[0];
bufferptr
= dest
->iobuffer
;
for (col
= cinfo
->output_width
; col
> 0; col
--) {
pixval
= GETJSAMPLE
(*ptr
++);
PUTPPMSAMPLE
(bufferptr
, GETJSAMPLE
(color_map0
[pixval
]));
PUTPPMSAMPLE
(bufferptr
, GETJSAMPLE
(color_map1
[pixval
]));
PUTPPMSAMPLE
(bufferptr
, GETJSAMPLE
(color_map2
[pixval
]));
}
(void) JFWRITE
(dest
->pub.
output_file, dest
->iobuffer
, dest
->buffer_width
);
}
METHODDEF
(void)
put_demapped_gray
(j_decompress_ptr cinfo
, djpeg_dest_ptr dinfo
,
JDIMENSION rows_supplied
)
{
ppm_dest_ptr dest
= (ppm_dest_ptr
) dinfo
;
register char * bufferptr
;
register JSAMPROW ptr
;
register JSAMPROW color_map
= cinfo
->colormap
[0];
register JDIMENSION col
;
ptr
= dest
->pub.
buffer[0];
bufferptr
= dest
->iobuffer
;
for (col
= cinfo
->output_width
; col
> 0; col
--) {
PUTPPMSAMPLE
(bufferptr
, GETJSAMPLE
(color_map
[GETJSAMPLE
(*ptr
++)]));
}
(void) JFWRITE
(dest
->pub.
output_file, dest
->iobuffer
, dest
->buffer_width
);
}
/*
* Startup: write the file header.
*/
METHODDEF
(void)
start_output_ppm
(j_decompress_ptr cinfo
, djpeg_dest_ptr dinfo
)
{
ppm_dest_ptr dest
= (ppm_dest_ptr
) dinfo
;
/* Emit file header */
switch (cinfo
->out_color_space
) {
case JCS_GRAYSCALE
:
/* emit header for raw PGM format */
fprintf(dest
->pub.
output_file, "P5\n%ld %ld\n%d\n",
(long) cinfo
->output_width
, (long) cinfo
->output_height
,
PPM_MAXVAL
);
break;
case JCS_RGB
:
/* emit header for raw PPM format */
fprintf(dest
->pub.
output_file, "P6\n%ld %ld\n%d\n",
(long) cinfo
->output_width
, (long) cinfo
->output_height
,
PPM_MAXVAL
);
break;
default:
ERREXIT
(cinfo
, JERR_PPM_COLORSPACE
);
}
}
/*
* Finish up at the end of the file.
*/
METHODDEF
(void)
finish_output_ppm
(j_decompress_ptr cinfo
, djpeg_dest_ptr dinfo
)
{
/* Make sure we wrote the output file OK */
fflush(dinfo
->output_file
);
if (ferror(dinfo
->output_file
))
ERREXIT
(cinfo
, JERR_FILE_WRITE
);
}
/*
* The module selection routine for PPM format output.
*/
GLOBAL
(djpeg_dest_ptr
)
jinit_write_ppm
(j_decompress_ptr cinfo
)
{
ppm_dest_ptr dest
;
/* Create module interface object, fill in method pointers */
dest
= (ppm_dest_ptr
)
(*cinfo
->mem
->alloc_small
) ((j_common_ptr
) cinfo
, JPOOL_IMAGE
,
SIZEOF
(ppm_dest_struct
));
dest
->pub.
start_output = start_output_ppm
;
dest
->pub.
finish_output = finish_output_ppm
;
/* Calculate output image dimensions so we can allocate space */
jpeg_calc_output_dimensions
(cinfo
);
/* Create physical I/O buffer. Note we make this near on a PC. */
dest
->samples_per_row
= cinfo
->output_width
* cinfo
->out_color_components
;
dest
->buffer_width
= dest
->samples_per_row
* (BYTESPERSAMPLE
* SIZEOF
(char));
dest
->iobuffer
= (char *) (*cinfo
->mem
->alloc_small
)
((j_common_ptr
) cinfo
, JPOOL_IMAGE
, dest
->buffer_width
);
if (cinfo
->quantize_colors
|| BITS_IN_JSAMPLE
!= 8 ||
SIZEOF
(JSAMPLE
) != SIZEOF
(char)) {
/* When quantizing, we need an output buffer for colormap indexes
* that's separate from the physical I/O buffer. We also need a
* separate buffer if pixel format translation must take place.
*/
dest
->pub.
buffer = (*cinfo
->mem
->alloc_sarray
)
((j_common_ptr
) cinfo
, JPOOL_IMAGE
,
cinfo
->output_width
* cinfo
->output_components
, (JDIMENSION
) 1);
dest
->pub.
buffer_height = 1;
if (! cinfo
->quantize_colors
)
dest
->pub.
put_pixel_rows = copy_pixel_rows
;
else if (cinfo
->out_color_space
== JCS_GRAYSCALE
)
dest
->pub.
put_pixel_rows = put_demapped_gray
;
else
dest
->pub.
put_pixel_rows = put_demapped_rgb
;
} else {
/* We will fwrite() directly from decompressor output buffer. */
/* Synthesize a JSAMPARRAY pointer structure */
/* Cast here implies near->far pointer conversion on PCs */
dest
->pixrow
= (JSAMPROW
) dest
->iobuffer
;
dest
->pub.
buffer = & dest
->pixrow
;
dest
->pub.
buffer_height = 1;
dest
->pub.
put_pixel_rows = put_pixel_rows
;
}
return (djpeg_dest_ptr
) dest
;
}
#endif /* PPM_SUPPORTED */