ref: bf4f158707ebfeacb15826ad4283ff247d7d81ae
dir: /sys/src/cmd/gs/jpeg/wrppm.c/
/*
* 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 */