/*

* wrppm.c

*

* Copyright (C) 1991-1996, Thomas G. Lane.

* Modified 2009 by Guido Vollbeding.

* 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 MSB first. */

#define PUTPPMSAMPLE(ptr,v) \

{ register int val_ = v; \

*ptr++ = (char) ((val_ >> 8) & 0xFF); \

*ptr++ = (char) (val_ & 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 */