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