2003-07-26 03:04:41 +00:00
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/*
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Code for JPEG decompression by the Independent JPEG Group. Please see
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README.jpeg in the top level directory.
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*/
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2009-02-01 15:21:46 +00:00
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#include "../include/sane/config.h"
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#ifdef HAVE_LIBJPEG
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2003-07-26 03:04:41 +00:00
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#include "sane/sanei_jpeg.h"
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typedef struct
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{
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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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}
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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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* 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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METHODDEF (void)
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sanei_jpeg_start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
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{
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cinfo = cinfo;
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dinfo = dinfo;
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/* header image is supplied for us */
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}
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METHODDEF (void)
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sanei_jpeg_finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
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{
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cinfo = cinfo;
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dinfo = dinfo;
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/* nothing to do */
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}
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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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sanei_jpeg_put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
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JDIMENSION rows_supplied, char *data)
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{
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ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
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cinfo = cinfo;
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dinfo = dinfo;
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rows_supplied = rows_supplied;
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memcpy (data, 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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sanei_jpeg_copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
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JDIMENSION rows_supplied, char *data)
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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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cinfo = cinfo;
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dinfo = dinfo;
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rows_supplied = rows_supplied;
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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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{
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PUTPPMSAMPLE (bufferptr, GETJSAMPLE (*ptr++));
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}
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memcpy (data, 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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sanei_jpeg_put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
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JDIMENSION rows_supplied, char *data)
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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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rows_supplied = rows_supplied;
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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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{
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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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memcpy (data, dest->iobuffer, dest->buffer_width);
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}
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METHODDEF (void)
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sanei_jpeg_put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
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JDIMENSION rows_supplied, char *data)
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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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rows_supplied = rows_supplied;
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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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{
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PUTPPMSAMPLE (bufferptr,
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GETJSAMPLE (color_map[GETJSAMPLE (*ptr++)]));
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}
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memcpy (data, dest->iobuffer, dest->buffer_width);
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}
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GLOBAL (djpeg_dest_ptr)
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sanei_jpeg_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 = sanei_jpeg_start_output_ppm;
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dest->pub.finish_output = sanei_jpeg_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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{
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/* When quantizing, we need an output buffer for clrmap 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,
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(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 = sanei_jpeg_copy_pixel_rows;
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else if (cinfo->out_color_space == JCS_GRAYSCALE)
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dest->pub.put_pixel_rows = sanei_jpeg_put_demapped_gray;
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else
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dest->pub.put_pixel_rows = sanei_jpeg_put_demapped_rgb;
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}
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else
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{
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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 = sanei_jpeg_put_pixel_rows;
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}
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return (djpeg_dest_ptr) dest;
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}
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2009-02-01 15:21:46 +00:00
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#endif
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