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Diffstat (limited to 'sanei/sanei_jpeg.c')
| -rw-r--r-- | sanei/sanei_jpeg.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/sanei/sanei_jpeg.c b/sanei/sanei_jpeg.c new file mode 100644 index 0000000..7b66dae --- /dev/null +++ b/sanei/sanei_jpeg.c @@ -0,0 +1,235 @@ +/* + Code for JPEG decompression by the Independent JPEG Group. Please see + README.jpeg in the top level directory. + */ + +#include "../include/sane/config.h" + +#ifdef HAVE_LIBJPEG + +#include "../include/sane/sanei_jpeg.h" + +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; + +/* + * 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 + +METHODDEF (void) +sanei_jpeg_start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) +{ + cinfo = cinfo; + dinfo = dinfo; + /* header image is supplied for us */ + +} + +METHODDEF (void) +sanei_jpeg_finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) +{ + cinfo = cinfo; + dinfo = dinfo; + + /* nothing to do */ +} + +/* + * 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) +sanei_jpeg_put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, + JDIMENSION rows_supplied, char *data) +{ + ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; + cinfo = cinfo; + dinfo = dinfo; + rows_supplied = rows_supplied; + + memcpy (data, 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) +sanei_jpeg_copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, + JDIMENSION rows_supplied, char *data) +{ + ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; + register char *bufferptr; + register JSAMPROW ptr; + register JDIMENSION col; + + cinfo = cinfo; + dinfo = dinfo; + rows_supplied = rows_supplied; + + ptr = dest->pub.buffer[0]; + bufferptr = dest->iobuffer; + for (col = dest->samples_per_row; col > 0; col--) + { + PUTPPMSAMPLE (bufferptr, GETJSAMPLE (*ptr++)); + } + memcpy (data, 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) +sanei_jpeg_put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, + JDIMENSION rows_supplied, char *data) +{ + + 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; + + rows_supplied = rows_supplied; + + 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])); + } + memcpy (data, dest->iobuffer, dest->buffer_width); +} + + +METHODDEF (void) +sanei_jpeg_put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, + JDIMENSION rows_supplied, char *data) +{ + ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; + register char *bufferptr; + register JSAMPROW ptr; + register JSAMPROW color_map = cinfo->colormap[0]; + register JDIMENSION col; + + rows_supplied = rows_supplied; + + ptr = dest->pub.buffer[0]; + bufferptr = dest->iobuffer; + for (col = cinfo->output_width; col > 0; col--) + { + PUTPPMSAMPLE (bufferptr, + GETJSAMPLE (color_map[GETJSAMPLE (*ptr++)])); + } + memcpy (data, dest->iobuffer, dest->buffer_width); +} + +GLOBAL (djpeg_dest_ptr) +sanei_jpeg_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 = sanei_jpeg_start_output_ppm; + dest->pub.finish_output = sanei_jpeg_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 clrmap 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 = sanei_jpeg_copy_pixel_rows; + else if (cinfo->out_color_space == JCS_GRAYSCALE) + dest->pub.put_pixel_rows = sanei_jpeg_put_demapped_gray; + else + dest->pub.put_pixel_rows = sanei_jpeg_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 = sanei_jpeg_put_pixel_rows; + } + + return (djpeg_dest_ptr) dest; +} + +#endif |