ref: 5c1feb0ef0b795e5de71e956f9ccddcd5c4b7f21
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 */