338 lines
8.9 KiB
C
338 lines
8.9 KiB
C
/*
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* jwrppm.c
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*
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* Copyright (C) 1991, 1992, 1993, 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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*
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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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* These routines are invoked via the methods put_pixel_rows, put_color_map,
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* and output_init/term.
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*/
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#include "jinclude.h"
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#ifdef PPM_SUPPORTED
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/*
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* Haven't yet got around to making this work with text-format output,
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* hence cannot handle pixels wider than 8 bits.
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*/
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#ifndef EIGHT_BIT_SAMPLES
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Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
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#endif
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/*
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* On most systems, writing individual bytes with putc() is drastically less
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* efficient than buffering a row at a time for fwrite(). But we must
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* allocate the row buffer in near data space on PCs, because we are assuming
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* small-data memory model, wherein fwrite() can't reach far memory. If you
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* need to process very wide images on a PC, you may have to use the putc()
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* approach. Also, there are still a few systems around wherein fwrite() is
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* actually implemented as a putc() loop, in which case this buffer is a waste
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* of space. So the putc() method can be used by defining USE_PUTC_OUTPUT.
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*/
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#ifndef USE_PUTC_OUTPUT
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static char * row_buffer; /* holds 1 pixel row's worth of output */
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#endif
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/*
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* Write the file header.
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*/
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METHODDEF void
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output_init (decompress_info_ptr cinfo)
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{
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if (cinfo->out_color_space == CS_GRAYSCALE) {
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/* emit header for raw PGM format */
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fprintf(cinfo->output_file, "P5\n%ld %ld\n%d\n",
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cinfo->image_width, cinfo->image_height, 255);
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#ifndef USE_PUTC_OUTPUT
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/* allocate space for row buffer: 1 byte/pixel */
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row_buffer = (char *) (*cinfo->emethods->alloc_small)
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((size_t) (SIZEOF(char) * cinfo->image_width));
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#endif
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} else if (cinfo->out_color_space == CS_RGB) {
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/* emit header for raw PPM format */
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fprintf(cinfo->output_file, "P6\n%ld %ld\n%d\n",
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cinfo->image_width, cinfo->image_height, 255);
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#ifndef USE_PUTC_OUTPUT
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/* allocate space for row buffer: 3 bytes/pixel */
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row_buffer = (char *) (*cinfo->emethods->alloc_small)
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((size_t) (3 * SIZEOF(char) * cinfo->image_width));
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#endif
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} else {
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ERREXIT(cinfo->emethods, "PPM output must be grayscale or RGB");
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}
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}
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/*
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* Write some pixel data.
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*/
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#ifdef USE_PUTC_OUTPUT
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METHODDEF void
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put_pixel_rows (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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register FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr0, ptr1, ptr2;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr0 = pixel_data[0][row];
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ptr1 = pixel_data[1][row];
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ptr2 = pixel_data[2][row];
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for (col = width; col > 0; col--) {
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putc(GETJSAMPLE(*ptr0), outfile);
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ptr0++;
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putc(GETJSAMPLE(*ptr1), outfile);
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ptr1++;
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putc(GETJSAMPLE(*ptr2), outfile);
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ptr2++;
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}
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}
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}
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METHODDEF void
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put_gray_rows (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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register FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr0;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr0 = pixel_data[0][row];
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for (col = width; col > 0; col--) {
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putc(GETJSAMPLE(*ptr0), outfile);
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ptr0++;
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}
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}
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}
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#else /* use row buffering */
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METHODDEF void
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put_pixel_rows (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr0, ptr1, ptr2;
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register char * row_bufferptr;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr0 = pixel_data[0][row];
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ptr1 = pixel_data[1][row];
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ptr2 = pixel_data[2][row];
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row_bufferptr = row_buffer;
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for (col = width; col > 0; col--) {
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*row_bufferptr++ = (char) GETJSAMPLE(*ptr0++);
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*row_bufferptr++ = (char) GETJSAMPLE(*ptr1++);
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*row_bufferptr++ = (char) GETJSAMPLE(*ptr2++);
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}
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(void) JFWRITE(outfile, row_buffer, 3*width);
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}
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}
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METHODDEF void
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put_gray_rows (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr0;
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register char * row_bufferptr;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr0 = pixel_data[0][row];
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row_bufferptr = row_buffer;
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for (col = width; col > 0; col--) {
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*row_bufferptr++ = (char) GETJSAMPLE(*ptr0++);
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}
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(void) JFWRITE(outfile, row_buffer, width);
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}
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}
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#endif /* USE_PUTC_OUTPUT */
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/*
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* Write some pixel data when color quantization is in effect.
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*/
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#ifdef USE_PUTC_OUTPUT
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METHODDEF void
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put_demapped_rgb (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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register FILE * outfile = cinfo->output_file;
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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 int pixval;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr = pixel_data[0][row];
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for (col = width; col > 0; col--) {
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pixval = GETJSAMPLE(*ptr++);
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putc(GETJSAMPLE(color_map0[pixval]), outfile);
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putc(GETJSAMPLE(color_map1[pixval]), outfile);
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putc(GETJSAMPLE(color_map2[pixval]), outfile);
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}
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}
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}
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METHODDEF void
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put_demapped_gray (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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register FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr;
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register JSAMPROW color_map0 = cinfo->colormap[0];
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register int pixval;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr = pixel_data[0][row];
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for (col = width; col > 0; col--) {
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pixval = GETJSAMPLE(*ptr++);
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putc(GETJSAMPLE(color_map0[pixval]), outfile);
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}
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}
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}
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#else /* use row buffering */
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METHODDEF void
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put_demapped_rgb (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr;
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register char * row_bufferptr;
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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 int pixval;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr = pixel_data[0][row];
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row_bufferptr = row_buffer;
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for (col = width; col > 0; col--) {
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pixval = GETJSAMPLE(*ptr++);
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*row_bufferptr++ = (char) GETJSAMPLE(color_map0[pixval]);
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*row_bufferptr++ = (char) GETJSAMPLE(color_map1[pixval]);
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*row_bufferptr++ = (char) GETJSAMPLE(color_map2[pixval]);
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}
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(void) JFWRITE(outfile, row_buffer, 3*width);
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}
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}
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METHODDEF void
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put_demapped_gray (decompress_info_ptr cinfo, int num_rows,
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JSAMPIMAGE pixel_data)
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{
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FILE * outfile = cinfo->output_file;
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register JSAMPROW ptr;
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register char * row_bufferptr;
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register JSAMPROW color_map0 = cinfo->colormap[0];
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register int pixval;
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register long col;
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long width = cinfo->image_width;
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int row;
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for (row = 0; row < num_rows; row++) {
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ptr = pixel_data[0][row];
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row_bufferptr = row_buffer;
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for (col = width; col > 0; col--) {
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pixval = GETJSAMPLE(*ptr++);
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*row_bufferptr++ = (char) GETJSAMPLE(color_map0[pixval]);
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}
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(void) JFWRITE(outfile, row_buffer, width);
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}
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}
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#endif /* USE_PUTC_OUTPUT */
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/*
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* Write the color map.
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* For PPM output, we just remember to demap the output data!
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*/
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METHODDEF void
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put_color_map (decompress_info_ptr cinfo, int num_colors, JSAMPARRAY colormap)
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{
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if (cinfo->out_color_space == CS_RGB)
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cinfo->methods->put_pixel_rows = put_demapped_rgb;
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else
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cinfo->methods->put_pixel_rows = put_demapped_gray;
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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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output_term (decompress_info_ptr cinfo)
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{
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/* No work except to make sure we wrote the output file OK; */
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/* we let free_all release any workspace */
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fflush(cinfo->output_file);
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if (ferror(cinfo->output_file))
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ERREXIT(cinfo->emethods, "Output file write error --- out of disk space?");
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}
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/*
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* The method selection routine for PPM format output.
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* This should be called from d_ui_method_selection if PPM output is wanted.
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*/
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GLOBAL void
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jselwppm (decompress_info_ptr cinfo)
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{
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cinfo->methods->output_init = output_init;
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cinfo->methods->put_color_map = put_color_map;
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if (cinfo->out_color_space == CS_RGB)
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cinfo->methods->put_pixel_rows = put_pixel_rows;
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else
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cinfo->methods->put_pixel_rows = put_gray_rows;
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cinfo->methods->output_term = output_term;
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}
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#endif /* PPM_SUPPORTED */
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