ref: dab539cd14726de15932b0310532212f8da29bf7
dir: /sys/src/cmd/gs/jpeg/wrtarga.c/
/*
* wrtarga.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 Targa format.
*
* These routines may need modification for non-Unix environments or
* specialized applications. As they stand, they assume output to
* an ordinary stdio stream.
*
* Based on code contributed by Lee Daniel Crocker.
*/
#include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */
#ifdef TARGA_SUPPORTED
/*
* To support 12-bit JPEG data, we'd have to scale output down to 8 bits.
* This is not yet implemented.
*/
#if BITS_IN_JSAMPLE != 8
Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
#endif
/*
* The output buffer needs to be writable by fwrite(). On PCs, we must
* allocate the buffer 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 */
char *iobuffer; /* physical I/O buffer */
JDIMENSION buffer_width; /* width of one row */
} tga_dest_struct;
typedef tga_dest_struct * tga_dest_ptr;
LOCAL(void)
write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors)
/* Create and write a Targa header */
{
char targaheader[18];
/* Set unused fields of header to 0 */
MEMZERO(targaheader, SIZEOF(targaheader));
if (num_colors > 0) {
targaheader[1] = 1; /* color map type 1 */
targaheader[5] = (char) (num_colors & 0xFF);
targaheader[6] = (char) (num_colors >> 8);
targaheader[7] = 24; /* 24 bits per cmap entry */
}
targaheader[12] = (char) (cinfo->output_width & 0xFF);
targaheader[13] = (char) (cinfo->output_width >> 8);
targaheader[14] = (char) (cinfo->output_height & 0xFF);
targaheader[15] = (char) (cinfo->output_height >> 8);
targaheader[17] = 0x20; /* Top-down, non-interlaced */
if (cinfo->out_color_space == JCS_GRAYSCALE) {
targaheader[2] = 3; /* image type = uncompressed gray-scale */
targaheader[16] = 8; /* bits per pixel */
} else { /* must be RGB */
if (num_colors > 0) {
targaheader[2] = 1; /* image type = colormapped RGB */
targaheader[16] = 8;
} else {
targaheader[2] = 2; /* image type = uncompressed RGB */
targaheader[16] = 24;
}
}
if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18)
ERREXIT(cinfo, JERR_FILE_WRITE);
}
/*
* Write some pixel data.
* In this module rows_supplied will always be 1.
*/
METHODDEF(void)
put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied)
/* used for unquantized full-color output */
{
tga_dest_ptr dest = (tga_dest_ptr) dinfo;
register JSAMPROW inptr;
register char * outptr;
register JDIMENSION col;
inptr = dest->pub.buffer[0];
outptr = dest->iobuffer;
for (col = cinfo->output_width; col > 0; col--) {
outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */
outptr[1] = (char) GETJSAMPLE(inptr[1]);
outptr[2] = (char) GETJSAMPLE(inptr[0]);
inptr += 3, outptr += 3;
}
(void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}
METHODDEF(void)
put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied)
/* used for grayscale OR quantized color output */
{
tga_dest_ptr dest = (tga_dest_ptr) dinfo;
register JSAMPROW inptr;
register char * outptr;
register JDIMENSION col;
inptr = dest->pub.buffer[0];
outptr = dest->iobuffer;
for (col = cinfo->output_width; col > 0; col--) {
*outptr++ = (char) GETJSAMPLE(*inptr++);
}
(void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}
/*
* Write some demapped pixel data when color quantization is in effect.
* For Targa, this is only applied to grayscale data.
*/
METHODDEF(void)
put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
JDIMENSION rows_supplied)
{
tga_dest_ptr dest = (tga_dest_ptr) dinfo;
register JSAMPROW inptr;
register char * outptr;
register JSAMPROW color_map0 = cinfo->colormap[0];
register JDIMENSION col;
inptr = dest->pub.buffer[0];
outptr = dest->iobuffer;
for (col = cinfo->output_width; col > 0; col--) {
*outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]);
}
(void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}
/*
* Startup: write the file header.
*/
METHODDEF(void)
start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
tga_dest_ptr dest = (tga_dest_ptr) dinfo;
int num_colors, i;
FILE *outfile;
if (cinfo->out_color_space == JCS_GRAYSCALE) {
/* Targa doesn't have a mapped grayscale format, so we will */
/* demap quantized gray output. Never emit a colormap. */
write_header(cinfo, dinfo, 0);
if (cinfo->quantize_colors)
dest->pub.put_pixel_rows = put_demapped_gray;
else
dest->pub.put_pixel_rows = put_gray_rows;
} else if (cinfo->out_color_space == JCS_RGB) {
if (cinfo->quantize_colors) {
/* We only support 8-bit colormap indexes, so only 256 colors */
num_colors = cinfo->actual_number_of_colors;
if (num_colors > 256)
ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors);
write_header(cinfo, dinfo, num_colors);
/* Write the colormap. Note Targa uses BGR byte order */
outfile = dest->pub.output_file;
for (i = 0; i < num_colors; i++) {
putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile);
putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile);
putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile);
}
dest->pub.put_pixel_rows = put_gray_rows;
} else {
write_header(cinfo, dinfo, 0);
dest->pub.put_pixel_rows = put_pixel_rows;
}
} else {
ERREXIT(cinfo, JERR_TGA_COLORSPACE);
}
}
/*
* Finish up at the end of the file.
*/
METHODDEF(void)
finish_output_tga (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 Targa format output.
*/
GLOBAL(djpeg_dest_ptr)
jinit_write_targa (j_decompress_ptr cinfo)
{
tga_dest_ptr dest;
/* Create module interface object, fill in method pointers */
dest = (tga_dest_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
SIZEOF(tga_dest_struct));
dest->pub.start_output = start_output_tga;
dest->pub.finish_output = finish_output_tga;
/* Calculate output image dimensions so we can allocate space */
jpeg_calc_output_dimensions(cinfo);
/* Create I/O buffer. Note we make this near on a PC. */
dest->buffer_width = cinfo->output_width * cinfo->output_components;
dest->iobuffer = (char *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
(size_t) (dest->buffer_width * SIZEOF(char)));
/* Create decompressor output buffer. */
dest->pub.buffer = (*cinfo->mem->alloc_sarray)
((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1);
dest->pub.buffer_height = 1;
return (djpeg_dest_ptr) dest;
}
#endif /* TARGA_SUPPORTED */