ref: 855cf4326f5a07d7142c2d8918f5fa856d912b85
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 */