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      1 /*
      2  * wrtarga.c
      3  *
      4  * Copyright (C) 1991-1996, Thomas G. Lane.
      5  * This file is part of the Independent JPEG Group's software.
      6  * For conditions of distribution and use, see the accompanying README file.
      7  *
      8  * This file contains routines to write output images in Targa format.
      9  *
     10  * These routines may need modification for non-Unix environments or
     11  * specialized applications.  As they stand, they assume output to
     12  * an ordinary stdio stream.
     13  *
     14  * Based on code contributed by Lee Daniel Crocker.
     15  */
     16 
     17 #include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
     18 
     19 #ifdef TARGA_SUPPORTED
     20 
     21 
     22 /*
     23  * To support 12-bit JPEG data, we'd have to scale output down to 8 bits.
     24  * This is not yet implemented.
     25  */
     26 
     27 #if BITS_IN_JSAMPLE != 8
     28   Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
     29 #endif
     30 
     31 /*
     32  * The output buffer needs to be writable by fwrite().  On PCs, we must
     33  * allocate the buffer in near data space, because we are assuming small-data
     34  * memory model, wherein fwrite() can't reach far memory.  If you need to
     35  * process very wide images on a PC, you might have to compile in large-memory
     36  * model, or else replace fwrite() with a putc() loop --- which will be much
     37  * slower.
     38  */
     39 
     40 
     41 /* Private version of data destination object */
     42 
     43 typedef struct {
     44   struct djpeg_dest_struct pub;	/* public fields */
     45 
     46   char *iobuffer;		/* physical I/O buffer */
     47   JDIMENSION buffer_width;	/* width of one row */
     48 } tga_dest_struct;
     49 
     50 typedef tga_dest_struct * tga_dest_ptr;
     51 
     52 
     53 LOCAL(void)
     54 write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors)
     55 /* Create and write a Targa header */
     56 {
     57   char targaheader[18];
     58 
     59   /* Set unused fields of header to 0 */
     60   MEMZERO(targaheader, SIZEOF(targaheader));
     61 
     62   if (num_colors > 0) {
     63     targaheader[1] = 1;		/* color map type 1 */
     64     targaheader[5] = (char) (num_colors & 0xFF);
     65     targaheader[6] = (char) (num_colors >> 8);
     66     targaheader[7] = 24;	/* 24 bits per cmap entry */
     67   }
     68 
     69   targaheader[12] = (char) (cinfo->output_width & 0xFF);
     70   targaheader[13] = (char) (cinfo->output_width >> 8);
     71   targaheader[14] = (char) (cinfo->output_height & 0xFF);
     72   targaheader[15] = (char) (cinfo->output_height >> 8);
     73   targaheader[17] = 0x20;	/* Top-down, non-interlaced */
     74 
     75   if (cinfo->out_color_space == JCS_GRAYSCALE) {
     76     targaheader[2] = 3;		/* image type = uncompressed gray-scale */
     77     targaheader[16] = 8;	/* bits per pixel */
     78   } else {			/* must be RGB */
     79     if (num_colors > 0) {
     80       targaheader[2] = 1;	/* image type = colormapped RGB */
     81       targaheader[16] = 8;
     82     } else {
     83       targaheader[2] = 2;	/* image type = uncompressed RGB */
     84       targaheader[16] = 24;
     85     }
     86   }
     87 
     88   if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18)
     89     ERREXIT(cinfo, JERR_FILE_WRITE);
     90 }
     91 
     92 
     93 /*
     94  * Write some pixel data.
     95  * In this module rows_supplied will always be 1.
     96  */
     97 
     98 METHODDEF(void)
     99 put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    100 		JDIMENSION rows_supplied)
    101 /* used for unquantized full-color output */
    102 {
    103   tga_dest_ptr dest = (tga_dest_ptr) dinfo;
    104   register JSAMPROW inptr;
    105   register char * outptr;
    106   register JDIMENSION col;
    107 
    108   inptr = dest->pub.buffer[0];
    109   outptr = dest->iobuffer;
    110   for (col = cinfo->output_width; col > 0; col--) {
    111     outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */
    112     outptr[1] = (char) GETJSAMPLE(inptr[1]);
    113     outptr[2] = (char) GETJSAMPLE(inptr[0]);
    114     inptr += 3, outptr += 3;
    115   }
    116   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
    117 }
    118 
    119 METHODDEF(void)
    120 put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    121 	       JDIMENSION rows_supplied)
    122 /* used for grayscale OR quantized color output */
    123 {
    124   tga_dest_ptr dest = (tga_dest_ptr) dinfo;
    125   register JSAMPROW inptr;
    126   register char * outptr;
    127   register JDIMENSION col;
    128 
    129   inptr = dest->pub.buffer[0];
    130   outptr = dest->iobuffer;
    131   for (col = cinfo->output_width; col > 0; col--) {
    132     *outptr++ = (char) GETJSAMPLE(*inptr++);
    133   }
    134   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
    135 }
    136 
    137 
    138 /*
    139  * Write some demapped pixel data when color quantization is in effect.
    140  * For Targa, this is only applied to grayscale data.
    141  */
    142 
    143 METHODDEF(void)
    144 put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    145 		   JDIMENSION rows_supplied)
    146 {
    147   tga_dest_ptr dest = (tga_dest_ptr) dinfo;
    148   register JSAMPROW inptr;
    149   register char * outptr;
    150   register JSAMPROW color_map0 = cinfo->colormap[0];
    151   register JDIMENSION col;
    152 
    153   inptr = dest->pub.buffer[0];
    154   outptr = dest->iobuffer;
    155   for (col = cinfo->output_width; col > 0; col--) {
    156     *outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]);
    157   }
    158   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
    159 }
    160 
    161 
    162 /*
    163  * Startup: write the file header.
    164  */
    165 
    166 METHODDEF(void)
    167 start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
    168 {
    169   tga_dest_ptr dest = (tga_dest_ptr) dinfo;
    170   int num_colors, i;
    171   FILE *outfile;
    172 
    173   if (cinfo->out_color_space == JCS_GRAYSCALE) {
    174     /* Targa doesn't have a mapped grayscale format, so we will */
    175     /* demap quantized gray output.  Never emit a colormap. */
    176     write_header(cinfo, dinfo, 0);
    177     if (cinfo->quantize_colors)
    178       dest->pub.put_pixel_rows = put_demapped_gray;
    179     else
    180       dest->pub.put_pixel_rows = put_gray_rows;
    181   } else if (cinfo->out_color_space == JCS_RGB) {
    182     if (cinfo->quantize_colors) {
    183       /* We only support 8-bit colormap indexes, so only 256 colors */
    184       num_colors = cinfo->actual_number_of_colors;
    185       if (num_colors > 256)
    186 	ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors);
    187       write_header(cinfo, dinfo, num_colors);
    188       /* Write the colormap.  Note Targa uses BGR byte order */
    189       outfile = dest->pub.output_file;
    190       for (i = 0; i < num_colors; i++) {
    191 	putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile);
    192 	putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile);
    193 	putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile);
    194       }
    195       dest->pub.put_pixel_rows = put_gray_rows;
    196     } else {
    197       write_header(cinfo, dinfo, 0);
    198       dest->pub.put_pixel_rows = put_pixel_rows;
    199     }
    200   } else {
    201     ERREXIT(cinfo, JERR_TGA_COLORSPACE);
    202   }
    203 }
    204 
    205 
    206 /*
    207  * Finish up at the end of the file.
    208  */
    209 
    210 METHODDEF(void)
    211 finish_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
    212 {
    213   /* Make sure we wrote the output file OK */
    214   fflush(dinfo->output_file);
    215   if (ferror(dinfo->output_file))
    216     ERREXIT(cinfo, JERR_FILE_WRITE);
    217 }
    218 
    219 
    220 /*
    221  * The module selection routine for Targa format output.
    222  */
    223 
    224 GLOBAL(djpeg_dest_ptr)
    225 jinit_write_targa (j_decompress_ptr cinfo)
    226 {
    227   tga_dest_ptr dest;
    228 
    229   /* Create module interface object, fill in method pointers */
    230   dest = (tga_dest_ptr)
    231       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    232 				  SIZEOF(tga_dest_struct));
    233   dest->pub.start_output = start_output_tga;
    234   dest->pub.finish_output = finish_output_tga;
    235 
    236   /* Calculate output image dimensions so we can allocate space */
    237   jpeg_calc_output_dimensions(cinfo);
    238 
    239   /* Create I/O buffer.  Note we make this near on a PC. */
    240   dest->buffer_width = cinfo->output_width * cinfo->output_components;
    241   dest->iobuffer = (char *)
    242     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    243 				(size_t) (dest->buffer_width * SIZEOF(char)));
    244 
    245   /* Create decompressor output buffer. */
    246   dest->pub.buffer = (*cinfo->mem->alloc_sarray)
    247     ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1);
    248   dest->pub.buffer_height = 1;
    249 
    250   return (djpeg_dest_ptr) dest;
    251 }
    252 
    253 #endif /* TARGA_SUPPORTED */
    254