/* 
 * 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 */ 
