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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)
write_header(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,int num_colors)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)
put_pixel_rows(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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)
put_gray_rows(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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)
put_demapped_gray(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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)
start_output_tga(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo)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)
finish_output_tga(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo)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)
jinit_write_targa(j_decompress_ptr cinfo)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