1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.23 |
static const char RCSid[] = "$Id: color.c,v 2.22 2022/03/05 17:18:02 greg Exp $"; |
3 |
greg |
1.1 |
#endif |
4 |
|
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/* |
5 |
|
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* color.c - routines for color calculations. |
6 |
|
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* |
7 |
greg |
2.9 |
* Externals declared in color.h |
8 |
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*/ |
9 |
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10 |
greg |
2.10 |
#include "copyright.h" |
11 |
greg |
1.1 |
|
12 |
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#include <stdio.h> |
13 |
greg |
2.9 |
#include <stdlib.h> |
14 |
greg |
2.7 |
#include <math.h> |
15 |
greg |
1.1 |
#include "color.h" |
16 |
greg |
2.14 |
|
17 |
|
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#ifdef getc_unlocked /* avoid horrendous overhead of flockfile */ |
18 |
greg |
2.15 |
#undef getc |
19 |
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#undef putc |
20 |
greg |
2.19 |
#undef ferror |
21 |
greg |
2.14 |
#define getc getc_unlocked |
22 |
|
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#define putc putc_unlocked |
23 |
greg |
2.18 |
#define ferror ferror_unlocked |
24 |
greg |
2.14 |
#endif |
25 |
greg |
1.1 |
|
26 |
greg |
1.14 |
#define MINELEN 8 /* minimum scanline length for encoding */ |
27 |
greg |
2.6 |
#define MAXELEN 0x7fff /* maximum scanline length for encoding */ |
28 |
greg |
1.14 |
#define MINRUN 4 /* minimum run length */ |
29 |
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30 |
greg |
2.4 |
|
31 |
greg |
2.22 |
void * |
32 |
greg |
2.17 |
tempbuffer( /* get a temporary buffer */ |
33 |
|
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unsigned int len |
34 |
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) |
35 |
greg |
1.14 |
{ |
36 |
greg |
2.22 |
static void *tempbuf = NULL; |
37 |
|
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static unsigned int tempbuflen = 0; |
38 |
greg |
1.14 |
|
39 |
greg |
2.22 |
if (!len) { /* call to free */ |
40 |
|
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if (tempbuflen) { |
41 |
greg |
2.20 |
free(tempbuf); |
42 |
greg |
2.22 |
tempbuf = NULL; |
43 |
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tempbuflen = 0; |
44 |
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} |
45 |
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return(NULL); |
46 |
greg |
1.14 |
} |
47 |
greg |
2.22 |
if (len <= tempbuflen) /* big enough already? */ |
48 |
|
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return(tempbuf); |
49 |
|
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/* else free & reallocate */ |
50 |
|
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if (tempbuflen) |
51 |
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free(tempbuf); |
52 |
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tempbuf = malloc(len); |
53 |
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tempbuflen = len*(tempbuf != NULL); |
54 |
greg |
1.14 |
return(tempbuf); |
55 |
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} |
56 |
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57 |
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|
58 |
greg |
2.9 |
int |
59 |
greg |
2.17 |
fwritecolrs( /* write out a colr scanline */ |
60 |
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COLR *scanline, |
61 |
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int len, |
62 |
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FILE *fp |
63 |
|
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) |
64 |
greg |
1.1 |
{ |
65 |
greg |
2.17 |
int i, j, beg, cnt = 1; |
66 |
greg |
1.14 |
int c2; |
67 |
greg |
1.1 |
|
68 |
schorsch |
2.13 |
if ((len < MINELEN) | (len > MAXELEN)) /* OOBs, write out flat */ |
69 |
greg |
1.14 |
return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len); |
70 |
greg |
2.2 |
/* put magic header */ |
71 |
|
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putc(2, fp); |
72 |
greg |
1.14 |
putc(2, fp); |
73 |
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putc(len>>8, fp); |
74 |
greg |
2.21 |
putc(len&0xff, fp); |
75 |
greg |
1.14 |
/* put components seperately */ |
76 |
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for (i = 0; i < 4; i++) { |
77 |
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for (j = 0; j < len; j += cnt) { /* find next run */ |
78 |
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for (beg = j; beg < len; beg += cnt) { |
79 |
greg |
2.20 |
for (cnt = 1; (cnt < 127) & (beg+cnt < len) && |
80 |
greg |
1.14 |
scanline[beg+cnt][i] == scanline[beg][i]; cnt++) |
81 |
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; |
82 |
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if (cnt >= MINRUN) |
83 |
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break; /* long enough */ |
84 |
greg |
1.1 |
} |
85 |
greg |
2.20 |
if ((beg-j > 1) & (beg-j < MINRUN)) { |
86 |
greg |
1.15 |
c2 = j+1; |
87 |
|
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while (scanline[c2++][i] == scanline[j][i]) |
88 |
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if (c2 == beg) { /* short run */ |
89 |
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putc(128+beg-j, fp); |
90 |
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putc(scanline[j][i], fp); |
91 |
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j = beg; |
92 |
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break; |
93 |
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} |
94 |
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} |
95 |
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while (j < beg) { /* write out non-run */ |
96 |
greg |
1.14 |
if ((c2 = beg-j) > 128) c2 = 128; |
97 |
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putc(c2, fp); |
98 |
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while (c2--) |
99 |
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putc(scanline[j++][i], fp); |
100 |
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} |
101 |
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if (cnt >= MINRUN) { /* write out run */ |
102 |
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putc(128+cnt, fp); |
103 |
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putc(scanline[beg][i], fp); |
104 |
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} else |
105 |
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cnt = 0; |
106 |
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} |
107 |
greg |
1.1 |
} |
108 |
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return(ferror(fp) ? -1 : 0); |
109 |
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} |
110 |
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|
111 |
greg |
2.23 |
/* |
112 |
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* An old-format scanline is either a stream of valid RGBE or XYZE real |
113 |
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* pixels or at least one real pixel followed by some number of |
114 |
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* invalid real pixels of the form (1,1,1,n), where n is a count. |
115 |
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* These can themselves be repeated to create a multibyte repeat |
116 |
|
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* count, with the least significant byte first (little-endian order.) |
117 |
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* Repeat counts are limited by the size of an int; if a repetition |
118 |
|
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* leads to an overrun, the rest of the the repetition will be |
119 |
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* silently ignored. |
120 |
|
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*/ |
121 |
greg |
2.9 |
static int |
122 |
greg |
2.19 |
oldreadcolrs( /* read in an old-style colr scanline */ |
123 |
greg |
2.17 |
COLR *scanline, |
124 |
|
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int len, |
125 |
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FILE *fp |
126 |
|
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) |
127 |
greg |
2.9 |
{ |
128 |
greg |
2.18 |
int rshift = 0; |
129 |
greg |
2.17 |
int i; |
130 |
greg |
2.9 |
|
131 |
|
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while (len > 0) { |
132 |
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scanline[0][RED] = getc(fp); |
133 |
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scanline[0][GRN] = getc(fp); |
134 |
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scanline[0][BLU] = getc(fp); |
135 |
greg |
2.18 |
scanline[0][EXP] = i = getc(fp); |
136 |
|
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if (i == EOF) |
137 |
greg |
2.9 |
return(-1); |
138 |
greg |
2.20 |
if (scanline[0][GRN] == 1 && |
139 |
|
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(scanline[0][RED] == 1) & |
140 |
|
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(scanline[0][BLU] == 1)) { |
141 |
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i = scanline[0][EXP] << rshift; |
142 |
|
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while (i--) { |
143 |
greg |
2.9 |
copycolr(scanline[0], scanline[-1]); |
144 |
greg |
2.20 |
if (--len <= 0) |
145 |
|
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return(0); |
146 |
greg |
2.9 |
scanline++; |
147 |
|
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} |
148 |
|
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rshift += 8; |
149 |
|
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} else { |
150 |
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scanline++; |
151 |
|
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len--; |
152 |
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rshift = 0; |
153 |
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} |
154 |
|
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} |
155 |
|
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return(0); |
156 |
|
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} |
157 |
|
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|
158 |
greg |
2.23 |
/* |
159 |
|
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* There are two scanline formats: old and new. The old format |
160 |
|
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* compresses runs of RGBE or XYZE four-byte real pixels; the new |
161 |
|
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* format breaks the pixels into R, G, B, and E lines (or XYZE lines) |
162 |
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* which are individually run-length encoded. |
163 |
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* |
164 |
|
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* An old-format scanline always begins with a valid real pixel; at |
165 |
|
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* least one of the RGB (or XYZ) values will have its high-order bit |
166 |
|
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* set. A new-format scanline begins with four bytes which are not a |
167 |
|
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* valid real pixel: (2, 2, lenhigh, lenlow) where lenhigh is always |
168 |
|
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* less than 128 and hence never has a high-order bit set. |
169 |
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* |
170 |
|
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* A new-format scanline is broken into its RGBE or XYZE components. |
171 |
|
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* Each is output and run-length encoded separately so that a scanline |
172 |
|
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* is broken into four records. In turn, each record is organized |
173 |
|
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* into chunks of up to 128 characters, which begin with a count byte. |
174 |
|
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* If the count byte is greater than 128, the following data byte is |
175 |
|
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* repeated (count-128) times. If not, the count byte is followed by |
176 |
|
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* that many data bytes. |
177 |
|
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*/ |
178 |
greg |
2.9 |
int |
179 |
greg |
2.17 |
freadcolrs( /* read in an encoded colr scanline */ |
180 |
|
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COLR *scanline, |
181 |
|
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int len, |
182 |
|
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FILE *fp |
183 |
|
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) |
184 |
greg |
1.1 |
{ |
185 |
greg |
2.17 |
int i, j; |
186 |
greg |
2.6 |
int code, val; |
187 |
greg |
1.14 |
/* determine scanline type */ |
188 |
schorsch |
2.13 |
if ((len < MINELEN) | (len > MAXELEN)) |
189 |
greg |
1.14 |
return(oldreadcolrs(scanline, len, fp)); |
190 |
|
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if ((i = getc(fp)) == EOF) |
191 |
|
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return(-1); |
192 |
|
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if (i != 2) { |
193 |
|
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ungetc(i, fp); |
194 |
|
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return(oldreadcolrs(scanline, len, fp)); |
195 |
|
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} |
196 |
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scanline[0][GRN] = getc(fp); |
197 |
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scanline[0][BLU] = getc(fp); |
198 |
|
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if ((i = getc(fp)) == EOF) |
199 |
|
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return(-1); |
200 |
greg |
2.21 |
if ((scanline[0][GRN] != 2) | ((scanline[0][BLU] & 0x80) != 0)) { |
201 |
greg |
1.14 |
scanline[0][RED] = 2; |
202 |
|
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scanline[0][EXP] = i; |
203 |
|
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return(oldreadcolrs(scanline+1, len-1, fp)); |
204 |
|
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} |
205 |
|
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if ((scanline[0][BLU]<<8 | i) != len) |
206 |
|
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return(-1); /* length mismatch! */ |
207 |
|
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/* read each component */ |
208 |
|
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for (i = 0; i < 4; i++) |
209 |
|
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for (j = 0; j < len; ) { |
210 |
|
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if ((code = getc(fp)) == EOF) |
211 |
|
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return(-1); |
212 |
|
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if (code > 128) { /* run */ |
213 |
greg |
2.6 |
code &= 127; |
214 |
greg |
2.9 |
if ((val = getc(fp)) == EOF) |
215 |
|
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return -1; |
216 |
greg |
2.16 |
if (j + code > len) |
217 |
|
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return -1; /* overrun */ |
218 |
greg |
2.6 |
while (code--) |
219 |
|
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scanline[j++][i] = val; |
220 |
greg |
2.16 |
} else { /* non-run */ |
221 |
|
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if (j + code > len) |
222 |
|
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return -1; /* overrun */ |
223 |
greg |
2.9 |
while (code--) { |
224 |
|
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if ((val = getc(fp)) == EOF) |
225 |
|
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return -1; |
226 |
|
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scanline[j++][i] = val; |
227 |
|
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} |
228 |
greg |
2.16 |
} |
229 |
greg |
1.14 |
} |
230 |
greg |
1.1 |
return(0); |
231 |
|
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} |
232 |
|
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|
233 |
|
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|
234 |
greg |
2.9 |
int |
235 |
greg |
2.17 |
fwritescan( /* write out a scanline */ |
236 |
|
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COLOR *scanline, |
237 |
|
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int len, |
238 |
|
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FILE *fp |
239 |
|
|
) |
240 |
greg |
1.1 |
{ |
241 |
greg |
1.14 |
COLR *clrscan; |
242 |
|
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int n; |
243 |
greg |
2.17 |
COLR *sp; |
244 |
greg |
1.14 |
/* get scanline buffer */ |
245 |
|
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if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
246 |
|
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return(-1); |
247 |
|
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clrscan = sp; |
248 |
|
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/* convert scanline */ |
249 |
|
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n = len; |
250 |
|
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while (n-- > 0) { |
251 |
|
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setcolr(sp[0], scanline[0][RED], |
252 |
greg |
1.1 |
scanline[0][GRN], |
253 |
|
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scanline[0][BLU]); |
254 |
|
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scanline++; |
255 |
greg |
1.14 |
sp++; |
256 |
greg |
1.1 |
} |
257 |
greg |
1.14 |
return(fwritecolrs(clrscan, len, fp)); |
258 |
greg |
1.1 |
} |
259 |
|
|
|
260 |
|
|
|
261 |
greg |
2.9 |
int |
262 |
greg |
2.17 |
freadscan( /* read in a scanline */ |
263 |
|
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COLOR *scanline, |
264 |
|
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int len, |
265 |
|
|
FILE *fp |
266 |
|
|
) |
267 |
greg |
1.1 |
{ |
268 |
greg |
2.17 |
COLR *clrscan; |
269 |
greg |
1.14 |
|
270 |
|
|
if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL) |
271 |
|
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return(-1); |
272 |
|
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if (freadcolrs(clrscan, len, fp) < 0) |
273 |
|
|
return(-1); |
274 |
|
|
/* convert scanline */ |
275 |
|
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colr_color(scanline[0], clrscan[0]); |
276 |
|
|
while (--len > 0) { |
277 |
|
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scanline++; clrscan++; |
278 |
greg |
2.20 |
if (clrscan[0][GRN] == clrscan[-1][GRN] && |
279 |
|
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(clrscan[0][RED] == clrscan[-1][RED]) & |
280 |
|
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(clrscan[0][BLU] == clrscan[-1][BLU]) & |
281 |
|
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(clrscan[0][EXP] == clrscan[-1][EXP])) |
282 |
greg |
1.14 |
copycolor(scanline[0], scanline[-1]); |
283 |
|
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else |
284 |
|
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colr_color(scanline[0], clrscan[0]); |
285 |
greg |
1.1 |
} |
286 |
|
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return(0); |
287 |
|
|
} |
288 |
|
|
|
289 |
|
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|
290 |
greg |
2.9 |
void |
291 |
greg |
2.17 |
setcolr( /* assign a short color value */ |
292 |
|
|
COLR clr, |
293 |
|
|
double r, |
294 |
|
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double g, |
295 |
|
|
double b |
296 |
|
|
) |
297 |
greg |
1.1 |
{ |
298 |
|
|
double d; |
299 |
|
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int e; |
300 |
|
|
|
301 |
|
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d = r > g ? r : g; |
302 |
|
|
if (b > d) d = b; |
303 |
|
|
|
304 |
greg |
1.4 |
if (d <= 1e-32) { |
305 |
greg |
1.1 |
clr[RED] = clr[GRN] = clr[BLU] = 0; |
306 |
|
|
clr[EXP] = 0; |
307 |
|
|
return; |
308 |
|
|
} |
309 |
|
|
|
310 |
greg |
2.21 |
d = frexp(d, &e) * 256.0 / d; |
311 |
greg |
1.1 |
|
312 |
greg |
2.11 |
if (r > 0.0) |
313 |
|
|
clr[RED] = r * d; |
314 |
|
|
else |
315 |
|
|
clr[RED] = 0; |
316 |
|
|
if (g > 0.0) |
317 |
|
|
clr[GRN] = g * d; |
318 |
|
|
else |
319 |
|
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clr[GRN] = 0; |
320 |
|
|
if (b > 0.0) |
321 |
|
|
clr[BLU] = b * d; |
322 |
|
|
else |
323 |
|
|
clr[BLU] = 0; |
324 |
|
|
|
325 |
greg |
1.1 |
clr[EXP] = e + COLXS; |
326 |
|
|
} |
327 |
|
|
|
328 |
|
|
|
329 |
greg |
2.9 |
void |
330 |
greg |
2.17 |
colr_color( /* convert short to float color */ |
331 |
|
|
COLOR col, |
332 |
|
|
COLR clr |
333 |
|
|
) |
334 |
greg |
1.1 |
{ |
335 |
greg |
1.6 |
double f; |
336 |
greg |
1.1 |
|
337 |
|
|
if (clr[EXP] == 0) |
338 |
|
|
col[RED] = col[GRN] = col[BLU] = 0.0; |
339 |
|
|
else { |
340 |
greg |
1.2 |
f = ldexp(1.0, (int)clr[EXP]-(COLXS+8)); |
341 |
greg |
1.1 |
col[RED] = (clr[RED] + 0.5)*f; |
342 |
|
|
col[GRN] = (clr[GRN] + 0.5)*f; |
343 |
|
|
col[BLU] = (clr[BLU] + 0.5)*f; |
344 |
|
|
} |
345 |
greg |
1.6 |
} |
346 |
|
|
|
347 |
|
|
|
348 |
greg |
2.9 |
int |
349 |
greg |
2.17 |
bigdiff( /* c1 delta c2 > md? */ |
350 |
|
|
COLOR c1, |
351 |
|
|
COLOR c2, |
352 |
|
|
double md |
353 |
|
|
) |
354 |
greg |
1.7 |
{ |
355 |
greg |
2.17 |
int i; |
356 |
greg |
1.7 |
|
357 |
|
|
for (i = 0; i < 3; i++) |
358 |
|
|
if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) || |
359 |
greg |
2.20 |
colval(c2,i)-colval(c1,i) > md*colval(c1,i)) |
360 |
greg |
1.7 |
return(1); |
361 |
|
|
return(0); |
362 |
|
|
} |