1 /**********************************************************************
2 * File: mod128.c (Formerly dir128.c)
3 * Description: Code to convert a DIR128 to an ICOORD.
4 * Author: Ray Smith
5 * Created: Tue Oct 22 11:56:09 BST 1991
6 *
7 * (C) Copyright 1991, Hewlett-Packard Ltd.
8 ** Licensed under the Apache License, Version 2.0 (the "License");
9 ** you may not use this file except in compliance with the License.
10 ** You may obtain a copy of the License at
11 ** http://www.apache.org/licenses/LICENSE-2.0
12 ** Unless required by applicable law or agreed to in writing, software
13 ** distributed under the License is distributed on an "AS IS" BASIS,
14 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 ** See the License for the specific language governing permissions and
16 ** limitations under the License.
17 *
18 **********************************************************************/
19
20 #include "mfcpch.h" //precompiled headers
21 #include "mod128.h"
22
23 static inT16 idirtab[] = {
24 1000, 0, 998, 49, 995, 98, 989, 146,
25 980, 195, 970, 242, 956, 290, 941, 336,
26 923, 382, 903, 427, 881, 471, 857, 514,
27 831, 555, 803, 595, 773, 634, 740, 671,
28 707, 707, 671, 740, 634, 773, 595, 803,
29 555, 831, 514, 857, 471, 881, 427, 903,
30 382, 923, 336, 941, 290, 956, 242, 970,
31 195, 980, 146, 989, 98, 995, 49, 998,
32 0, 1000, -49, 998, -98, 995, -146, 989,
33 -195, 980, -242, 970, -290, 956, -336, 941,
34 -382, 923, -427, 903, -471, 881, -514, 857,
35 -555, 831, -595, 803, -634, 773, -671, 740,
36 -707, 707, -740, 671, -773, 634, -803, 595,
37 -831, 555, -857, 514, -881, 471, -903, 427,
38 -923, 382, -941, 336, -956, 290, -970, 242,
39 -980, 195, -989, 146, -995, 98, -998, 49,
40 -1000, 0, -998, -49, -995, -98, -989, -146,
41 -980, -195, -970, -242, -956, -290, -941, -336,
42 -923, -382, -903, -427, -881, -471, -857, -514,
43 -831, -555, -803, -595, -773, -634, -740, -671,
44 -707, -707, -671, -740, -634, -773, -595, -803,
45 -555, -831, -514, -857, -471, -881, -427, -903,
46 -382, -923, -336, -941, -290, -956, -242, -970,
47 -195, -980, -146, -989, -98, -995, -49, -998,
48 0, -1000, 49, -998, 98, -995, 146, -989,
49 195, -980, 242, -970, 290, -956, 336, -941,
50 382, -923, 427, -903, 471, -881, 514, -857,
51 555, -831, 595, -803, 634, -773, 671, -740,
52 707, -707, 740, -671, 773, -634, 803, -595,
53 831, -555, 857, -514, 881, -471, 903, -427,
54 923, -382, 941, -336, 956, -290, 970, -242,
55 980, -195, 989, -146, 995, -98, 998, -49
56 };
57
58 static ICOORD *dirtab = (ICOORD *) idirtab;
59
60 /**********************************************************************
61 * DIR128::DIR128
62 *
63 * Quantize the direction of an FCOORD to make a DIR128.
64 **********************************************************************/
65
DIR128(const FCOORD fc)66 DIR128::DIR128( //from fcoord
67 const FCOORD fc //vector to quantize
68 ) {
69 int high, low, current; //binary search
70
71 low = 0;
72 if (fc.y () == 0) {
73 if (fc.x () >= 0)
74 dir = 0;
75 else
76 dir = MODULUS / 2;
77 return;
78 }
79 high = MODULUS;
80 do {
81 current = (high + low) / 2;
82 if (dirtab[current] * fc >= 0)
83 low = current;
84 else
85 high = current;
86 }
87 while (high - low > 1);
88 dir = low;
89 }
90
91
92 /**********************************************************************
93 * dir_to_gradient
94 *
95 * Convert a direction to a vector.
96 **********************************************************************/
97
vector() const98 ICOORD DIR128::vector() const { //convert to vector
99 return dirtab[dir]; //easy really
100 }
101