1 /*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 ///////////////////////////////////////////////////////////
18 // Interp.h
19 // $Id: Interp.h,v 1.2 2011/06/17 13:35:48 mbansal Exp $
20
21 #ifndef INTERP_H
22 #define INTERP_H
23
24 #include "Pyramid.h"
25
26 #define CTAPS 40
27 static double ciTable[81] = {
28 1, 0.998461, 0.993938, 0.98657, 0.9765,
29 0.963867, 0.948813, 0.931477, 0.912, 0.890523,
30 0.867188, 0.842133, 0.8155, 0.78743, 0.758062,
31 0.727539, 0.696, 0.663586, 0.630437, 0.596695,
32 0.5625, 0.527992, 0.493312, 0.458602, 0.424,
33 0.389648, 0.355687, 0.322258, 0.2895, 0.257555,
34 0.226562, 0.196664, 0.168, 0.140711, 0.114937,
35 0.0908203, 0.0685, 0.0481172, 0.0298125, 0.0137266,
36 0, -0.0118828, -0.0225625, -0.0320859, -0.0405,
37 -0.0478516, -0.0541875, -0.0595547, -0.064, -0.0675703,
38 -0.0703125, -0.0722734, -0.0735, -0.0740391, -0.0739375,
39 -0.0732422, -0.072, -0.0702578, -0.0680625, -0.0654609,
40 -0.0625, -0.0592266, -0.0556875, -0.0519297, -0.048,
41 -0.0439453, -0.0398125, -0.0356484, -0.0315, -0.0274141,
42 -0.0234375, -0.0196172, -0.016, -0.0126328, -0.0095625,
43 -0.00683594, -0.0045, -0.00260156, -0.0011875, -0.000304687, 0.0
44 };
45
ciCalc(PyramidShort * img,int xi,int yi,double xfrac,double yfrac)46 inline double ciCalc(PyramidShort *img, int xi, int yi, double xfrac, double yfrac)
47 {
48 double tmpf[4];
49
50 // Interpolate using 16 points
51 ImageTypeShortBase *in = img->ptr[yi-1] + xi - 1;
52 int off = (int)(xfrac * CTAPS);
53
54 tmpf[0] = in[0] * ciTable[off + 40];
55 tmpf[0] += in[1] * ciTable[off];
56 tmpf[0] += in[2] * ciTable[40 - off];
57 tmpf[0] += in[3] * ciTable[80 - off];
58 in += img->pitch;
59 tmpf[1] = in[0] * ciTable[off + 40];
60 tmpf[1] += in[1] * ciTable[off];
61 tmpf[1] += in[2] * ciTable[40 - off];
62 tmpf[1] += in[3] * ciTable[80 - off];
63 in += img->pitch;
64 tmpf[2] = in[0] * ciTable[off + 40];
65 tmpf[2] += in[1] * ciTable[off];
66 tmpf[2] += in[2] * ciTable[40 - off];
67 tmpf[2] += in[3] * ciTable[80 - off];
68 in += img->pitch;
69 tmpf[3] = in[0] * ciTable[off + 40];
70 tmpf[3] += in[1] * ciTable[off];
71 tmpf[3] += in[2] * ciTable[40 - off];
72 tmpf[3] += in[3] * ciTable[80 - off];
73
74 // this is the final interpolation
75 off = (int)(yfrac * CTAPS);
76 return (ciTable[off + 40] * tmpf[0] + ciTable[off] * tmpf[1] +
77 ciTable[40 - off] * tmpf[2] + ciTable[80 - off] * tmpf[3]);
78 }
79
80 #endif
81