2 * PerspectiveTransform.cpp
5 * Created by Christian Brunschen on 12/05/2008.
6 * Copyright 2008 Google UK. All rights reserved.
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
12 * http://www.apache.org/licenses/LICENSE-2.0
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
21 #include <zxing/common/PerspectiveTransform.h>
26 PerspectiveTransform::PerspectiveTransform(float a11, float a21, float a31, float a12, float a22, float a32, float a13,
27 float a23, float a33) {
39 Ref<PerspectiveTransform> PerspectiveTransform::quadrilateralToQuadrilateral(float x0, float y0, float x1, float y1,
40 float x2, float y2, float x3, float y3, float x0p, float y0p, float x1p, float y1p, float x2p, float y2p,
41 float x3p, float y3p) {
42 Ref<PerspectiveTransform> qToS = PerspectiveTransform::quadrilateralToSquare(x0, y0, x1, y1, x2, y2, x3, y3);
43 Ref<PerspectiveTransform> sToQ =
44 PerspectiveTransform::squareToQuadrilateral(x0p, y0p, x1p, y1p, x2p, y2p, x3p, y3p);
45 return sToQ->times(qToS);
48 Ref<PerspectiveTransform> PerspectiveTransform::squareToQuadrilateral(float x0, float y0, float x1, float y1, float x2,
49 float y2, float x3, float y3) {
51 float dy3 = y0 - y1 + y2 - y3;
52 if (dy2 == 0.0f && dy3 == 0.0f) {
53 Ref<PerspectiveTransform> result(new PerspectiveTransform(x1 - x0, x2 - x1, x0, y1 - y0, y2 - y1, y0, 0.0f,
59 float dx3 = x0 - x1 + x2 - x3;
61 float denominator = dx1 * dy2 - dx2 * dy1;
62 float a13 = (dx3 * dy2 - dx2 * dy3) / denominator;
63 float a23 = (dx1 * dy3 - dx3 * dy1) / denominator;
64 Ref<PerspectiveTransform> result(new PerspectiveTransform(x1 - x0 + a13 * x1, x3 - x0 + a23 * x3, x0, y1 - y0
65 + a13 * y1, y3 - y0 + a23 * y3, y0, a13, a23, 1.0f));
70 Ref<PerspectiveTransform> PerspectiveTransform::quadrilateralToSquare(float x0, float y0, float x1, float y1, float x2,
71 float y2, float x3, float y3) {
72 // Here, the adjoint serves as the inverse:
73 return squareToQuadrilateral(x0, y0, x1, y1, x2, y2, x3, y3)->buildAdjoint();
76 Ref<PerspectiveTransform> PerspectiveTransform::buildAdjoint() {
77 // Adjoint is the transpose of the cofactor matrix:
78 Ref<PerspectiveTransform> result(new PerspectiveTransform(a22 * a33 - a23 * a32, a23 * a31 - a21 * a33, a21 * a32
79 - a22 * a31, a13 * a32 - a12 * a33, a11 * a33 - a13 * a31, a12 * a31 - a11 * a32, a12 * a23 - a13 * a22,
80 a13 * a21 - a11 * a23, a11 * a22 - a12 * a21));
84 Ref<PerspectiveTransform> PerspectiveTransform::times(Ref<PerspectiveTransform> other) {
85 Ref<PerspectiveTransform> result(new PerspectiveTransform(a11 * other->a11 + a21 * other->a12 + a31 * other->a13,
86 a11 * other->a21 + a21 * other->a22 + a31 * other->a23, a11 * other->a31 + a21 * other->a32 + a31
87 * other->a33, a12 * other->a11 + a22 * other->a12 + a32 * other->a13, a12 * other->a21 + a22
88 * other->a22 + a32 * other->a23, a12 * other->a31 + a22 * other->a32 + a32 * other->a33, a13
89 * other->a11 + a23 * other->a12 + a33 * other->a13, a13 * other->a21 + a23 * other->a22 + a33
90 * other->a23, a13 * other->a31 + a23 * other->a32 + a33 * other->a33));
94 void PerspectiveTransform::transformPoints(valarray<float> &points) {
95 int max = points.size();
96 float a11 = this->a11;
97 float a12 = this->a12;
98 float a13 = this->a13;
99 float a21 = this->a21;
100 float a22 = this->a22;
101 float a23 = this->a23;
102 float a31 = this->a31;
103 float a32 = this->a32;
104 float a33 = this->a33;
105 for (int i = 0; i < max; i += 2) {
107 float y = points[i + 1];
108 float denominator = a13 * x + a23 * y + a33;
109 points[i] = (a11 * x + a21 * y + a31) / denominator;
110 points[i + 1] = (a12 * x + a22 * y + a32) / denominator;
114 ostream& operator<<(ostream& out, PerspectiveTransform &pt) {
115 out << pt.a11 << ", " << pt.a12 << ", " << pt.a13 << ", \n";
116 out << pt.a21 << ", " << pt.a22 << ", " << pt.a23 << ", \n";
117 out << pt.a31 << ", " << pt.a32 << ", " << pt.a33 << "\n";