mirror of https://github.com/NekoX-Dev/NekoX.git
157 lines
6.1 KiB
Java
Executable File
157 lines
6.1 KiB
Java
Executable File
/*
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* Copyright 2007 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.zxing.common;
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/**
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* <p>This class implements a perspective transform in two dimensions. Given four source and four
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* destination points, it will compute the transformation implied between them. The code is based
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* directly upon section 3.4.2 of George Wolberg's "Digital Image Warping"; see pages 54-56.</p>
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*
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* @author Sean Owen
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*/
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public final class PerspectiveTransform {
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private final float a11;
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private final float a12;
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private final float a13;
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private final float a21;
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private final float a22;
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private final float a23;
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private final float a31;
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private final float a32;
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private final float a33;
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private PerspectiveTransform(float a11, float a21, float a31,
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float a12, float a22, float a32,
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float a13, float a23, float a33) {
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this.a11 = a11;
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this.a12 = a12;
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this.a13 = a13;
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this.a21 = a21;
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this.a22 = a22;
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this.a23 = a23;
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this.a31 = a31;
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this.a32 = a32;
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this.a33 = a33;
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}
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public static PerspectiveTransform quadrilateralToQuadrilateral(float x0, float y0,
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float x1, float y1,
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float x2, float y2,
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float x3, float y3,
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float x0p, float y0p,
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float x1p, float y1p,
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float x2p, float y2p,
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float x3p, float y3p) {
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PerspectiveTransform qToS = quadrilateralToSquare(x0, y0, x1, y1, x2, y2, x3, y3);
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PerspectiveTransform sToQ = squareToQuadrilateral(x0p, y0p, x1p, y1p, x2p, y2p, x3p, y3p);
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return sToQ.times(qToS);
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}
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public void transformPoints(float[] points) {
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float a11 = this.a11;
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float a12 = this.a12;
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float a13 = this.a13;
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float a21 = this.a21;
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float a22 = this.a22;
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float a23 = this.a23;
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float a31 = this.a31;
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float a32 = this.a32;
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float a33 = this.a33;
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int maxI = points.length - 1; // points.length must be even
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for (int i = 0; i < maxI; i += 2) {
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float x = points[i];
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float y = points[i + 1];
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float denominator = a13 * x + a23 * y + a33;
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points[i] = (a11 * x + a21 * y + a31) / denominator;
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points[i + 1] = (a12 * x + a22 * y + a32) / denominator;
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}
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}
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public void transformPoints(float[] xValues, float[] yValues) {
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int n = xValues.length;
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for (int i = 0; i < n; i++) {
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float x = xValues[i];
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float y = yValues[i];
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float denominator = a13 * x + a23 * y + a33;
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xValues[i] = (a11 * x + a21 * y + a31) / denominator;
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yValues[i] = (a12 * x + a22 * y + a32) / denominator;
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}
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}
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public static PerspectiveTransform squareToQuadrilateral(float x0, float y0,
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float x1, float y1,
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float x2, float y2,
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float x3, float y3) {
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float dx3 = x0 - x1 + x2 - x3;
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float dy3 = y0 - y1 + y2 - y3;
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if (dx3 == 0.0f && dy3 == 0.0f) {
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// Affine
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return new PerspectiveTransform(x1 - x0, x2 - x1, x0,
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y1 - y0, y2 - y1, y0,
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0.0f, 0.0f, 1.0f);
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} else {
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float dx1 = x1 - x2;
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float dx2 = x3 - x2;
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float dy1 = y1 - y2;
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float dy2 = y3 - y2;
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float denominator = dx1 * dy2 - dx2 * dy1;
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float a13 = (dx3 * dy2 - dx2 * dy3) / denominator;
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float a23 = (dx1 * dy3 - dx3 * dy1) / denominator;
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return new PerspectiveTransform(x1 - x0 + a13 * x1, x3 - x0 + a23 * x3, x0,
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y1 - y0 + a13 * y1, y3 - y0 + a23 * y3, y0,
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a13, a23, 1.0f);
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}
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}
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public static PerspectiveTransform quadrilateralToSquare(float x0, float y0,
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float x1, float y1,
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float x2, float y2,
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float x3, float y3) {
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// Here, the adjoint serves as the inverse:
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return squareToQuadrilateral(x0, y0, x1, y1, x2, y2, x3, y3).buildAdjoint();
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}
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PerspectiveTransform buildAdjoint() {
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// Adjoint is the transpose of the cofactor matrix:
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return new PerspectiveTransform(a22 * a33 - a23 * a32,
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a23 * a31 - a21 * a33,
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a21 * a32 - a22 * a31,
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a13 * a32 - a12 * a33,
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a11 * a33 - a13 * a31,
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a12 * a31 - a11 * a32,
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a12 * a23 - a13 * a22,
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a13 * a21 - a11 * a23,
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a11 * a22 - a12 * a21);
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}
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PerspectiveTransform times(PerspectiveTransform other) {
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return new PerspectiveTransform(a11 * other.a11 + a21 * other.a12 + a31 * other.a13,
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a11 * other.a21 + a21 * other.a22 + a31 * other.a23,
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a11 * other.a31 + a21 * other.a32 + a31 * other.a33,
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a12 * other.a11 + a22 * other.a12 + a32 * other.a13,
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a12 * other.a21 + a22 * other.a22 + a32 * other.a23,
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a12 * other.a31 + a22 * other.a32 + a32 * other.a33,
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a13 * other.a11 + a23 * other.a12 + a33 * other.a13,
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a13 * other.a21 + a23 * other.a22 + a33 * other.a23,
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a13 * other.a31 + a23 * other.a32 + a33 * other.a33);
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}
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}
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