main.cc

#include <Eigen/Core>
#include <Eigen/Dense>
#include <Eigen/Geometry>
#include <iostream>
#include <opencv2/opencv.hpp>
#include "unit.h"

std::string img_path = "test.png";
std::string output = "rota_test.png";

Eigen::Matrix2d rotate_matrix(const double &angle) {
  Eigen::Matrix2d R;
  R << cos(angle), -sin(angle), sin(angle), cos(angle);
  return R;
}

void rotate_img(const cv::Mat &src, cv::Mat &dst, double angle,
                const double &zoom) {
  angle -= static_cast<int>(angle / PI) * PI;
  Eigen::Matrix2d R = rotate_matrix(angle) * zoom;
  std::cout << "R:" << std::endl;
  std::cout << R << std::endl;
  Eigen::Matrix3d T = Eigen::Matrix3d::Zero();
  Eigen::Vector3d center = Eigen::Vector3d::Zero();
  T.block<2, 2>(0, 0) = R;
  T(2, 2) = 1;
  std::cout << "T:" << std::endl;
  std::cout << T << std::endl;
  // 获取原图像中心点坐标
  center << src.rows / 2, src.cols / 2, 1;
  // 获取从dst到src的T
  Eigen::Matrix3d TT = T.inverse();
  TT.block<3, 1>(0, 2) = center;
  std::cout << "TT:" << std::endl;
  std::cout << TT << std::endl;
  dst = cv::Mat(src.size(), src.type());
  auto func = [&src](Eigen::Vector3d pose) -> uint8_t {
    int x = static_cast<int>(pose[0]), y = static_cast<int>(pose[1]);
    if (x < 0 || y < 0 || x > src.rows || y > src.cols) {
      return 0;
    }
    return src.at<uint8_t>(x, y);
  };
  // 不好算范围，所以就不改变图像框大小了，（方案1）
  for (int i = 0; i < src.rows; i++) {
    for (int j = 0; j < src.cols; j++) {
      Eigen::Vector3d pose = Eigen::Vector3d::Zero();
      pose << i - src.rows / 2, j - src.cols / 2, 1;
      dst.at<uint8_t>(i, j) = func(TT * pose);
    }
  }
}

int main(int argc, char **argv) {
  if (argc != 4) {
    std::cout << "Usage : main {imag_path} {output_path} {rotate_angle}" << std::endl;
    exit(-1);
  }
  img_path = std::string(argv[1]);
  output = std::string(argv[2]);
  double angle = std::stod(argv[3]);

  cv::Mat img = cv::imread(img_path);
  cv::Mat gray;
  MY_IMG::Rgb2Gray(img, gray);
  std::cout << "gray img" << std::endl;

  cv::Mat dimg;
  rotate_img(gray, dimg, angle, 5);

  cv::imshow("dimg", dimg);

  cv::waitKey(0);

  cv::imwrite(output, dimg);
  return 0;
}