c语言如何读取像素

#include <opencv2/opencv.hpp>

int main() {
  // 加载图像
  cv::Mat image = cv::imread("image.jpg");

  // 获取图像大小
  int width = image.cols;
  int height = image.rows;

  // 遍历像素
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      // 获取像素值
      cv::Vec3b pixel = image.at<cv::Vec3b>(y, x);

      // 访问并打印像素的 RGB 值
      std::cout << "Pixel (" << x << ", " << y << "): R=" << (int)pixel[2]
                << ", G=" << (int)pixel[1] << ", B=" << (int)pixel[0] << std::endl;
    }
  }

  return 0;
}

#include <gdal/gdal.h>

int main() {
  // 打开图像数据集
  GDALDataset *dataset = GDALOpen("image.tif", GA_ReadOnly);

  // 获取图像大小
  int width = GDALGetRasterXSize(dataset);
  int height = GDALGetRasterYSize(dataset);

  // 获取图像波段
  GDALRasterBand *band = GDALGetRasterBand(dataset, 1);

  // 遍历像素
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      // 获取像素值
      double value;
      GDALRasterIO(band, GF_Read, x, y, 1, 1, &value, 1, 1, GDT_Float64, 0, 0);

      // 打印像素值
      std::cout << "Pixel (" << x << ", " << y << "): " << value << std::endl;
    }
  }

  // 关闭图像数据集
  GDALClose(dataset);

  return 0;
}