阅读BMP像素并写入控制台

Question

我正在阅读此stackoverflow Post 尝试在BMP文件中手动阅读像素。我真的不明白如何将图像的像素实际打印到控制台上？在主要功能中，要打印第一个，第二，第三，...图像的像素我应该替换“？”通过以下内容？

cout＆lt;＆lt;缓冲区[？]＆lt;＆lt; endl;

代码

#pragma pack(1)

#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

#include "bmp.h"

vector<char> buffer;
PBITMAPFILEHEADER file_header;
PBITMAPINFOHEADER info_header;

void fill() {
    std::ifstream file("test.bmp");

    if (file) {
        file.seekg(0, std::ios::end);
        streampos length = file.tellg();
        file.seekg(0, std::ios::beg);

        buffer.resize(length);
        file.read(&buffer[0], length);

        file_header = (PBITMAPFILEHEADER)(&buffer[0]);
        info_header = (PBITMAPINFOHEADER)(&buffer[0] + sizeof(BITMAPFILEHEADER));
       
        cout << "hello" << endl;
    }
}

int main() {
    fill();

    cout << buffer[0] << buffer[1] << endl;
    cout << file_header->bfSize << endl;
    cout << info_header->biWidth << " " << info_header->biHeight << endl;
    unsigned char* start = (unsigned char*)(&buffer[0] + file_header->bfOffBits);
    cout << start[0] << endl;
    return 0;
}

bmp.hi中已定义结构：

#pragma once

typedef int LONG;
typedef unsigned short WORD;
typedef unsigned int DWORD;

typedef struct tagBITMAPFILEHEADER {
  WORD  bfType;
  DWORD bfSize;
  WORD  bfReserved1;
  WORD  bfReserved2;
  DWORD bfOffBits;
} BITMAPFILEHEADER, *PBITMAPFILEHEADER;

typedef struct tagBITMAPINFOHEADER {
  DWORD biSize;
  LONG  biWidth;
  LONG  biHeight;
  WORD  biPlanes;
  WORD  biBitCount;
  DWORD biCompression;
  DWORD biSizeImage;
  LONG  biXPelsPerMeter;
  LONG  biYPelsPerMeter;
  DWORD biClrUsed;
  DWORD biClrImportant;
} BITMAPINFOHEADER, *PBITMAPINFOHEADER;