How can I draw a string of text onto the pixels of a BGR image so that the text is readable when displayed, c++?

Is there a simple way to modify the pixels of a 72x72 pixel BGR image so that it contains a string of text that is readable when the image is displayed.

Essentially, I need to draw the text in str on the image buffer img created below in a way that would allow it to be read when the image is displayed.

unsigned char img[72*72*3]; // 72*72*3 BGR image buffer
unsigned char B = 0x00; 
unsigned char G = 0x00;
unsigned char R = 0x00;
std::string str = "Test Text";

// Create BGR image
for (int i = 0; i < (72*72*3); i += 3)
{
    img[i + 0] = B;
    img[i + 1] = G;
    img[i + 2] = R;
}

// Draw str on BGR image buffer?

I would suggest CImg like this:

#include <iostream>
#include <cstdlib>
#define cimg_display 0
#include "CImg.h"

using namespace cimg_library;
using namespace std;

int main() {
   // Create 72x72 RGB image
   CImg<unsigned char> image(72,72,1,3);

   // Fill with magenta
   cimg_forXY(image,x,y) {
      image(x,y,0,0)=255;
      image(x,y,0,1)=0;
      image(x,y,0,2)=255;
   }

   // Make some colours
   unsigned char cyan[]    = {0,   255, 255 };
   unsigned char black[]   = {0,   0,   0   };

   // Draw black text on cyan
   image.draw_text(3,20,"Test text",black,cyan,1,16);

   // Save result image as NetPBM PNM - no libraries required
   image.save_pnm("result.pnm");
}

It is small, fast, comprehensive in terms of functionality, modern C++ and "header only" which means you don't need to link against anything either.