Make a path straighter

Question

I'm working on a C++ project whose goal is to find a path in an image that represents a circuit.

After successfully implementing the A* algorithm I get this plot.

I would have liked to make my path straighter like that but I have no idea how to do it.

So I would like some help in finding a solution to this problem.

About the code, here is the function that will draw the path on the image. The plot is represented by a vector of integer pairs (x and y).

void AStar::tracePath(Pair &d) {
    std::vector<Pair> path;

    int i = d.first, j = d.second;
    Pair next_node = this->nodeDetails[j][i].parent;
    do {
        path.push_back(next_node);
        next_node = this->nodeDetails[j][i].parent;
        i = next_node.first;
        j = next_node.second;
    } while (this->nodeDetails[j][i].parent != next_node);

    path.emplace_back(i, j);
    path.push_back(d);

    // The algorithm to optimize the path
    // optimizePath(path);

    // save path on image
    for (Pair p: path) {
        const unsigned char color_mag[] = {0, 255, 0};
        imageObject.draw_point(p.first, p.second, color_mag);
    }
    imageObject.save("output.png");
}

And this is to check if the point is not in a "wall" (grid is the image converted to black (0) and white (1))

bool AStar::isUnBlocked(const Pair &point) const {
    return isValid(point) && grid[point.first][point.second] == 1;
}