fltk attach image to window from a button

Question

So my question is: I'm trying to make a "carousel" of images (select image from file, load it and display it using "next_button" or load the previous one using "previous_button"). My problem is that i have no clue how to access the same window, I have defined at main, so I can attach the selected picture. I tried passing my_Window& win but I get an error at cb_next saying that I cannot use this type (struct) Any ideas would be greatly appreciated. Thank you very much for your valuable time: Here is a sample of the code:

struct my_Window : Graph_lib :: Window
{
    //Defined buttons
    //...
    //Example of how I create and call the next_button(to display the next picture)
    static void cb_next(Address, Address); // callback for next_button
    void next(); 
};

//Here is what I use to make the button work
void my_Window::cb_next(Address, Address pw)
{
    reference_to<my_Window>(pw).next(); //cannot pass my_Window
}
void my_Window::next()
{
    //Load the next picture!
    //This is where I want to attach the image
    //but when I use attach(image) it doesn't know where to attach ( as expected)
    redraw();
}
int main()
{
    my_Window win(Point(100,100),800,600,"Images");  //I want this "win" to be accessed by the next button so I can attach the new picture.
    return gui_main();
}

Answer 1

It's more of a C++ question. Why is cb_next() a static method? If you make it a normal method, you can access the same struct/window you defined in main using the this pointer. Writing this is also optional, you already call redraw in the next() method, which is actually this->redraw(); .