Help with cairo and pointers

I am trying to create a c++ widgets toolkit. I am having problems with accessing the cairo_t object to draw on. I am trying to make a copy of the pointer so that it can be stored in a button class. Here is the code

main.cpp

Code:

---

#include <X11/Xlib.h>
#include "ys_window.h"

int main(){

    //window object
    ys_window wind;

    wind.showwindow(true);

    while(1){
        //XEvent e;
    }

    return 0;
}

---

ys_window.h

Code:

---

#ifndef YS_WINDOW_H_INCLUDED
#define YS_WINDOW_H_INCLUDED

#include <X11/Xlib.h>
#include <cairo.h>
#include <cairo-xlib.h>

//widget includes
#include "ys_button.h"

class ys_window{
    private:
        int xsize;
        int ysize;
        int xpos;
        int ypos;

        bool visible;

        //cairo variables
        cairo_surface_t *cs;
        cairo_t *c;

        //xlib variables
        Display *dpy;
        int blackcolour;
        Window w;

    public:

        //widget objects
        ys_button butt;

        ys_window(){
            //set the default values to create the window
            xsize = 500;
            ysize = 500;
            xpos = 200;
            ypos = 200;
            visible = false;

            //the xlib display variable
            dpy = XOpenDisplay(0);

            //colour used to blackout the window
            blackcolour = BlackPixel(dpy, DefaultScreen(dpy));

            //create the window
            w = XCreateSimpleWindow(dpy, DefaultRootWindow(dpy), xpos, ypos, xsize, ysize, 0, blackcolour, blackcolour);
            cs = cairo_xlib_surface_create(dpy, w, DefaultVisual(dpy, 0), xsize, ysize);
            c = cairo_create(cs);

            XFlush(dpy);

        };

        void showwindow(bool vis);
        void windowposition(int x, int y);
        void windowsize(int x, int y);
        void addbutton();
};

void ys_window::showwindow(bool vis)
{
    if(vis == true){

        XMapWindow(dpy, w);

    }else{

        XUnmapWindow(dpy, w);

    }

    XFlush(dpy);

    butt.surfaceset(c);
    butt.redraw();

    visible = vis;
}

void ys_window::windowposition(int x, int y)
{
    xpos = x;
    ypos = y;

    XMoveWindow(dpy, w, xpos, ypos);

    XFlush(dpy);
}

void ys_window::windowsize(int x, int y)
{
    xsize = x;
    ysize = y;

    XResizeWindow(dpy, w, xsize, ysize);

    cairo_surface_destroy(cs);
    cs = cairo_xlib_surface_create(dpy, w, DefaultVisual(dpy, 0), xsize, ysize);
    c = cairo_create(cs);

    XFlush(dpy);

}


#endif // YS_WINDOW_H_INCLUDED

---

ys_button.h

Code:

---

#ifndef YS_BUTTON_H_INCLUDED
#define YS_BUTTON_H_INCLUDED

#include <X11/Xlib.h>
#include <cairo.h>
#include <cairo-xlib.h>

class ys_button{
    private:
        int xpos;
        int ypos;
        int xsize;
        int ysize;

        bool visible;

        cairo_t *surface;

    public:
        ys_button(){
            xpos = 200;
            ypos = 200;
            xsize = 0;
            ysize = 0;
            visible = false;

        };

    void surfaceset(cairo_t* c);
    void redraw();


};

void ys_button::surfaceset(cairo_t* c)
{

    surface = c;

    cairo_set_source_rgba(surface, 1, 1, 1, 1);

    cairo_move_to (surface, 50.0, 75.0);
    cairo_line_to (surface, 200.0, 75.0);

    cairo_set_line_width (surface, 30.0);
    cairo_stroke (surface);


}

void ys_button::redraw()
{
            cairo_set_source_rgba(surface, 1, 1, 1, 1);

            cairo_move_to (surface, 50.0, 75.0);
            cairo_line_to (surface, 200.0, 75.0);

            cairo_set_line_width (surface, 30.0);
            cairo_set_line_cap (surface, CAIRO_LINE_CAP_ROUND);
            cairo_stroke (surface);

}

#endif // YS_BUTTON_H_INCLUDED

---

currently im trying to create a copy of the c pointer from ys_window in ys_button but it isn't working

Code:

---

class ys_window{
    private:
        int xsize;
        int ysize;
        int xpos;
        int ypos;

        bool visible;

        //cairo variables
        cairo_surface_t *cs;
        cairo_t *c;

        //xlib variables
        Display *dpy;
        int blackcolour;
        Window w;

---

cairo_t *c; is a private data member of your ys_window class and cannot be passed to the ys_button object. If you make cairo_t *c; public this should work.

Nope that has made no difference.