//
// This is example code from Chapter 15.2 "Graphing simple functions" of
// "Programming -- Principles and Practice Using C++" by Bjarne Stroustrup
//

#include "Simple_window.h"  // get access to our window library
#include "Graph.h"          // get access to our graphics library facilities

//------------------------------------------------------------------------------

double one(double) { return 1; }

double slope(double x) { return x/2; }

double square(double x) { return x*x; }

//------------------------------------------------------------------------------

int main()
try
{
    const int xmax = 600;    // window size
    const int ymax = 400;

    const int x_orig = xmax/2;    // position of (0,0) is center of window
    const int y_orig = ymax/2; 
    const Point orig(x_orig,y_orig);

    const int r_min = -10;    // range [-10:11) 
    const int r_max = 11;

    const int n_points = 400;    // number of points used in range

    const int x_scale = 30;    // scaling factors
    const int y_scale = 30;

    Simple_window win0(Point(100,100),xmax,ymax,"Function graphing");

    Function s1(one,   r_min,r_max,orig,n_points,x_scale,y_scale);
    Function s2(slope, r_min,r_max,orig,n_points,x_scale,y_scale);
    Function s3(square,r_min,r_max,orig,n_points,x_scale,y_scale);

    win0.attach(s1);
    win0.attach(s2);
    win0.attach(s3);

    Text ts(Point(100,y_orig-40),"one");
    Text ts2(Point(100,y_orig+y_orig/2-20),"x/2");
    Text ts3(Point(x_orig-100,20),"x*x");
    win0.attach(ts);
    win0.attach(ts2);
    win0.attach(ts3);
    win0.set_label("Function graphing: label functions");

    const int xlength = xmax-40;   // make the axis a bit smaller than the window
    const int ylength = ymax-40;

    Axis x(Axis::x,Point(20,y_orig), xlength, xlength/x_scale, "one notch == 1");
    Axis y(Axis::y,Point(x_orig, ylength+20), ylength, ylength/y_scale, "one notch == 1");
    win0.attach(x);
    win0.attach(y);

    win0.wait_for_button();
}
catch(exception& e) {
    // some error reporting
    return 1;
}
catch(...) {
    // some more error reporting
    return 2;
}

//------------------------------------------------------------------------------