//
// 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);
	 x.set_color(Color::red);
	 y.set_color(Color::red);
	 win0.wait_for_button();
      }
   catch(exception& e) {
      // some error reporting
      return 1;
   }
   catch(...) {
      // some more error reporting
      return 2;
   }

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