/*  draw_arc.cpp
 *  This program demonstrates the drawing of an arc.
 *  Click the right button to exit.
 */
#include << X11/Xlib.h>
#include << fstream.h>
#include << math.h>
#include << GL/glut.h>
#include << GL/gl.h>
#include << stdlib.h>
#include << stdio.h>
#include "Canvas.h"

const int numVerts = 6;
const double radius = 2.0;
const double worldWidth = 4.0;
const double worldHeight = 3.0;        
const int screenWidth = 640;
const int screenHeight = 480;
Canvas cvs(screenWidth, screenHeight, "Try out Canvas");

void myInit(void) 
{
    cvs.setBackgroundColor (1.0, 1.0, 1.0);   // set black background color
    cvs.setColor (0.0, 0.0, 0.0);       // set the drawing color
    glPointSize (4.0);                  // set dot size 2 x 2
}

void drawArc(Point2 center, float radius, float startAngle, float sweep)
{    // startAngle and sweep are in degrees
const int n = 40; // number of intermediate segments in arc
    float angle = startAngle * 3.14159265 / 180; // initial angle in radians
    float angleInc = sweep * 3.14159265 /(180 * n); // angle increment
    float cx = center.getX(), cy = center.getY();
    cvs.moveTo(cx + radius * cos(angle), cy + radius * sin(angle));
    angle += angleInc;
    for(int k = 0; k < n; k++, angle += angleInc)
        cvs.lineTo(cx + radius * cos(angle), cy + radius * sin(angle));
}

void myDisplay(void)
{
Point2 p;

    cvs.clearScreen();     // clear the screen
    cvs.setWindow(-worldWidth, worldWidth, -worldHeight, worldHeight);
    cvs.setViewport(0, screenWidth, 0, screenHeight);
    p.set(0.0, 0.0);
    drawArc(p, radius, 30.0, 200.0);
}

void myMouse(int button, int state, int x, int y)
{
  switch (button) {
     case GLUT_RIGHT_BUTTON:
        if (state == GLUT_DOWN)
           exit (-1);
        break;
     default:
        break;
  }
}

int main(int argc, char** argv)
{
   myInit ();
   glutDisplayFunc(myDisplay);              // register redraw function
   glutMouseFunc(myMouse);                  // register myMouse function
   glutMainLoop();                          // go into a perpetual loop
   return 0;
}