// Circle.cpp
// ----------------------------------------------------
// Shows off the core of the midpoint algorithm
// for scan conversion of circles. 
// ----------------------------------------------------


#include "MFC_Framework.h"



void eighthArc( CDC& dc, int r, COLORREF color )
// Draw a 45 degree arc from "6 o'clock" to "4:30". 
{
    int x= 0 ;
    int y= r ;
    int p= 5 - 4*r ;
    dc.SetPixel( x, y, color ) ;
    while ( x < y )
    {
        ++x ;
        if ( p < 0 )
            p+= 8*x + 4 ;
        else
        {
            --y ;
            p+= 8*x + 4 - 8*y ;
        }
        dc.SetPixel( x, y, color ) ;
    }
}



void paint( CDC& dc, int width, int height ) 
{
    for ( int r= 10 ; r < 450 ; r+= 10 )
        eighthArc( dc, r, RGB(0,0,0) ) ;
}