中心椭圆算法画图C++

中心椭圆算法画图C++

//中心椭圆算法画图inline int round(const float a){return int(a+0.5);}void ellipsePlotPoints(int xCenter,int yCenter,int x,int y){setPixel(xCenter+x,yCenter+y);setPixel(xCenter-x,yCenter+y);setPixel(xCenter+x,yCenter-y);setPixel(xCenter-x,yCenter-y);}void ellipseMidpoint(int xCenter,int yCenter,int Rx,int Ry){int Rx2=Rx*Rx;int Ry2=Ry*Ry;int twoRx2=2*Rx2;int twoRy2=2*Ry2;int p;int x=0;int y=Ry;int px=0;int py=twoRx2*y;ellipsePlotPoints(xCenter,yCenter,x,y);//区域1p=round(Ry2-(Rx2*Ry)+(0.25*Rx2));while(px<py){x++;px+=twoRy2;if(p<0) p+=Ry2+px;else {y--;py-=twoRx2;p+=Ry2+px-py;}ellipsePlotPoints(xCenter,yCenter,x,y);}//区域2p=round(Ry2*(x+0.5)*(x+0.5)+Rx2*(y-1)*(y-1)-Rx2*Ry2);while(y>0){y--;py-=twoRx2;if(p>0) p+=Rx2-py;else{x++;px+=twoRy2;p+=Rx2-py+px;}ellipsePlotPoints(xCenter,yCenter,x,y);}}