中點Bresenham演算法光柵化畫圓（八分法）__演算法

代碼如下，原理對比上篇畫直線方法

void Bresenham_Circle(CDC *pDC, int ox, int oy, int r){float d = 1.25 - r;int x = 0, y = r, fx = r/1.4;while (x != fx){if (d < 0)d += 2 * x + 3;else{d += 2 * (x - y) + 5;--y;}pDC->SetPixel(ox + x, oy + y, RGB(0, 0, 255));pDC->SetPixel(ox + x, oy - y, RGB(0, 0, 255));pDC->SetPixel(ox - x, oy + y, RGB(0, 0, 255));pDC->SetPixel(ox - x, oy - y, RGB(0, 0, 255));pDC->SetPixel(ox + y, oy - x, RGB(0, 0, 255));pDC->SetPixel(ox + y, oy + x, RGB(0, 0, 255));pDC->SetPixel(ox - y, oy + x, RGB(0, 0, 255));pDC->SetPixel(ox - y, oy - x, RGB(0, 0, 255));++x;}}