Bezier曲线简单实现

关键的公式,此公式不能画出匀速曲线

		// completedPercent为当前所想得到位置的百分比0.0f-1.0f
		// 根据贝塞尔曲线函数，求得取得此时的x,y坐标
		pt.x = (1-completedPercent)*(1-completedPercent)*x1 +2*(1-completedPercent)*completedPercent*x2 + completedPercent*completedPercent*x3;
		pt.y = (1-completedPercent)*(1-completedPercent)*y1 +2*(1-completedPercent)*completedPercent*y2 + completedPercent*completedPercent*y3;

 

实例:

void CTrackGetterView::DrawBezier(CDC *pDC)
{
	//CTrackGetterDoc* pDoc = GetDocument();
	//CRect rect;
	int x1 = 18;	// 点1
	int y1 = 446;

	int x2 = 144;	// 点2
	int y2 = 270;

	int x3 = 284;	// 点3
	int y3 = 382;

	POINT pt;
	COLORREF rbg = RGB(255, 0, 0);

	for (float completedPercent=0.0f; completedPercent<=1.0f; completedPercent+=0.01f)
	{
		//根据贝塞尔曲线函数，求得取得此时的x,y坐标
		pt.x = (1-completedPercent)*(1-completedPercent)*x1 +2*(1-completedPercent)*completedPercent*x2 + completedPercent*completedPercent*x3;
		pt.y = (1-completedPercent)*(1-completedPercent)*y1 +2*(1-completedPercent)*completedPercent*y2 + completedPercent*completedPercent*y3;
			
		pDC->SetPixel(pt, rbg);
	}
	
}

 如图: