基于CE平台下调用底层API画圆弧？希望给予指导~~

 

在windows PC下GDI32.dll中有arc或者是ArcTo这个画圆弧函数，但是基于windows CE下没有，本人利用的就算计图形学画的圆弧，有什么不当的地方请指出，O(∩_∩)O谢谢（这里只考虑了画圆~而不是椭圆）

代码如下：

 

  /// <summary> /// 获取圆弧上的点(中点画圆法) /// </summary> /// <param name="x0">中心点X坐标</param> /// <param name="y0">中心点Y坐标</param> /// <param name="r">半径</param> /// <returns>所有圆上的点</returns> private List<Point> Bresebhan(int x0, int y0, int r) { List<Point>[] pts = new List<Point>[4]; for (int i = 0; i < 4; i++) { pts[i] = new List<Point>(); } int x = r; int y = 0; int delta = 2 * (1 - r); int delta1 = 0; int delta2 = 0; byte direction = 0; //添加起点 pts[0].Add(new Point(x + x0, y + y0)); while (x >= 0) { if (delta < 0) { delta1 = 2 * (delta + x) - 1; if (delta1 <= 0) direction = 1; else direction = 2; } else if (delta > 0) { delta2 = 2 * (delta - y) - 1; if (delta2 <= 0) direction = 2; else direction = 3; } else direction = 2; switch (direction) { case 1: y++; delta += 2 * y + 1; break; case 2: y++; x--; delta += 2 * (y - x + 1); break; case 3: x--; delta += (-2 * x + 1); break; } pts[0].Add(new Point(x + x0, y + y0)); pts[1].Add(new Point(x0 - y, y0 + x)); pts[2].Add(new Point(x0 - x, y0 - y)); pts[3].Add(new Point(y + x0, y0 - x)); } //pts[1].Reverse(); //pts[3].Reverse(); List<Point> lines = new List<Point>(); lines.AddRange(pts[0]); lines.AddRange(pts[1]); lines.AddRange(pts[2]); lines.AddRange(pts[3]); return lines; } /// <summary> /// 判断距离该点最近的点 /// </summary> /// <param name="X">判断点的X坐标</param> /// <param name="Y">判断点的Y坐标</param> /// <param name="pt">所有判断点</param> /// <returns>最近点的位置</returns> private int GetClosePoint(int X, int Y, Point[] pt) { for (int i = 0; i < pt.Length; i++) { if ((Math.Abs(X - pt[i].X) + Math.Abs(Y - pt[i].Y)) < 3) { return i; } } return -1; } /// <summary> /// 获取圆弧坐标库 /// </summary> /// <param name="x0">中心点X坐标</param> /// <param name="y0">中心点Y坐标</param> /// <param name="r">半径</param> /// <param name="start_angel">起始角度(度)</param> /// <param name="end_angel">终止角度(度)</param> /// <returns>圆弧坐标库</returns> private Point[] GetArcPoints(int x0, int y0, int r, double start_angel, double end_angel) { List<Point> temp = new List<Point>(); List<Point> pts = Bresebhan(x0, y0, r); //将度转换成弧度 start_angel = start_angel * Math.PI / 180; end_angel = end_angel * Math.PI / 180; //计算始末点坐标 int startx = (int)(x0 + r * Math.Cos(start_angel)); int starty = (int)(y0 + r * Math.Sin(start_angel)); int endx = (int)(x0 + r * Math.Cos(end_angel)); int endy = (int)(y0 + r * Math.Sin(end_angel)); temp.Add(new Point(startx, starty)); //开始点指针 int start_index = GetClosePoint(startx, starty, pts.ToArray()); //结束点指针 int end_index = GetClosePoint(endx, endy, pts.ToArray()); //判断方向 if (start_index < end_index) { pts.RemoveRange(end_index, pts.Count - end_index); pts.RemoveRange(0, start_index); temp = pts; } else if (start_index > end_index) { // temp = pts; temp.AddRange(pts.GetRange(start_index, pts.Count - start_index - 1)); temp.AddRange(pts.GetRange(0, end_index)); } //pts.Insert(0,new Point(startx, starty)); //加末点 pts.Add(new Point(endx, endy)); return temp.ToArray(); }

这里要说明一下，基于GDI32.dll中的画圆弧中的顺序是逆时针，请留意，不过将起始点和终止点互换就能达到顺时针了。