GDI+(C#)绘图，实现地球绕太阳旋转，月亮绕地球旋转
- C# code
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Drawing.Drawing2D;using System.Linq;using System.Text;using System.Windows.Forms;namespace SunEarthMoon{ public partial class Form1 : Form { private Graphics g; private const int sunr = 100; //太阳的半径 private const int earthr = 60; //地球的半径 private const int moonr = 40; // 月亮的半径 private const int dissunearth = 260; // 太阳到地球的距离 private const int disearthmoon = 150; //地球到月球的距离 double earthradian =360d/365d*Math.PI/180; // 地球一天旋转角度 double moonradian = 360d / 30d * Math.PI / 180; // 月球一天旋转角度 Point sunp = new Point(0, 0); //设置太阳的位置在原点 Point earthp, moonp; //地球，月球的位置 int earthCount = 1; //地球旋转的天数 int moonCount = 1; //月球旋转的天数 public Form1() { InitializeComponent(); } private void InitGraphics() { g = this.CreateGraphics(); g.Clear(Color.White); drawSence(); } /// <summary> /// 点的平移变换 /// </summary> /// <param name="s">要平移的点</param> /// <param name="deltax">要平移的X值</param> /// <param name="deltay">要平移的Y值</param> /// <returns>平移后的点</returns> private Point translatePoint(Point s, int deltax, int deltay) { s.X += deltax; s.Y += deltay; return s; } private Point rotatePoint(Point s,double radian) { s.X =(int)( s.X * Math.Cos(radian) - s.Y * Math.Sin(radian)); s.Y = (int)(s.X * Math.Sin(radian) + s.Y * Math.Cos(radian)); return s; } private void drawCircel(Point s,int r) { g.DrawEllipse(new Pen(Color.Blue), s.X, s.Y, r, r); } private void drawSence() { int x = this.Width; int y = this.Height; //画坐标的箭头 AdjustableArrowCap arrow = new AdjustableArrowCap(4, 4, true); Pen myPen = new Pen(Color.Black, 1); myPen.CustomEndCap = arrow; //确定坐标原点 g.TranslateTransform(x / 2, y / 2); // 画X坐标轴 g.DrawLine(myPen, -x / 2, 0, x / 2, 0); //画Y坐标轴 g.DrawLine(myPen, 0, y / 2, 0, -y / 2); earthp = translatePoint(sunp, dissunearth, 0); earthp = rotatePoint(earthp, earthradian * earthCount); if (earthCount == 365) { earthCount = 1; } else { earthCount++; } moonp = rotatePoint(new Point(disearthmoon, 0), moonradian * moonCount); moonp = translatePoint(moonp, earthp.X, earthp.Y); if (moonCount == 30) { moonCount = 1; } else { moonCount++; } drawCircel(sunp, sunr); drawCircel(earthp, earthr); drawCircel(moonp, moonr); } private void timer1_Tick(object sender, EventArgs e) { this.Refresh(); } private void Form1_Paint(object sender, PaintEventArgs e) { InitGraphics(); } }}运行后地球和月亮的运行轨迹都是倒立的“8”，并不是地球绕太阳，月球绕地球旋转。
估计应该是求旋转后的点的位置出错，但是不知道怎么改，望指教！！
[解决办法]
圆的公式怎么这个样子的?
几个地方不对,改了下,正常了
- C# code
public partial class Form3 : Form { private Graphics g; private const int sunr = 100; //太阳的半径 private const int earthr = 60; //地球的半径 private const int moonr = 40; // 月亮的半径 private const int dissunearth = 260; // 太阳到地球的距离 private const int disearthmoon = 150; //地球到月球的距离 double earthradian = 360d / 365d * Math.PI / 180; // 地球一天旋转角度 double moonradian = 360d / 30d * Math.PI / 180; // 月球一天旋转角度 Point sunp = new Point(0, 0); //设置太阳的位置在原点 Point earthp, moonp; //地球，月球的位置 int earthCount = 1; //地球旋转的天数 int moonCount = 1; //月球旋转的天数 public Form3() { InitializeComponent(); } private void InitGraphics() { g = this.CreateGraphics(); g.Clear(Color.White); drawSence(); } /// <summary> /// 点的平移变换 /// </summary> /// <param name="s">要平移的点</param> /// <param name="deltax">要平移的X值</param> /// <param name="deltay">要平移的Y值</param> /// <returns>平移后的点</returns> private Point translatePoint(Point s, int deltax, int deltay) { s.X += deltax; s.Y += deltay; return s; } //这里改了 private Point rotatePoint(int r, double radian) { //圆公式不对 //s.X = (int)(s.X * Math.Cos(radian) - s.Y * Math.Sin(radian)); //s.Y = (int)(s.X * Math.Sin(radian) + s.Y * Math.Cos(radian)); Point s = new Point(); s.X = (int)(r * Math.Cos(radian)); s.Y = (int)(r * Math.Sin(radian)); return s; } private void drawCircel(Point s, int r) { g.DrawEllipse(new Pen(Color.Blue), s.X - r / 2, s.Y - r / 2, r, r); //这里改了 } private void drawSence() { int x = this.Width; int y = this.Height; //画坐标的箭头 AdjustableArrowCap arrow = new AdjustableArrowCap(4, 4, true); Pen myPen = new Pen(Color.Black, 1); myPen.CustomEndCap = arrow; //确定坐标原点 g.TranslateTransform(x / 2, y / 2); // 画X坐标轴 g.DrawLine(myPen, -x / 2, 0, x / 2, 0); //画Y坐标轴 g.DrawLine(myPen, 0, y / 2, 0, -y / 2); earthp = translatePoint(sunp, dissunearth, 0); earthp = rotatePoint(dissunearth, earthradian * earthCount);//这里改了 if (earthCount == 365) { earthCount = 1; } else { earthCount++; } moonp = rotatePoint(disearthmoon, moonradian * moonCount);//这里改了 moonp = translatePoint(moonp, earthp.X, earthp.Y); if (moonCount == 30) { moonCount = 1; } else { moonCount++; } drawCircel(sunp, sunr); drawCircel(earthp, earthr); drawCircel(moonp, moonr); } private void timer1_Tick(object sender, EventArgs e) { this.Refresh(); } private void Form3_Paint(object sender, PaintEventArgs e) { InitGraphics(); } private void Form3_Load(object sender, EventArgs e) { this.timer1.Interval = 10; this.timer1.Start(); } }