先画一个水平椭圆吧！（参考计算机图形学基础）
以下是画旋转椭圆的C#代码：
//因为是11*11，不妥,X12,所以改为44*44*3*3，最终放大了16倍
byte[] gaos = new byte[11 * 11];
for (int j = 0; j < 11; j++)
{
for (int i = 0; i < 11; i = i + 1)
{
int nn = j * 11 + i;
int temp3 = pdKernal_2[nn]==4.0?255:(int)(pdKernal_2[nn] * 10);//白色主档边界
// int temp3 = (int)(pdKernal_2[nn] * 10);
gaos[nn] = temp3 > 255 ? (byte)255 : (byte)temp3;//此处是24位灰度图像（黑白）
//此处glob_rgbValues[nn * 3+0]=glob_rgbValues[nn * 3+1]=glob_rgbValues[nn * 3+2]
}
}
int ww = 132 + 44;
int hh = 132 + 44;
//int ww = 132 ;
//int hh = 132 ;
byte[] glob_buffer8 = new byte[ww * hh];
//ZoomNormal(gaos, ref glob_buffer8, 11, 11,
//ref ww, ref hh, 12, 12);
ZoomNormal(gaos, ref glob_buffer8, 11, 11,
ref ww, ref hh, 16, 16);//这个函数前面已经出现
/
///测试24位显示
Bitmap cutPic88 = new Bitmap(ww, hh, PixelFormat.Format24bppRgb);
BitmapData _cutPic8 = cutPic88.LockBits(new Rectangle(0, 0, ww, hh), ImageLockMode.ReadWrite,
cutPic88.PixelFormat);
IntPtr ptr00 = _cutPic8.Scan0;//得到首地址
byte[] buffer24=new byte[ww*hh*3];
for (int j = 0; j < hh; j++)
for (int i = 0; i < ww;i++ )
{
int tt = j * ww + i;
buffer24[3*tt]=glob_buffer8[tt];
buffer24[3 * tt+1] = glob_buffer8[tt];
buffer24[3 * tt+2] = glob_buffer8[tt];
}
//把cutvalues数组给ptr
System.Runtime.InteropServices.Marshal.Copy(buffer24, 0, ptr00, ww * hh*3);
cutPic88.UnlockBits(_cutPic8);
旋转椭圆(16 * 5, 16 * 5, 3.8 * 16 / 2, 2.8 * 16 / 2, 3.1416 / 4, ref cutPic88);
旋转椭圆(16 * 5, 16 * 5, 3.8 * 16, 2.8 * 16, 3.1416 / 4, ref cutPic88);
旋转椭圆(16 * 5, 16 * 5, 3.8 * 21, 2.8 * 21, 3.1416 / 4, ref cutPic88);
///
void 旋转椭圆(int 中心x, int 中心y, double la1, double la2, double 弧度, ref Bitmap curbmp)
{
//int x0 = 200;
//int y0 = 100;
//int iamuda1 = 120;//a
//int iamuda2 = 60;//b
//int x0 = 16 * 5;
//int y0 = 16 * 5;
int x0 = 中心x;
int y0 = 中心y;
//double iamuda1 = 3.8 * 16 / 2;//a
//double iamuda2 = 2.8 * 16 / 2;//b
double iamuda1 = la1;//a
double iamuda2 = la2;//b
int x = 0;
int y = (int)(iamuda2 + 0.5);
double d1 = iamuda2 * iamuda2 + iamuda1 * iamuda1 * (-iamuda2 + 0.25);
double d2 = 0;
//cutPic88.SetPixel(x+x0, y+y0, Color.Red);
//cutPic88.SetPixel(-x + x0, -y + y0, Color.Red);
//cutPic88.SetPixel(-x + x0, y + y0, Color.Red);
//cutPic88.SetPixel(x + x0, -y + y0, Color.Red);
int xxx = x + x0; int yyy = y + y0;
点旋转(ref xxx, ref yyy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xxx, yyy, Color.Red);
xxx = -x + x0; yyy = -y + y0; 点旋转(ref xxx, ref yyy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xxx, yyy, Color.Red);
xxx = -x + x0; yyy = y + y0; 点旋转(ref xxx, ref yyy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xxx, yyy, Color.Red);
xxx = x + x0; yyy = -y + y0; 点旋转(ref xxx, ref yyy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xxx, yyy, Color.Red);
while (iamuda2 * iamuda2 * (x + 1) < iamuda1 * iamuda1 * (y - 0.5))
{
if (d1 <= 0)
{ d1 += iamuda2 * iamuda2 * (2 * x + 1 + 2); x++; }
else { d1 += iamuda2 * iamuda2 * (2 * x + 1 + 2) + iamuda1 * iamuda1 * (-2 * y + 2); x++; y--; }
int xx = x + x0; int yy = y + y0;
点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
xx = -x + x0; yy = -y + y0; 点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
xx = -x + x0; yy = y + y0; 点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
xx = x + x0; yy = -y + y0; 点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
}
d2 = iamuda2 * iamuda2 * (x + 0.5) * (x + 0.5) + iamuda1 * iamuda1 * (y - 1) * (y - 1) - iamuda2 * iamuda2 * iamuda1 * iamuda1;
while (y > 0)
{
if (d2 <= 0)
{ d2 += iamuda2 * iamuda2 * (2 * x + 2) + iamuda1 * iamuda1 * (-2 * y + 3); x++; y--; }
else { d2 += iamuda1 * iamuda1 * (-2 * y + 3); y--; }
//cutPic88.SetPixel(x + x0, y + y0, Color.Red);
//cutPic88.SetPixel(-x + x0, -y + y0, Color.Red);
//cutPic88.SetPixel(-x + x0, y + y0, Color.Red);
//cutPic88.SetPixel(x + x0, -y + y0, Color.Red);
//3.1416 / 4
int xx = x + x0; int yy = y + y0;
点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
xx = -x + x0; yy = -y + y0; 点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
xx = -x + x0; yy = y + y0; 点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
xx = x + x0; yy = -y + y0; 点旋转(ref xx, ref yy, 弧度, (float)x0, (float)y0);
curbmp.SetPixel(xx, yy, Color.Red);
}
}
void 点旋转(ref int xx, ref int yy, double 弧度, float 中心x, float 中心y)
{
矩阵变换 temp = new 矩阵变换();
PointF tempPt = new PointF(-中心x, -中心y);
PointF 指定点 = new PointF(中心x, 中心y);
PointF 旋转点 = new PointF(xx, yy);
temp.点平移(指定点, ref 旋转点);
temp.基于原点旋转(弧度, ref 旋转点);
temp.点平移(tempPt, ref 旋转点);
xx = (int)旋转点.X;
yy = (int)旋转点.Y;
}
//以下是矩阵变换类
public class 矩阵变换//这个类我们前面直线旋转也是用它
{
public double[,] 单位矩阵 = new double[3, 3];//单位矩阵
public 矩阵变换()
{
int i, j;
for (i = 0; i < 3; i++)
for (j = 0; j < 3; j++)
{
if (i == j) 单位矩阵[i, j] = 1;
else 单位矩阵[i, j] = 0;
}
}
public void 点平移(PointF 指定点 ,ref PointF sp)
{
矩阵变换 M = new 矩阵变换();
M. 单位矩阵[2, 0] = -指定点.X;
M. 单位矩阵[2, 1] = -指定点.Y;
double x, y;
x = M.单位矩阵[0, 0] * sp.X + M.单位矩阵[1, 0] * sp.Y + M.单位矩阵[2, 0];
y = M.单位矩阵[0, 1] * sp.X + M.单位矩阵[1, 1] * sp.Y + M.单位矩阵[2, 1];
sp.X = (float)x;
sp.Y = (float)y;
}
public void 基于原点旋转(double 弧度 ,ref PointF sp)
{矩阵变换 M = new 矩阵变换();
M.单位矩阵[0, 0] = M.单位矩阵[1, 1] = Math.Cos(弧度);//Math.Cos
M.单位矩阵[0, 1] = Math.Sin(弧度);//Math.Sin
M.单位矩阵[1, 0] = -M.单位矩阵[0, 1];
double x, y;
x = M.单位矩阵[0, 0] * sp.X + M.单位矩阵[1, 0] * sp.Y + M.单位矩阵[2, 0];
y = M.单位矩阵[0, 1] * sp.X + M.单位矩阵[1, 1] * sp.Y + M.单位矩阵[2, 1];
sp.X = (float)x;
sp.Y = (float)y;
}
}
