Silverlight 引路蜂二维图形库示例:坐标变换

类AffineTransform用于二维平面上坐标变换。可以对坐标进行平移，缩放，旋转等变换。下面例子显示了坐标变换的用法。

private void Transform()
{
 Path path;

 /* The first matrix */
 AffineTransform matrix1 = new AffineTransform();
 /* The second matrix */
 AffineTransform matrix2 = new AffineTransform();
 /* The third matrix */
 AffineTransform matrix3 = new AffineTransform();

 /** Colors */
 Color blackColor = new Color(0xff000000, false);
 Color redColor = new Color(0xffff0000, false);
 Color greenColor = new Color(0xff00ff00, false);
 Color blueColor = new Color(0xff0000ff, false);
 Color fillColor = new Color(0x4f0000ff, true);
 /* Define the path */
 path = new Path();
 path.MoveTo(50, 0);
 path.LineTo(0, 0);
 path.LineTo(0, 50);

 /* Define the matrix1 as  "translate(50,50)"  */
 matrix1.Translate(50, 50);

 /* Define the matrix2 as "translate(50,50) + rotate(-45)" */
 matrix2 = new AffineTransform(matrix1);
 AffineTransform m = new AffineTransform();

 m.Rotate(-45 * Math.PI / 180.0, 0, 0);
 /* Concatenates the m  to the matrix2.
  * [matrix2] =  [matrix2] * [m];
  */
 matrix2.Concatenate(m);

 /* Define the matrix3 as
  * "translate(50,50) + rotate(-45) + translate(-20,80)"  */
 /* Copy the matrix2 to the matrix3 */
 matrix3 = new AffineTransform(matrix2);
 m = new AffineTransform();

 m.Translate(-20, 80);
 /* Concatenates the m  to the matrix3.
  * [matrix3] =  [matrix3] * [m]
  */
 matrix3.Concatenate(m);
 //Clear the canvas with white color.
 graphics2D.Clear(Color.White);

 graphics2D.AffineTransform = (matrix1);
 SolidBrush brush = new SolidBrush(fillColor);
 Pen pen = new Pen(redColor, 4);

 graphics2D.SetPenAndBrush(pen, brush);
 graphics2D.Draw(null, path);

 graphics2D.AffineTransform = (matrix2);

 pen = new Pen(greenColor, 4);

 graphics2D.SetPenAndBrush(pen, brush);
 graphics2D.Draw(null, path);
 graphics2D.AffineTransform = (matrix3);

 pen = new Pen(blueColor, 4);

 graphics2D.SetPenAndBrush(pen, brush);
 graphics2D.Draw(null, path);

}