Silverlight 领道蜂二维图形库示例:动画Beziers曲线

2012-07-18

Silverlight 引路蜂二维图形库示例:动画Beziers曲线类Path为一条几何路径，可以通过直线，二次曲线，三次曲线

Silverlight 引路蜂二维图形库示例:动画Beziers曲线

类Path为一条几何路径，可以通过直线，二次曲线，三次曲线来构成任意路径。Path提供了moveTo, lineTo, curveTo, curveToCubic, closePath方法来构成路径。

下面的例子动态显示一条Bezier曲线。

/*** The animation thread.*/Thread _thread;bool _drawn;/** * The random number generator. */readonly Random _random = new Random();/** * The animated path */readonly Path _path = new Path();/** * Red brush used to fill the path. */readonly SolidBrush _brush = new SolidBrush(Color.Red);const int Numpts = 6;readonly int[] _animpts = new int[Numpts * 2];readonly int[] _deltas = new int[Numpts * 2]; private void Beziers(){ Reset(screenWidth, screenHeight); _thread = new Thread(RunBeziers); _thread.Start();} private void RunBeziers(){  Thread me = Thread.CurrentThread;  if (!_drawn) {  lock (this)  {   graphics2D.Clear(Color.White);   graphics2D.Fill(_brush, _path);   _drawn = true;  } } while (_thread == me) {  DrawDemo(screenWidth, screenHeight); }} /*** Generates new points for the path.*/private void Animate(int[] pts, int[] deltas, int i, int limit){ int newpt = pts[i] + deltas[i]; if (newpt <= 0) {  newpt = -newpt;  deltas[i] = (_random.Next() & 0x00000003) + 2; } else if (newpt >= limit) {  newpt = 2 * limit - newpt;  deltas[i] = -((_random.Next() & 0x00000003) + 2); } pts[i] = newpt;} /*** Resets the animation data.*/private void Reset(int w, int h){ for (int i = 0; i < _animpts.Length; i += 2) {  _animpts[i + 0] = (_random.Next() & 0x00000003) * w / 2;  _animpts[i + 1] = (_random.Next() & 0x00000003) * h / 2;  _deltas[i + 0] = (_random.Next() & 0x00000003) * 6 + 4;  _deltas[i + 1] = (_random.Next() & 0x00000003) * 6 + 4;  if (_animpts[i + 0] > w / 2)  {   _deltas[i + 0] = -_deltas[i + 0];  }  if (_animpts[i + 1] > h / 2)  {   _deltas[i + 1] = -_deltas[i + 1];  } }} /** * Sets the points of the path and draws and fills the path. */private void DrawDemo(int w, int h){ for (int i = 0; i < _animpts.Length; i += 2) {  Animate(_animpts, _deltas, i + 0, w);  Animate(_animpts, _deltas, i + 1, h); } //Generates the new pata data. _path.Reset(); int[] ctrlpts = _animpts; int len = ctrlpts.Length; int prevx = ctrlpts[len - 2]; int prevy = ctrlpts[len - 1]; int curx = ctrlpts[0]; int cury = ctrlpts[1]; int midx = (curx + prevx) / 2; int midy = (cury + prevy) / 2; _path.MoveTo(midx, midy); for (int i = 2; i <= ctrlpts.Length; i += 2) {  int x1 = (curx + midx) / 2;  int y1 = (cury + midy) / 2;  prevx = curx;  prevy = cury;  if (i < ctrlpts.Length)  {   curx = ctrlpts[i + 0];   cury = ctrlpts[i + 1];  }  else  {   curx = ctrlpts[0];   cury = ctrlpts[1];  }  midx = (curx + prevx) / 2;  midy = (cury + prevy) / 2;  int x2 = (prevx + midx) / 2;  int y2 = (prevy + midy) / 2;  _path.CurveTo(x1, y1, x2, y2, midx, midy); } _path.ClosePath(); // clear the clipRect area before production  graphics2D.Clear(Color.White); graphics2D.Fill(_brush, _path);  RefreshBitmap(); }

其中实时更新图像需要CompositionTarget.Rendering事件来处理。CompositionTarget.Rendering += CompositionTargetRendering;

private void CompositionTargetRendering(object sender, EventArgs e){ bmp.Invalidate();}

Silverlight 领道蜂二维图形库示例:动画Beziers曲线

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Silverlight 领道蜂二维图形库示例:动画Beziers曲线