Android贝塞尔曲线实现填充不规则图形并随手指运动

private Paint mPaint;
private int centerX, centerY;

private PointF start, end, control;

mPaint = new Paint();
mPaint.setColor(Color.WHITE);
mPaint.setStyle(Paint.Style.FILL);
mPaint.setAntiAlias(true);

//起点
start = new PointF(0, 0);
//终点
end = new PointF(0, 0);
//控制点
control = new PointF(0, 0);

@Override
 protected void onSizeChanged(int w, int h, int oldw, int oldh) {
  super.onSizeChanged(w, h, oldw, oldh);

  centerX = w / 2;
  centerY = h / 2;

  // 初始化数据点和各点的位置
  start.x = 0;
  start.y = 0;
  end.x = w;
  end.y = 0;
  control.x = centerX;
  control.y = centerY;
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  Path path = new Path();

  path.moveTo(start.x, start.y);
  path.quadTo(control.x, control.y, end.x, end.y);
  //上面这两句就画出了贝塞尔曲线了
  path.lineTo(end.x, 40);
  path.lineTo(0, 40);
  path.close();
  //填充图形
  canvas.drawPath(path, mPaint);
 }