Update

CustomView/Advance/[6]Path_Bessel.md

@@ -138,7 +138,85 @@ rXxx方法   | rMoveTo, rLineTo, rQuadTo, rCubicTo | **不带r的方法是基于
 
 首先，两个数据点是控制贝塞尔曲线开始和结束的位置，比较容易理解，而控制点则是控制贝塞尔的弯曲状态，相对来说比较难以理解，所以本示例重点在于理解贝塞尔曲线弯曲状态与控制点的关系，废话不多说，先上效果图：
 
+![](http://ww2.sinaimg.cn/large/005Xtdi2gw1f39vugjg0vg308c0e8409.gif)
 
+主要代码如下：
+
+``` java
+public class Bessel1 extends View {
+
+    private Paint mPaint;
+    private int centerX, centerY;
+
+    private PointF start, end, control;
+
+    public Bessel1(Context context) {
+        super(context);
+        mPaint = new Paint();
+        mPaint.setColor(Color.BLACK);
+        mPaint.setStrokeWidth(8);
+        mPaint.setStyle(Paint.Style.STROKE);
+        mPaint.setTextSize(60);
+
+        start = new PointF(0,0);
+        end = new PointF(0,0);
+        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;
+
+        // 初始化数据点和控制点的位置
+        start.x = centerX-200;
+        start.y = centerY;
+        end.x = centerX+200;
+        end.y = centerY;
+        control.x = centerX;
+        control.y = centerY-100;
+    }
+
+    @Override
+    public boolean onTouchEvent(MotionEvent event) {
+        // 根据触摸位置更新控制点，并提示重绘
+        control.x = event.getX();
+        control.y = event.getY();
+        invalidate();
+        return true;
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        super.onDraw(canvas);
+
+        // 绘制数据点和控制点
+        mPaint.setColor(Color.GRAY);
+        mPaint.setStrokeWidth(20);
+        canvas.drawPoint(start.x,start.y,mPaint);
+        canvas.drawPoint(end.x,end.y,mPaint);
+        canvas.drawPoint(control.x,control.y,mPaint);
+
+        // 绘制辅助线
+        mPaint.setStrokeWidth(4);
+        canvas.drawLine(start.x,start.y,control.x,control.y,mPaint);
+        canvas.drawLine(end.x,end.y,control.x,control.y,mPaint);
+
+        // 绘制贝塞尔曲线
+        mPaint.setColor(Color.RED);
+        mPaint.setStrokeWidth(8);
+
+        Path path = new Path();
+
+        path.moveTo(start.x,start.y);
+        path.quadTo(control.x,control.y,end.x,end.y);
+
+        canvas.drawPath(path, mPaint);
+    }
+}
+
+```