通過UIBezierPath貝塞爾曲線畫圓形、橢圓、矩形

/**創建橢圓形的貝塞爾曲線*/
    UIBezierPath *_ovalPath=[UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 200, 100)];
    
    /**創建矩形的貝塞爾曲線*/
    UIBezierPath *_rectPath=[UIBezierPath bezierPathWithRect:CGRectMake(0, 0, 200, 100)];
    
    
    /**創建圓形的貝塞爾曲線*/
    
    UIBezierPath *_circlePath=[UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 100, 100)];
    UIBezierPath *_shapePath=[UIBezierPath bezierPathWithArcCenter:CGPointMake(20, 0) radius:100 startAngle:0 endAngle:3.14*2 clockwise:YES];

    /**創建帶形狀的圖層*/
    CAShapeLayer *_shapeLayer=[CAShapeLayer layer];
    _shapeLayer.frame=CGRectMake(0, 0, 200, 100);
    _shapeLayer.position=self.view.center;
    
    /**注意:圖層之間與貝塞爾曲線之間通過path進行關聯*/
    _shapeLayer.path=_shapePath.CGPath;
    
    _shapeLayer.fillColor=[UIColor redColor].CGColor;
    [self.view.layer addSublayer:_shapeLayer];