showing shdow to uibiezierpath

Question

我使用以下代码绘制了一个三角形形状，我想为我使用贝塞尔路径绘制的这个形状应用阴影。

CGContextRef context = UIGraphicsGetCurrentContext();
    //creating a new nsshadow
    NSShadow* shadow = [[NSShadow alloc] init];
    [shadow setShadowColor: UIColor.blackColor];
    [shadow setShadowOffset: CGSizeMake(3.1, 3.1)];
    [shadow setShadowBlurRadius: 5];       
    //view to add a bezier path
    UIView *triangleView = [[UIView alloc] initWithFrame:CGRectMake(67.0f,33.4f, 40.0f ,20.0f)];
    // code for drawing a triangular shape
    UIBezierPath* trianglePath = [UIBezierPath bezierPath];
    [trianglePath moveToPoint:CGPointMake(0, 0)];
    [trianglePath addQuadCurveToPoint:CGPointMake(7.0f, 3.0f) controlPoint:CGPointMake(4.0f, 0.0f)];
    [trianglePath addLineToPoint:CGPointMake(17.0f,15.0f)];
    [trianglePath addQuadCurveToPoint:CGPointMake(23.0f,15.0f) controlPoint:CGPointMake(20.0f, 20.0f)];
    [trianglePath addLineToPoint:CGPointMake(33.0f, 3.0f)];
    [trianglePath addQuadCurveToPoint:CGPointMake(40.0, 0.0f) controlPoint:CGPointMake(36.5f, 0.0f)];
    [trianglePath addLineToPoint:CGPointMake(0.0f, 0.0f)];

    CGContextAddPath(context, trianglePath.CGPath);      
    CGContextSaveGState(context);
    CGContextSetShadowWithColor(context, shadow.shadowOffset, shadow.shadowBlurRadius, [shadow.shadowColor CGColor]);
    [UIColor.redColor setFill];
    [trianglePath fill];
    CGContextRestoreGState(context);
    [UIColor.blackColor setStroke];
    trianglePath.lineWidth = 1;
    [trianglePath stroke];
    CGContextFillPath(context);
    //CAShapeLayer to set the bezier path
    CAShapeLayer *triangleMaskLayer = [CAShapeLayer layer];
    [triangleMaskLayer setPath:trianglePath.CGPath];
    triangleMaskLayer.lineWidth = 0.1f;
    triangleMaskLayer.fillColor = [[UIColor whiteColor] CGColor];   
    [triangleView.layer addSublayer:triangleMaskLayer];

我想为这条乌比泽尔路径设置阴影吗？我尝试过使用一些方法，但无法弄清楚出了什么问题？

Answer 1

尝试将

阴影属性设置为CAShapeLayer如下所示：

    CAShapeLayer *triangleMaskLayer = [CAShapeLayer layer];
    triangleMaskLayer.shadowColor=[UIColor blackColor].CGColor;
    triangleMaskLayer.shadowOffset=CGSizeMake(3.1, 3.1);
    triangleMaskLayer.shadowRadius=5.0;
    [triangleView.layer addSublayer:triangleMaskLayer];

Answer 2

SWIFT 3您可以先创建一个阴影图层，然后可以将形状图层添加为此阴影图层的子图层。其他的很简单。

 let triangleView = UIView(frame: CGRect(x: 67, y: 33, width: 40, height: 20))
    let trianglePath = UIBezierPath()
    trianglePath.move(to: CGPoint(x:0, y:0))
    trianglePath.addQuadCurve(to: CGPoint(x:7, y:3), controlPoint: CGPoint(x:4, y:0))
    trianglePath.addLine(to: CGPoint(x:17, y:15))
    trianglePath.addQuadCurve(to: CGPoint(x:23, y:15), controlPoint: CGPoint(x:20, y:20))
    trianglePath.addLine(to: CGPoint(x:33, y:3))
    trianglePath.addQuadCurve(to: CGPoint(x:40, y:0), controlPoint: CGPoint(x:36, y:0))
    trianglePath.addLine(to: CGPoint(x:0, y:0))
    trianglePath.close()

    //CAShapeLayer to set the bezier path
    let triangleMaskLayer = CAShapeLayer()
    triangleMaskLayer.path = trianglePath.cgPath
    triangleMaskLayer.lineWidth = 1
    triangleMaskLayer.strokeColor = UIColor.black.cgColor
    triangleMaskLayer.fillColor = UIColor.red.cgColor

    let shadowlayer = CALayer()
    shadowlayer.frame = CGRect(x: 100, y: 100, width: 200, height: 200)
    shadowlayer.shadowColor = UIColor.black.cgColor
    shadowlayer.shadowRadius = 5.0
    shadowlayer.shadowOffset = CGSize(width: 3.1, height: 3.1)
    shadowlayer.shadowOpacity = 1.0
    shadowlayer.addSublayer(triangleMaskLayer)
    triangleView.layer.addSublayer(shadowlayer)
    self.view .addSubview(triangleView)