Swift-UI按钮阴影渐变 [英] Swift - UI Button Shadow Gradient

问题描述

我正在尝试在Swift中重新创建这样的按钮:

I am trying to recreate a button like this in Swift:

我已经能够使用此处的帮助从Sketch中准确地在按钮内部创建渐变: 已回答的问题

I have been able to create the gradient inside of the button accurately from Sketch using the help from here: Answered Question

现在，我正在尝试在按钮后面重新创建发光效果.我当时正在考虑在其后面创建一个子视图，并使用高斯模糊滤镜对其进行绘制.现在，我被困在如何实现这一点上，还没有找到一个好的解决方案.正常的CALayer阴影不适用于渐变色，我迷路了.感谢您的帮助

Now I am trying to recreate the glow effect behind the button. I was thinking creating a subview behind it and using a gaussian blur filter to draw it. Now I am stuck in how to implement this, and haven't found a good solution. The normal CALayer shadow doesn't work with gradients, and I am lost. Any help is appreciated

推荐答案

您可以这样做

初始化您的渐变层

let gradientLayer = CAGradientLayer.init()

gradientLayer.colors = [UIColor.red.cgColor,
                        UIColor.yellow.cgColor,
                        UIColor.green.cgColor,
                        UIColor.blue.cgColor]

gradientLayer.transform = CATransform3DMakeRotation(CGFloat.pi / 2, 0, 0, 1)

设置按钮边框的首选大小，例如40

Set preferable size for example 40 from button's frame

gradientLayer.frame = CGRect.init(
x: button.frame.minX - 40,
y: button.frame.minY - 40, 
width: button.frame.width + 80, 
height: button.frame.height + 80)
gradientLayer.masksToBounds = true

初始化阴影层

let shadowLayer = CALayer.init()
shadowLayer.frame = gradientLayer.bounds
shadowLayer.shadowColor = UIColor.black.cgColor
shadowLayer.shadowOpacity = 0.08
shadowLayer.shadowRadius = 20
shadowLayer.shadowPath = CGPath.init(rect: shadowLayer.bounds, transform: nil)

将阴影层设置为渐变层的蒙版

Set the shadow layer as a mask for gradient layer

gradientLayer.mask = shadowLayer

在按钮的superView中将渐变图层插入按钮的图层下方

Insert gradient layer in button's superView below button's layer

backgroungView.layer.insertSublayer(gradientLayer, below: button.layer)

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