Question

var navigationImageView:UIImageView! = UIImageView()
navigationImageView.frame = (0,0,320,64)

var gradient = CAGradientLayer()
let gradientDark = UIColor(red: 148/255.0, green:210/255.0, blue: 245/255.0, alpha: 1.0)
let gradientLight = UIColor(red: 222/255.0, green:247/255.0, blue: 230/255.0, alpha: 1.0)
let gradientLight1 = UIColor(red: 245/255.0, green:247/255.0, blue: 206/255.0, alpha: 1.0)
gradient.frame = navigationImageView.bounds

let color1 = gradientDark.cgColor
let color2 = gradientLight.cgColor
let color3 = gradientLight1.cgColor

gradient.colors = [color1, color2, color3]

gradient.colors = [gradientDark.cgColor,gradientLight.cgColor,gradientLight1.cgColor];

navigationImageView.layer.insertSublayer(gradient, at: 0)

它无法正常工作......如何设置cgradient图像backgorund颜色？

Answer 1

您可以使用渐变制作图像并在imageView

中进行设置

let gradient = CAGradientLayer()
let screenWidth = UIScreen.main.bounds.size.width
let defaultNavigationBarFrame = CGRect(x: 0, y: 0, width: screenWidth, height: 64)
gradient.frame = defaultNavigationBarFrame

//colors
let gradientDark = UIColor(red: 148/255.0, green:210/255.0, blue: 245/255.0, alpha: 1.0)
let gradientLight = UIColor(red: 222/255.0, green:247/255.0, blue: 230/255.0, alpha: 1.0)
let gradientLight1 = UIColor(red: 245/255.0, green:247/255.0, blue: 206/255.0, alpha: 1.0)

gradient.colors = [gradientDark.cgColor,gradientLight.cgColor,gradientLight1.cgColor]
// Create image.
let imageBG: UIImage = self.gradientImage(fromLayer: gradient)

如果您想在导航栏中设置它。

self.navigationController?.navigationBar.setBackgroundImage(imageBG,
                                                                for: .default)

从渐变中创建图像。

func gradientImage(fromLayer layer: CALayer) -> UIImage {
    UIGraphicsBeginImageContext(layer.frame.size)

    layer.render(in: UIGraphicsGetCurrentContext()!)

    let outputImage = UIGraphicsGetImageFromCurrentImageContext()

    UIGraphicsEndImageContext()

    return outputImage!
}

对于Uiimageview，如何在ios swift4中将CGgradient背景颜色设置为背景颜色？

1 个答案: