iOS 方形径向渐变

Question

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Answer 1

您可以像这样直接在 UIView 子类中绘制径向渐变:

override func draw(_ rect: CGRect) {
    let context = UIGraphicsGetCurrentContext()!
    let colorSpace = CGColorSpaceCreateDeviceRGB()
    let colors = [UIColor.red.cgColor, UIColor.green.cgColor] as NSArray
    let gradient = CGGradient(colorsSpace: colorSpace, colors: colors, locations: nil)!
    let center = CGPoint(x: bounds.midX, y: bounds.midY)
    context.drawRadialGradient(gradient, startCenter: center, startRadius: 0, endCenter: center, endRadius: bounds.width/2, options: [.drawsAfterEndLocation])
}

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或者简单地检查这个库来绘制任何你想要的开箱即用的渐变 - https://github.com/maxkonovalov/MKGradientView