背景渐变：线性从左到右 objective C

Question

我的客户想要这种渐变效果的背景View 背景渐变：rgb(118,118,118) | #ffffff | rgb(198,198,197) 线性从左到右 我已经尝试过这种方式，但它是在垂直方向发生的，我希望它以水平方式发生

UIColor *leftColor = [UIColor colorWithRed:118.0/255.0 green:118.0/255.0 blue:118.0/255.0 alpha:1.0];
UIColor *middleColor = [UIColor colorWithRed:255.0/255.0 green:255.0/255.0 blue:255.0/255.0 alpha:1.0];
UIColor *rightColor = [UIColor colorWithRed:198.0/255.0 green:198.0/255.0 blue:197.0/255.0 alpha:1.0];

// Create the gradient
CAGradientLayer *theViewGradient = [CAGradientLayer layer];
theViewGradient.colors = [NSArray arrayWithObjects: (id)leftColor.CGColor, (id)middleColor.CGColor,(id)rightColor.CGColor, nil];
theViewGradient.frame = self.view.bounds;
//Add gradient to view
[self.view.layer insertSublayer:theViewGradient atIndex:0];

像这样??

Answer 1

您需要设置 gradientLayer 的起点和终点属性。它们代表您的第一种颜色的起始坐标和最后一种颜色的结束坐标。

它们都是 CGPoints，它们的 x 和 y 值应该介于 0.0 和 1.0 之间。

默认情况下，startPoint 具有这些坐标 (0.5, 0.0)，而 endPoint 具有这些坐标 (0.5, 1.0)。

(0.0, 0.0) 是左上角，(1.0, 1.0) 是右下角

所以尝试：

theViewGradient.startPoint = CGPointMake(0.0, 0.5);
theViewGradient.endPoint = CGPointMake(1.0, 0.5);

Answer 2

 **The start and end points of the gradient when drawn into the layer's
 coordinate space. The start point corresponds to the first gradient
 stop, the end point to the last gradient stop. Both points are
 defined in a unit coordinate space that is then mapped to the
 layer's bounds rectangle when drawn. (i.e. [0,0] is the bottom-left
 corner of the layer, [1,1] is the top-right corner.).The default values
 are [.5,0] and [.5,1] respectively.** 

theViewGradient.startPoint = CGPointMake(0.0, 0.5);
theViewGradient.endPoint = CGPointMake(1.0, 0.5);

Answer 3

在 Swift 3.0 和 4.0 中，从左到右：

    gradientLayer.startPoint = CGPoint(x: 0.0, y: 0.5)
    gradientLayer.endPoint = CGPoint(x: 1.0, y: 0.5)

Answer 4

 enum GradiantDirection {
        case leftToRight
        case rightToLeft
        case topToBottom
        case bottomToTop
    }
    
 class  func setGradiantColor(view : UIView, topColor : UIColor, bottomColor:UIColor, cornerRadius : CGFloat = 0.0,gradiantDirection : GradiantDirection = .topToBottom )
    {
        
        view.layer.sublayers?.filter{ [=10=] is CAGradientLayer }.forEach{ [=10=].removeFromSuperlayer() }
        
        let gradient: CAGradientLayer = CAGradientLayer()
        gradient.colors = [topColor.cgColor,bottomColor.cgColor]
        gradient.frame = view.bounds
        
        switch gradiantDirection {
        case .topToBottom:
            gradient.startPoint = CGPoint(x: 0.0, y: 0.0)
            gradient.endPoint = CGPoint(x: 0.0, y: 1.0)
        case .bottomToTop:
            gradient.startPoint = CGPoint(x: 1.0, y: 0.5)
            gradient.endPoint = CGPoint(x: 0.0, y: 0.5)
        case .leftToRight:
            gradient.startPoint = CGPoint(x: 0.0, y: 0.5)
            gradient.endPoint = CGPoint(x: 1.0, y: 0.5)
        case .rightToLeft:
            gradient.startPoint = CGPoint(x: 1.0, y: 0.5)
            gradient.endPoint = CGPoint(x: 0.0, y: 0.5)
        }
        
        gradient.masksToBounds = true
        let gradientLayer = CAGradientLayer()
        gradientLayer.cornerRadius = cornerRadius
        gradient.rasterizationScale = 100
        view.layer.insertSublayer(gradient, at: 0)
    }

背景渐变：线性从左到右 objective C

background Gradient : linear left to right in objective C

ios

objective-c

cagradientlayer