Gradient Fill in Swift for iOS-Charts

问题:

I am trying to create a nice gradient fill as seen in the demos on the ios-charts page. However, I cannot figure this out in swift vs obj-c. Here is the obj-c code:

NSArray *gradientColors = @[
                    (id)[ChartColorTemplates colorFromString:@"#00ff0000"].CGColor,
                    (id)[ChartColorTemplates colorFromString:@"#ffff0000"].CGColor
                    ];
CGGradientRef gradient = CGGradientCreateWithColors(nil, (CFArrayRef)gradientColors, nil);

set1.fillAlpha = 1.f;
set1.fill = [ChartFill fillWithLinearGradient:gradient angle:90.f];

Now here is my version of that in swift:

    let gradColors = [UIColor.cyanColor().CGColor, UIColor.init(red: 0.0, green: 0.0, blue: 0.0, alpha: 0.0)]
    let colorLocations:[CGFloat] = [0.0, 1.0]
    let gradient = CGGradientCreateWithColors(CGColorSpaceCreateDeviceRGB(), gradColors, colorLocations)

What I am missing is the : Chart Fill fillWithLinearGradient

I can't find the fillWithLinearGradient in the pod anywhere so I am a bit confused.

Thanks in advance for any help! Rob

回答1:

This works perfectly (Swift 3.1 and ios-charts 3.0.1)

---

let gradientColors = [UIColor.cyan.cgColor, UIColor.clear.cgColor] as CFArray // Colors of the gradient
let colorLocations:[CGFloat] = [1.0, 0.0] // Positioning of the gradient
let gradient = CGGradient.init(colorsSpace: CGColorSpaceCreateDeviceRGB(), colors: gradientColors, locations: colorLocations) // Gradient Object
yourDataSetName.fill = Fill.fillWithLinearGradient(gradient!, angle: 90.0) // Set the Gradient
set.drawFilledEnabled = true // Draw the Gradient

Result

回答2:

I believe this is the code that you are looking for. You should be able to use the same ChartFill class in Swift to set set1.fill.

let gradColors = [UIColor.cyanColor().CGColor, UIColor.clearColor.CGColor]
let colorLocations:[CGFloat] = [0.0, 1.0]
if let gradient = CGGradientCreateWithColors(CGColorSpaceCreateDeviceRGB(), gradColors, colorLocations) {
    set1.fill = ChartFill(linearGradient: gradient, angle: 90.0)
}

回答3:

For swift4

let colorTop =  UIColor(red: 255.0/255.0, green: 149.0/255.0, blue: 0.0/255.0, alpha: 1.0).cgColor
let colorBottom = UIColor(red: 255.0/255.0, green: 94.0/255.0, blue: 58.0/255.0, alpha: 1.0).cgColor

let gradientColors = [colorTop, colorBottom] as CFArray
let colorLocations:[CGFloat] = [0.0, 1.0]
let gradient = CGGradient.init(colorsSpace: CGColorSpaceCreateDeviceRGB(), colors: gradientColors, locations: colorLocations) // Gradient Object
yourDataSetName.fill = Fill.fillWithLinearGradient(gradient!, angle: 90.0)

回答4:

Make sure to use the latest version of ios-charts. If you use CocoaPods to install ios-charts change this:

pod 'Charts'

to this

pod 'Charts', '~> 2.2'