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https://github.com/onevcat/Rainbow

Delightful console output for Swift developers.
https://github.com/onevcat/Rainbow

console log output swift

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Delightful console output for Swift developers.

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README 

        
![Rainbow](https://raw.githubusercontent.com/onevcat/Rainbow/assets/rainbow.png)


















`Rainbow` adds text color, background color and style for console and command 

line output in Swift. It is born for cross-platform software logging 

in terminals, working in both Apple's platforms and Linux.



## Basic Usage



Nifty way, using the `String` extension, and print the colorized string.



### Named Color & Style



```swift

import Rainbow



print("Red text".red)

print("Blue background".onBlue)

print("Light green text on white background".lightGreen.onWhite)



print("Underline".underline)

print("Cyan with bold and blinking".cyan.bold.blink)



print("Plain text".red.onYellow.bold.clearColor.clearBackgroundColor.clearStyles)

```



It gives you something like this:



![](https://user-images.githubusercontent.com/1019875/110485682-3fdfa700-812f-11eb-83f7-ca79795a0514.png)



## Installation



### Swift Package Manager



If you are developing a cross platform software in Swift, 

[Swift Package Manager](https://github.com/apple/swift-package-manager) might 

be your choice for package management. Just add the url of this repo to your 

`Package.swift` file as a dependency:



```swift

import PackageDescription



let package = Package(

    name: "YourAwesomeSoftware",

    dependencies: [

        .package(url: "https://github.com/onevcat/Rainbow", .upToNextMajor(from: "4.0.0"))

    ],

    targets: [

        .target(

            name: "MyApp",

            dependencies: ["Rainbow"]

        )

    ]

)

```



Then run `swift build` whenever you get prepared.



You could know more information on how to use Swift Package Manager in Apple's [official page](https://swift.org/package-manager/).



## Other Usage



### String Interpolation & Nested



Swift string interpolation is supported. Define the color for part of the string. Or even create nested colorful strings. The inner color style will be kept:



```swift

print("接天莲叶\("无穷碧".green)，映日荷花\("别样红".red)")

print("\("两只黄鹂".yellow)鸣翠柳，一行白鹭\("上青天".lightBlue)。".lightGreen.underline)

```



![](https://user-images.githubusercontent.com/1019875/110489426-bcc05000-8132-11eb-8b13-caab01faa416.png)



### ANSI 256-Color Mode



[8-bit color](https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit) is fully supported, for both text color and background color:



```swift

print("停车坐爱\("枫林晚".bit8(31))，\("霜叶".bit8(160))红于\("二月花".bit8(198))。")

print("\("一道残阳".bit8(202))铺水中，\("半江瑟瑟".bit8(30).onBit8(226))半江红。")

```



![](https://user-images.githubusercontent.com/1019875/110490505-bda5b180-8133-11eb-97b2-f376d62e07de.png)



### Hex Colors (approximated)



It also accepts a Hex color. Rainbow tries to convert it to a most approximate `.bit8` color:



```swift

print("黑云压城\("城欲摧".hex("#666"))，甲光向日\("金鳞开".hex("000000").onHex("#E6B422"))。")

print("日出江花\("红胜火".hex(0xd11a2d))，春来江水\("绿如蓝".hex(0x10aec2))")

```



![](https://user-images.githubusercontent.com/1019875/110492277-60aafb00-8135-11eb-9aba-e25658f5bc06.png)



> Valid format: `"FFF"`, `"#FFF"`, `"FFFFFF"`, `"#FFFFFF"`, `0xFFFFFF`



### True color



A few terminal emulators supports 24-bit true color. If you are sure the 24-bit colors can be displayed in your user's

terminal, Rainbow has no reason to refuse them!



```swift

print("疏影横斜\("水清浅".bit24(36,116,181))，暗香浮动\("月黄昏".bit24(254,215,26))")

print("\("春色满园".hex("#ea517f", to: .bit24))关不住，\("一枝红杏".hex("#f43e06", to: .bit24))出墙来。")

```



![](https://user-images.githubusercontent.com/1019875/110496210-9d2c2600-8138-11eb-803d-15a745ef1dfb.png)



### Output Target



By default, Rainbow should be smart enough to detect the output target, to determine if it is a tty. For example, it

automatically output plain text if written to a file:



```sh

// main.swift

print("Hello Rainbow".red)



$ .build/debug/RainbowDemo > output.txt



// output.txt

Hello Rainbow

```



This is useful for sharing the same code for logging to console and to a log file.



You can manually change this behavior by either:



- Set the `Rainbow.outputTarget` yourself.

- Pass a `"NO_COLOR"` environment value when executing your app.

- Or set the `Rainbow.enabled` to `false`.



### Verbose Way



You can also use the more verbose way if you want:



```swift

import Rainbow

let output = "The quick brown fox jumps over the lazy dog"

                .applyingCodes(Color.red, BackgroundColor.yellow, Style.bold)

print(output) // Red text on yellow, bold of course :)

```



Or even construct everything from scratch:



```swift

let entry = Rainbow.Entry(

    segments: [

        .init(text: "Hello ", color: .named(.magenta)),

        .init(text: "Rainbow", color: .bit8(214), backgroundColor: .named(.lightBlue), styles: [.underline]),

    ]

)

print(Rainbow.generateString(for: entry))

```



Please remember, the string extensions (such as `"Hello".red`) is `O(n)`. So if you are handling a huge string or very 

complex nesting, there might be a performance issue or hard to make things in stream. The manual way is a rescue for these

cases.



## Motivation and Compatibility



Thanks to the open source of Swift, developers now could write cross platform 

programs with the same language. And I believe the command line software would be 

the next great platform for Swift. Colorful and well-organized output always 

helps us to understand what happens. It is really a necessary utility to create 

wonderful software. 



`Rainbow` should work well in both OS X and Linux terminals. It is smart enough 

to check whether the output is connected to a valid text terminal or not, to 

decide the log should be modified or not. This could be useful when you want to

 send your log to a file instead to console.



## Contact



Follow and contact me on [Twitter](http://twitter.com/onevcat) or 

[Sina Weibo](http://weibo.com/onevcat). If you find an issue, 

just [open a ticket](https://github.com/onevcat/Rainbow/issues/new) on it. Pull 

requests are warmly welcome as well.



## Backers & Sponsors



Open-source projects cannot live long without your help. If you find Kingfisher is useful, please consider supporting this

project by becoming a sponsor. Your user icon or company logo shows up [on my blog](https://onevcat.com/tabs/about/) with a link to your home page.



Become a sponsor through [GitHub Sponsors](https://github.com/sponsors/onevcat). :heart:



## License



Rainbow is released under the MIT license. See LICENSE for details.