# gradient-string

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> Beautiful color gradients in terminal output

[![gradient-string](http://bit.ly/gradient-string-preview)](http://bit.ly/gradient-string-large)


## Install

```
$ npm i gradient-string
```

## Usage

```javascript
const gradient = require('gradient-string');

console.log(gradient('cyan', 'pink')('Hello world!'));
```

### Initialize a gradient

```javascript
// Using varargs
let coolGradient = gradient('red', 'green', 'blue');

// Using array
let coolGradient = gradient(['#FF0000', '#00FF00', '#0000FF']);
```

The colors are parsed with TinyColor, [multiple formats are accepted](https://github.com/bgrins/TinyColor/blob/master/README.md#accepted-string-input).

```javascript
let coolGradient = gradient([
  tinycolor('#FFBB65'),       // tinycolor object
  {r: 0, g: 255, b: 0},       // RGB object
  {h: 240, s: 1, v: 1, a: 1}, // HSVa object
  'rgb(120, 120, 0)',         // RGB CSS string
  'gold'                      // named color
]);
```

### Use a gradient

```javascript
let coolString = coolGradient('This is a fancy string!');
console.log(coolString);
```

## Built-in gradients

### Usage

```javascript
const gradient = require('gradient-string');

// Use the rainbow gradient
console.log(gradient.rainbow('I love gradient-strings!'))
```

### Available built-in gradients

[![Built-in gradients](http://bit.ly/2uFygrL)](http://bit.ly/2ufX07r)

## Multi line gradients

In some cases, you may want to apply the same horizontal gradient on each line of a long text (or a piece of ASCII art).

You can use the `multiline()` method of a gradient to ensure that the colors are vertically aligned.

```javascript
const gradient = require('gradient-string');

// Use the same gradient on every line
let duck = gradient('orange', 'yellow').multiline([
    "  __",
    "<(o )___",
    " ( ._> /",
    "  `---'",
].join('\n'));
console.log(duck);

// Works with aliases
gradient.atlas.multiline('Multi line\nstring');

// Works with advanced options
gradient('cyan', 'pink').multiline('Multi line\nstring', {interpolation: 'hsv'});
```


## Advanced gradients

There are also more advanced options for gradient customization, such as custom color stops, or choice of color interpolation
  
### Custom color stops

By default, the gradient color stops are distributed equidistantly.

You can specify the position of each color stop (between `0` and `1`), using the following syntax:

```javascript
let coolGradient = gradient([
  {color: '#d8e0de', pos: 0},
  {color: '#255B53', pos: 0.8},
  {color: '#000000', pos: 1}
]);
```

### Color interpolation

When using a gradient, you can actually add a second parameter to choose how the colors will be generated.

Here is the full gradient API:

#### myGradient(text, [options])

##### text
Type: `string`<br>
String you want to color.

##### options
Type: `Object`<br>

###### interpolation
Type: `string`<br>
The gradient can be generated using RGB or HSV interpolation. HSV usually produces brighter colors.
`interpolation` can be set to `rgb` for RGB interpolation, or`hsv` for HSV interpolation.<br>
Defaults to `rgb`. Case insentitive

###### hsvSpin
Type: `string`<br>
Used only in the case of HSV interpolation.<br>
Because hue can be considered as a circle, there are two ways to go from a color to another color.<br>
`hsvSpin` can be either `short` or `long`, depending on if you want to take the shortest or the longest way between two colors.<br>
Defaults to `short`. Case insensitive

#### Example
##### Code
```javascript
const redToGreen = gradient('red', 'green');
const str = '■'.repeat(48);

// Standard RGB gradient
console.log(redToGreen(str)); 

// Short HSV gradient: red -> yellow -> green
console.log(redToGreen(str, {interpolation: 'hsv'}));

// Long HSV gradient: red -> magenta -> blue -> cyan -> green
console.log(redToGreen(str, {interpolation: 'hsv', hsvSpin: 'long'}));
```
##### Result
![Example result](http://i.imgur.com/plQAN2Q.png)

## Typescript

Typescript definitions of gradient-string are available on [DefinitelyTyped](https://www.npmjs.com/package/@types/gradient-string)

```sh
npm i @types/gradient-string
```


## Dependencies

- [tinygradient](https://github.com/mistic100/tinygradient) - Generate gradients
- [chalk](https://github.com/chalk/chalk) - Output colored text to terminal


## License

MIT © [Boris K](https://github.com/bokub)

[build-src]: https://flat.badgen.net/travis/bokub/gradient-string
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[build-href]: https://travis-ci.org/bokub/gradient-string
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[downloads-href]: https://www.npmjs.com/package/gradient-string
[xo-href]: https://github.com/sindresorhus/xo
[awesome-href]: https://github.com/sindresorhus/awesome-nodejs