颜色定义函数

### rgb

Creates an opaque color object from decimal red, green and blue (RGB) values.
Literal color values in standard HTML/CSS formats may also be used to define colors, for example `#ff0000`.

Parameters:

- `red`: An integer 0-255 or percentage 0-100%.
- `green`: An integer 0-255 or percentage 0-100%.
- `blue`: An integer 0-255 or percentage 0-100%.

Returns: `color`

Example: `rgb(90, 129, 32)`

Output: `#5a8120`

### rgba

Creates a transparent color object from decimal red, green, blue and alpha (RGBA) values.
Parameters:

- `red`: An integer 0-255 or percentage 0-100%.
- `green`: An integer 0-255 or percentage 0-100%.
- `blue`: An integer 0-255 or percentage 0-100%.
- `alpha`: A number 0-1 or percentage 0-100%.

Returns: `color`

Example: `rgba(90, 129, 32, 0.5)`

Output: `rgba(90, 129, 32, 0.5)`

### argb

Creates a hex representation of a color in `#AARRGGBB` format (NOT `#RRGGBBAA`!).
This format is used in Internet Explorer, and .NET and Android development.

Parameters: `color`, color object.

Returns: `string`

Example: `argb(rgba(90, 23, 148, 0.5));`

Output: `#805a1794`

### hsl

Creates an opaque color object from hue, saturation and lightness (HSL) values.
Parameters:

- `hue`: An integer 0-360 representing degrees.
- `saturation`: A percentage 0-100% or number 0-1.
- `lightness`: A percentage 0-100% or number 0-1.

Returns: `color`

Example: `hsl(90, 100%, 50%)`

Output: `#80ff00`

This is useful if you want to create a new color based on another color's channel, forExample: `@new: hsl(hue(@old), 45%, 90%);`

`@new` will have `@old`'s hue, and its own saturation and lightness.

### hsla

Creates a transparent color object from hue, saturation, lightness and alpha (HSLA) values.
Parameters:

- `hue`: An integer 0-360 representing degrees.
- `saturation`: A percentage 0-100% or number 0-1.
- `lightness`: A percentage 0-100% or number 0-1.
- `alpha`: A percentage 0-100% or number 0-1.

Returns: `color`

Example: `hsla(90, 100%, 50%, 0.5)`

Output: `rgba(128, 255, 0, 0.5)`

### hsv

Creates an opaque color object from hue, saturation and value (HSV) values.
Note that this is a color space available in Photoshop, and is not the same as `hsl`.

Parameters:

- `hue`: An integer 0-360 representing degrees.
- `saturation`: A percentage 0-100% or number 0-1.
- `value`: A percentage 0-100% or number 0-1.

Returns: `color`

Example: `hsv(90, 100%, 50%)`

Output: `#408000`

### hsva

Creates a transparent color object from hue, saturation, value and alpha (HSVA) values.
Note that this is not the same as `hsla`, and is a color space available in Photoshop.

Parameters:

- `hue`: An integer 0-360 representing degrees.
- `saturation`: A percentage 0-100% or number 0-1.
- `value`: A percentage 0-100% or number 0-1.
- `alpha`: A percentage 0-100% or number 0-1.

Returns: `color`

Example: `hsva(90, 100%, 50%, 0.5)`

Output: `rgba(64, 128, 0, 0.5)`