CloudControl Pro 9 Docs / color / HSLColor

Class: HSLColor

color.HSLColor

A color represented using [alpha], [hue], [saturation], and [lightness].

An [HSLColor] is represented in a parameter space that's based up human perception of colored light. The representation is useful for some color computations (e.g., combining colors of light), because interpolation and picking of colors as red, green, and blue channels doesn't always produce intuitive results.

HSL is a perceptual color model, placing fully saturated colors around a circle (conceptually) at a lightness of ​0.5, with a lightness of 0.0 being completely black, and a lightness of 1.0 being completely white. As the lightness increases or decreases from 0.5, the apparent saturation decreases proportionally (even though the [saturation] parameter hasn't changed).

See also:

• [HSVColor], a color that uses a color space based on human perception of pigments (e.g. paint and printer's ink).
• HSV and HSL Wikipedia article, which this implementation is based upon.

Table of contents

Properties

• alpha
• hue
• lightness
• saturation

Methods

• _scaleAlpha
• equals
• toColor
• toString
• withAlpha
• withHue
• withLightness
• withSaturation
• fromAHSL
• fromColor
• lerp

Properties

alpha

• Readonly alpha: number

Alpha, from 0.0 to 1.0. The describes the transparency of the color. A value of 0.0 is fully transparent, and 1.0 is fully opaque.

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hue

• Readonly hue: number

Hue, from 0.0 to 360.0. Describes which color of the spectrum is represented. A value of 0.0 represents red, as does 360.0. Values in between go through all the hues representable in RGB. You can think of this as selecting which color filter is placed over a light.

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lightness

• Readonly lightness: number

Lightness, from 0.0 to 1.0. The lightness of a color describes how bright a color is. A value of 0.0 indicates black, and 1.0 indicates white. You can think of this as the intensity of the light behind the filter. As the lightness approaches 0.5, the colors get brighter and appear more saturated, and over 0.5, the colors start to become less saturated and approach white at 1.0.

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saturation

• Readonly saturation: number

Saturation, from 0.0 to 1.0. This describes how colorful the color is. 0.0 implies a shade of grey (i.e. no pigment), and 1.0 implies a color as vibrant as that hue gets. You can think of this as the purity of the color filter over the light.

Methods

_scaleAlpha

▸ _scaleAlpha(factor): HSLColor

Parameters

Name	Type
factor	number

Returns

HSLColor

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equals

▸ equals(other): boolean

Parameters

Name	Type
other	any

Returns

boolean

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toColor

▸ toColor(): Color

Returns this HSL color in RGB.

Returns

Color

---

toString

▸ toString(): String

Returns

String

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withAlpha

▸ withAlpha(alpha): HSLColor

Returns a copy of this color with the alpha parameter replaced with the given value.

Parameters

Name	Type
alpha	number

Returns

HSLColor

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withHue

▸ withHue(hue): HSLColor

Returns a copy of this color with the [hue] parameter replaced with the given value.

Parameters

Name	Type
hue	number

Returns

HSLColor

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withLightness

▸ withLightness(lightness): HSLColor

Returns a copy of this color with the [lightness] parameter replaced with the given value.

Parameters

Name	Type
lightness	number

Returns

HSLColor

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withSaturation

▸ withSaturation(saturation): HSLColor

Returns a copy of this color with the [saturation] parameter replaced with the given value.

Parameters

Name	Type
saturation	number

Returns

HSLColor

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fromAHSL

▸ Static fromAHSL(alpha, hue, saturation, lightness): HSLColor

Creates a color.

All the arguments must not be null and be in their respective ranges. See the fields for each parameter for a description of their ranges.

Parameters

Name	Type
alpha	number
hue	number
saturation	number
lightness	number

Returns

HSLColor

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fromColor

▸ Static fromColor(color): HSLColor

Creates an [HSLColor] from an RGB [Color].

This constructor does not necessarily round-trip with [toColor] because of floating point imprecision.

Parameters

Name	Type
color	Color

Returns

HSLColor

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lerp

▸ Static lerp(a, b, t): null | HSLColor

Linearly interpolate between two HSLColors.

The colors are interpolated by interpolating the [alpha], [hue], [saturation], and [lightness] channels separately, which usually leads to a more pleasing effect than [Color.lerp] (which interpolates the red, green, and blue channels separately).

If either color is null, this function linearly interpolates from a transparent instance of the other color. This is usually preferable to interpolating from [Colors.transparent] (const Color(0x00000000)) since that will interpolate from a transparent red and cycle through the hues to match the target color, regardless of what that color's hue is.

The t argument represents position on the timeline, with 0.0 meaning that the interpolation has not started, returning a (or something equivalent to a), 1.0 meaning that the interpolation has finished, returning b (or something equivalent to b), and values between them meaning that the interpolation is at the relevant point on the timeline between a and b. The interpolation can be extrapolated beyond 0.0 and 1.0, so negative values and values greater than 1.0 are valid (and can easily be generated by curves such as [Curves.elasticInOut]).

Values outside of the valid range for each channel will be clamped.

Values for t are usually obtained from an [Animation<double>], such as an [AnimationController].

Parameters

Name	Type
a	null | HSLColor
b	null | HSLColor
t	number

Returns

null | HSLColor