o-colors

A component to manage colours. Includes the FT colour palette.

• Usage
• Markup
• CSS Custom Properties
• Sass
• Migration
• Contact
• Licence

Usage

Check out how to include Origami components in your project to get started with o-colors.

Markup

Colour Usecase Classes

A limited number of colour usecases are available as CSS classes, including:

• .o-colors-page-background
• .o-colors-box-background
• .o-colors-body-text
• .o-colors-muted-text

More colours are available for build service users as CSS Custom Properties.

CSS Custom Properties

Colour Palette Custom Properties

All palette colors, including default mixes and tones, are available as CSS Custom Properties (CSS Variables) in the format --o-colors-[NAME].

See all palette colours available in the registry.

.ft-pink {
	background: var(--o-colors-paper);
	color: var(--o-colors-black-80);
}

Colour Usecase Custom Properties

A limited number of colour usecases are also available as CSS Custom Properties (CSS Variables), including:

• --o-colors-page-background
• --o-colors-box-background
• --o-colors-body-text
• --o-colors-muted-text
• --o-colors-link-text
• --o-colors-link-hover-text

body {
	background: var(--o-colors-page-background);
}

Sass

o-colors has a number of mixins and functions for you to access the color palette in your project. We recommend Sass projects use these mixins and functions directly. E.g. oColorsByName and oColorsByUsecase. However, it is also possible to output all o-colors CSS Custom Properties (CSS Variables) and classes using the oColors mixin.

@import '@financial-times/o-colors/main';
@include oColors(
	$opts: (
		'palette-custom-properties': true,
		// e.g. --o-colors-paper
		'usecase-custom-properties': true,
		// e.g. --o-colors-page-background
		'usecase-classes': true // e.g. .o-colors-page-background,
	)
);

Palette Colours

o-colors defines a colour palette (a set of named colours) which may be previewed in the registry. Custom palette colours may be added to the palette to share them with dependencies.

There are additional colours in the palette by default including tones and mixes. See the registry demos for a full list.

ft-pink and ft-grey are brand colours which are used in some digital assets, such as the FT logo, but have a limited number of valid use-cases for digital UI. Instead consider paper and slate or a black/paper mix such as black-80. As an example of a usecase for ft-pink, it could be used to prevent a flash of the wrong colour as a logo image loads.

Default Palette Colours

Get a default colour from the palette using oColorsByName.

.example {
	// Get a default o-colors palette colour.
	background: oColorsByName('paper');
}

Custom Palette Colours

To set a custom palette colour to share with other components call oColorsSetColor. Colour names must be namespaced for the project or component using a forward slash.

// Set a custom palette colour within a project `o-example`.
@include oColorsSetColor(
	$color-name: 'o-example/myhotpink',
	$color-value: #ff69b4
);

.example {
	// Get a custom palette colour from a project `o-example`.
	background: oColorsByName('o-example/myhotpink');
}

By default custom colours do not allow tones to reduce the number of colours used within a project. To allow tones set the allow-tones option.

// Set a custom palette colour within a project `o-example`,
// which allows tones of the same colour.
@include oColorsSetColor(
	$color-name: 'o-example/myhotpink',
	$color-value: #ff69b4,
	$opts: (
		'allow-tones': true,
	)
);

.example {
	// Get a toned custom palette colour from a project `o-example`.
	background-color: oColorsGetTone('o-example/myhotpink', 80);
}

Removing a colour is considered a breaking change and requires a major release. To inform users a colour should not be used deprecate it by passing an $opts argument with a deprecation message.

// Deprecate a custom colour, which will be removed in a future major release.
@include oColorsSetColor(
	$color-name: 'o-example/myhotpink',
	$color-value #ff69b4,
	$opts: (
		'deprecated': 'Use the default colour claret instead.',
	)
);

See o-colors SassDoc for more details and examples.

Usecases

A colour palette helps products use the same set of colours, but does not help them use the colours consistently. Therefore o-colors provides tools to return colours based on usecases. E.g. a colour for the page background or body text.

Default Usecases

To get a colour for a default usecase call oColorsByUsecase.

html {
	// get the background colour for the page usecase
	background: oColorsByUsecase('page', 'background');
}

.paragraph {
	// get the text colour for the body usecase
	color: oColorsByUsecase('body', 'text');
}

Custom Usecase

To create a new usecase call oColorsSetUseCase.

• $usecase: The name of the usecase, e.g. 'page'. This must include a namespace for your component or project followed by a forward slash.
• $colors: A map of properties ('text', 'background', 'border', or 'outline') to a palette color name.
• $opts (optional):
  • deprecated: A deprecation message for the usecase.

// set colours for a "stripes" in o-example.
@include oColorsSetUseCase(
	'o-example/stripes',
	(
		'text': 'white',
		'background': 'black',
		'border': 'black-50',
	)
);

Removing a usecase is a breaking change and requires a major release. To inform users a usecase should not be used it should be deprecated. Deprecate a usecase by passing an $opts argument with a deprecation message.

Deprecate all usecase properties:

// deprecate all usecase properties for the o-example custom usecase "stripes".
@include oColorsSetUseCase(
	'o-example',
	'stripes',
	(
		'text': 'white',
		'background': 'black',
		'border': 'black-50',
	),
	(
		'deprecated': 'o-example has no stripes anymore, use a different colour',
	)
);

Deprecate individual usecase properties:

// deprecate only the background property for the o-example custom usecase "stripes".
@include oColorsSetUseCase(
	'o-example',
	'stripes',
	(
		'text': 'white',
		'background': 'black',
		'border': 'black-50',
	),
	(
		'deprecated': (
			'background':
				'o-example stripes has no background anymore, use a different colour',
		),
	)
);

Generated Text Colors

oColorsGetTextColor will return a light or dark text color based on the background and an opacity specified.

.example {
	background: oColorsByName('teal');
	// Get a text colour for a teal background
	color: oColorsGetTextColor('teal');
}

.example {
	background: oColorsByName('teal');
	// Get a text colour for a teal background,
	// with greater than usual opacity (80)
	color: oColorsGetTextColor('teal', 80);
}

The contrast of the background and resulting text colour is checked against WCAG 2.1 guidelines. If the contrast is too low an error is thrown. By default the contrast is checked for normal text at AA level. The contrast may be checked for large text or against stricter AAA recommendations (aa-normal, aa-large, aaa-normal, or aaa-large).

.example-large-text {
	background: oColorsByName('teal');
	// Get a text colour for a teal background,
	// enforce a lower level of contrast "large text".
	color: oColorsGetTextColor('teal', $minimum-contrast: 'aa-large');
}

Set $minimum-contrast to null to remove contrast checking. Only ignore contrast for incidental or logo text, otherwise your project may be inaccessible.

Mix colors

oColorsMix will mix two colors based on a percentage. This gives the impression of the base color appearing at the percentage opacity over the background color. oColorsMix will accept either a color value or the name of an o-colors palette color as arguments.

By default oColorsMix mixes with the page background colour usecase:

$color: oColorsMix(
	$color: 'black',
	$percentage: 30,
); // same as black-30

But two colours may be given. For example to mix claret over slate at 20%:

$color: oColorsMix(
	$color: 'claret',
	$background: 'slate',
	$percentage: 20,
);

Tone Palette Colors

An o-colors tone is a palette colour with modified saturation and luminosity, to create a lighter or darker colour whilst retaining vibrancy.

Recommended tones are already in the colour palette, e.g. teal-80 (see default tones in the registry). However for cases where a new tone is required use oColorsGetTone. It will return a new color based on a specified brightness.

.teal-tone-example {
	background-color: oColorsGetTone('teal', 80);
}

For design consistency not all colours are allowed to be toned. Only colours with default tones in the palette (e.g. teal, oxford, and claret) may be used. Other colours may still be mixed. If your project has defined custom colours using oColorsSetColor, these may be toned by setting the allow-tones option.

Colour Tools

o-colors provides other useful functions for working with colours, including:

• oColorsGetContrastRatio
• oColorsColorBrightness
• oColorsColorLuminance

See o-colors SassDoc for more details and examples.

Migration

Contact

If you have any questions or comments about this component, or need help using it, please either raise an issue, visit #origami-support or email Origami Support.

Licence

This software is published by the Financial Times under the MIT licence.