Work with Grafana themes

Overview

Themes in Grafana are implemented in TypeScript. We chose the TypeScript language in part because it shares variables between Grafana TypeScript and Sass code.

Theme definitions are located in the following files:

• packages/grafana-data/src/themes/createTheme.ts
• packages/grafana-data/src/themes/createColors.ts

Usage

This section provides usage guidelines for themes.

Use themes in React components

The following section describes how to use Grafana themes in React components.

The useStyles2 hook

The useStyles2 hook memoizes the function and provides access to the theme.

import { FC } from 'react';
import { GrafanaTheme2 } from '@grafana/data';
import { useStyles2 } from '@grafana/ui';
import { css } from '@emotion/css';

function Foo(props: FooProps) {
  const styles = useStyles2(getStyles);
  // Use styles with className
}

const getStyles = (theme: GrafanaTheme2) =>
  css({
    padding: theme.spacing(1, 2),
  });

Get the theme object

Use code similar to the following to give your component access to the theme variables:

import { FC } from 'react';
import { useTheme2 } from '@grafana/ui';

const Foo: FC<FooProps> = () => {
  const theme = useTheme2();

  // Your component has access to the theme variables now
};

Select a variable

This section explains how to select the correct variables in your theme.

The rich color object and the state colors

The theme.colors object has six rich color objects:

• primary
• secondary
• info
• success
• warning
• error

All these objects use the same secondary colors which are associated with different use cases.

Example use cases:

• Want a red background? Use theme.colors.error.main.
• Want green text? Use theme.colors.success.text.
• Want text to be visible when placed inside a background that uses theme.colors.error.main? Use theme.colors.error.contrastText.

Text colors

Background colors

Borders

Actions

Paddings and margins

Border radius

Typography

To customize font family, font sizes, and line heights, use the variables under theme.typography.

Set the context directly

Use ThemeContext like this:

import { ThemeContext } from '@grafana/data';

<ThemeContext.Consumer>{(theme) => <Foo theme={theme} />}</ThemeContext.Consumer>;

Use withTheme higher-order component

With this method your component will be automatically wrapped in ThemeContext.Consumer and provided with current theme via the theme prop. Components used with withTheme must implement the Themeable interface.

import  { ThemeContext, Themeable } from '@grafana/ui';

interface FooProps extends Themeable2 {}

const Foo: React.FunctionComponent<FooProps> = () => ...

export default withTheme2(Foo);

Use a theme in tests

If you need to pass a theme object to a function that you are testing, then import createTheme and call it without any arguments. For example:

import { createTheme } from '@grafana/data';

describe('MyComponent', () => {
  it('should work', () => {
    result = functionThatNeedsTheme(createTheme());
    expect(result).toBe(true);
  });
});

Modify Sass variables

If you need to modify the Sass variable files, we recommend that you migrate the styles to Emotion.

For the following variables to apply, you need to run this yarn dev task:

• [_variables|_variables.dark|_variables.light].generated.scss: These files must be referenced in the main Sass files for Sass variables to be available.

If you need to modify the Sass variable files, be sure to update the files that end with .tmpl.ts and not the .generated.scss files.

Important: These variable files are automatically generated and should never be modified by hand.