Utopia Core

The calculations behind Utopia.fyi. Available in JS/TS.

Documentation

Note: Complete documentation to follow in the coming weeks.

calculateTypeScale()

Create a fluid type scale between two widths, sizes and scales. Set the number of positive and negative steps, and whether you want the scale to be relative to the viewport or the container.

If any step in the type scale fails WCAG SC 1.4.4, the viewports where the step fails to be zoomable to 200% are returned in wcagViolation.

Schema

type UtopiaTypeConfig = {
  minWidth: number;
  maxWidth: number;
  minFontSize: number;
  maxFontSize: number;
  minTypeScale: number;
  maxTypeScale: number;
  negativeSteps?: number;
  positiveSteps?: number;
  relativeTo?: UtopiaRelativeTo;
}

type UtopiaStep = {
  step: number;
  minFontSize: number;
  maxFontSize: number;
  wcagViolation: {
    from: number;
    to: number;
  } | null;
  clamp: string;
}

calculateTypeScale(config: UtopiaTypeConfig): UtopiaStep[];

Example

calculateTypeScale({
  minWidth: 320,
  maxWidth: 1240,
  minFontSize: 18,
  maxFontSize: 20,
  minTypeScale: 1.2,
  maxTypeScale: 1.25,
  positiveSteps: 5,
  negativeSteps: 2
});

// [
//  {
//    step: 5,
//    minFontSize: 44.79,
//    maxFontSize: 61.04,
//    wcagViolation: 1200,
//    clamp: 'clamp(2.7994rem, 2.4461rem + 1.7663vw, 3.815rem)',
//  }
//  ...
// ]

calculateSpaceScale()

Create a set of fluid spaces from min/max width/base sizes, and a number of positive/negative multipliers. Fluid spaces & one-up pairs are automatically created, and custom pairs can be created by supplying the keys you wish to interpolate between. Clamp provided in rem and px.

Schema

type UtopiaSpaceConfig = {
  minWidth: number;
  maxWidth: number;
  minSize: number;
  maxSize: number;
  negativeSteps?: number[];
  positiveSteps?: number[];
  customSizes?: string[];
  relativeTo?: UtopiaRelativeTo;
}

type UtopiaSize = {
  label: string;
  minSize: number;
  maxSize: number;
  clamp: string;
  clampPx: string;
}

type UtopiaSpaceScale = {
  sizes: UtopiaSize[];
  oneUpPairs: UtopiaSize[];
  customPairs: UtopiaSize[];
};

calculateSpaceScale(config: UtopiaSpaceConfig): UtopiaSpaceScale;

Example

calculateSpaceScale({
  minWidth: 320,
  maxWidth: 1240,
  minSize: 18,
  maxSize: 20,
  positiveSteps: [1.5, 2, 3, 4, 6],
  negativeSteps: [0.75, 0.5, 0.25],
  customSizes: ['s-l', '2xl-4xl']
});

// {
//  sizes: [
//    {
//      label: 's',
//      minSize: 18,
//      maxSize: 20,
//      clamp: 'clamp(1.125rem, 1.0815rem + 0.2174vw, 1.25rem)',
//      clampPx: 'clamp(18px, 17.034px + 0.2174vw, 20rem)'
//    },
//    ...
//  ],
//  oneUpPairs: [...],
//  customPairs: [...],
// }

calculateClamp

Generate a single clamp calculation from a min/max width & size. Default to using rem and vi but this can be overriden to use px and cqi.

Schema

type UtopiaClampConfig = {
  minWidth: number;
  maxWidth: number;
  minSize: number;
  maxSize: number;
  usePx?: boolean;
  relativeTo?: UtopiaRelativeTo;
};

calculateClamp(UtopiaClampConfig): string;

Example

calculateClamp({
  minWidth: 320,
  maxWidth: 1240,
  minSize: 16,
  maxSize: 48,
})

// clamp(...)

calculateClamps

Generate multiple clamps from a single set of min/max widths. Supply an array of number pairs to interpolate between.

Schema

type UtopiaClampsConfig = {
  minWidth: number;
  maxWidth: number;
  pairs: [number, number][];
  usePx?: boolean;
  relativeTo?: UtopiaRelativeTo;
};

type UtopiaClamp = {
  label: string;
  clamp: string;
};

calculateClamps(config: UtopiaClampsConfig): UtopiaClamp[]

Example

calculateClamps({
  minWidth: 320,
  maxWidth: 1240,
  pairs: [
    [16, 48],
    [32, 40]
  ]
})

// [
//  {
//    label: '16-48',
//    clamp: 'clamp(...)',
//  },
//  ...
//]