@wordpress/block-editor
Version:
253 lines (227 loc) • 10.5 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.getComputedFluidTypographyValue = getComputedFluidTypographyValue;
exports.getTypographyValueAndUnit = getTypographyValueAndUnit;
exports.roundToPrecision = roundToPrecision;
/**
* The fluid utilities must match the backend equivalent.
* See: gutenberg_get_typography_font_size_value() in lib/block-supports/typography.php
* ---------------------------------------------------------------
*/
// Defaults.
const DEFAULT_MAXIMUM_VIEWPORT_WIDTH = '1600px';
const DEFAULT_MINIMUM_VIEWPORT_WIDTH = '320px';
const DEFAULT_SCALE_FACTOR = 1;
const DEFAULT_MINIMUM_FONT_SIZE_FACTOR_MIN = 0.25;
const DEFAULT_MINIMUM_FONT_SIZE_FACTOR_MAX = 0.75;
const DEFAULT_MINIMUM_FONT_SIZE_LIMIT = '14px';
/**
* Computes a fluid font-size value that uses clamp(). A minimum and maximum
* font size OR a single font size can be specified.
*
* If a single font size is specified, it is scaled up and down using a logarithmic scale.
*
* @example
* ```js
* // Calculate fluid font-size value from a minimum and maximum value.
* const fontSize = getComputedFluidTypographyValue( {
* minimumFontSize: '20px',
* maximumFontSize: '45px'
* } );
* // Calculate fluid font-size value from a single font size.
* const fontSize = getComputedFluidTypographyValue( {
* fontSize: '30px',
* } );
* ```
*
* @param {Object} args
* @param {?string} args.minimumViewportWidth Minimum viewport size from which type will have fluidity. Optional if fontSize is specified.
* @param {?string} args.maximumViewportWidth Maximum size up to which type will have fluidity. Optional if fontSize is specified.
* @param {string|number} [args.fontSize] Size to derive maximumFontSize and minimumFontSize from, if necessary. Optional if minimumFontSize and maximumFontSize are specified.
* @param {?string} args.maximumFontSize Maximum font size for any clamp() calculation. Optional.
* @param {?string} args.minimumFontSize Minimum font size for any clamp() calculation. Optional.
* @param {?number} args.scaleFactor A scale factor to determine how fast a font scales within boundaries. Optional.
* @param {?string} args.minimumFontSizeLimit The smallest a calculated font size may be. Optional.
*
* @return {string|null} A font-size value using clamp().
*/
function getComputedFluidTypographyValue({
minimumFontSize,
maximumFontSize,
fontSize,
minimumViewportWidth = DEFAULT_MINIMUM_VIEWPORT_WIDTH,
maximumViewportWidth = DEFAULT_MAXIMUM_VIEWPORT_WIDTH,
scaleFactor = DEFAULT_SCALE_FACTOR,
minimumFontSizeLimit
}) {
// Validate incoming settings and set defaults.
minimumFontSizeLimit = !!getTypographyValueAndUnit(minimumFontSizeLimit) ? minimumFontSizeLimit : DEFAULT_MINIMUM_FONT_SIZE_LIMIT;
/*
* Calculates missing minimumFontSize and maximumFontSize from
* defaultFontSize if provided.
*/
if (fontSize) {
// Parses default font size.
const fontSizeParsed = getTypographyValueAndUnit(fontSize);
// Protect against invalid units.
if (!fontSizeParsed?.unit) {
return null;
}
// Parses the minimum font size limit, so we can perform checks using it.
const minimumFontSizeLimitParsed = getTypographyValueAndUnit(minimumFontSizeLimit, {
coerceTo: fontSizeParsed.unit
});
// Don't enforce minimum font size if a font size has explicitly set a min and max value.
if (!!minimumFontSizeLimitParsed?.value && !minimumFontSize && !maximumFontSize) {
/*
* If a minimum size was not passed to this function
* and the user-defined font size is lower than $minimum_font_size_limit,
* do not calculate a fluid value.
*/
if (fontSizeParsed?.value <= minimumFontSizeLimitParsed?.value) {
return null;
}
}
// If no fluid max font size is available use the incoming value.
if (!maximumFontSize) {
maximumFontSize = `${fontSizeParsed.value}${fontSizeParsed.unit}`;
}
/*
* If no minimumFontSize is provided, create one using
* the given font size multiplied by the min font size scale factor.
*/
if (!minimumFontSize) {
const fontSizeValueInPx = fontSizeParsed.unit === 'px' ? fontSizeParsed.value : fontSizeParsed.value * 16;
/*
* The scale factor is a multiplier that affects how quickly the curve will move towards the minimum,
* that is, how quickly the size factor reaches 0 given increasing font size values.
* For a - b * log2(), lower values of b will make the curve move towards the minimum faster.
* The scale factor is constrained between min and max values.
*/
const minimumFontSizeFactor = Math.min(Math.max(1 - 0.075 * Math.log2(fontSizeValueInPx), DEFAULT_MINIMUM_FONT_SIZE_FACTOR_MIN), DEFAULT_MINIMUM_FONT_SIZE_FACTOR_MAX);
// Calculates the minimum font size.
const calculatedMinimumFontSize = roundToPrecision(fontSizeParsed.value * minimumFontSizeFactor, 3);
// Only use calculated min font size if it's > $minimum_font_size_limit value.
if (!!minimumFontSizeLimitParsed?.value && calculatedMinimumFontSize < minimumFontSizeLimitParsed?.value) {
minimumFontSize = `${minimumFontSizeLimitParsed.value}${minimumFontSizeLimitParsed.unit}`;
} else {
minimumFontSize = `${calculatedMinimumFontSize}${fontSizeParsed.unit}`;
}
}
}
// Grab the minimum font size and normalize it in order to use the value for calculations.
const minimumFontSizeParsed = getTypographyValueAndUnit(minimumFontSize);
// We get a 'preferred' unit to keep units consistent when calculating,
// otherwise the result will not be accurate.
const fontSizeUnit = minimumFontSizeParsed?.unit || 'rem';
// Grabs the maximum font size and normalize it in order to use the value for calculations.
const maximumFontSizeParsed = getTypographyValueAndUnit(maximumFontSize, {
coerceTo: fontSizeUnit
});
// Checks for mandatory min and max sizes, and protects against unsupported units.
if (!minimumFontSizeParsed || !maximumFontSizeParsed) {
return null;
}
// Uses rem for accessible fluid target font scaling.
const minimumFontSizeRem = getTypographyValueAndUnit(minimumFontSize, {
coerceTo: 'rem'
});
// Viewport widths defined for fluid typography. Normalize units
const maximumViewportWidthParsed = getTypographyValueAndUnit(maximumViewportWidth, {
coerceTo: fontSizeUnit
});
const minimumViewportWidthParsed = getTypographyValueAndUnit(minimumViewportWidth, {
coerceTo: fontSizeUnit
});
// Protect against unsupported units.
if (!maximumViewportWidthParsed || !minimumViewportWidthParsed || !minimumFontSizeRem) {
return null;
}
// Calculates the linear factor denominator. If it's 0, we cannot calculate a fluid value.
const linearDenominator = maximumViewportWidthParsed.value - minimumViewportWidthParsed.value;
if (!linearDenominator) {
return null;
}
// Build CSS rule.
// Borrowed from https://websemantics.uk/tools/responsive-font-calculator/.
const minViewportWidthOffsetValue = roundToPrecision(minimumViewportWidthParsed.value / 100, 3);
const viewportWidthOffset = roundToPrecision(minViewportWidthOffsetValue, 3) + fontSizeUnit;
const linearFactor = 100 * ((maximumFontSizeParsed.value - minimumFontSizeParsed.value) / linearDenominator);
const linearFactorScaled = roundToPrecision((linearFactor || 1) * scaleFactor, 3);
const fluidTargetFontSize = `${minimumFontSizeRem.value}${minimumFontSizeRem.unit} + ((1vw - ${viewportWidthOffset}) * ${linearFactorScaled})`;
return `clamp(${minimumFontSize}, ${fluidTargetFontSize}, ${maximumFontSize})`;
}
/**
* Internal method that checks a string for a unit and value and returns an array consisting of `'value'` and `'unit'`, e.g., [ '42', 'rem' ].
* A raw font size of `value + unit` is expected. If the value is an integer, it will convert to `value + 'px'`.
*
* @param {string|number} rawValue Raw size value from theme.json.
* @param {Object|undefined} options Calculation options.
*
* @return {{ unit: string, value: number }|null} An object consisting of `'value'` and `'unit'` properties.
*/
function getTypographyValueAndUnit(rawValue, options = {}) {
if (typeof rawValue !== 'string' && typeof rawValue !== 'number') {
return null;
}
// Converts numeric values to pixel values by default.
if (isFinite(rawValue)) {
rawValue = `${rawValue}px`;
}
const {
coerceTo,
rootSizeValue,
acceptableUnits
} = {
coerceTo: '',
// Default browser font size. Later we could inject some JS to compute this `getComputedStyle( document.querySelector( "html" ) ).fontSize`.
rootSizeValue: 16,
acceptableUnits: ['rem', 'px', 'em'],
...options
};
const acceptableUnitsGroup = acceptableUnits?.join('|');
const regexUnits = new RegExp(`^(\\d*\\.?\\d+)(${acceptableUnitsGroup}){1,1}$`);
const matches = rawValue.match(regexUnits);
// We need a number value and a unit.
if (!matches || matches.length < 3) {
return null;
}
let [, value, unit] = matches;
let returnValue = parseFloat(value);
if ('px' === coerceTo && ('em' === unit || 'rem' === unit)) {
returnValue = returnValue * rootSizeValue;
unit = coerceTo;
}
if ('px' === unit && ('em' === coerceTo || 'rem' === coerceTo)) {
returnValue = returnValue / rootSizeValue;
unit = coerceTo;
}
/*
* No calculation is required if swapping between em and rem yet,
* since we assume a root size value. Later we might like to differentiate between
* :root font size (rem) and parent element font size (em) relativity.
*/
if (('em' === coerceTo || 'rem' === coerceTo) && ('em' === unit || 'rem' === unit)) {
unit = coerceTo;
}
return {
value: roundToPrecision(returnValue, 3),
unit
};
}
/**
* Returns a value rounded to defined precision.
* Returns `undefined` if the value is not a valid finite number.
*
* @param {number} value Raw value.
* @param {number} digits The number of digits to appear after the decimal point
*
* @return {number|undefined} Value rounded to standard precision.
*/
function roundToPrecision(value, digits = 3) {
const base = Math.pow(10, digits);
return Number.isFinite(value) ? parseFloat(Math.round(value * base) / base) : undefined;
}
//# sourceMappingURL=fluid-utils.js.map