wp_get_computed_fluid_typography_value

wp_get_computed_fluid_typography_value: 这个函数根据用户的设置检索计算出的流体排版值。它将CSS属性名称作为参数，并返回计算的流体排版值: 这个函数是用来根据用户的设备屏幕尺寸和字体大小偏好来计算流体排版的值。

根据可用的最小/最大视口宽度和最小/最大字体大小，在内部实现CSS clamp()。

function wp_get_computed_fluid_typography_value( $args = array() ) {
	$maximum_viewport_width_raw = isset( $args['maximum_viewport_width'] ) ? $args['maximum_viewport_width'] : null;
	$minimum_viewport_width_raw = isset( $args['minimum_viewport_width'] ) ? $args['minimum_viewport_width'] : null;
	$maximum_font_size_raw      = isset( $args['maximum_font_size'] ) ? $args['maximum_font_size'] : null;
	$minimum_font_size_raw      = isset( $args['minimum_font_size'] ) ? $args['minimum_font_size'] : null;
	$scale_factor               = isset( $args['scale_factor'] ) ? $args['scale_factor'] : null;

	// Normalizes the minimum font size in order to use the value for calculations.
	$minimum_font_size = wp_get_typography_value_and_unit( $minimum_font_size_raw );

	/*
	 * We get a 'preferred' unit to keep units consistent when calculating,
	 * otherwise the result will not be accurate.
	 */
	$font_size_unit = isset( $minimum_font_size['unit'] ) ? $minimum_font_size['unit'] : 'rem';

	// Normalizes the maximum font size in order to use the value for calculations.
	$maximum_font_size = wp_get_typography_value_and_unit(
		$maximum_font_size_raw,
		array(
			'coerce_to' => $font_size_unit,
		)
	);

	// Checks for mandatory min and max sizes, and protects against unsupported units.
	if ( ! $maximum_font_size || ! $minimum_font_size ) {
		return null;
	}

	// Uses rem for accessible fluid target font scaling.
	$minimum_font_size_rem = wp_get_typography_value_and_unit(
		$minimum_font_size_raw,
		array(
			'coerce_to' => 'rem',
		)
	);

	// Viewport widths defined for fluid typography. Normalize units.
	$maximum_viewport_width = wp_get_typography_value_and_unit(
		$maximum_viewport_width_raw,
		array(
			'coerce_to' => $font_size_unit,
		)
	);
	$minimum_viewport_width = wp_get_typography_value_and_unit(
		$minimum_viewport_width_raw,
		array(
			'coerce_to' => $font_size_unit,
		)
	);

	/*
	 * Build CSS rule.
	 * Borrowed from https://websemantics.uk/tools/responsive-font-calculator/.
	 */
	$view_port_width_offset = round( $minimum_viewport_width['value'] / 100, 3 ) . $font_size_unit;
	$linear_factor          = 100 * ( ( $maximum_font_size['value'] - $minimum_font_size['value'] ) / ( $maximum_viewport_width['value'] - $minimum_viewport_width['value'] ) );
	$linear_factor_scaled   = round( $linear_factor * $scale_factor, 3 );
	$linear_factor_scaled   = empty( $linear_factor_scaled ) ? 1 : $linear_factor_scaled;
	$fluid_target_font_size = implode( '', $minimum_font_size_rem ) . " + ((1vw - $view_port_width_offset) * $linear_factor_scaled)";

	return "clamp($minimum_font_size_raw, $fluid_target_font_size, $maximum_font_size_raw)";
}