// stylelint-disable property-blacklist, scss/dollar-variable-default
// SCSS RFS mixin
//
// Automated font-resizing
//
// See https://github.com/twbs/rfs
// Configuration
// Base font size
$rfs-base-font-size: 1.25rem !default;
$rfs-font-size-unit: rem !default;
// Breakpoint at where font-size starts decreasing if screen width is smaller
$rfs-breakpoint: 1200px !default;
$rfs-breakpoint-unit: px !default;
// Resize font-size based on screen height and width
$rfs-two-dimensional: false !default;
// Factor of decrease
$rfs-factor: 10 !default;
@if type-of($rfs-factor) != "number" or $rfs-factor <= 1 {
@error "`#{$rfs-factor}` is not a valid $rfs-factor, it must be greater than 1.";
}
// Generate enable or disable classes. Possibilities: false, "enable" or "disable"
$rfs-class: false !default;
// 1 rem = $rfs-rem-value px
$rfs-rem-value: 16 !default;
// Safari iframe resize bug: https://github.com/twbs/rfs/issues/14
$rfs-safari-iframe-resize-bug-fix: false !default;
// Disable RFS by setting $enable-responsive-font-sizes to false
$enable-responsive-font-sizes: true !important;
// Cache $rfs-base-font-size unit
$rfs-base-font-size-unit: unit($rfs-base-font-size);
// Remove px-unit from $rfs-base-font-size for calculations
@if $rfs-base-font-size-unit == "px" {
$rfs-base-font-size: $rfs-base-font-size / ($rfs-base-font-size * 0 + 1);
}
@else if $rfs-base-font-size-unit == "rem" {
$rfs-base-font-size: $rfs-base-font-size / ($rfs-base-font-size * 0 + 1 / $rfs-rem-value);
}
// Cache $rfs-breakpoint unit to prevent multiple calls
$rfs-breakpoint-unit-cache: unit($rfs-breakpoint);
// Remove unit from $rfs-breakpoint for calculations
@if $rfs-breakpoint-unit-cache == "px" {
$rfs-breakpoint: $rfs-breakpoint / ($rfs-breakpoint * 0 + 1);
}
@else if $rfs-breakpoint-unit-cache == "rem" or $rfs-breakpoint-unit-cache == "em" {
$rfs-breakpoint: $rfs-breakpoint / ($rfs-breakpoint * 0 + 1 / $rfs-rem-value);
}
// Responsive font-size mixin
@mixin rfs($fs, $important: false) {
// Cache $fs unit
$fs-unit: if(type-of($fs) == "number", unit($fs), false);
// Add !important suffix if needed
$rfs-suffix: if($important, " !important", "");
// If $fs isn't a number (like inherit) or $fs has a unit (not px or rem, like 1.5em) or $ is 0, just print the value
@if not $fs-unit or $fs-unit != "" and $fs-unit != "px" and $fs-unit != "rem" or $fs == 0 {
font-size: #{$fs}#{$rfs-suffix};
}
@else {
// Variables for storing static and fluid rescaling
$rfs-static: null;
$rfs-fluid: null;
// Remove px-unit from $fs for calculations
@if $fs-unit == "px" {
$fs: $fs / ($fs * 0 + 1);
}
@else if $fs-unit == "rem" {
$fs: $fs / ($fs * 0 + 1 / $rfs-rem-value);
}
// Set default font-size
@if $rfs-font-size-unit == rem {
$rfs-static: #{$fs / $rfs-rem-value}rem#{$rfs-suffix};
}
@else if $rfs-font-size-unit == px {
$rfs-static: #{$fs}px#{$rfs-suffix};
}
@else {
@error "`#{$rfs-font-size-unit}` is not a valid unit for $rfs-font-size-unit. Use `px` or `rem`.";
}
// Only add media query if font-size is bigger as the minimum font-size
// If $rfs-factor == 1, no rescaling will take place
@if $fs > $rfs-base-font-size and $enable-responsive-font-sizes {
$min-width: null;
$variable-unit: null;
// Calculate minimum font-size for given font-size
$fs-min: $rfs-base-font-size + ($fs - $rfs-base-font-size) / $rfs-factor;
// Calculate difference between given font-size and minimum font-size for given font-size
$fs-diff: $fs - $fs-min;
// Base font-size formatting
// No need to check if the unit is valid, because we did that before
$min-width: if($rfs-font-size-unit == rem, #{$fs-min / $rfs-rem-value}rem, #{$fs-min}px);
// If two-dimensional, use smallest of screen width and height
$variable-unit: if($rfs-two-dimensional, vmin, vw);
// Calculate the variable width between 0 and $rfs-breakpoint
$variable-width: #{$fs-diff * 100 / $rfs-breakpoint}#{$variable-unit};
// Set the calculated font-size.
$rfs-fluid: calc(#{$min-width} + #{$variable-width}) #{$rfs-suffix};
}
// Rendering
@if $rfs-fluid == null {
// Only render static font-size if no fluid font-size is available
font-size: $rfs-static;
}
@else {
$mq-value: null;
// RFS breakpoint formatting
@if $rfs-breakpoint-unit == em or $rfs-breakpoint-unit == rem {
$mq-value: #{$rfs-breakpoint / $rfs-rem-value}#{$rfs-breakpoint-unit};
}
@else if $rfs-breakpoint-unit == px {
$mq-value: #{$rfs-breakpoint}px;
}
@else {
@error "`#{$rfs-breakpoint-unit}` is not a valid unit for $rfs-breakpoint-unit. Use `px`, `em` or `rem`.";
}
@if $rfs-class == "disable" {
// Adding an extra class increases specificity,
// which prevents the media query to override the font size
&,
.disable-responsive-font-size &,
&.disable-responsive-font-size {
font-size: $rfs-static;
}
}
@else {
font-size: $rfs-static;
}
@if $rfs-two-dimensional {
@media (max-width: #{$mq-value}), (max-height: #{$mq-value}) {
@if $rfs-class == "enable" {
.enable-responsive-font-size &,
&.enable-responsive-font-size {
font-size: $rfs-fluid;
}
}
@else {
font-size: $rfs-fluid;
}
@if $rfs-safari-iframe-resize-bug-fix {
// stylelint-disable-next-line length-zero-no-unit
min-width: 0vw;
}
}
}
@else {
@media (max-width: #{$mq-value}) {
@if $rfs-class == "enable" {
.enable-responsive-font-size &,
&.enable-responsive-font-size {
font-size: $rfs-fluid;
}
}
@else {
font-size: $rfs-fluid;
}
@if $rfs-safari-iframe-resize-bug-fix {
// stylelint-disable-next-line length-zero-no-unit
min-width: 0vw;
}
}
}
}
}
}
// The font-size & responsive-font-size mixin uses RFS to rescale font sizes
@mixin font-size($fs, $important: false) {
@include rfs($fs, $important);
}
@mixin responsive-font-size($fs, $important: false) {
@include rfs($fs, $important);
}
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