material-web/elevationold/lib/_elevation-theme.scss

//
// Copyright 2021 Google LLC
// SPDX-License-Identifier: Apache-2.0
//

@use 'sass:map';
@use 'sass:meta';
@use '../../sass/theme';
@use '../../sass/var';
@use './elevation-overlay-theme';

@function resolve-theme(
  $theme,
  $resolver,
  $shadow-color-token,
  $elevation-tokens
) {
  @if $resolver == null {
    @return $theme;
  }

  $shadow-color: map.get($theme, $shadow-color-token);

  // Resolve the value for each state key.
  @each $token in $elevation-tokens {
    $value: map.get($theme, $token);
    $elevation-theme: meta.call(
      $resolver,
      $elevation: $value,
      $shadow-color: $shadow-color
    );

    @each $resolved-token, $resolved-value in $elevation-theme {
      $theme: map.set($theme, #{$token}-#{$resolved-token}, $resolved-value);
    }

    // clean up unused elevation token
    $theme: map.remove($theme, $token);
  }

  // clean up unused shadow color token
  $theme: map.remove($theme, $shadow-color-token);

  @return $theme;
}

/// Represents the configurable values of the elevation theme.
$_flat-theme: map.merge(
  elevation-overlay-theme.$transparent-theme,
  (
    shadow: none,
  )
);

/// Applies the given theme styles.
///
/// @param {Map} $theme - @see $_flat-theme for accepted theme properties.
@mixin theme-styles($theme) {
  $theme: theme.validate-theme-styles(
    $_flat-theme,
    $theme,
    $require-all: false
  );

  @include _box-shadow(map.get($theme, shadow));
  @include elevation-overlay-theme.theme-styles($theme);
}

/// Sets the box shadow of the element.
///
/// @param {String} $box-shadow - The shadow to apply to the element.
@mixin _box-shadow($box-shadow) {
  box-shadow: $box-shadow;
}