refactor(material/button): switch to tokens theming API (#27784)

* refactor(material/button): switch to tokens theming API

* fixup! refactor(material/button): switch to tokens theming API

* fixup! refactor(material/button): switch to tokens theming API

* fixup! refactor(material/button): switch to tokens theming API

* fixup! refactor(material/button): switch to tokens theming API

* fixup! refactor(material/button): switch to tokens theming API

Author: wagnermaciel

src/material/button/_button-theme.scss

@@ -11,20 +11,19 @@
 @use '../core/theming/theming';
 @use '../core/theming/inspection';
 @use '../core/typography/typography';
+@use '../core/tokens/m2/mdc/button-filled' as tokens-mdc-button-filled;
+
+@function on-color($theme, $palette) {
+  $is-dark: inspection.get-theme-type($theme) == dark;
+  @return if(mdc-helpers.variable-safe-contrast-tone($palette, $is-dark) == 'dark', #000, #fff);
+}
 
 @mixin _button-variant($color) {
   @include mdc-button-text-theme.theme((
     label-text-color: $color,
   ));
 }
 
-@mixin _unelevated-button-variant($foreground, $background) {
-  @include mdc-button-filled-theme.theme((
-    container-color: $background,
-    label-text-color: $foreground,
-  ));
-}
-
 @mixin _raised-button-variant($foreground, $background) {
   @include mdc-button-protected-theme.theme((
     container-color: $background,
@@ -79,35 +78,6 @@
       }
     }
 
-    .mat-mdc-unelevated-button {
-      &.mat-unthemed {
-        @include _unelevated-button-variant($on-surface, $surface);
-      }
-
-      &.mat-primary {
-        @include _unelevated-button-variant($on-primary, $primary);
-      }
-
-      &.mat-accent {
-        @include _unelevated-button-variant($on-secondary, $secondary);
-      }
-
-      &.mat-warn {
-        @include _unelevated-button-variant($on-error, $error);
-      }
-
-      @include button-theme-private.apply-disabled-style() {
-        @include mdc-button-filled-theme.theme((
-          // We need to pass both the disabled and enabled values, because the enabled
-          // ones apply to anchors while the disabled ones are for buttons.
-          disabled-container-color: $disabled-container-color,
-          disabled-label-text-color: $disabled-ink-color,
-          container-color: $disabled-container-color,
-          label-text-color: $disabled-ink-color,
-        ));
-      }
-    }
-
     .mat-mdc-raised-button {
       &.mat-unthemed {
         @include _raised-button-variant($on-surface, $surface);
@@ -180,6 +150,52 @@
       @include button-theme-private.ripple-theme-styles($theme, true);
     }
   }
+
+  .mat-mdc-unelevated-button {
+    $surface: inspection.get-theme-color($theme, background, card);
+    $primary: inspection.get-theme-color($theme, primary);
+    $accent: inspection.get-theme-color($theme, accent);
+    $error: inspection.get-theme-color($theme, warn);
+
+    $on-surface: on-color($theme, $surface);
+    $on-primary: on-color($theme, $primary);
+    $on-accent: on-color($theme, $accent);
+    $on-error: on-color($theme, $error);
+
+    $default-color-tokens: tokens-mdc-button-filled.get-color-tokens($theme, $surface, $on-surface);
+    $primary-color-tokens: tokens-mdc-button-filled.get-color-tokens($theme, $primary, $on-primary);
+    $accent-color-tokens: tokens-mdc-button-filled.get-color-tokens($theme, $accent, $on-accent);
+    $warn-color-tokens: tokens-mdc-button-filled.get-color-tokens($theme, $error, $on-error);
+
+    &.mat-unthemed {
+      @include mdc-button-filled-theme.theme($default-color-tokens);
+    }
+
+    &.mat-primary {
+      @include mdc-button-filled-theme.theme($primary-color-tokens);
+    }
+
+    &.mat-accent {
+      @include mdc-button-filled-theme.theme($accent-color-tokens);
+    }
+
+    &.mat-warn {
+      @include mdc-button-filled-theme.theme($warn-color-tokens);
+    }
+
+    @include button-theme-private.apply-disabled-style() {
+      $is-dark: inspection.get-theme-type($theme) == dark;
+      $disabled-ink-color: rgba($on-surface, if($is-dark, 0.5, 0.38));
+      $disabled-container-color: rgba($on-surface, 0.12);
+
+      @include mdc-button-filled-theme.theme((
+        disabled-container-color: $disabled-container-color,
+        disabled-label-text-color: $disabled-ink-color,
+        container-color: $disabled-container-color,
+        label-text-color: $disabled-ink-color,
+      ));
+    }
+  }
 }
 
 @mixin typography($theme) {

src/material/button/button.scss

@@ -6,11 +6,13 @@
 @use '@material/button/button-filled-theme' as mdc-button-filled-theme;
 @use '@material/button/button-protected-theme' as mdc-button-protected-theme;
 @use '@material/button/button-outlined-theme' as mdc-button-outlined-theme;
+@use '@material/theme/custom-properties' as mdc-custom-properties;
 
 @use './button-base';
 @use '../core/mdc-helpers/mdc-helpers';
 @use '../core/style/private' as style-private;
 @use '../core/focus-indicators/private' as focus-indicators-private;
+@use '../core/tokens/m2/mdc/button-filled' as tokens-mdc-button-filled;
 
 @include mdc-helpers.disable-mdc-fallback-declarations {
   @include mdc-button.static-styles-without-ripple($query: mdc-helpers.$mdc-base-styles-query);
@@ -33,13 +35,6 @@
       map.merge(mdc-button-text-theme.$light-theme, $override-keys));
   }
 
-  .mat-mdc-unelevated-button {
-    @include mdc-button-filled-theme.theme-styles(
-      map.merge(map.merge(mdc-button-filled-theme.$light-theme, $override-keys), (
-        container-color: transparent,
-      )));
-  }
-
   .mat-mdc-raised-button {
     @include mdc-button-protected-theme.theme-styles(
       map.merge(map.merge(mdc-button-protected-theme.$light-theme, $override-keys), (
@@ -53,6 +48,20 @@
   }
 }
 
+@include mdc-custom-properties.configure($emit-fallback-values: false, $emit-fallback-vars: false) {
+  // Note that we don't include a feature query, because this mixins declare
+  // all the "slots" for CSS variables that will be defined in the theme.
+  .mat-mdc-unelevated-button {
+    $mdc-button-filled-slots: tokens-mdc-button-filled.get-token-slots();
+
+    // Add the slots for MDC text button.
+    @include mdc-button-filled-theme.theme-styles($mdc-button-filled-slots);
+
+    // Add default values for MDC text button tokens that aren't outputted by the theming API.
+    @include mdc-button-filled-theme.theme(tokens-mdc-button-filled.get-unthemable-tokens());
+  }
+}
+
 .mat-mdc-button,
 .mat-mdc-unelevated-button,
 .mat-mdc-raised-button,

src/material/core/tokens/m2/mdc/_button-filled.scss

@@ -0,0 +1,92 @@
+@use '../../token-utils';
+@use '../../../mdc-helpers/mdc-helpers';
+@use '../../../style/sass-utils';
+@use '../../../theming/inspection';
+
+// The prefix used to generate the fully qualified name for tokens in this file.
+$prefix: (mdc, button-filled);
+
+// Tokens that can't be configured through Angular Material's current theming API,
+// but may be in a future version of the theming API.
+//
+// Tokens that are available in MDC, but not used in Angular Material should be mapped to `null`.
+// `null` indicates that we are intentionally choosing not to emit a slot or value for the token in
+// our CSS.
+@function get-unthemable-tokens() {
+  @return (
+    container-elevation: 0,
+    container-height: 36px,
+    container-shape: 4px,
+    disabled-container-elevation: 0,
+    focus-container-elevation: 0,
+    hover-container-elevation: 0,
+    keep-touch-target: false,
+    pressed-container-elevation: 0,
+
+    focus-state-layer-opacity: null,
+    hover-state-layer-opacity: null,
+    pressed-state-layer-opacity: null,
+    container-shadow-color: null,
+    focus-label-text-color: null,
+    hover-label-text-color: null,
+    label-text-font: null,
+    label-text-size: null,
+    label-text-tracking: null,
+    label-text-transform: null,
+    label-text-weight: null,
+    pressed-label-text-color: null,
+    with-icon-disabled-icon-color: null,
+    with-icon-focus-icon-color: null,
+    with-icon-hover-icon-color: null,
+    with-icon-icon-color: null,
+    with-icon-icon-size: null,
+    with-icon-pressed-icon-color: null
+  );
+}
+
+@function on-color($theme, $palette) {
+  @if ($palette) {
+    $is-dark: inspection.get-theme-type($theme) == dark;
+    @return if(mdc-helpers.variable-safe-contrast-tone($palette, $is-dark) == 'dark', #000, #fff);
+  }
+}
+
+// Tokens that can be configured through Angular Material's color theming API.
+@function get-color-tokens($theme, $color: null, $on-color: null) {
+  $is-dark: inspection.get-theme-type($theme) == dark;
+  $primary: inspection.get-theme-color($theme, primary);
+  $surface: inspection.get-theme-color($theme, background, card);
+  $on-primary: on-color($theme, $primary);
+  $on-surface: on-color($theme, $surface);
+
+  @return (
+    container-color: if($color, $color, transparent),
+    disabled-container-color: rgba($on-surface, 0.12),
+    disabled-label-text-color: rgba($on-surface, if($is-dark, 0.5, 0.38)),
+    focus-state-layer-color: $on-primary,
+    hover-state-layer-color: $on-primary,
+    label-text-color: if($on-color, $on-color, inherit),
+    pressed-state-layer-color: $on-primary
+  );
+}
+
+// Tokens that can be configured through Angular Material's typography theming API.
+@function get-typography-tokens($theme) {
+  @return ();
+}
+
+// Tokens that can be configured through Angular Material's density theming API.
+@function get-density-tokens($theme) {
+  @return ();
+}
+
+// Combines the tokens generated by the above functions into a single map with placeholder values.
+// This is used to create token slots.
+@function get-token-slots() {
+  @return sass-utils.deep-merge-all(
+    get-unthemable-tokens(),
+    get-color-tokens(token-utils.$placeholder-color-config),
+    get-typography-tokens(token-utils.$placeholder-typography-config),
+    get-density-tokens(token-utils.$placeholder-density-config)
+  );
+}

src/material/core/tokens/tests/test-validate-tokens.scss

@@ -104,7 +104,7 @@
 @include validate-slots(
   $component: 'm2.mdc.switch',
   $slots: tokens-mdc-switch.get-token-slots(),
-  $reference: mdc-switch-theme.$light-theme,
+  $reference: mdc-switch-theme.$light-theme
 );
 @include validate-slots(
   $component: 'm2.mdc.tab-indicator',
@@ -156,3 +156,8 @@
   $slots: tokens-mdc-outlined-text-field.get-token-slots(),
   $reference: mdc-outlined-text-field-theme.$light-theme
 );
+@include validate-slots(
+  $component: 'm2.mdc.button-filled',
+  $slots: tokens-mdc-extended-fab.get-token-slots(),
+  $reference: mdc-extended-fab-theme.$extended-light-theme
+);