Reader mode: Generate styles for color palette, gradient presets, and font sizes from the theme support features of the primary theme

.phpstorm.meta.php

@@ -40,6 +40,7 @@
 			'plugin_registry'                    => \AmpProject\AmpWP\PluginRegistry::class,
 			'plugin_suppression'                 => \AmpProject\AmpWP\PluginSuppression::class,
 			'reader_theme_loader'                => \AmpProject\AmpWP\ReaderThemeLoader::class,
+			'reader_theme_support_features'      => \AmpProject\AmpWP\ReaderThemeSupportFeatures::class,
 			'rest.options_controller'            => \AmpProject\AmpWP\OptionsRESTController::class,
 			'rest.validation_counts_controller'  => \AmpProject\AmpWP\Validation\ValidationCountsRestController::class,
 			'server_timing'                      => \AmpProject\AmpWP\Instrumentation\ServerTiming::class,

includes/amp-helper-functions.php

@@ -134,9 +134,10 @@ function () {
 	$old_version = isset( $options[ Option::VERSION ] ) ? $options[ Option::VERSION ] : '0.0';
 
 	if ( AMP__VERSION !== $old_version && is_admin() && current_user_can( 'manage_options' ) ) {
-		// This waits to happen until the very end of init to ensure that amp theme support and amp post type support have all been added.
+		// This waits to happen until the very end of admin_init to ensure that amp theme support and amp post type
+		// support have all been added, and that the settings have been registered.
 		add_action(
-			'init',
+			'admin_init',
 			static function () use ( $old_version ) {
 				/**
 				 * Triggers when after amp_init when the plugin version has updated.

src/AmpWpPlugin.php

@@ -99,6 +99,7 @@ final class AmpWpPlugin extends ServiceBasedPlugin {
 		'plugin_registry'                    => PluginRegistry::class,
 		'plugin_suppression'                 => PluginSuppression::class,
 		'reader_theme_loader'                => ReaderThemeLoader::class,
+		'reader_theme_support_features'      => ReaderThemeSupportFeatures::class,
 		'rest.options_controller'            => OptionsRESTController::class,
 		'rest.validation_counts_controller'  => Validation\ValidationCountsRestController::class,
 		'server_timing'                      => Instrumentation\ServerTiming::class,
@@ -193,6 +194,7 @@ protected function get_shared_instances() {
 			DevTools\CallbackReflection::class,
 			DevTools\FileReflection::class,
 			ReaderThemeLoader::class,
+			ReaderThemeSupportFeatures::class,
 			BackgroundTask\BackgroundTaskDeactivator::class,
 			PairedRouting::class,
 			Injector::class,

src/Option.php

@@ -142,6 +142,16 @@ interface Option {
 	 */
 	const READER_THEME = 'reader_theme';
 
+	/**
+	 * Theme support features from the primary theme.
+	 *
+	 * When using a Reader theme, the theme support features from the primary theme are stored in this option so that
+	 * they will be available when the Reader theme is active.
+	 *
+	 * @var string
+	 */
+	const PRIMARY_THEME_SUPPORT = 'primary_theme_support';
+
 	/**
 	 * The key of the option storing whether the setup wizard has been completed.
 	 *

src/ReaderThemeLoader.php

@@ -69,22 +69,34 @@ public function __construct( PairedRouting $paired_routing ) {
 	/**
 	 * Is Reader mode with a Reader theme selected.
 	 *
+	 * @param array $options Options to check. If omitted, the currently-saved options are used.
 	 * @return bool Whether new Reader mode.
 	 */
-	public function is_enabled() {
+	public function is_enabled( $options = null ) {
 		// If the theme was overridden then we know it is enabled. We can't check get_template() at this point because
 		// it will be identical to $reader_theme.
 		if ( $this->is_theme_overridden() ) {
 			return true;
 		}
 
+		if ( null === $options ) {
+			$options = AMP_Options_Manager::get_options();
+		}
+
 		// If Reader mode is not enabled, then a Reader theme is definitely not going to be served.
-		if ( AMP_Theme_Support::READER_MODE_SLUG !== AMP_Options_Manager::get_option( Option::THEME_SUPPORT ) ) {
+		if (
+			! isset( $options[ Option::THEME_SUPPORT ] )
+			||
+			AMP_Theme_Support::READER_MODE_SLUG !== $options[ Option::THEME_SUPPORT ]
+		) {
 			return false;
 		}
 
 		// If the Legacy Reader mode is active, then a Reader theme is not going to be served.
-		$reader_theme = AMP_Options_Manager::get_option( Option::READER_THEME );
+		if ( ! isset( $options[ Option::READER_THEME ] ) ) {
+			return false;
+		}
+		$reader_theme = $options[ Option::READER_THEME ];
 		if ( ReaderThemes::DEFAULT_READER_THEME === $reader_theme ) {
 			return false;
 		}