Icons API: Add wp_get_icon() to render registered icons as inline SVG

src/wp-includes/icons.php

@@ -0,0 +1,68 @@
+<?php
+/**
+ * Icons API: Icon rendering helper functions.
+ *
+ * @package WordPress
+ * @subpackage Icons
+ * @since 7.1.0
+ */
+
+/**
+ * Returns the SVG markup for a registered icon.
+ *
+ * @since 7.1.0
+ *
+ * @param string $name The namespaced icon name (e.g. 'core/plus').
+ * @param array  $args {
+ *     Optional. Arguments for the icon. Default empty array.
+ *
+ *     @type int    $size  Width and height in pixels. Default 24.
+ *     @type string $class Additional CSS class names. Default empty string.
+ *     @type string $label Accessible label. If provided, the SVG gets
+ *                         role="img" and aria-label. If omitted, the SVG
+ *                         gets aria-hidden="true". Default empty string.
+ * }
+ * @return string SVG markup for the icon, or empty string if not found.
+ */
+function wp_get_icon( $name, $args = array() ) {
+	$icon = WP_Icons_Registry::get_instance()->get_registered_icon( $name );
+	if ( is_null( $icon ) ) {
+		return '';
+	}
+
+	$svg = $icon['content'];
+	if ( empty( $svg ) ) {
+		return '';
+	}
+
+	$args = wp_parse_args(
+		$args,
+		array(
+			'size'  => 24,
+			'class' => '',
+			'label' => '',
+		)
+	);
+
+	$processor = new WP_HTML_Tag_Processor( $svg );
+	if ( ! $processor->next_tag( 'svg' ) ) {
+		return '';
+	}
+
+	$processor->set_attribute( 'width', (string) $args['size'] );
+	$processor->set_attribute( 'height', (string) $args['size'] );
+	$processor->add_class( 'wp-icon' );
+
+	if ( ! empty( $args['class'] ) ) {
+		$processor->add_class( $args['class'] );
+	}
+
+	if ( ! empty( $args['label'] ) ) {
+		$processor->set_attribute( 'role', 'img' );
+		$processor->set_attribute( 'aria-label', $args['label'] );
+	} else {
+		$processor->set_attribute( 'aria-hidden', 'true' );
+	}
+
+	return $processor->get_updated_html();
+}

src/wp-settings.php

@@ -297,6 +297,7 @@
 require ABSPATH . WPINC . '/class-wp-connector-registry.php';
 require ABSPATH . WPINC . '/connectors.php';
 require ABSPATH . WPINC . '/class-wp-icons-registry.php';
+require ABSPATH . WPINC . '/icons.php';
 require ABSPATH . WPINC . '/widgets.php';
 require ABSPATH . WPINC . '/class-wp-widget.php';
 require ABSPATH . WPINC . '/class-wp-widget-factory.php';

tests/phpunit/tests/icons/wpGetIcon.php

@@ -0,0 +1,97 @@
+<?php
+/**
+ * Unit tests covering the wp_get_icon() function.
+ *
+ * @package WordPress
+ * @subpackage Icons
+ * @since 7.1.0
+ *
+ * @group icons
+ *
+ * @covers ::wp_get_icon
+ */
+class Tests_Icons_WpGetIcon extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_returns_svg_for_known_icon() {
+		$output = wp_get_icon( 'core/plus' );
+		$this->assertStringStartsWith( '<svg ', $output );
+		$this->assertStringContainsString( '</svg>', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_returns_empty_string_for_unknown_icon() {
+		$output = wp_get_icon( 'this-icon-does-not-exist' );
+		$this->assertSame( '', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_default_attributes() {
+		$output = wp_get_icon( 'core/plus' );
+		// WP_HTML_Tag_Processor lowercases attribute names.
+		$this->assertStringContainsString( 'viewbox="0 0 24 24"', $output );
+		$this->assertStringContainsString( 'width="24"', $output );
+		$this->assertStringContainsString( 'height="24"', $output );
+		$this->assertStringContainsString( 'class="wp-icon"', $output );
+		$this->assertStringContainsString( 'aria-hidden="true"', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_custom_size() {
+		$output = wp_get_icon( 'core/plus', array( 'size' => 32 ) );
+		$this->assertStringContainsString( 'width="32"', $output );
+		$this->assertStringContainsString( 'height="32"', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_custom_class() {
+		$output = wp_get_icon( 'core/plus', array( 'class' => 'my-button-icon' ) );
+		$this->assertStringContainsString( 'class="wp-icon my-button-icon"', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_with_label() {
+		$output = wp_get_icon( 'core/plus', array( 'label' => 'Add item' ) );
+		$this->assertStringContainsString( 'role="img"', $output );
+		$this->assertStringContainsString( 'aria-label="Add item"', $output );
+		$this->assertStringNotContainsString( 'aria-hidden', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_without_label_is_hidden() {
+		$output = wp_get_icon( 'core/plus' );
+		$this->assertStringContainsString( 'aria-hidden="true"', $output );
+		$this->assertStringNotContainsString( 'role="img"', $output );
+		$this->assertStringNotContainsString( 'aria-label', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_contains_svg_content() {
+		$output = wp_get_icon( 'core/plus' );
+		$this->assertStringContainsString( '<path ', $output );
+	}
+
+	/**
+	 * @ticket 64847
+	 */
+	public function test_wp_get_icon_escapes_attributes() {
+		$output = wp_get_icon( 'core/plus', array( 'class' => '"><script>alert(1)</script>' ) );
+		$this->assertStringNotContainsString( '<script>', $output );
+	}
+}