Wordpress++

wp-admin/includes/screen.php

@@ -20,8 +20,22 @@ function get_column_headers( $screen ) {
 
 	static $column_headers = array();
 
-	if ( ! isset( $column_headers[ $screen->id ] ) )
-		$column_headers[ $screen->id ] = apply_filters( 'manage_' . $screen->id . '_columns', array() );
+	if ( ! isset( $column_headers[ $screen->id ] ) ) {
+
+		/**
+		 * Filter the column headers for a list table on a specific screen.
+		 *
+		 * The dynamic portion of the hook name, `$screen->id`, refers to the
+		 * ID of a specific screen. For example, the screen ID for the Posts
+		 * list table is edit-post, so the filter for that screen would be
+		 * manage_edit-post_columns.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param array $columns An array of column headers. Default empty.
+		 */
+		$column_headers[ $screen->id ] = apply_filters( "manage_{$screen->id}_columns", array() );
+	}
 
 	return $column_headers[ $screen->id ];
 }
@@ -46,7 +60,7 @@ function get_hidden_columns( $screen ) {
  *
  * @since 2.7.0
  *
- * @param string|WP_Screen $screen
+ * @param WP_Screen $screen
  */
 function meta_box_prefs( $screen ) {
 	global $wp_meta_boxes;
@@ -96,14 +110,33 @@ function get_hidden_meta_boxes( $screen ) {
 	if ( $use_defaults ) {
 		$hidden = array();
 		if ( 'post' == $screen->base ) {
-			if ( 'post' == $screen->post_type || 'page' == $screen->post_type )
+			if ( 'post' == $screen->post_type || 'page' == $screen->post_type || 'attachment' == $screen->post_type )
 				$hidden = array('slugdiv', 'trackbacksdiv', 'postcustom', 'postexcerpt', 'commentstatusdiv', 'commentsdiv', 'authordiv', 'revisionsdiv');
 			else
 				$hidden = array( 'slugdiv' );
 		}
+
+		/**
+		 * Filter the default list of hidden meta boxes.
+		 *
+		 * @since 3.1.0
+		 *
+		 * @param array     $hidden An array of meta boxes hidden by default.
+		 * @param WP_Screen $screen WP_Screen object of the current screen.
+		 */
 		$hidden = apply_filters( 'default_hidden_meta_boxes', $hidden, $screen );
 	}
 
+	/**
+	 * Filter the list of hidden meta boxes.
+	 *
+	 * @since 3.3.0
+	 *
+	 * @param array     $hidden       An array of hidden meta boxes.
+	 * @param WP_Screen $screen       WP_Screen object of the current screen.
+	 * @param bool      $use_defaults Whether to show the default meta boxes.
+	 *                                Default true.
+	 */
 	return apply_filters( 'hidden_meta_boxes', $hidden, $screen, $use_defaults );
 }
 
@@ -114,7 +147,6 @@ function get_hidden_meta_boxes( $screen ) {
  *
  * @param string $option An option name.
  * @param mixed $args Option-dependent arguments.
- * @return void
  */
 function add_screen_option( $option, $args = array() ) {
 	$current_screen = get_current_screen();
@@ -125,58 +157,12 @@ function add_screen_option( $option, $args = array() ) {
 	$current_screen->add_option( $option, $args );
 }
 
-/**
- * Displays a screen icon.
- *
- * @uses get_screen_icon()
- * @since 2.7.0
- *
- * @param string|WP_Screen $screen Optional. Accepts a screen object (and defaults to the current screen object)
- * 	which it uses to determine an icon HTML ID. Or, if a string is provided, it is used to form the icon HTML ID.
- */
-function screen_icon( $screen = '' ) {
-	echo get_screen_icon( $screen );
-}
-
-/**
- * Gets a screen icon.
- *
- * @since 3.2.0
- *
- * @param string|WP_Screen $screen Optional. Accepts a screen object (and defaults to the current screen object)
- * 	which it uses to determine an icon HTML ID. Or, if a string is provided, it is used to form the icon HTML ID.
- * @return string HTML for the screen icon.
- */
-function get_screen_icon( $screen = '' ) {
-	if ( empty( $screen ) )
-		$screen = get_current_screen();
-	elseif ( is_string( $screen ) )
-		$icon_id = $screen;
-
-	$class = 'icon32';
-
-	if ( empty( $icon_id ) ) {
-		if ( ! empty( $screen->parent_base ) )
-			$icon_id = $screen->parent_base;
-		else
-			$icon_id = $screen->base;
-
-		if ( 'page' == $screen->post_type )
-			$icon_id = 'edit-pages';
-
-		if ( $screen->post_type )
-			$class .= ' ' . sanitize_html_class( 'icon32-posts-' . $screen->post_type );
-	}
-
-	return '<div id="icon-' . esc_attr( $icon_id ) . '" class="' . $class . '"><br /></div>';
-}
-
 /**
  * Get the current screen object
  *
  * @since 3.1.0
  *
- * @return object Current screen object
+ * @return WP_Screen Current screen object
  */
 function get_current_screen() {
 	global $current_screen;
@@ -191,12 +177,11 @@ function get_current_screen() {
  * Set the current screen object
  *
  * @since 3.0.0
- * @uses $current_screen
  *
  * @param mixed $hook_name Optional. The hook name (also known as the hook suffix) used to determine the screen,
  *	or an existing screen object.
  */
-function set_current_screen( $hook_name =  '' ) {
+function set_current_screen( $hook_name = '' ) {
 	WP_Screen::get( $hook_name )->set_current_screen();
 }
 
@@ -208,7 +193,7 @@ function set_current_screen( $hook_name =  '' ) {
  */
 final class WP_Screen {
 	/**
-	 * Any action associated with the screen. 'add' for *-add.php and *-new.php screens.  Empty otherwise.
+	 * Any action associated with the screen. 'add' for *-add.php and *-new.php screens. Empty otherwise.
 	 *
 	 * @since 3.3.0
 	 * @var string
@@ -217,7 +202,7 @@ final class WP_Screen {
 	public $action;
 
 	/**
-	 * The base type of the screen.  This is typically the same as $id but with any post types and taxonomies stripped.
+	 * The base type of the screen. This is typically the same as $id but with any post types and taxonomies stripped.
 	 * For example, for an $id of 'edit-post' the base is 'edit'.
 	 *
 	 * @since 3.3.0
@@ -226,6 +211,15 @@ final class WP_Screen {
 	 */
 	public $base;
 
+	/**
+	 * The number of columns to display. Access with get_columns().
+	 *
+	 * @since 3.4.0
+	 * @var int
+	 * @access private
+	 */
+	private $columns = 0;
+
 	/**
 	 * The unique ID of the screen.
 	 *
@@ -235,10 +229,22 @@ final class WP_Screen {
 	 */
 	public $id;
 
+	/**
+	 * Which admin the screen is in. network | user | site | false
+	 *
+	 * @since 3.5.0
+	 * @var string
+	 * @access protected
+	 */
+	protected $in_admin;
+
 	/**
 	 * Whether the screen is in the network admin.
 	 *
+	 * Deprecated. Use in_admin() instead.
+	 *
 	 * @since 3.3.0
+	 * @deprecated 3.5.0
 	 * @var bool
 	 * @access public
 	 */
@@ -247,7 +253,10 @@ final class WP_Screen {
 	/**
 	 * Whether the screen is in the user admin.
 	 *
+	 * Deprecated. Use in_admin() instead.
+	 *
 	 * @since 3.3.0
+	 * @deprecated 3.5.0
 	 * @var bool
 	 * @access public
 	 */
@@ -296,20 +305,20 @@ final class WP_Screen {
 
 	/**
 	 * The help tab data associated with the screen, if any.
- 	 *
- 	 * @since 3.3.0
- 	 * @var array
- 	 * @access private
- 	 */
+	 *
+	 * @since 3.3.0
+	 * @var array
+	 * @access private
+	 */
 	private $_help_tabs = array();
 
- 	/**
+	/**
 	 * The help sidebar data associated with screen, if any.
 	 *
 	 * @since 3.3.0
 	 * @var string
 	 * @access private
- 	 */
+	 */
 	private $_help_sidebar = '';
 
 	/**
@@ -353,23 +362,24 @@ final class WP_Screen {
 	 */
 	private $_screen_settings;
 
- 	/**
+	/**
 	 * Fetches a screen object.
- 	 *
- 	 * @since 3.3.0
+	 *
+	 * @since 3.3.0
 	 * @access public
- 	 *
-	 * @param string $hook_name Optional. The hook name (also known as the hook suffix) used to determine the screen.
+	 *
+	 * @param string|WP_Screen $hook_name Optional. The hook name (also known as the hook suffix) used to determine the screen.
 	 * 	Defaults to the current $hook_suffix global.
 	 * @return WP_Screen Screen object.
- 	 */
+	 */
 	public static function get( $hook_name = '' ) {
 
-		if ( is_a( $hook_name, 'WP_Screen' ) )
+		if ( $hook_name instanceof WP_Screen ) {
 			return $hook_name;
+		}
 
 		$post_type = $taxonomy = null;
-		$is_network = $is_user = false;
+		$in_admin = false;
 		$action = '';
 
 		if ( $hook_name )
@@ -394,30 +404,39 @@ final class WP_Screen {
 		if ( ! $post_type && $hook_name ) {
 			if ( '-network' == substr( $id, -8 ) ) {
 				$id = substr( $id, 0, -8 );
-				$is_network = true;
+				$in_admin = 'network';
 			} elseif ( '-user' == substr( $id, -5 ) ) {
 				$id = substr( $id, 0, -5 );
-				$is_user = true;
+				$in_admin = 'user';
 			}
 
 			$id = sanitize_key( $id );
 			if ( 'edit-comments' != $id && 'edit-tags' != $id && 'edit-' == substr( $id, 0, 5 ) ) {
 				$maybe = substr( $id, 5 );
 				if ( taxonomy_exists( $maybe ) ) {
- 					$id = 'edit-tags';
+					$id = 'edit-tags';
 					$taxonomy = $maybe;
 				} elseif ( post_type_exists( $maybe ) ) {
 					$id = 'edit';
 					$post_type = $maybe;
 				}
- 			}
+			}
+
+			if ( ! $in_admin )
+				$in_admin = 'site';
 		} else {
-			$is_network = is_network_admin();
-			$is_user = is_user_admin();
+			if ( defined( 'WP_NETWORK_ADMIN' ) && WP_NETWORK_ADMIN )
+				$in_admin = 'network';
+			elseif ( defined( 'WP_USER_ADMIN' ) && WP_USER_ADMIN )
+				$in_admin = 'user';
+			else
+				$in_admin = 'site';
 		}
 
 		if ( 'index' == $id )
 			$id = 'dashboard';
+		elseif ( 'front' == $id )
+			$in_admin = false;
 
 		$base = $id;
 
@@ -448,7 +467,7 @@ final class WP_Screen {
 						$post_type = 'post';
 					break;
 			}
- 		}
+		}
 
 		switch ( $base ) {
 			case 'post' :
@@ -464,17 +483,24 @@ final class WP_Screen {
 			case 'edit-tags' :
 				if ( null === $taxonomy )
 					$taxonomy = 'post_tag';
+				// The edit-tags ID does not contain the post type. Look for it in the request.
+				if ( null === $post_type ) {
+					$post_type = 'post';
+					if ( isset( $_REQUEST['post_type'] ) && post_type_exists( $_REQUEST['post_type'] ) )
+						$post_type = $_REQUEST['post_type'];
+				}
+
 				$id = 'edit-' . $taxonomy;
 				break;
 		}
 
-		if ( $is_network ) {
+		if ( 'network' == $in_admin ) {
 			$id   .= '-network';
 			$base .= '-network';
-		} elseif ( $is_user ) {
+		} elseif ( 'user' == $in_admin ) {
 			$id   .= '-user';
 			$base .= '-user';
- 		}
+		}
 
 		if ( isset( self::$_registry[ $id ] ) ) {
 			$screen = self::$_registry[ $id ];
@@ -489,13 +515,14 @@ final class WP_Screen {
 		$screen->action     = $action;
 		$screen->post_type  = (string) $post_type;
 		$screen->taxonomy   = (string) $taxonomy;
-		$screen->is_user    = $is_user;
-		$screen->is_network = $is_network;
+		$screen->is_user    = ( 'user' == $in_admin );
+		$screen->is_network = ( 'network' == $in_admin );
+		$screen->in_admin   = $in_admin;
 
 		self::$_registry[ $id ] = $screen;
 
 		return $screen;
- 	}
+	}
 
 	/**
 	 * Makes the screen object the current screen.
@@ -503,11 +530,19 @@ final class WP_Screen {
 	 * @see set_current_screen()
 	 * @since 3.3.0
 	 */
-	function set_current_screen() {
+	public function set_current_screen() {
 		global $current_screen, $taxnow, $typenow;
 		$current_screen = $this;
 		$taxnow = $this->taxonomy;
 		$typenow = $this->post_type;
+
+		/**
+		 * Fires after the current screen has been set.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param WP_Screen $current_screen Current WP_Screen object.
+		 */
 		do_action( 'current_screen', $current_screen );
 	}
 
@@ -519,6 +554,23 @@ final class WP_Screen {
 	 */
 	private function __construct() {}
 
+	/**
+	 * Indicates whether the screen is in a particular admin
+	 *
+	 * @since 3.5.0
+	 *
+	 * @param string $admin The admin to check against (network | user | site).
+	 * If empty any of the three admins will result in true.
+	 * @return boolean True if the screen is in the indicated admin, false otherwise.
+	 *
+	 */
+	public function in_admin( $admin = null ) {
+		if ( empty( $admin ) )
+			return (bool) $this->in_admin;
+
+		return ( $admin == $this->in_admin );
+	}
+
 	/**
 	 * Sets the old string-based contextual help for the screen.
 	 *
@@ -529,7 +581,7 @@ final class WP_Screen {
 	 * @param WP_Screen $screen A screen object.
 	 * @param string $help Help text.
 	 */
-	static function add_old_compat_help( $screen, $help ) {
+	public static function add_old_compat_help( $screen, $help ) {
 		self::$_old_compat_help[ $screen->id ] = $help;
 	}
 
@@ -539,9 +591,9 @@ final class WP_Screen {
 	 *
 	 * @since 3.3.0
 	 *
-	 * @param string $parent_file The parent file of the screen.  Typically the $parent_file global.
+	 * @param string $parent_file The parent file of the screen. Typically the $parent_file global.
 	 */
-	function set_parentage( $parent_file ) {
+	public function set_parentage( $parent_file ) {
 		$this->parent_file = $parent_file;
 		list( $this->parent_base ) = explode( '?', $parent_file );
 		$this->parent_base = str_replace( '.php', '', $this->parent_base );
@@ -560,12 +612,46 @@ final class WP_Screen {
 		$this->_options[ $option ] = $args;
 	}
 
+	/**
+	 * Remove an option from the screen.
+	 *
+	 * @since 3.8.0
+	 *
+	 * @param string $option Option ID.
+	 */
+	public function remove_option( $option ) {
+		unset( $this->_options[ $option ] );
+	}
+
+	/**
+	 * Remove all options from the screen.
+	 *
+	 * @since 3.8.0
+	 */
+	public function remove_options() {
+		$this->_options = array();
+	}
+
+	/**
+	 * Get the options registered for the screen.
+	 *
+	 * @since 3.8.0
+	 *
+	 * @return array Options with arguments.
+	 */
+	public function get_options() {
+		return $this->_options;
+	}
+
 	/**
 	 * Gets the arguments for an option for the screen.
 	 *
 	 * @since 3.3.0
 	 *
-	 * @param string
+	 * @param string $option Option name.
+	 * @param string $key    Optional. Specific array key for when the option is an array.
+	 *                       Default false.
+	 * @return string The option value if set, null otherwise.
 	 */
 	public function get_option( $option, $key = false ) {
 		if ( ! isset( $this->_options[ $option ] ) )
@@ -578,6 +664,31 @@ final class WP_Screen {
 		return $this->_options[ $option ];
 	}
 
+	/**
+	 * Gets the help tabs registered for the screen.
+	 *
+	 * @since 3.4.0
+	 *
+	 * @return array Help tabs with arguments.
+	 */
+	public function get_help_tabs() {
+		return $this->_help_tabs;
+	}
+
+	/**
+	 * Gets the arguments for a help tab.
+	 *
+	 * @since 3.4.0
+	 *
+	 * @param string $id Help Tab ID.
+	 * @return array Help tab arguments.
+	 */
+	public function get_help_tab( $id ) {
+		if ( ! isset( $this->_help_tabs[ $id ] ) )
+			return null;
+		return $this->_help_tabs[ $id ];
+	}
+
 	/**
 	 * Add a help tab to the contextual help for the screen.
 	 * Call this on the load-$pagenow hook for the relevant screen.
@@ -606,7 +717,8 @@ final class WP_Screen {
 		if ( ! $args['id'] || ! $args['title'] )
 			return;
 
-		$this->_help_tabs[] = $args;
+		// Allows for overriding an existing tab with that ID.
+		$this->_help_tabs[ $args['id'] ] = $args;
 	}
 
 	/**
@@ -629,6 +741,17 @@ final class WP_Screen {
 		$this->_help_tabs = array();
 	}
 
+	/**
+	 * Gets the content from a contextual help sidebar.
+	 *
+	 * @since 3.4.0
+	 *
+	 * @return string Contents of the help sidebar.
+	 */
+	public function get_help_sidebar() {
+		return $this->_help_sidebar;
+	}
+
 	/**
 	 * Add a sidebar to the contextual help for the screen.
 	 * Call this in template files after admin.php is loaded and before admin-header.php is loaded to add a sidebar to the contextual help.
@@ -641,6 +764,23 @@ final class WP_Screen {
 		$this->_help_sidebar = $content;
 	}
 
+	/**
+	 * Gets the number of layout columns the user has selected.
+	 *
+	 * The layout_columns option controls the max number and default number of
+	 * columns. This method returns the number of columns within that range selected
+	 * by the user via Screen Options. If no selection has been made, the default
+	 * provisioned in layout_columns is returned. If the screen does not support
+	 * selecting the number of layout columns, 0 is returned.
+	 *
+	 * @since 3.4.0
+	 *
+	 * @return int Number of columns to display.
+	 */
+	public function get_columns() {
+		return $this->columns;
+	}
+
 	/**
 	 * Render the screen's help section.
 	 *
@@ -650,14 +790,46 @@ final class WP_Screen {
 	 */
 	public function render_screen_meta() {
 
-		// Call old contextual_help_list filter.
+		/**
+		 * Filter the legacy contextual help list.
+		 *
+		 * @since 2.7.0
+		 * @deprecated 3.3.0 Use get_current_screen()->add_help_tab() or
+		 *                   get_current_screen()->remove_help_tab() instead.
+		 *
+		 * @param array     $old_compat_help Old contextual help.
+		 * @param WP_Screen $this            Current WP_Screen instance.
+		 */
 		self::$_old_compat_help = apply_filters( 'contextual_help_list', self::$_old_compat_help, $this );
 
 		$old_help = isset( self::$_old_compat_help[ $this->id ] ) ? self::$_old_compat_help[ $this->id ] : '';
+
+		/**
+		 * Filter the legacy contextual help text.
+		 *
+		 * @since 2.7.0
+		 * @deprecated 3.3.0 Use get_current_screen()->add_help_tab() or
+		 *                   get_current_screen()->remove_help_tab() instead.
+		 *
+		 * @param string    $old_help  Help text that appears on the screen.
+		 * @param string    $screen_id Screen ID.
+		 * @param WP_Screen $this      Current WP_Screen instance.
+		 *
+		 */
 		$old_help = apply_filters( 'contextual_help', $old_help, $this->id, $this );
 
 		// Default help only if there is no old-style block of text and no new-style help tabs.
-		if ( empty( $old_help ) && empty( $this->_help_tabs ) ) {
+		if ( empty( $old_help ) && ! $this->get_help_tabs() ) {
+
+			/**
+			 * Filter the default legacy contextual help text.
+			 *
+			 * @since 2.8.0
+			 * @deprecated 3.3.0 Use get_current_screen()->add_help_tab() or
+			 *                   get_current_screen()->remove_help_tab() instead.
+			 *
+			 * @param string $old_help_default Default contextual help text.
+			 */
 			$default_help = apply_filters( 'default_contextual_help', '' );
 			if ( $default_help )
 				$old_help = '<p>' . $default_help . '</p>';
@@ -671,50 +843,54 @@ final class WP_Screen {
 			) );
 		}
 
-		$has_sidebar = ! empty( $this->_help_sidebar );
+		$help_sidebar = $this->get_help_sidebar();
 
 		$help_class = 'hidden';
-		if ( ! $has_sidebar )
+		if ( ! $help_sidebar )
 			$help_class .= ' no-sidebar';
 
 		// Time to render!
 		?>
 		<div id="screen-meta" class="metabox-prefs">
 
-			<div id="contextual-help-wrap" class="<?php echo esc_attr( $help_class ); ?>">
+			<div id="contextual-help-wrap" class="<?php echo esc_attr( $help_class ); ?>" tabindex="-1" aria-label="<?php esc_attr_e('Contextual Help Tab'); ?>">
 				<div id="contextual-help-back"></div>
 				<div id="contextual-help-columns">
 					<div class="contextual-help-tabs">
 						<ul>
-						<?php foreach ( $this->_help_tabs as $i => $tab ):
+						<?php
+						$class = ' class="active"';
+						foreach ( $this->get_help_tabs() as $tab ) :
 							$link_id  = "tab-link-{$tab['id']}";
 							$panel_id = "tab-panel-{$tab['id']}";
-							$classes  = ( $i == 0 ) ? 'active' : '';
 							?>
 
-							<li id="<?php echo esc_attr( $link_id ); ?>" class="<?php echo esc_attr( $classes ); ?>">
-								<a href="<?php echo esc_url( "#$panel_id" ); ?>">
+							<li id="<?php echo esc_attr( $link_id ); ?>"<?php echo $class; ?>>
+								<a href="<?php echo esc_url( "#$panel_id" ); ?>" aria-controls="<?php echo esc_attr( $panel_id ); ?>">
 									<?php echo esc_html( $tab['title'] ); ?>
 								</a>
 							</li>
-						<?php endforeach; ?>
+						<?php
+							$class = '';
+						endforeach;
+						?>
 						</ul>
 					</div>
 
-					<?php if ( $has_sidebar ) : ?>
+					<?php if ( $help_sidebar ) : ?>
 					<div class="contextual-help-sidebar">
-						<?php echo self::$this->_help_sidebar; ?>
+						<?php echo $help_sidebar; ?>
 					</div>
 					<?php endif; ?>
 
 					<div class="contextual-help-tabs-wrap">
-						<?php foreach ( $this->_help_tabs as $i => $tab ):
+						<?php
+						$classes = 'help-tab-content active';
+						foreach ( $this->get_help_tabs() as $tab ):
 							$panel_id = "tab-panel-{$tab['id']}";
-							$classes  = ( $i == 0 ) ? 'active' : '';
-							$classes .= ' help-tab-content';
 							?>
 
-							<div id="<?php echo esc_attr( $panel_id ); ?>" class="<?php echo esc_attr( $classes ); ?>">
+							<div id="<?php echo esc_attr( $panel_id ); ?>" class="<?php echo $classes; ?>">
 								<?php
 								// Print tab content.
 								echo $tab['content'];
@@ -724,29 +900,59 @@ final class WP_Screen {
 									call_user_func_array( $tab['callback'], array( $this, $tab ) );
 								?>
 							</div>
-						<?php endforeach; ?>
+						<?php
+							$classes = 'help-tab-content';
+						endforeach;
+						?>
 					</div>
 				</div>
 			</div>
 		<?php
+		// Setup layout columns
+
+		/**
+		 * Filter the array of screen layout columns.
+		 *
+		 * This hook provides back-compat for plugins using the back-compat
+		 * filter instead of add_screen_option().
+		 *
+		 * @since 2.8.0
+		 *
+		 * @param array     $empty_columns Empty array.
+		 * @param string    $screen_id     Screen ID.
+		 * @param WP_Screen $this          Current WP_Screen instance.
+		 */
+		$columns = apply_filters( 'screen_layout_columns', array(), $this->id, $this );
+
+		if ( ! empty( $columns ) && isset( $columns[ $this->id ] ) )
+			$this->add_option( 'layout_columns', array('max' => $columns[ $this->id ] ) );
+
+		if ( $this->get_option( 'layout_columns' ) ) {
+			$this->columns = (int) get_user_option("screen_layout_$this->id");
+
+			if ( ! $this->columns && $this->get_option( 'layout_columns', 'default' ) )
+				$this->columns = $this->get_option( 'layout_columns', 'default' );
+		}
+		$GLOBALS[ 'screen_layout_columns' ] = $this->columns; // Set the global for back-compat.
+
 		// Add screen options
 		if ( $this->show_screen_options() )
 			$this->render_screen_options();
 		?>
 		</div>
 		<?php
-		if ( ! $this->_help_tabs && ! $this->show_screen_options() )
+		if ( ! $this->get_help_tabs() && ! $this->show_screen_options() )
 			return;
 		?>
 		<div id="screen-meta-links">
-		<?php if ( $this->_help_tabs ) : ?>
+		<?php if ( $this->get_help_tabs() ) : ?>
 			<div id="contextual-help-link-wrap" class="hide-if-no-js screen-meta-toggle">
-			<a href="#contextual-help-wrap" id="contextual-help-link" class="show-settings"><?php _e( 'Help' ); ?></a>
+			<a href="#contextual-help-wrap" id="contextual-help-link" class="show-settings" aria-controls="contextual-help-wrap" aria-expanded="false"><?php _e( 'Help' ); ?></a>
 			</div>
 		<?php endif;
 		if ( $this->show_screen_options() ) : ?>
 			<div id="screen-options-link-wrap" class="hide-if-no-js screen-meta-toggle">
-			<a href="#screen-options-wrap" id="show-settings-link" class="show-settings"><?php _e( 'Screen Options' ); ?></a>
+			<a href="#screen-options-wrap" id="show-settings-link" class="show-settings" aria-controls="screen-options-wrap" aria-expanded="false"><?php _e( 'Screen Options' ); ?></a>
 			</div>
 		<?php endif; ?>
 		</div>
@@ -763,17 +969,46 @@ final class WP_Screen {
 
 		$show_screen = ! empty( $wp_meta_boxes[ $this->id ] ) || $columns || $this->get_option( 'per_page' );
 
-		$this->_screen_settings = apply_filters( 'screen_settings', '', $this );
-
-		switch ( $this->id ) {
+		switch ( $this->base ) {
 			case 'widgets':
 				$this->_screen_settings = '<p><a id="access-on" href="widgets.php?widgets-access=on">' . __('Enable accessibility mode') . '</a><a id="access-off" href="widgets.php?widgets-access=off">' . __('Disable accessibility mode') . "</a></p>\n";
 				break;
+			case 'post' :
+				$expand = '<div class="editor-expand hidden"><label for="editor-expand-toggle">';
+				$expand .= '<input type="checkbox" id="editor-expand-toggle"' . checked( get_user_setting( 'editor_expand', 'on' ), 'on', false ) . ' />';
+				$expand .= __( 'Enable full-height editor and distraction-free functionality.' ) . '</label></div>';
+				$this->_screen_settings = $expand;
+				break;
+			default:
+				$this->_screen_settings = '';
+				break;
 		}
 
+		/**
+		 * Filter the screen settings text displayed in the Screen Options tab.
+		 *
+		 * This filter is currently only used on the Widgets screen to enable
+		 * accessibility mode.
+		 *
+		 * @since 3.0.0
+		 *
+		 * @param string    $screen_settings Screen settings.
+		 * @param WP_Screen $this            WP_Screen object.
+		 */
+		$this->_screen_settings = apply_filters( 'screen_settings', $this->_screen_settings, $this );
+
 		if ( $this->_screen_settings || $this->_options )
 			$show_screen = true;
 
+		/**
+		 * Filter whether to show the Screen Options tab.
+		 *
+		 * @since 3.2.0
+		 *
+		 * @param bool      $show_screen Whether to show Screen Options tab.
+		 *                               Default true.
+		 * @param WP_Screen $this        Current WP_Screen instance.
+		 */
 		$this->_show_screen_options = apply_filters( 'screen_options_show_screen', $show_screen, $this );
 		return $this->_show_screen_options;
 	}
@@ -784,22 +1019,25 @@ final class WP_Screen {
 	 * @since 3.3.0
 	 */
 	public function render_screen_options() {
-		global $wp_meta_boxes, $wp_list_table;
+		global $wp_meta_boxes;
 
 		$columns = get_column_headers( $this );
 		$hidden  = get_hidden_columns( $this );
 
 		?>
-		<div id="screen-options-wrap" class="hidden">
-		<form id="adv-settings" action="" method="post">
+		<div id="screen-options-wrap" class="hidden" tabindex="-1" aria-label="<?php esc_attr_e('Screen Options Tab'); ?>">
+		<form id="adv-settings" method="post">
+		<?php if ( isset( $wp_meta_boxes[ $this->id ] ) || $this->get_option( 'per_page' ) || ( $columns && empty( $columns['_title'] ) ) ) : ?>
+			<h5><?php _e( 'Show on screen' ); ?></h5>
 		<?php
+		endif;
+
 		if ( isset( $wp_meta_boxes[ $this->id ] ) ) : ?>
-			<h5><?php _ex('Show on screen', 'Metaboxes') ?></h5>
 			<div class="metabox-prefs">
 				<?php
 					meta_box_prefs( $this );
 
-					if ( 'dashboard' === $this->id && current_user_can( 'edit_theme_options' ) ) {
+					if ( 'dashboard' === $this->id && has_action( 'welcome_panel' ) && current_user_can( 'edit_theme_options' ) ) {
 						if ( isset( $_GET['welcome'] ) ) {
 							$welcome_checked = empty( $_GET['welcome'] ) ? 0 : 1;
 							update_user_meta( get_current_user_id(), 'show_welcome_panel', $welcome_checked );
@@ -809,15 +1047,17 @@ final class WP_Screen {
 								$welcome_checked = false;
 						}
 						echo '<label for="wp_welcome_panel-hide">';
-						echo '<input type="checkbox" id="wp_welcome_panel-hide"' . checked( (bool) $welcome_checked, true, false )  . ' />';
-						echo __( 'Welcome' ) . "</label>\n";
+						echo '<input type="checkbox" id="wp_welcome_panel-hide"' . checked( (bool) $welcome_checked, true, false ) . ' />';
+						echo _x( 'Welcome', 'Welcome panel' ) . "</label>\n";
 					}
 				?>
 				<br class="clear" />
 			</div>
 			<?php endif;
-			if ( ! empty( $columns ) ) : ?>
-			<h5><?php echo ( isset( $columns['_title'] ) ?  $columns['_title'] :  _x('Show on screen', 'Columns') ) ?></h5>
+			if ( $columns ) :
+				if ( ! empty( $columns['_title'] ) ) : ?>
+			<h5><?php echo $columns['_title']; ?></h5>
+			<?php endif; ?>
 			<div class="metabox-prefs">
 				<?php
 				$special = array('_title', 'cb', 'comment', 'media', 'name', 'title', 'username', 'blogname');
@@ -857,35 +1097,20 @@ final class WP_Screen {
 	 *
 	 * @since 3.3.0
 	 */
-	function render_screen_layout() {
-		global $screen_layout_columns;
-
-		// Back compat for plugins using the filter instead of add_screen_option()
-		$columns = apply_filters( 'screen_layout_columns', array(), $this->id, $this );
-
-		if ( ! empty( $columns ) && isset( $columns[ $this->id ] ) )
-			$this->add_option( 'layout_columns', array('max' => $columns[ $this->id ] ) );
-
-		if ( ! $this->get_option('layout_columns') ) {
-			$screen_layout_columns = 0;
+	public function render_screen_layout() {
+		if ( ! $this->get_option('layout_columns') )
 			return;
-		}
 
-		$screen_layout_columns = get_user_option("screen_layout_$this->id");
+		$screen_layout_columns = $this->get_columns();
 		$num = $this->get_option( 'layout_columns', 'max' );
 
-		if ( ! $screen_layout_columns || 'auto' == $screen_layout_columns ) {
-			if ( $this->get_option( 'layout_columns', 'default' ) )
-				$screen_layout_columns = $this->get_option( 'layout_columns', 'default' );
-		}
-
 		?>
-		<h5><?php _e('Screen Layout'); ?></h5>
+		<h5 class="screen-layout"><?php _e('Screen Layout'); ?></h5>
 		<div class='columns-prefs'><?php
 			_e('Number of Columns:');
 			for ( $i = 1; $i <= $num; ++$i ):
 				?>
-				<label>
+				<label class="columns-prefs-<?php echo $i; ?>">
 					<input type='radio' name='screen_columns' value='<?php echo esc_attr( $i ); ?>'
 						<?php checked( $screen_layout_columns, $i ); ?> />
 					<?php echo esc_html( $i ); ?>
@@ -901,50 +1126,59 @@ final class WP_Screen {
 	 *
 	 * @since 3.3.0
 	 */
-	function render_per_page_options() {
-		if ( ! $this->get_option( 'per_page' ) )
+	public function render_per_page_options() {
+		if ( null === $this->get_option( 'per_page' ) ) {
 			return;
+		}
 
 		$per_page_label = $this->get_option( 'per_page', 'label' );
+		if ( null === $per_page_label ) {
+			$per_page_label = __( 'Number of items per page:' );
+		}
 
 		$option = $this->get_option( 'per_page', 'option' );
-		if ( ! $option )
+		if ( ! $option ) {
 			$option = str_replace( '-', '_', "{$this->id}_per_page" );
+		}
 
 		$per_page = (int) get_user_option( $option );
 		if ( empty( $per_page ) || $per_page < 1 ) {
 			$per_page = $this->get_option( 'per_page', 'default' );
-			if ( ! $per_page )
+			if ( ! $per_page ) {
 				$per_page = 20;
+			}
 		}
 
 		if ( 'edit_comments_per_page' == $option ) {
 			$comment_status = isset( $_REQUEST['comment_status'] ) ? $_REQUEST['comment_status'] : 'all';
+
+			/** This filter is documented in wp-admin/includes/class-wp-comments-list-table.php */
 			$per_page = apply_filters( 'comments_per_page', $per_page, $comment_status );
 		} elseif ( 'categories_per_page' == $option ) {
+			/** This filter is documented in wp-admin/includes/class-wp-terms-list-table.php */
 			$per_page = apply_filters( 'edit_categories_per_page', $per_page );
 		} else {
+			/** This filter is documented in wp-admin/includes/class-wp-list-table.php */
 			$per_page = apply_filters( $option, $per_page );
 		}
 
 		// Back compat
-		if ( isset( $this->post_type ) )
+		if ( isset( $this->post_type ) ) {
+			/** This filter is documented in wp-admin/includes/class-wp-posts-list-table.php */
 			$per_page = apply_filters( 'edit_posts_per_page', $per_page, $this->post_type );
+		}
 
 		?>
-		<h5><?php _ex('Show on screen', 'Screen Options') ?></h5>
-		<div class='screen-options'>
-			<?php if ( !empty($per_page_label) ): ?>
-				<input type='text' class='screen-per-page' name='wp_screen_options[value]'
-					id='<?php echo esc_attr( $option ); ?>' maxlength='3'
-					value='<?php echo esc_attr( $per_page ); ?>' />
-				<label for='<?php echo esc_attr( $option ); ?>'>
-					<?php echo esc_html( $per_page_label ); ?>
-				</label>
+		<div class="screen-options">
+			<?php if ( $per_page_label ) : ?>
+				<label for="<?php echo esc_attr( $option ); ?>"><?php echo $per_page_label; ?></label>
+				<input type="number" step="1" min="1" max="999" class="screen-per-page" name="wp_screen_options[value]"
+					id="<?php echo esc_attr( $option ); ?>" maxlength="3"
+					value="<?php echo esc_attr( $per_page ); ?>" />
 			<?php endif;
 
 			echo get_submit_button( __( 'Apply' ), 'button', 'screen-options-apply', false ); ?>
-			<input type='hidden' name='wp_screen_options[option]' value='<?php echo esc_attr($option); ?>' />
+			<input type="hidden" name="wp_screen_options[option]" value="<?php echo esc_attr( $option ); ?>" />
 		</div>
 		<?php
 	}