Add option to display featured post images in the header.

Thanks to Martin Lormes for suggesting this change and writing the
initial implementation, which was inspired by a feature in the
default WordPress theme Twenty Eleven.

changelog.txt

@@ -2,6 +2,7 @@
 
 ### Version 3.2.0
 
+  * Added option to display featured post images in the header.
   * Moved language files to `/languages` directory.
   * Added POT file to theme files in `languages` directory.
   * Replaced use of deprecated `add_custom_image_header` function.

functions.php

@@ -156,10 +156,18 @@
 
 // Post thumbnails; change these settings via a child theme or plugin
 add_theme_support('post-thumbnails');
-if (get_tarski_option('featured_header'))
-set_post_thumbnail_size(HEADER_IMAGE_WIDTH, HEADER_IMAGE_HEIGHT, true);
-else
-set_post_thumbnail_size(150, 150, false);
+
+if (get_tarski_option('featured_header')) {
+    set_post_thumbnail_size(HEADER_IMAGE_WIDTH, HEADER_IMAGE_HEIGHT, true);
+} else {
+    set_post_thumbnail_size($content_width, 300, false);
+}
+
+// Image size for large feature images, used in the header
+add_image_size('large-feature', HEADER_IMAGE_WIDTH, HEADER_IMAGE_HEIGHT, true);
+
+// Image size for featured posts if a large-feature doesn't exist
+add_image_size('small-feature', $content_width, 300);
 
 // Post types
 add_theme_support('post-formats', array('aside'));

library/helpers/admin_helper.php

@@ -317,7 +317,7 @@ function tarski_miscellaneous_options() {
         'centred_theme'    => __('Centrally align the theme', 'tarski'),
         'swap_sides'       => __('Switch column order', 'tarski'),
         'swap_title_order' => __('Reverse document title order', 'tarski'),
-        'featured_header'  => __('Featured images in header', 'tarski'));
+        'featured_header'  => __('Display featured images in header', 'tarski'));
 
     foreach ($checkboxes as $name => $label)
         $output .= tarski_option_checkbox($name, $label) . "\n\n";

library/helpers/template_helper.php

@@ -277,32 +277,37 @@ function _tarski_asset_output($type, $assets) {
  * @uses user_trailingslashit
  * @uses home_url
  *
+ * @global object $post
+ *
  * @return string
  */
 function tarski_headerimage() {
     global $post;
+
     if (!get_theme_mod('header_image')) return;
 
     $header_img_url = get_header_image();
 
-    // inspired by twentyeleven
-    if ( get_tarski_option('featured_header') &&
-      is_singular() &&
-      has_post_thumbnail( $post->ID ) &&
-      ( /* $src, $width, $height */ $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), array( HEADER_IMAGE_WIDTH, HEADER_IMAGE_WIDTH ) ) ) &&
-      $image[1] >= HEADER_IMAGE_WIDTH )
-      // Houston, we have a new header image!
-      $header_img_tag = get_the_post_thumbnail( $post->ID, 'post-thumbnail' );
-    else {
+    if (get_tarski_option('featured_header') &&
+        is_singular($post) &&
+        has_post_thumbnail($post->ID)) {
+        $image_size = array(HEADER_IMAGE_WIDTH, HEADER_IMAGE_WIDTH);
+        $image_id   = get_post_thumbnail_id($post->ID);
+        $image      = wp_get_attachment_image_src($image_id, $image_size);
+
+        if ($image[1] >= HEADER_IMAGE_WIDTH) {
+            $header_img_tag = get_the_post_thumbnail($post->ID, $image_size);
+        }
+    }
 
     if (!$header_img_url) return;
 
-    $header_img_tag = sprintf('<img alt="%s" src="%s">',
-        get_tarski_option('display_title')
-            ? __('Header image', 'tarski')
-            : get_bloginfo('name'),
-        $header_img_url);
-
+    if (!isset($header_img_tag)) {
+        $header_img_tag = sprintf('<img alt="%s" src="%s">',
+            get_tarski_option('display_title')
+                ? __('Header image', 'tarski')
+                : get_bloginfo('name'),
+            $header_img_url);
     }
 
     if (!(get_tarski_option('display_title') || is_front_page()))