Patch for tickets #1428 and #1760

Create the concept of a Photo_Display_Context.  If the user is browsing a dynamic album (i.e. tags) and chooses to
look at an image in that album.  The display of the image happens correctly, but the 'next' and 'previous' buttons
are no longer consistent.  When one of these is clicked, Gallery  will open the adjacent image in the actuall album,
not the dynamic album.

1 files changed, 19 insertions, 0 deletions

diff --git a/modules/tag/helpers/tag.php b/modules/tag/helpers/tag.php
index c21104ee..83a00080 100644
--- a/modules/tag/helpers/tag.php
+++ b/modules/tag/helpers/tag.php
@@ -136,4 +136,23 @@ class tag_Core {
     // extremely rare case.
     db::build()->delete("tags")->where("count", "=", 0)->execute();
   }
+
+  /**
+   * Find the position of the given item in the tag collection.  The resulting
+   * value is 1-indexed, so the first child in the album is at position 1.
+   *
+   * @param Tag_Model  $tag
+   * @param Item_Model $item
+   * @param array      $where an array of arrays, each compatible with ORM::where()
+   */
+  static function get_position($tag, $item, $where=array()) {
+    return ORM::factory("item")
+      ->viewable()
+      ->join("items_tags", "items.id", "items_tags.item_id")
+      ->where("items_tags.tag_id", "=", $tag->id)
+      ->where("items.id", "<=", $item->id)
+      ->merge_where($where)
+      ->order_by("items.id")
+      ->count_all();
+  }
 }
\ No newline at end of file