make themes configurable (fixes #50)

* gallery.ini:
  - remove theme specific configuration
  - add default theme name
 * includes/galleryfunctions.php:
  - implement theme initialization
  - configure common parameters from theme
 * includes/theme.class.php:
  - implement a simple theme class
 * index.php:
  - assign $gallery to template
 * themes/default_horizontal/theme.ini:
  - add theme specific configuration
 * themes/default_horizontal/theme.php:
  - use $content['gallery'] instead of undefined $gallery

includes/theme.class.php

@@ -0,0 +1,70 @@
+<?php
+/**
+ * @file defines a theme class for ScrollingJQueryGallery
+ *
+ * @author Jan Dittberner <jan@dittberner.info>
+ *
+ * @version $Id$
+ *
+ * Copyright (c) 2009 Jan Dittberner
+ * Jan Dittberner IT-Consulting & -Solutions
+ * Cottbuser Str. 1, D-01129 Dresden
+ *
+ * This file is part of the ScrollingJQueryGallery component of the
+ * gnuviech-server.de Websitetools
+ *
+ * ScrollingJQueryGallery is free software: you can redistribute it
+ * and/or modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * ScrollingJQueryGallery is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with ScrollingJQueryGallery.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Theme class.
+ */
+class Theme {
+  /**
+   * Theme type 'horizontal' or 'vertical'
+   * @var string
+   */
+  var $themetype;
+
+  /**
+   * Size of preview images. Used for calculating preview image sizes.
+   * @var int
+   */
+  var $previewsize;
+
+  /**
+   * Size of thumbnail images. Depending on the theme type this is
+   * used for calculating the width (vertical themes) or height
+   * (horizontal themes) of the thumbnal images.
+   * @var int
+   */
+  var $thumbsize;
+
+  /**
+   * Constructor for themes. Expects a theme name and initializes the
+   * internal state of the instance from the 'theme.ini' file in the
+   * named theme's directory.
+   * @param string $name the directory name of the theme
+   */
+  function __construct($name) {
+    $themeconfig = parse_ini_file(
+      realpath(implode(DIRECTORY_SEPARATOR,
+                       array('themes', $name, 'theme.ini'))));
+    $this->themetype = $themeconfig['themetype'];
+    $this->previewsize = intval($themeconfig['previewsize']);
+    $this->thumbsize = intval($themeconfig['thumbsize']);
+  }
+}
+?>