Added fullscreen cover viewer

cps/static/css/style.css

@@ -417,3 +417,9 @@ div.log {
   white-space: nowrap;
   padding: 0.5em;
 }
+
+#detailcover { cursor:zoom-in; }
+#detailcover:-webkit-full-screen { cursor:zoom-out; }
+#detailcover:-moz-full-screen { cursor:zoom-out; }
+#detailcover:-ms-fullscreen { cursor:zoom-out; }
+#detailcover:fullscreen { cursor:zoom-out; }

cps/static/js/fullscreen.js

@@ -0,0 +1,45 @@
+/* This file is part of the Calibre-Web (https://github.com/janeczku/calibre-web)
+ *    Copyright (C) 2021  OzzieIsaacs
+ *
+ *  This program 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.
+ *
+ *  This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+function toggleFullscreen(elem) {
+  if (!document.fullscreenElement && !document.mozFullScreenElement &&
+    !document.webkitFullscreenElement && !document.msFullscreenElement) {
+    if (elem.requestFullscreen) {
+      elem.requestFullscreen();
+    } else if (elem.msRequestFullscreen) {
+      elem.msRequestFullscreen();
+    } else if (elem.mozRequestFullScreen) {
+      elem.mozRequestFullScreen();
+    } else if (elem.webkitRequestFullscreen) {
+      elem.webkitRequestFullscreen(Element.ALLOW_KEYBOARD_INPUT);
+    }
+  } else {
+    if (document.exitFullscreen) {
+      document.exitFullscreen();
+    } else if (document.msExitFullscreen) {
+      document.msExitFullscreen();
+    } else if (document.mozCancelFullScreen) {
+      document.mozCancelFullScreen();
+    } else if (document.webkitExitFullscreen) {
+      document.webkitExitFullscreen();
+    }
+  }
+}
+
+$("#detailcover").click(function() {
+  toggleFullscreen(this);
+});