--- a/webapp/src/main/webapp/jquery/jquery.digilib.geometry.js	Sat Feb 18 10:00:26 2012 +0100
+++ b/webapp/src/main/webapp/jquery/jquery.digilib.geometry.js	Sat Feb 18 17:10:24 2012 +0100
@@ -9,7 +9,7 @@
     var size = function(w, h) {
         var that;
         if (typeof w === "object") {
-            // assume its size
+            // assume an object having width and height
             that = {
                 width : w.width,
                 height : w.height
@@ -20,9 +20,25 @@
                 height : parseFloat(h)
             };
         }
+        // returns true if both sizes are equal
         that.equals = function(other) {
             return (this.width === other.width && this.height === other.height);
         };
+        // returns the aspect ratio of this size
+        that.getAspect = function() {
+            return (this.width / this.height);
+        };
+        // returns a size of a given aspect ratio that fits into this one 
+        that.fitAspect = function(aspect) {
+            var s = size(this);
+            if (aspect > this.getAspect()) {
+                // size is more horizontally stretched than this
+                s.height = s.width / aspect;
+            } else {
+                s.width = s.height * aspect;
+            }
+            return s;
+        };
         // adjusts size of jQuery element "$elem" to this size
         that.adjustDiv = function($elem) {
             $elem.width(this.width).height(this.height);
@@ -301,6 +317,7 @@
             }
             return r.intersect(this);
         };
+
         // adjusts position and size of jQuery element "$elem" to this rectangle
         that.adjustDiv = function($elem) {
             $elem.offset({

--- a/webapp/src/main/webapp/jquery/jquery.digilib.js	Sat Feb 18 10:00:26 2012 +0100
+++ b/webapp/src/main/webapp/jquery/jquery.digilib.js	Sat Feb 18 17:10:24 2012 +0100
@@ -937,7 +937,7 @@
             // fullscreen
             $elem.addClass(cssPrefix+'fullscreen');
             var imgSize = getFullscreenImgSize(data);
-            data.fullscreenImgSize = imgSize;
+            data.maxImgSize = imgSize;
             // fitwidth/height omits destination height/width
             if (data.dlOpts.fitheight == null) {
                 settings.dw = imgSize.width;
@@ -1109,7 +1109,7 @@
 			data.imgTrafo = getImgTrafo($img, data.zoomArea, data.settings.rot,
 					data.scalerFlags.hmir, data.scalerFlags.vmir,
 					data.scaleMode, data);
-			console.debug("imgTrafo=", data.imgTrafo);
+			console.debug("updateImgTrafo: ", data.imgTrafo);
 		}
     };
 
@@ -1266,12 +1266,15 @@
         };
         if (newZoomArea != null) {
         	// check if aspect ratio has changed
-        	if (newZoomArea.getAspect() !== data.zoomArea.getAspect()) {
-        		console.debug("aspect ratio changed!");
-        		// what now?
+        	newAspect = newZoomArea.getAspect();
+        	if (newAspect !== data.zoomArea.getAspect()) {
+        		var newSize = data.maxImgSize.fitAspect(newAspect);
+        		// set scaler to presumed new size
+        		newSize.adjustDiv($scaler);
+        		console.debug("adjusting aspect ratio for preview", data.maxImgSize, newSize);
         	}
         	// get transform for new zoomArea (use 'screen' instead of data.scaleMode)
-        	imgTrafo = getImgTrafo($img, newZoomArea, data.settings.rot,
+        	imgTrafo = getImgTrafo($scaler, newZoomArea, data.settings.rot,
 					data.scalerFlags.hmir, data.scalerFlags.vmir,
 					'screen', data);
         	// for new background coordinates transform old zoomArea with new Transform
@@ -1387,7 +1390,7 @@
         data.oldZoomArea = data.zoomArea;
         data.zoomArea = za;
     };
-    
+
     /** get image quality as a number (0..2).
      * 
      */
@@ -1451,13 +1454,13 @@
     	// "both" is default
     	return "both";
     };
-    
+
     /** 
      * set screen fit mode (width, height, both).
      */
     var setFitMode = function (data, mode) {
         var settings = data.settings;
-        var imgSize = data.fullscreenImgSize;
+        var imgSize = data.maxImgSize;
     	if (mode === 'width') {
     		data.dlOpts.fitwidth = 1;
     		delete data.dlOpts.fitheight;