diff -r 2a93b8166531 -r 19f87d783168 client/js/paper-renderer.js
--- a/client/js/paper-renderer.js	Fri Feb 14 12:42:09 2014 +0100
+++ b/client/js/paper-renderer.js	Mon Feb 17 17:20:30 2014 +0100
@@ -17,6 +17,7 @@
     _MIN_DRAG_DISTANCE = 2,
         /* Distance between the inner and outer radius of buttons that appear when hovering on a node */
     _NODE_BUTTON_WIDTH = 40,
+    
     _EDGE_BUTTON_INNER = 2,
     _EDGE_BUTTON_OUTER = 40,
         /* Constants used to know if a specific action is to be performed when clicking on the canvas */
@@ -27,6 +28,7 @@
     _NODE_SIZE_STEP = Math.LN2/4,
     _MIN_SCALE = 1/20,
     _MAX_SCALE = 20,
+    _SCALE_STEPS = 16,
     _MOUSEMOVE_RATE = 80,
     _DOUBLETAP_DELAY = 800,
         /* Maximum distance in pixels (squared, to reduce calculations)
@@ -1792,6 +1794,50 @@
     bindClick(".Rk-ZoomOut", "zoomOut");
     bindClick(".Rk-ZoomIn", "zoomIn");
     bindClick(".Rk-ZoomFit", "autoScale");
+    this.$.find(".Rk-ZoomSet").click( function() { _this.$.find(".Rk-ZoomSetContainer").toggle(); } );
+    this.$.find(".Rk-ZoomSlider").slider({
+    	orientation: "vertical",
+    	value:8,
+    	min: 1,
+    	max: 16,
+    	step: 1,
+    	slide: function( event, ui ) {
+    		_this.$.find(".Rk-ZoomSetValue").val( ui.value );
+    	},
+    	change: function( event, ui ) {
+    		_this.$.find(".Rk-ZoomSetValue").val( ui.value );
+    	},
+    	stop: function( event, ui ) {
+    		_this.$.find(".Rk-ZoomSetValue").val( ui.value );
+        	// Get value 
+        	var current_zoom = parseInt(_this.$.find(".Rk-ZoomSetValue").val()),
+        		nb_step = 0,
+        		mid_step = (_SCALE_STEPS/2),
+        		scale_factor = 1;
+        	if(current_zoom < mid_step){
+        		nb_step = mid_step - current_zoom;
+        		scale_factor = Math.SQRT1_2;
+        	}
+        	else if(current_zoom > mid_step){
+        		nb_step = current_zoom - mid_step;
+        		scale_factor = Math.SQRT2;
+        	}
+        	var _newScale = _this.initialScale;
+        	for(var i=0;i<nb_step;i++){
+        		_newScale = _newScale * scale_factor;
+        	}
+    		var _offset = new paper.Point([
+    		                           _this.canvas_$.width(),
+    		                           _this.canvas_$.height()
+    		                       ]).multiply( .5 * ( 1 - _newScale ) ).add(_this.offset.multiply( _newScale ));
+        	_this.setScale( _newScale, _offset );
+    	}
+    });
+    this.$.find(".Rk-ZoomSetButton").click( function() {
+    	console.log("SAVE ZOOM FOR REAL", _this, _this.scale);
+    	_this.renkan.project.set("zoom_level", _this.scale); // Save scale
+    	//_this.$.find(".Rk-ZoomSetContainer").toggle();
+    });
     this.$.find(".Rk-CurrentUser").mouseenter(
         function() { _this.$.find(".Rk-UserList").slideDown(); }
     );
@@ -2001,10 +2047,13 @@
     + '<div class="Rk-Editing-Space<% if (!options.show_top_bar) { %> Rk-Editing-Space-Full<% } %>">'
     + '<div class="Rk-Labels"></div><canvas class="Rk-Canvas" resize></canvas><div class="Rk-Notifications"></div><div class="Rk-Editor">'
     + '<% if (options.show_bins) { %><div class="Rk-Fold-Bins">&laquo;</div><% } %>'
-    + '<div class="Rk-ZoomButtons"><div class="Rk-ZoomIn" title="<%-translate("Zoom In")%>"></div><div class="Rk-ZoomFit" title="<%-translate("Zoom Fit")%>"></div><div class="Rk-ZoomOut" title="<%-translate("Zoom Out")%>"></div></div>'
+    + '<div class="Rk-ZoomButtons"><div class="Rk-ZoomIn" title="<%-translate("Zoom In")%>"></div><div class="Rk-ZoomFit" title="<%-translate("Zoom Fit")%>"></div><div class="Rk-ZoomOut" title="<%-translate("Zoom Out")%>"></div>'
+    + '<div class="Rk-ZoomSet" title="<%-translate("Zoom Set")%>"></div><div class="Rk-ZoomSetContainer"><div class="Rk-ZoomSlider"></div>'
+    + '<p><input type="text" class="Rk-ZoomSetValue" value="8" /><span class="Rk-ZoomSetButton ui-icon ui-icon-disk large" title="<%-translate("Save")%>"></span></p></div>'
     + '</div></div>'
 ),
 fixSize: function(_autoscale) {
+	console.log("fixSize", _autoscale, this.renkan.project.get("zoom_level"));
     var w = this.$.width(),
         h = this.$.height();
     if (this.renkan.options.show_top_bar) {
@@ -2018,7 +2067,8 @@
     paper.view.viewSize = new paper.Size([w, h]);
     
     if (_autoscale) {
-        this.autoScale();
+    	// If _autoscale, we get the initial zoom level set in the project datas.
+        this.autoScale(this.renkan.project.get("zoom_level"));
     }
 },
 drawSector: function(_repr, _inR, _outR, _startAngle, _endAngle, _padding, _imgname, _caption) {
@@ -2177,7 +2227,8 @@
         this.redraw();
     }
 },
-autoScale: function() {
+autoScale: function(force_scale) {
+	console.log("autoScale", force_scale);
     var nodes = this.renkan.project.get("nodes");
     if (nodes.length > 1) {
         var _xx = nodes.map(function(_node) { return _node.get("position").x; }),
@@ -2188,11 +2239,16 @@
             _maxy = Math.max.apply(Math, _yy);
         var _scale = Math.min( (paper.view.size.width - 2 * this.renkan.options.autoscale_padding) / (_maxx - _minx), (paper.view.size.height - 2 * this.renkan.options.autoscale_padding) / (_maxy - _miny));
         this.initialScale = _scale;
+        // Override calculated scale if asked
+        if((typeof force_scale !== "undefined") && parseFloat(force_scale)>0){
+        	_scale = parseFloat(force_scale);
+        }
         this.setScale(_scale, paper.view.center.subtract(new paper.Point([(_maxx + _minx) / 2, (_maxy + _miny) / 2]).multiply(_scale)));
     }
     if (nodes.length === 1) {
         this.setScale(1, paper.view.center.subtract(new paper.Point([nodes.at(0).get("position").x, nodes.at(0).get("position").y])));
     }
+    this.$.find(".Rk-ZoomSlider").slider('value', (_SCALE_STEPS/2));
 },
 redrawMiniframe: function() {
     var topleft = this.toMinimapCoords(this.toModelCoords(new paper.Point([0,0]))),
@@ -2669,6 +2725,7 @@
             this.canvas_$.width(),
             this.canvas_$.height()
         ]).multiply( .5 * ( 1 - Math.SQRT1_2 ) ).add(this.offset.multiply( Math.SQRT1_2 ));
+    this.$.find(".Rk-ZoomSlider").slider('value', this.$.find(".Rk-ZoomSlider").slider("option", "value") - 1);
     this.setScale( _newScale, _offset );
 },
 zoomIn: function() {
@@ -2677,6 +2734,7 @@
             this.canvas_$.width(),
             this.canvas_$.height()
         ]).multiply( .5 * ( 1 - Math.SQRT2 ) ).add(this.offset.multiply( Math.SQRT2 ));
+    this.$.find(".Rk-ZoomSlider").slider('value', this.$.find(".Rk-ZoomSlider").slider("option", "value") + 1);
     this.setScale( _newScale, _offset );
 },
 addNodeBtn: function() {