shows a problem with the smooth saddle approach. The max and min are no longer...

shows a problem with the smooth saddle approach. The max and min are no longer all at points. The smooth saddle approach adds no additional points at a saddle point and this causes problems with the example data.

flot/jquery.flot.navigate.js

+/* Flot plugin for adding the ability to pan and zoom the plot.
+
+Copyright (c) 2007-2013 IOLA and Ole Laursen.
+Licensed under the MIT license.
+
+The default behaviour is double click and scrollwheel up/down to zoom in, drag
+to pan. The plugin defines plot.zoom({ center }), plot.zoomOut() and
+plot.pan( offset ) so you easily can add custom controls. It also fires
+"plotpan" and "plotzoom" events, useful for synchronizing plots.
+
+The plugin supports these options:
+
+	zoom: {
+		interactive: false
+		trigger: "dblclick" // or "click" for single click
+		amount: 1.5         // 2 = 200% (zoom in), 0.5 = 50% (zoom out)
+	}
+
+	pan: {
+		interactive: false
+		cursor: "move"      // CSS mouse cursor value used when dragging, e.g. "pointer"
+		frameRate: 20
+	}
+
+	xaxis, yaxis, x2axis, y2axis: {
+		zoomRange: null  // or [ number, number ] (min range, max range) or false
+		panRange: null   // or [ number, number ] (min, max) or false
+	}
+
+"interactive" enables the built-in drag/click behaviour. If you enable
+interactive for pan, then you'll have a basic plot that supports moving
+around; the same for zoom.
+
+"amount" specifies the default amount to zoom in (so 1.5 = 150%) relative to
+the current viewport.
+
+"cursor" is a standard CSS mouse cursor string used for visual feedback to the
+user when dragging.
+
+"frameRate" specifies the maximum number of times per second the plot will
+update itself while the user is panning around on it (set to null to disable
+intermediate pans, the plot will then not update until the mouse button is
+released).
+
+"zoomRange" is the interval in which zooming can happen, e.g. with zoomRange:
+[1, 100] the zoom will never scale the axis so that the difference between min
+and max is smaller than 1 or larger than 100. You can set either end to null
+to ignore, e.g. [1, null]. If you set zoomRange to false, zooming on that axis
+will be disabled.
+
+"panRange" confines the panning to stay within a range, e.g. with panRange:
+[-10, 20] panning stops at -10 in one end and at 20 in the other. Either can
+be null, e.g. [-10, null]. If you set panRange to false, panning on that axis
+will be disabled.
+
+Example API usage:
+
+	plot = $.plot(...);
+
+	// zoom default amount in on the pixel ( 10, 20 )
+	plot.zoom({ center: { left: 10, top: 20 } });
+
+	// zoom out again
+	plot.zoomOut({ center: { left: 10, top: 20 } });
+
+	// zoom 200% in on the pixel (10, 20)
+	plot.zoom({ amount: 2, center: { left: 10, top: 20 } });
+
+	// pan 100 pixels to the left and 20 down
+	plot.pan({ left: -100, top: 20 })
+
+Here, "center" specifies where the center of the zooming should happen. Note
+that this is defined in pixel space, not the space of the data points (you can
+use the p2c helpers on the axes in Flot to help you convert between these).
+
+"amount" is the amount to zoom the viewport relative to the current range, so
+1 is 100% (i.e. no change), 1.5 is 150% (zoom in), 0.7 is 70% (zoom out). You
+can set the default in the options.
+
+*/
+
+// First two dependencies, jquery.event.drag.js and
+// jquery.mousewheel.js, we put them inline here to save people the
+// effort of downloading them.
+
+/*
+jquery.event.drag.js ~ v1.5 ~ Copyright (c) 2008, Three Dub Media (http://threedubmedia.com)
+Licensed under the MIT License ~ http://threedubmedia.googlecode.com/files/MIT-LICENSE.txt
+*/
+(function(a){function e(h){var k,j=this,l=h.data||{};if(l.elem)j=h.dragTarget=l.elem,h.dragProxy=d.proxy||j,h.cursorOffsetX=l.pageX-l.left,h.cursorOffsetY=l.pageY-l.top,h.offsetX=h.pageX-h.cursorOffsetX,h.offsetY=h.pageY-h.cursorOffsetY;else if(d.dragging||l.which>0&&h.which!=l.which||a(h.target).is(l.not))return;switch(h.type){case"mousedown":return a.extend(l,a(j).offset(),{elem:j,target:h.target,pageX:h.pageX,pageY:h.pageY}),b.add(document,"mousemove mouseup",e,l),i(j,!1),d.dragging=null,!1;case!d.dragging&&"mousemove":if(g(h.pageX-l.pageX)+g(h.pageY-l.pageY)<l.distance)break;h.target=l.target,k=f(h,"dragstart",j),k!==!1&&(d.dragging=j,d.proxy=h.dragProxy=a(k||j)[0]);case"mousemove":if(d.dragging){if(k=f(h,"drag",j),c.drop&&(c.drop.allowed=k!==!1,c.drop.handler(h)),k!==!1)break;h.type="mouseup"}case"mouseup":b.remove(document,"mousemove mouseup",e),d.dragging&&(c.drop&&c.drop.handler(h),f(h,"dragend",j)),i(j,!0),d.dragging=d.proxy=l.elem=!1}return!0}function f(b,c,d){b.type=c;var e=a.event.dispatch.call(d,b);return e===!1?!1:e||b.result}function g(a){return Math.pow(a,2)}function h(){return d.dragging===!1}function i(a,b){a&&(a.unselectable=b?"off":"on",a.onselectstart=function(){return b},a.style&&(a.style.MozUserSelect=b?"":"none"))}a.fn.drag=function(a,b,c){return b&&this.bind("dragstart",a),c&&this.bind("dragend",c),a?this.bind("drag",b?b:a):this.trigger("drag")};var b=a.event,c=b.special,d=c.drag={not:":input",distance:0,which:1,dragging:!1,setup:function(c){c=a.extend({distance:d.distance,which:d.which,not:d.not},c||{}),c.distance=g(c.distance),b.add(this,"mousedown",e,c),this.attachEvent&&this.attachEvent("ondragstart",h)},teardown:function(){b.remove(this,"mousedown",e),this===d.dragging&&(d.dragging=d.proxy=!1),i(this,!0),this.detachEvent&&this.detachEvent("ondragstart",h)}};c.dragstart=c.dragend={setup:function(){},teardown:function(){}}})(jQuery);
+
+/* jquery.mousewheel.min.js
+ * Copyright (c) 2011 Brandon Aaron (http://brandonaaron.net)
+ * Licensed under the MIT License (LICENSE.txt).
+ * Thanks to: http://adomas.org/javascript-mouse-wheel/ for some pointers.
+ * Thanks to: Mathias Bank(http://www.mathias-bank.de) for a scope bug fix.
+ * Thanks to: Seamus Leahy for adding deltaX and deltaY
+ *
+ * Version: 3.0.6
+ *
+ * Requires: 1.2.2+
+ */
+(function(d){function e(a){var b=a||window.event,c=[].slice.call(arguments,1),f=0,e=0,g=0,a=d.event.fix(b);a.type="mousewheel";b.wheelDelta&&(f=b.wheelDelta/120);b.detail&&(f=-b.detail/3);g=f;void 0!==b.axis&&b.axis===b.HORIZONTAL_AXIS&&(g=0,e=-1*f);void 0!==b.wheelDeltaY&&(g=b.wheelDeltaY/120);void 0!==b.wheelDeltaX&&(e=-1*b.wheelDeltaX/120);c.unshift(a,f,e,g);return(d.event.dispatch||d.event.handle).apply(this,c)}var c=["DOMMouseScroll","mousewheel"];if(d.event.fixHooks)for(var h=c.length;h;)d.event.fixHooks[c[--h]]=d.event.mouseHooks;d.event.special.mousewheel={setup:function(){if(this.addEventListener)for(var a=c.length;a;)this.addEventListener(c[--a],e,!1);else this.onmousewheel=e},teardown:function(){if(this.removeEventListener)for(var a=c.length;a;)this.removeEventListener(c[--a],e,!1);else this.onmousewheel=null}};d.fn.extend({mousewheel:function(a){return a?this.bind("mousewheel",a):this.trigger("mousewheel")},unmousewheel:function(a){return this.unbind("mousewheel",a)}})})(jQuery);
+
+
+
+
+(function ($) {
+    var options = {
+        xaxis: {
+            zoomRange: null, // or [number, number] (min range, max range)
+            panRange: null // or [number, number] (min, max)
+        },
+        zoom: {
+            interactive: false,
+            trigger: "dblclick", // or "click" for single click
+            amount: 1.5 // how much to zoom relative to current position, 2 = 200% (zoom in), 0.5 = 50% (zoom out)
+        },
+        pan: {
+            interactive: false,
+            cursor: "move",
+            frameRate: 20
+        }
+    };
+
+    function init(plot) {
+        function onZoomClick(e, zoomOut) {
+            var c = plot.offset();
+            c.left = e.pageX - c.left;
+            c.top = e.pageY - c.top;
+            if (zoomOut)
+                plot.zoomOut({ center: c });
+            else
+                plot.zoom({ center: c });
+        }
+
+        function onMouseWheel(e, delta) {
+            e.preventDefault();
+            onZoomClick(e, delta < 0);
+            return false;
+        }
+        
+        var prevCursor = 'default', prevPageX = 0, prevPageY = 0,
+            panTimeout = null;
+
+        function onDragStart(e) {
+            if (e.which != 1)  // only accept left-click
+                return false;
+            var c = plot.getPlaceholder().css('cursor');
+            if (c)
+                prevCursor = c;
+            plot.getPlaceholder().css('cursor', plot.getOptions().pan.cursor);
+            prevPageX = e.pageX;
+            prevPageY = e.pageY;
+        }
+        
+        function onDrag(e) {
+            var frameRate = plot.getOptions().pan.frameRate;
+            if (panTimeout || !frameRate)
+                return;
+
+            panTimeout = setTimeout(function () {
+                plot.pan({ left: prevPageX - e.pageX,
+                           top: prevPageY - e.pageY });
+                prevPageX = e.pageX;
+                prevPageY = e.pageY;
+                                                    
+                panTimeout = null;
+            }, 1 / frameRate * 1000);
+        }
+
+        function onDragEnd(e) {
+            if (panTimeout) {
+                clearTimeout(panTimeout);
+                panTimeout = null;
+            }
+                    
+            plot.getPlaceholder().css('cursor', prevCursor);
+            plot.pan({ left: prevPageX - e.pageX,
+                       top: prevPageY - e.pageY });
+        }
+        
+        function bindEvents(plot, eventHolder) {
+            var o = plot.getOptions();
+            if (o.zoom.interactive) {
+                eventHolder[o.zoom.trigger](onZoomClick);
+                eventHolder.mousewheel(onMouseWheel);
+            }
+
+            if (o.pan.interactive) {
+                eventHolder.bind("dragstart", { distance: 10 }, onDragStart);
+                eventHolder.bind("drag", onDrag);
+                eventHolder.bind("dragend", onDragEnd);
+            }
+        }
+
+        plot.zoomOut = function (args) {
+            if (!args)
+                args = {};
+            
+            if (!args.amount)
+                args.amount = plot.getOptions().zoom.amount;
+
+            args.amount = 1 / args.amount;
+            plot.zoom(args);
+        };
+        
+        plot.zoom = function (args) {
+            if (!args)
+                args = {};
+            
+            var c = args.center,
+                amount = args.amount || plot.getOptions().zoom.amount,
+                w = plot.width(), h = plot.height();
+
+            if (!c)
+                c = { left: w / 2, top: h / 2 };
+                
+            var xf = c.left / w,
+                yf = c.top / h,
+                minmax = {
+                    x: {
+                        min: c.left - xf * w / amount,
+                        max: c.left + (1 - xf) * w / amount
+                    },
+                    y: {
+                        min: c.top - yf * h / amount,
+                        max: c.top + (1 - yf) * h / amount
+                    }
+                };
+
+            $.each(plot.getAxes(), function(_, axis) {
+                var opts = axis.options,
+                    min = minmax[axis.direction].min,
+                    max = minmax[axis.direction].max,
+                    zr = opts.zoomRange,
+                    pr = opts.panRange;
+
+                if (zr === false) // no zooming on this axis
+                    return;
+                    
+                min = axis.c2p(min);
+                max = axis.c2p(max);
+                if (min > max) {
+                    // make sure min < max
+                    var tmp = min;
+                    min = max;
+                    max = tmp;
+                }
+
+                //Check that we are in panRange
+                if (pr) {
+                    if (pr[0] != null && min < pr[0]) {
+                        min = pr[0];
+                    }
+                    if (pr[1] != null && max > pr[1]) {
+                        max = pr[1];
+                    }
+                }
+
+                var range = max - min;
+                if (zr &&
+                    ((zr[0] != null && range < zr[0]) ||
+                     (zr[1] != null && range > zr[1])))
+                    return;
+            
+                opts.min = min;
+                opts.max = max;
+            });
+            
+            plot.setupGrid();
+            plot.draw();
+            
+            if (!args.preventEvent)
+                plot.getPlaceholder().trigger("plotzoom", [ plot, args ]);
+        };
+
+        plot.pan = function (args) {
+            var delta = {
+                x: +args.left,
+                y: +args.top
+            };
+
+            if (isNaN(delta.x))
+                delta.x = 0;
+            if (isNaN(delta.y))
+                delta.y = 0;
+
+            $.each(plot.getAxes(), function (_, axis) {
+                var opts = axis.options,
+                    min, max, d = delta[axis.direction];
+
+                min = axis.c2p(axis.p2c(axis.min) + d),
+                max = axis.c2p(axis.p2c(axis.max) + d);
+
+                var pr = opts.panRange;
+                if (pr === false) // no panning on this axis
+                    return;
+                
+                if (pr) {
+                    // check whether we hit the wall
+                    if (pr[0] != null && pr[0] > min) {
+                        d = pr[0] - min;
+                        min += d;
+                        max += d;
+                    }
+                    
+                    if (pr[1] != null && pr[1] < max) {
+                        d = pr[1] - max;
+                        min += d;
+                        max += d;
+                    }
+                }
+                
+                opts.min = min;
+                opts.max = max;
+            });
+            
+            plot.setupGrid();
+            plot.draw();
+            
+            if (!args.preventEvent)
+                plot.getPlaceholder().trigger("plotpan", [ plot, args ]);
+        };
+
+        function shutdown(plot, eventHolder) {
+            eventHolder.unbind(plot.getOptions().zoom.trigger, onZoomClick);
+            eventHolder.unbind("mousewheel", onMouseWheel);
+            eventHolder.unbind("dragstart", onDragStart);
+            eventHolder.unbind("drag", onDrag);
+            eventHolder.unbind("dragend", onDragEnd);
+            if (panTimeout)
+                clearTimeout(panTimeout);
+        }
+        
+        plot.hooks.bindEvents.push(bindEvents);
+        plot.hooks.shutdown.push(shutdown);
+    }
+    
+    $.plot.plugins.push({
+        init: init,
+        options: options,
+        name: 'navigate',
+        version: '1.3'
+    });
+})(jQuery);

tests/testSaddleProblem.htm

+<hmtl>
+	<head>
+		<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
+		<title>CurvedLines Plugin for flot</title>
+		<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
+		<!--[if lte IE 8]><script language="javascript" type="text/javascript" src="../flot/excanvas.min.js"></script><![endif]-->
+		<script language="javascript" type="text/javascript" src="../flot/jquery.flot.js"></script>
+		<script language="javascript" type="text/javascript" src="../flot/jquery.flot.time.js"></script>
+		<script language="JavaScript" type="text/javascript" src="../curvedLines.js"></script>
+		<script language="JavaScript" type="text/javascript" src="../flot/jquery.flot.navigate.js"></script>
+	</head>
+	<body>
+		<div id="placeholder" style="width: 800;height: 400;"></div>
+		<div id="placeholder2" style="width: 800;height: 400;"></div>
+
+		<script id="source" language="javascript" type="text/javascript">
+			var options = {
+						series: {
+							curvedLines: {
+								active: true,
+								fit: true,
+								curvePointFactor: 200
+							}
+						},
+						xaxis: {
+							mode: "time",
+							tickSize: [1, "day"],
+							timezone: "browser",
+							timeformat: "%m/%d %a",
+							min: 1393828200000,
+							max: 1394505000000,
+							tickLength: 0,
+							panRange: [1378809000000, 1394505000000],
+							dayNames: ["S", "M", "T", "W", "T", "F", "S"]
+						},
+						yaxis: {
+							panRange: [0, 2000],
+							ticks: ['0', '70', '130', '180', '200', '300', '400', '500'],
+							tickLength: 0,
+							tickDecimals: 0
+						},
+						grid: {
+							borderWidth: {
+								top: 0,
+								right: 0,
+								bottom: 1,
+								left: 1
+							},
+							clickable: true,
+							hoverable: true
+						},
+						pan: {
+							interactive: true
+						}
+			};
+			
+			var d1 = [[1385490600000, 150],[1386009000000, 450],[1392834600000, 444],[1393266600000, 100],[1393353000000, 147],[1393439400000, 105],
+									[1393525800000, 179.5],[1393612200000, 85],[1393871400000, 107.5]];
+			
+			$.plot($("#placeholder"), [{data: d1, lines: { show: true }, curvedLines: {apply: true}}, {data: d1, points: {show: true}}], options);
+		</script>
+	</body>
+
+</hmtl>
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