plugins/range-selector.js

   1 /**
   2  * @license
   3  * Copyright 2013 Paul Felix (paul.eric.felix@gmail.com)
   4  * MIT-licensed (http://opensource.org/licenses/MIT)
   5  */
   6
   7 /**
   8  * @fileoverview This file contains the RangeSelector plugin used to provide
   9  * a timeline range selector widget for dygraphs.
  10  */
  11
  12 Dygraph.Plugins.RangeSelector = (function() {
  13
  14 /*jshint globalstrict: true */
  15 /*global Dygraph:false */
  16 "use strict";
  17
  18 var NOT_CREATED = 0;
  19 var CREATED = 1<<0;
  20 var ADDED_TO_GRAPH = 1<<1;
  21
  22 var rangeSelector = function() {
  23   this.isIE_ = /MSIE/.test(navigator.userAgent) && !window.opera;
  24   this.hasTouchInterface_ = typeof(TouchEvent) != 'undefined';
  25   this.isMobileDevice_ = /mobile|android/gi.test(navigator.appVersion);
  26   this.status_ = NOT_CREATED;
  27 };
  28
  29 rangeSelector.prototype.toString = function() {
  30   return "RangeSelector Plugin";
  31 };
  32
  33 rangeSelector.prototype.activate = function(dygraph) {
  34   this.dygraph_ = dygraph;
  35   this.layout_ = this.dygraph_.layout_;
  36   this.isUsingExcanvas_ = dygraph.isUsingExcanvas_;
  37   if (this.attr_('showRangeSelector')) {
  38     this.createInterface_();
  39   }
  40   return {
  41     layout: this.reserveSpace_,
  42     predraw: this.renderStaticLayer_,
  43     didDrawChart: this.renderInteractiveLayer_
  44   };
  45 };
  46
  47 rangeSelector.prototype.destroy = function() {
  48   this.bgcanvas_ = null;
  49   this.fgcanvas_ = null;
  50   this.leftZoomHandle_ = null;
  51   this.rightZoomHandle_ = null;
  52   this.iePanOverlay_ = null;
  53 };
  54
  55 //------------------------------------------------------------------
  56 // Private methods
  57 //------------------------------------------------------------------
  58
  59 rangeSelector.prototype.attr_ = function(name) {
  60   return this.dygraph_.attr_(name);
  61 };
  62
  63 /**
  64  * @private
  65  * Creates the range selector elements and adds them to the graph.
  66  */
  67 rangeSelector.prototype.createInterface_ = function() {
  68   this.createCanvases_();
  69   if (this.isUsingExcanvas_) {
  70     this.createIEPanOverlay_();
  71   }
  72   this.createZoomHandles_();
  73   this.initInteraction_();
  74
  75   // Range selector and animatedZooms have a bad interaction. See issue 359.
  76   if (this.attr_('animatedZooms')) {
  77     this.dygraph_.warn('You should not set animatedZooms=true when using the range selector.');
  78     this.dygraph_.attrs_.animatedZooms = false;
  79   }
  80
  81   this.addToGraph_();
  82   this.status_ = CREATED;
  83 };
  84
  85 /**
  86  * @private
  87  * Adds the range selector to the graph.
  88  */
  89 rangeSelector.prototype.addToGraph_ = function() {
  90   var graphDiv = this.dygraph_.graphDiv;
  91   graphDiv.appendChild(this.bgcanvas_);
  92   graphDiv.appendChild(this.fgcanvas_);
  93   graphDiv.appendChild(this.leftZoomHandle_);
  94   graphDiv.appendChild(this.rightZoomHandle_);
  95   this.status_ |= ADDED_TO_GRAPH;
  96 };
  97
  98 /**
  99  * @private
 100  * Removes the range selector from the graph.
 101  */
 102 rangeSelector.prototype.removeFromGraph_ = function() {
 103   var graphDiv = this.dygraph_.graphDiv;
 104   graphDiv.removeChild(this.bgcanvas_);
 105   graphDiv.removeChild(this.fgcanvas_);
 106   graphDiv.removeChild(this.leftZoomHandle_);
 107   graphDiv.removeChild(this.rightZoomHandle_);
 108   this.status_ ^= ADDED_TO_GRAPH;
 109 };
 110
 111 /**
 112  * @private
 113  * Called by Layout to allow range selector to reserve its space.
 114  */
 115 rangeSelector.prototype.reserveSpace_ = function(e) {
 116   if (this.attr_('showRangeSelector')) {
 117     e.reserveSpaceBottom(this.attr_('rangeSelectorHeight') + 4);
 118   }
 119 };
 120
 121 /**
 122  * @private
 123  * Renders the static portion of the range selector at the predraw stage.
 124  */
 125 rangeSelector.prototype.renderStaticLayer_ = function() {
 126   if (!this.isEnabled_()) {
 127     return;
 128   }
 129   this.resize_();
 130   this.drawStaticLayer_();
 131 };
 132
 133 /**
 134  * @private
 135  * Renders the interactive portion of the range selector after the chart has been drawn.
 136  */
 137 rangeSelector.prototype.renderInteractiveLayer_ = function() {
 138   if (!this.isEnabled_() || this.isChangingRange_) {
 139     return;
 140   }
 141   this.placeZoomHandles_();
 142   this.drawInteractiveLayer_();
 143 };
 144
 145 /**
 146  * @private
 147  * Check to see if the range selector is enabled and needs to be created or added to graph.
 148  */
 149 rangeSelector.prototype.isEnabled_ = function() {
 150   var enabled = this.attr_('showRangeSelector');
 151   if (enabled) {
 152     if (!(this.status_ & CREATED)) {
 153       this.createInterface_();
 154     } else if (!(this.status_ & ADDED_TO_GRAPH)) {
 155       this.addToGraph_();
 156     }
 157   } else if (this.status_ & ADDED_TO_GRAPH) {
 158     this.removeFromGraph_();
 159     var dygraph = this.dygraph_;
 160     setTimeout(function() { dygraph.width_ = 0; dygraph.resize(); }, 1);
 161   }
 162   return enabled;
 163 }
 164
 165 /**
 166  * @private
 167  * Resizes the range selector.
 168  */
 169 rangeSelector.prototype.resize_ = function() {
 170   function setElementRect(canvas, rect) {
 171     canvas.style.top = rect.y + 'px';
 172     canvas.style.left = rect.x + 'px';
 173     canvas.width = rect.w;
 174     canvas.height = rect.h;
 175     canvas.style.width = canvas.width + 'px';    // for IE
 176     canvas.style.height = canvas.height + 'px';  // for IE
 177   }
 178
 179   var plotArea = this.layout_.getPlotArea();
 180   var xAxisLabelHeight = this.attr_('xAxisHeight') || (this.attr_('axisLabelFontSize') + 2 * this.attr_('axisTickSize'));
 181   this.canvasRect_ = {
 182     x: plotArea.x,
 183     y: plotArea.y + plotArea.h + xAxisLabelHeight + 4,
 184     w: plotArea.w,
 185     h: this.attr_('rangeSelectorHeight')
 186   };
 187
 188   setElementRect(this.bgcanvas_, this.canvasRect_);
 189   setElementRect(this.fgcanvas_, this.canvasRect_);
 190 };
 191
 192 /**
 193  * @private
 194  * Creates the background and foreground canvases.
 195  */
 196 rangeSelector.prototype.createCanvases_ = function() {
 197   this.bgcanvas_ = Dygraph.createCanvas();
 198   this.bgcanvas_.className = 'dygraph-rangesel-bgcanvas';
 199   this.bgcanvas_.style.position = 'absolute';
 200   this.bgcanvas_.style.zIndex = 9;
 201   this.bgcanvas_ctx_ = Dygraph.getContext(this.bgcanvas_);
 202
 203   this.fgcanvas_ = Dygraph.createCanvas();
 204   this.fgcanvas_.className = 'dygraph-rangesel-fgcanvas';
 205   this.fgcanvas_.style.position = 'absolute';
 206   this.fgcanvas_.style.zIndex = 9;
 207   this.fgcanvas_.style.cursor = 'default';
 208   this.fgcanvas_ctx_ = Dygraph.getContext(this.fgcanvas_);
 209 };
 210
 211 /**
 212  * @private
 213  * Creates overlay divs for IE/Excanvas so that mouse events are handled properly.
 214  */
 215 rangeSelector.prototype.createIEPanOverlay_ = function() {
 216   this.iePanOverlay_ = document.createElement("div");
 217   this.iePanOverlay_.style.position = 'absolute';
 218   this.iePanOverlay_.style.backgroundColor = 'white';
 219   this.iePanOverlay_.style.filter = 'alpha(opacity=0)';
 220   this.iePanOverlay_.style.display = 'none';
 221   this.iePanOverlay_.style.cursor = 'move';
 222   this.fgcanvas_.appendChild(this.iePanOverlay_);
 223 };
 224
 225 /**
 226  * @private
 227  * Creates the zoom handle elements.
 228  */
 229 rangeSelector.prototype.createZoomHandles_ = function() {
 230   var img = new Image();
 231   img.className = 'dygraph-rangesel-zoomhandle';
 232   img.style.position = 'absolute';
 233   img.style.zIndex = 10;
 234   img.style.visibility = 'hidden'; // Initially hidden so they don't show up in the wrong place.
 235   img.style.cursor = 'col-resize';
 236
 237   if (/MSIE 7/.test(navigator.userAgent)) { // IE7 doesn't support embedded src data.
 238     img.width = 7;
 239     img.height = 14;
 240     img.style.backgroundColor = 'white';
 241     img.style.border = '1px solid #333333'; // Just show box in IE7.
 242   } else {
 243     img.width = 9;
 244     img.height = 16;
 245     img.src = 'data:image/png;base64,' +
 246 'iVBORw0KGgoAAAANSUhEUgAAAAkAAAAQCAYAAADESFVDAAAAAXNSR0IArs4c6QAAAAZiS0dEANAA' +
 247 'zwDP4Z7KegAAAAlwSFlzAAAOxAAADsQBlSsOGwAAAAd0SU1FB9sHGw0cMqdt1UwAAAAZdEVYdENv' +
 248 'bW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAAaElEQVQoz+3SsRFAQBCF4Z9WJM8KCDVwownl' +
 249 '6YXsTmCUsyKGkZzcl7zkz3YLkypgAnreFmDEpHkIwVOMfpdi9CEEN2nGpFdwD03yEqDtOgCaun7s' +
 250 'qSTDH32I1pQA2Pb9sZecAxc5r3IAb21d6878xsAAAAAASUVORK5CYII=';
 251   }
 252
 253   if (this.isMobileDevice_) {
 254     img.width *= 2;
 255     img.height *= 2;
 256   }
 257
 258   this.leftZoomHandle_ = img;
 259   this.rightZoomHandle_ = img.cloneNode(false);
 260 };
 261
 262 /**
 263  * @private
 264  * Sets up the interaction for the range selector.
 265  */
 266 rangeSelector.prototype.initInteraction_ = function() {
 267   var self = this;
 268   var topElem = this.isIE_ ? document : window;
 269   var xLast = 0;
 270   var handle = null;
 271   var isZooming = false;
 272   var isPanning = false;
 273   var dynamic = !this.isMobileDevice_ && !this.isUsingExcanvas_;
 274
 275   // We cover iframes during mouse interactions. See comments in
 276   // dygraph-utils.js for more info on why this is a good idea.
 277   var tarp = new Dygraph.IFrameTarp();
 278
 279   // functions, defined below.  Defining them this way (rather than with
 280   // "function foo() {...}" makes JSHint happy.
 281   var toXDataWindow, onZoomStart, onZoom, onZoomEnd, doZoom, isMouseInPanZone,
 282       onPanStart, onPan, onPanEnd, doPan, onCanvasMouseMove, applyBrowserZoomLevel;
 283
 284   // Touch event functions
 285   var onZoomHandleTouchEvent, onCanvasTouchEvent, addTouchEvents;
 286
 287   toXDataWindow = function(zoomHandleStatus) {
 288     var xDataLimits = self.dygraph_.xAxisExtremes();
 289     var fact = (xDataLimits[1] - xDataLimits[0])/self.canvasRect_.w;
 290     var xDataMin = xDataLimits[0] + (zoomHandleStatus.leftHandlePos - self.canvasRect_.x)*fact;
 291     var xDataMax = xDataLimits[0] + (zoomHandleStatus.rightHandlePos - self.canvasRect_.x)*fact;
 292     return [xDataMin, xDataMax];
 293   };
 294
 295   applyBrowserZoomLevel = function(delX) {
 296     var zoom = window.outerWidth/document.documentElement.clientWidth;
 297     if (!isNaN(zoom)) {
 298       return delX/zoom;
 299     } else {
 300       return delX;
 301     }
 302   };
 303
 304   onZoomStart = function(e) {
 305     Dygraph.cancelEvent(e);
 306     isZooming = true;
 307     xLast = e.screenX;
 308     handle = e.target ? e.target : e.srcElement;
 309     self.dygraph_.addEvent(topElem, 'mousemove', onZoom);
 310     self.dygraph_.addEvent(topElem, 'mouseup', onZoomEnd);
 311     self.fgcanvas_.style.cursor = 'col-resize';
 312     tarp.cover();
 313     return true;
 314   };
 315
 316   onZoom = function(e) {
 317     if (!isZooming) {
 318       return false;
 319     }
 320     Dygraph.cancelEvent(e);
 321     var delX = e.screenX - xLast;
 322     if (Math.abs(delX) < 4 || e.screenX === 0) {
 323       // First iPad move event seems to have screenX = 0
 324       return true;
 325     }
 326     xLast = e.screenX;
 327     delX = applyBrowserZoomLevel(delX);
 328
 329     // Move handle.
 330     var zoomHandleStatus = self.getZoomHandleStatus_();
 331     var newPos;
 332     if (handle == self.leftZoomHandle_) {
 333       newPos = zoomHandleStatus.leftHandlePos + delX;
 334       newPos = Math.min(newPos, zoomHandleStatus.rightHandlePos - handle.width - 3);
 335       newPos = Math.max(newPos, self.canvasRect_.x);
 336     } else {
 337       newPos = zoomHandleStatus.rightHandlePos + delX;
 338       newPos = Math.min(newPos, self.canvasRect_.x + self.canvasRect_.w);
 339       newPos = Math.max(newPos, zoomHandleStatus.leftHandlePos + handle.width + 3);
 340     }
 341     var halfHandleWidth = handle.width/2;
 342     handle.style.left = (newPos - halfHandleWidth) + 'px';
 343     self.drawInteractiveLayer_();
 344
 345     // Zoom on the fly (if not using excanvas).
 346     if (dynamic) {
 347       doZoom();
 348     }
 349     return true;
 350   };
 351
 352   onZoomEnd = function(e) {
 353     if (!isZooming) {
 354       return false;
 355     }
 356     isZooming = false;
 357     tarp.uncover();
 358     Dygraph.removeEvent(topElem, 'mousemove', onZoom);
 359     Dygraph.removeEvent(topElem, 'mouseup', onZoomEnd);
 360     self.fgcanvas_.style.cursor = 'default';
 361
 362     // If using excanvas, Zoom now.
 363     if (!dynamic) {
 364       doZoom();
 365     }
 366     return true;
 367   };
 368
 369   doZoom = function() {
 370     try {
 371       var zoomHandleStatus = self.getZoomHandleStatus_();
 372       self.isChangingRange_ = true;
 373       if (!zoomHandleStatus.isZoomed) {
 374         self.dygraph_.resetZoom();
 375       } else {
 376         var xDataWindow = toXDataWindow(zoomHandleStatus);
 377         self.dygraph_.doZoomXDates_(xDataWindow[0], xDataWindow[1]);
 378       }
 379     } finally {
 380       self.isChangingRange_ = false;
 381     }
 382   };
 383
 384   isMouseInPanZone = function(e) {
 385     if (self.isUsingExcanvas_) {
 386         return e.srcElement == self.iePanOverlay_;
 387     } else {
 388       var rect = self.leftZoomHandle_.getBoundingClientRect();
 389       var leftHandleClientX = rect.left + rect.width/2;
 390       rect = self.rightZoomHandle_.getBoundingClientRect();
 391       var rightHandleClientX = rect.left + rect.width/2;
 392       return (e.clientX > leftHandleClientX && e.clientX < rightHandleClientX);
 393     }
 394   };
 395
 396   onPanStart = function(e) {
 397     if (!isPanning && isMouseInPanZone(e) && self.getZoomHandleStatus_().isZoomed) {
 398       Dygraph.cancelEvent(e);
 399       isPanning = true;
 400       xLast = e.screenX;
 401       self.dygraph_.addEvent(topElem, 'mousemove', onPan);
 402       self.dygraph_.addEvent(topElem, 'mouseup', onPanEnd);
 403       return true;
 404     }
 405     return false;
 406   };
 407
 408   onPan = function(e) {
 409     if (!isPanning) {
 410       return false;
 411     }
 412     Dygraph.cancelEvent(e);
 413
 414     var delX = e.screenX - xLast;
 415     if (Math.abs(delX) < 4) {
 416       return true;
 417     }
 418     xLast = e.screenX;
 419     delX = applyBrowserZoomLevel(delX);
 420
 421     // Move range view
 422     var zoomHandleStatus = self.getZoomHandleStatus_();
 423     var leftHandlePos = zoomHandleStatus.leftHandlePos;
 424     var rightHandlePos = zoomHandleStatus.rightHandlePos;
 425     var rangeSize = rightHandlePos - leftHandlePos;
 426     if (leftHandlePos + delX <= self.canvasRect_.x) {
 427       leftHandlePos = self.canvasRect_.x;
 428       rightHandlePos = leftHandlePos + rangeSize;
 429     } else if (rightHandlePos + delX >= self.canvasRect_.x + self.canvasRect_.w) {
 430       rightHandlePos = self.canvasRect_.x + self.canvasRect_.w;
 431       leftHandlePos = rightHandlePos - rangeSize;
 432     } else {
 433       leftHandlePos += delX;
 434       rightHandlePos += delX;
 435     }
 436     var halfHandleWidth = self.leftZoomHandle_.width/2;
 437     self.leftZoomHandle_.style.left = (leftHandlePos - halfHandleWidth) + 'px';
 438     self.rightZoomHandle_.style.left = (rightHandlePos - halfHandleWidth) + 'px';
 439     self.drawInteractiveLayer_();
 440
 441     // Do pan on the fly (if not using excanvas).
 442     if (dynamic) {
 443       doPan();
 444     }
 445     return true;
 446   };
 447
 448   onPanEnd = function(e) {
 449     if (!isPanning) {
 450       return false;
 451     }
 452     isPanning = false;
 453     Dygraph.removeEvent(topElem, 'mousemove', onPan);
 454     Dygraph.removeEvent(topElem, 'mouseup', onPanEnd);
 455     // If using excanvas, do pan now.
 456     if (!dynamic) {
 457       doPan();
 458     }
 459     return true;
 460   };
 461
 462   doPan = function() {
 463     try {
 464       self.isChangingRange_ = true;
 465       self.dygraph_.dateWindow_ = toXDataWindow(self.getZoomHandleStatus_());
 466       self.dygraph_.drawGraph_(false);
 467     } finally {
 468       self.isChangingRange_ = false;
 469     }
 470   };
 471
 472   onCanvasMouseMove = function(e) {
 473     if (isZooming || isPanning) {
 474       return;
 475     }
 476     var cursor = isMouseInPanZone(e) ? 'move' : 'default';
 477     if (cursor != self.fgcanvas_.style.cursor) {
 478       self.fgcanvas_.style.cursor = cursor;
 479     }
 480   };
 481
 482   onZoomHandleTouchEvent = function(e) {
 483     if (e.type == 'touchstart' && e.targetTouches.length == 1) {
 484       if (onZoomStart(e.targetTouches[0])) {
 485         Dygraph.cancelEvent(e);
 486       }
 487     } else if (e.type == 'touchmove' && e.targetTouches.length == 1) {
 488       if (onZoom(e.targetTouches[0])) {
 489         Dygraph.cancelEvent(e);
 490       }
 491     } else {
 492       onZoomEnd(e);
 493     }
 494   };
 495
 496   onCanvasTouchEvent = function(e) {
 497     if (e.type == 'touchstart' && e.targetTouches.length == 1) {
 498       if (onPanStart(e.targetTouches[0])) {
 499         Dygraph.cancelEvent(e);
 500       }
 501     } else if (e.type == 'touchmove' && e.targetTouches.length == 1) {
 502       if (onPan(e.targetTouches[0])) {
 503         Dygraph.cancelEvent(e);
 504       }
 505     } else {
 506       onPanEnd(e);
 507     }
 508   };
 509
 510   addTouchEvents = function(elem, fn) {
 511     var types = ['touchstart', 'touchend', 'touchmove', 'touchcancel'];
 512     for (var i = 0; i < types.length; i++) {
 513       self.dygraph_.addEvent(elem, types[i], fn);
 514     }
 515   };
 516
 517   this.dygraph_.attrs_.interactionModel =
 518       Dygraph.Interaction.dragIsPanInteractionModel;
 519   this.dygraph_.attrs_.panEdgeFraction = 0.0001;
 520
 521   var dragStartEvent = window.opera ? 'mousedown' : 'dragstart';
 522   this.dygraph_.addEvent(this.leftZoomHandle_, dragStartEvent, onZoomStart);
 523   this.dygraph_.addEvent(this.rightZoomHandle_, dragStartEvent, onZoomStart);
 524
 525   if (this.isUsingExcanvas_) {
 526     this.dygraph_.addEvent(this.iePanOverlay_, 'mousedown', onPanStart);
 527   } else {
 528     this.dygraph_.addEvent(this.fgcanvas_, 'mousedown', onPanStart);
 529     this.dygraph_.addEvent(this.fgcanvas_, 'mousemove', onCanvasMouseMove);
 530   }
 531
 532   // Touch events
 533   if (this.hasTouchInterface_) {
 534     addTouchEvents(this.leftZoomHandle_, onZoomHandleTouchEvent);
 535     addTouchEvents(this.rightZoomHandle_, onZoomHandleTouchEvent);
 536     addTouchEvents(this.fgcanvas_, onCanvasTouchEvent);
 537   }
 538 };
 539
 540 /**
 541  * @private
 542  * Draws the static layer in the background canvas.
 543  */
 544 rangeSelector.prototype.drawStaticLayer_ = function() {
 545   var ctx = this.bgcanvas_ctx_;
 546   ctx.clearRect(0, 0, this.canvasRect_.w, this.canvasRect_.h);
 547   try {
 548     this.drawMiniPlot_();
 549   } catch(ex) {
 550     Dygraph.warn(ex);
 551   }
 552
 553   var margin = 0.5;
 554   this.bgcanvas_ctx_.lineWidth = 1;
 555   ctx.strokeStyle = 'gray';
 556   ctx.beginPath();
 557   ctx.moveTo(margin, margin);
 558   ctx.lineTo(margin, this.canvasRect_.h-margin);
 559   ctx.lineTo(this.canvasRect_.w-margin, this.canvasRect_.h-margin);
 560   ctx.lineTo(this.canvasRect_.w-margin, margin);
 561   ctx.stroke();
 562 };
 563
 564
 565 /**
 566  * @private
 567  * Draws the mini plot in the background canvas.
 568  */
 569 rangeSelector.prototype.drawMiniPlot_ = function() {
 570   var fillStyle = this.attr_('rangeSelectorPlotFillColor');
 571   var strokeStyle = this.attr_('rangeSelectorPlotStrokeColor');
 572   if (!fillStyle && !strokeStyle) {
 573     return;
 574   }
 575
 576   var stepPlot = this.attr_('stepPlot');
 577
 578   var combinedSeriesData = this.computeCombinedSeriesAndLimits_();
 579   var yRange = combinedSeriesData.yMax - combinedSeriesData.yMin;
 580
 581   // Draw the mini plot.
 582   var ctx = this.bgcanvas_ctx_;
 583   var margin = 0.5;
 584
 585   var xExtremes = this.dygraph_.xAxisExtremes();
 586   var xRange = Math.max(xExtremes[1] - xExtremes[0], 1.e-30);
 587   var xFact = (this.canvasRect_.w - margin)/xRange;
 588   var yFact = (this.canvasRect_.h - margin)/yRange;
 589   var canvasWidth = this.canvasRect_.w - margin;
 590   var canvasHeight = this.canvasRect_.h - margin;
 591
 592   var prevX = null, prevY = null;
 593
 594   ctx.beginPath();
 595   ctx.moveTo(margin, canvasHeight);
 596   for (var i = 0; i < combinedSeriesData.data.length; i++) {
 597     var dataPoint = combinedSeriesData.data[i];
 598     var x = ((dataPoint[0] !== null) ? ((dataPoint[0] - xExtremes[0])*xFact) : NaN);
 599     var y = ((dataPoint[1] !== null) ? (canvasHeight - (dataPoint[1] - combinedSeriesData.yMin)*yFact) : NaN);
 600     if (isFinite(x) && isFinite(y)) {
 601       if(prevX === null) {
 602         ctx.lineTo(x, canvasHeight);
 603       }
 604       else if (stepPlot) {
 605         ctx.lineTo(x, prevY);
 606       }
 607       ctx.lineTo(x, y);
 608       prevX = x;
 609       prevY = y;
 610     }
 611     else {
 612       if(prevX !== null) {
 613         if (stepPlot) {
 614           ctx.lineTo(x, prevY);
 615           ctx.lineTo(x, canvasHeight);
 616         }
 617         else {
 618           ctx.lineTo(prevX, canvasHeight);
 619         }
 620       }
 621       prevX = prevY = null;
 622     }
 623   }
 624   ctx.lineTo(canvasWidth, canvasHeight);
 625   ctx.closePath();
 626
 627   if (fillStyle) {
 628     var lingrad = this.bgcanvas_ctx_.createLinearGradient(0, 0, 0, canvasHeight);
 629     lingrad.addColorStop(0, 'white');
 630     lingrad.addColorStop(1, fillStyle);
 631     this.bgcanvas_ctx_.fillStyle = lingrad;
 632     ctx.fill();
 633   }
 634
 635   if (strokeStyle) {
 636     this.bgcanvas_ctx_.strokeStyle = strokeStyle;
 637     this.bgcanvas_ctx_.lineWidth = 1.5;
 638     ctx.stroke();
 639   }
 640 };
 641
 642 /**
 643  * @private
 644  * Computes and returns the combinded series data along with min/max for the mini plot.
 645  * @return {Object} An object containing combinded series array, ymin, ymax.
 646  */
 647 rangeSelector.prototype.computeCombinedSeriesAndLimits_ = function() {
 648   var data = this.dygraph_.rawData_;
 649   var logscale = this.attr_('logscale');
 650
 651   // Create a combined series (average of all series values).
 652   var combinedSeries = [];
 653   var sum;
 654   var count;
 655   var mutipleValues;
 656   var i, j, k;
 657   var xVal, yVal;
 658
 659   // Find out if data has multiple values per datapoint.
 660   // Go to first data point that actually has values (see http://code.google.com/p/dygraphs/issues/detail?id=246)
 661   for (i = 0; i < data.length; i++) {
 662     if (data[i].length > 1 && data[i][1] !== null) {
 663       mutipleValues = typeof data[i][1] != 'number';
 664       if (mutipleValues) {
 665         sum = [];
 666         count = [];
 667         for (k = 0; k < data[i][1].length; k++) {
 668           sum.push(0);
 669           count.push(0);
 670         }
 671       }
 672       break;
 673     }
 674   }
 675
 676   for (i = 0; i < data.length; i++) {
 677     var dataPoint = data[i];
 678     xVal = dataPoint[0];
 679
 680     if (mutipleValues) {
 681       for (k = 0; k < sum.length; k++) {
 682         sum[k] = count[k] = 0;
 683       }
 684     } else {
 685       sum = count = 0;
 686     }
 687
 688     for (j = 1; j < dataPoint.length; j++) {
 689       if (this.dygraph_.visibility()[j-1]) {
 690         var y;
 691         if (mutipleValues) {
 692           for (k = 0; k < sum.length; k++) {
 693             y = dataPoint[j][k];
 694             if (y === null || isNaN(y)) continue;
 695             sum[k] += y;
 696             count[k]++;
 697           }
 698         } else {
 699           y = dataPoint[j];
 700           if (y === null || isNaN(y)) continue;
 701           sum += y;
 702           count++;
 703         }
 704       }
 705     }
 706
 707     if (mutipleValues) {
 708       for (k = 0; k < sum.length; k++) {
 709         sum[k] /= count[k];
 710       }
 711       yVal = sum.slice(0);
 712     } else {
 713       yVal = sum/count;
 714     }
 715
 716     combinedSeries.push([xVal, yVal]);
 717   }
 718
 719   // Account for roll period, fractions.
 720   combinedSeries = this.dygraph_.rollingAverage(combinedSeries, this.dygraph_.rollPeriod_);
 721
 722   if (typeof combinedSeries[0][1] != 'number') {
 723     for (i = 0; i < combinedSeries.length; i++) {
 724       yVal = combinedSeries[i][1];
 725       combinedSeries[i][1] = yVal[0];
 726     }
 727   }
 728
 729   // Compute the y range.
 730   var yMin = Number.MAX_VALUE;
 731   var yMax = -Number.MAX_VALUE;
 732   for (i = 0; i < combinedSeries.length; i++) {
 733     yVal = combinedSeries[i][1];
 734     if (yVal !== null && isFinite(yVal) && (!logscale || yVal > 0)) {
 735       yMin = Math.min(yMin, yVal);
 736       yMax = Math.max(yMax, yVal);
 737     }
 738   }
 739
 740   // Convert Y data to log scale if needed.
 741   // Also, expand the Y range to compress the mini plot a little.
 742   var extraPercent = 0.25;
 743   if (logscale) {
 744     yMax = Dygraph.log10(yMax);
 745     yMax += yMax*extraPercent;
 746     yMin = Dygraph.log10(yMin);
 747     for (i = 0; i < combinedSeries.length; i++) {
 748       combinedSeries[i][1] = Dygraph.log10(combinedSeries[i][1]);
 749     }
 750   } else {
 751     var yExtra;
 752     var yRange = yMax - yMin;
 753     if (yRange <= Number.MIN_VALUE) {
 754       yExtra = yMax*extraPercent;
 755     } else {
 756       yExtra = yRange*extraPercent;
 757     }
 758     yMax += yExtra;
 759     yMin -= yExtra;
 760   }
 761
 762   return {data: combinedSeries, yMin: yMin, yMax: yMax};
 763 };
 764
 765 /**
 766  * @private
 767  * Places the zoom handles in the proper position based on the current X data window.
 768  */
 769 rangeSelector.prototype.placeZoomHandles_ = function() {
 770   var xExtremes = this.dygraph_.xAxisExtremes();
 771   var xWindowLimits = this.dygraph_.xAxisRange();
 772   var xRange = xExtremes[1] - xExtremes[0];
 773   var leftPercent = Math.max(0, (xWindowLimits[0] - xExtremes[0])/xRange);
 774   var rightPercent = Math.max(0, (xExtremes[1] - xWindowLimits[1])/xRange);
 775   var leftCoord = this.canvasRect_.x + this.canvasRect_.w*leftPercent;
 776   var rightCoord = this.canvasRect_.x + this.canvasRect_.w*(1 - rightPercent);
 777   var handleTop = Math.max(this.canvasRect_.y, this.canvasRect_.y + (this.canvasRect_.h - this.leftZoomHandle_.height)/2);
 778   var halfHandleWidth = this.leftZoomHandle_.width/2;
 779   this.leftZoomHandle_.style.left = (leftCoord - halfHandleWidth) + 'px';
 780   this.leftZoomHandle_.style.top = handleTop + 'px';
 781   this.rightZoomHandle_.style.left = (rightCoord - halfHandleWidth) + 'px';
 782   this.rightZoomHandle_.style.top = this.leftZoomHandle_.style.top;
 783
 784   this.leftZoomHandle_.style.visibility = 'visible';
 785   this.rightZoomHandle_.style.visibility = 'visible';
 786 };
 787
 788 /**
 789  * @private
 790  * Draws the interactive layer in the foreground canvas.
 791  */
 792 rangeSelector.prototype.drawInteractiveLayer_ = function() {
 793   var ctx = this.fgcanvas_ctx_;
 794   ctx.clearRect(0, 0, this.canvasRect_.w, this.canvasRect_.h);
 795   var margin = 1;
 796   var width = this.canvasRect_.w - margin;
 797   var height = this.canvasRect_.h - margin;
 798   var zoomHandleStatus = this.getZoomHandleStatus_();
 799
 800   ctx.strokeStyle = 'black';
 801   if (!zoomHandleStatus.isZoomed) {
 802     ctx.beginPath();
 803     ctx.moveTo(margin, margin);
 804     ctx.lineTo(margin, height);
 805     ctx.lineTo(width, height);
 806     ctx.lineTo(width, margin);
 807     ctx.stroke();
 808     if (this.iePanOverlay_) {
 809       this.iePanOverlay_.style.display = 'none';
 810     }
 811   } else {
 812     var leftHandleCanvasPos = Math.max(margin, zoomHandleStatus.leftHandlePos - this.canvasRect_.x);
 813     var rightHandleCanvasPos = Math.min(width, zoomHandleStatus.rightHandlePos - this.canvasRect_.x);
 814
 815     ctx.fillStyle = 'rgba(240, 240, 240, 0.6)';
 816     ctx.fillRect(0, 0, leftHandleCanvasPos, this.canvasRect_.h);
 817     ctx.fillRect(rightHandleCanvasPos, 0, this.canvasRect_.w - rightHandleCanvasPos, this.canvasRect_.h);
 818
 819     ctx.beginPath();
 820     ctx.moveTo(margin, margin);
 821     ctx.lineTo(leftHandleCanvasPos, margin);
 822     ctx.lineTo(leftHandleCanvasPos, height);
 823     ctx.lineTo(rightHandleCanvasPos, height);
 824     ctx.lineTo(rightHandleCanvasPos, margin);
 825     ctx.lineTo(width, margin);
 826     ctx.stroke();
 827
 828     if (this.isUsingExcanvas_) {
 829       this.iePanOverlay_.style.width = (rightHandleCanvasPos - leftHandleCanvasPos) + 'px';
 830       this.iePanOverlay_.style.left = leftHandleCanvasPos + 'px';
 831       this.iePanOverlay_.style.height = height + 'px';
 832       this.iePanOverlay_.style.display = 'inline';
 833     }
 834   }
 835 };
 836
 837 /**
 838  * @private
 839  * Returns the current zoom handle position information.
 840  * @return {Object} The zoom handle status.
 841  */
 842 rangeSelector.prototype.getZoomHandleStatus_ = function() {
 843   var halfHandleWidth = this.leftZoomHandle_.width/2;
 844   var leftHandlePos = parseInt(this.leftZoomHandle_.style.left, 10) + halfHandleWidth;
 845   var rightHandlePos = parseInt(this.rightZoomHandle_.style.left, 10) + halfHandleWidth;
 846   return {
 847       leftHandlePos: leftHandlePos,
 848       rightHandlePos: rightHandlePos,
 849       isZoomed: (leftHandlePos - 1 > this.canvasRect_.x || rightHandlePos + 1 < this.canvasRect_.x+this.canvasRect_.w)
 850   };
 851 };
 852
 853 return rangeSelector;
 854
 855 })();