src/plugins/range-selector.js

   1 /**
   2  * @license
   3  * Copyright 2011 Paul Felix (paul.eric.felix@gmail.com)
   4  * MIT-licensed (http://opensource.org/licenses/MIT)
   5  */
   6 /*global Dygraph:false,TouchEvent:false */
   7
   8 /**
   9  * @fileoverview This file contains the RangeSelector plugin used to provide
  10  * a timeline range selector widget for dygraphs.
  11  */
  12
  13 Dygraph.Plugins.RangeSelector = (function() {
  14
  15 /*global Dygraph:false */
  16 "use strict";
  17
  18 var rangeSelector = function() {
  19   this.hasTouchInterface_ = typeof(TouchEvent) != 'undefined';
  20   this.isMobileDevice_ = /mobile|android/gi.test(navigator.appVersion);
  21   this.interfaceCreated_ = false;
  22 };
  23
  24 rangeSelector.prototype.toString = function() {
  25   return "RangeSelector Plugin";
  26 };
  27
  28 rangeSelector.prototype.activate = function(dygraph) {
  29   this.dygraph_ = dygraph;
  30   if (this.getOption_('showRangeSelector')) {
  31     this.createInterface_();
  32   }
  33   return {
  34     layout: this.reserveSpace_,
  35     predraw: this.renderStaticLayer_,
  36     didDrawChart: this.renderInteractiveLayer_
  37   };
  38 };
  39
  40 rangeSelector.prototype.destroy = function() {
  41   this.bgcanvas_ = null;
  42   this.fgcanvas_ = null;
  43   this.leftZoomHandle_ = null;
  44   this.rightZoomHandle_ = null;
  45 };
  46
  47 //------------------------------------------------------------------
  48 // Private methods
  49 //------------------------------------------------------------------
  50
  51 rangeSelector.prototype.getOption_ = function(name, opt_series) {
  52   return this.dygraph_.getOption(name, opt_series);
  53 };
  54
  55 rangeSelector.prototype.setDefaultOption_ = function(name, value) {
  56   this.dygraph_.attrs_[name] = value;
  57 };
  58
  59 /**
  60  * @private
  61  * Creates the range selector elements and adds them to the graph.
  62  */
  63 rangeSelector.prototype.createInterface_ = function() {
  64   this.createCanvases_();
  65   this.createZoomHandles_();
  66   this.initInteraction_();
  67
  68   // Range selector and animatedZooms have a bad interaction. See issue 359.
  69   if (this.getOption_('animatedZooms')) {
  70     console.warn('Animated zooms and range selector are not compatible; disabling animatedZooms.');
  71     this.dygraph_.updateOptions({animatedZooms: false}, true);
  72   }
  73
  74   this.interfaceCreated_ = true;
  75   this.addToGraph_();
  76 };
  77
  78 /**
  79  * @private
  80  * Adds the range selector to the graph.
  81  */
  82 rangeSelector.prototype.addToGraph_ = function() {
  83   var graphDiv = this.graphDiv_ = this.dygraph_.graphDiv;
  84   graphDiv.appendChild(this.bgcanvas_);
  85   graphDiv.appendChild(this.fgcanvas_);
  86   graphDiv.appendChild(this.leftZoomHandle_);
  87   graphDiv.appendChild(this.rightZoomHandle_);
  88 };
  89
  90 /**
  91  * @private
  92  * Removes the range selector from the graph.
  93  */
  94 rangeSelector.prototype.removeFromGraph_ = function() {
  95   var graphDiv = this.graphDiv_;
  96   graphDiv.removeChild(this.bgcanvas_);
  97   graphDiv.removeChild(this.fgcanvas_);
  98   graphDiv.removeChild(this.leftZoomHandle_);
  99   graphDiv.removeChild(this.rightZoomHandle_);
 100   this.graphDiv_ = null;
 101 };
 102
 103 /**
 104  * @private
 105  * Called by Layout to allow range selector to reserve its space.
 106  */
 107 rangeSelector.prototype.reserveSpace_ = function(e) {
 108   if (this.getOption_('showRangeSelector')) {
 109     e.reserveSpaceBottom(this.getOption_('rangeSelectorHeight') + 4);
 110   }
 111 };
 112
 113 /**
 114  * @private
 115  * Renders the static portion of the range selector at the predraw stage.
 116  */
 117 rangeSelector.prototype.renderStaticLayer_ = function() {
 118   if (!this.updateVisibility_()) {
 119     return;
 120   }
 121   this.resize_();
 122   this.drawStaticLayer_();
 123 };
 124
 125 /**
 126  * @private
 127  * Renders the interactive portion of the range selector after the chart has been drawn.
 128  */
 129 rangeSelector.prototype.renderInteractiveLayer_ = function() {
 130   if (!this.updateVisibility_() || this.isChangingRange_) {
 131     return;
 132   }
 133   this.placeZoomHandles_();
 134   this.drawInteractiveLayer_();
 135 };
 136
 137 /**
 138  * @private
 139  * Check to see if the range selector is enabled/disabled and update visibility accordingly.
 140  */
 141 rangeSelector.prototype.updateVisibility_ = function() {
 142   var enabled = this.getOption_('showRangeSelector');
 143   if (enabled) {
 144     if (!this.interfaceCreated_) {
 145       this.createInterface_();
 146     } else if (!this.graphDiv_ || !this.graphDiv_.parentNode) {
 147       this.addToGraph_();
 148     }
 149   } else if (this.graphDiv_) {
 150     this.removeFromGraph_();
 151     var dygraph = this.dygraph_;
 152     setTimeout(function() { dygraph.width_ = 0; dygraph.resize(); }, 1);
 153   }
 154   return enabled;
 155 };
 156
 157 /**
 158  * @private
 159  * Resizes the range selector.
 160  */
 161 rangeSelector.prototype.resize_ = function() {
 162   function setElementRect(canvas, context, rect) {
 163     var canvasScale = Dygraph.getContextPixelRatio(context);
 164
 165     canvas.style.top = rect.y + 'px';
 166     canvas.style.left = rect.x + 'px';
 167     canvas.width = rect.w * canvasScale;
 168     canvas.height = rect.h * canvasScale;
 169     canvas.style.width = rect.w + 'px';
 170     canvas.style.height = rect.h + 'px';
 171
 172     if(canvasScale != 1) {
 173       context.scale(canvasScale, canvasScale);
 174     }
 175   }
 176
 177   var plotArea = this.dygraph_.layout_.getPlotArea();
 178
 179   var xAxisLabelHeight = 0;
 180   if (this.dygraph_.getOptionForAxis('drawAxis', 'x')) {
 181     xAxisLabelHeight = this.getOption_('xAxisHeight') || (this.getOption_('axisLabelFontSize') + 2 * this.getOption_('axisTickSize'));
 182   }
 183   this.canvasRect_ = {
 184     x: plotArea.x,
 185     y: plotArea.y + plotArea.h + xAxisLabelHeight + 4,
 186     w: plotArea.w,
 187     h: this.getOption_('rangeSelectorHeight')
 188   };
 189
 190   setElementRect(this.bgcanvas_, this.bgcanvas_ctx_, this.canvasRect_);
 191   setElementRect(this.fgcanvas_, this.fgcanvas_ctx_, this.canvasRect_);
 192 };
 193
 194 /**
 195  * @private
 196  * Creates the background and foreground canvases.
 197  */
 198 rangeSelector.prototype.createCanvases_ = function() {
 199   this.bgcanvas_ = Dygraph.createCanvas();
 200   this.bgcanvas_.className = 'dygraph-rangesel-bgcanvas';
 201   this.bgcanvas_.style.position = 'absolute';
 202   this.bgcanvas_.style.zIndex = 9;
 203   this.bgcanvas_ctx_ = Dygraph.getContext(this.bgcanvas_);
 204
 205   this.fgcanvas_ = Dygraph.createCanvas();
 206   this.fgcanvas_.className = 'dygraph-rangesel-fgcanvas';
 207   this.fgcanvas_.style.position = 'absolute';
 208   this.fgcanvas_.style.zIndex = 9;
 209   this.fgcanvas_.style.cursor = 'default';
 210   this.fgcanvas_ctx_ = Dygraph.getContext(this.fgcanvas_);
 211 };
 212
 213 /**
 214  * @private
 215  * Creates the zoom handle elements.
 216  */
 217 rangeSelector.prototype.createZoomHandles_ = function() {
 218   var img = new Image();
 219   img.className = 'dygraph-rangesel-zoomhandle';
 220   img.style.position = 'absolute';
 221   img.style.zIndex = 10;
 222   img.style.visibility = 'hidden'; // Initially hidden so they don't show up in the wrong place.
 223   img.style.cursor = 'col-resize';
 224   // TODO: change image to more options
 225   img.width = 9;
 226   img.height = 16;
 227   img.src = 'data:image/png;base64,' +
 228 'iVBORw0KGgoAAAANSUhEUgAAAAkAAAAQCAYAAADESFVDAAAAAXNSR0IArs4c6QAAAAZiS0dEANAA' +
 229 'zwDP4Z7KegAAAAlwSFlzAAAOxAAADsQBlSsOGwAAAAd0SU1FB9sHGw0cMqdt1UwAAAAZdEVYdENv' +
 230 'bW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAAaElEQVQoz+3SsRFAQBCF4Z9WJM8KCDVwownl' +
 231 '6YXsTmCUsyKGkZzcl7zkz3YLkypgAnreFmDEpHkIwVOMfpdi9CEEN2nGpFdwD03yEqDtOgCaun7s' +
 232 'qSTDH32I1pQA2Pb9sZecAxc5r3IAb21d6878xsAAAAAASUVORK5CYII=';
 233
 234   if (this.isMobileDevice_) {
 235     img.width *= 2;
 236     img.height *= 2;
 237   }
 238
 239   this.leftZoomHandle_ = img;
 240   this.rightZoomHandle_ = img.cloneNode(false);
 241 };
 242
 243 /**
 244  * @private
 245  * Sets up the interaction for the range selector.
 246  */
 247 rangeSelector.prototype.initInteraction_ = function() {
 248   var self = this;
 249   var topElem = document;
 250   var clientXLast = 0;
 251   var handle = null;
 252   var isZooming = false;
 253   var isPanning = false;
 254   var dynamic = !this.isMobileDevice_;
 255
 256   // We cover iframes during mouse interactions. See comments in
 257   // dygraph-utils.js for more info on why this is a good idea.
 258   var tarp = new Dygraph.IFrameTarp();
 259
 260   // functions, defined below.  Defining them this way (rather than with
 261   // "function foo() {...}" makes JSHint happy.
 262   var toXDataWindow, onZoomStart, onZoom, onZoomEnd, doZoom, isMouseInPanZone,
 263       onPanStart, onPan, onPanEnd, doPan, onCanvasHover;
 264
 265   // Touch event functions
 266   var onZoomHandleTouchEvent, onCanvasTouchEvent, addTouchEvents;
 267
 268   toXDataWindow = function(zoomHandleStatus) {
 269     var xDataLimits = self.dygraph_.xAxisExtremes();
 270     var fact = (xDataLimits[1] - xDataLimits[0])/self.canvasRect_.w;
 271     var xDataMin = xDataLimits[0] + (zoomHandleStatus.leftHandlePos - self.canvasRect_.x)*fact;
 272     var xDataMax = xDataLimits[0] + (zoomHandleStatus.rightHandlePos - self.canvasRect_.x)*fact;
 273     return [xDataMin, xDataMax];
 274   };
 275
 276   onZoomStart = function(e) {
 277     Dygraph.cancelEvent(e);
 278     isZooming = true;
 279     clientXLast = e.clientX;
 280     handle = e.target ? e.target : e.srcElement;
 281     if (e.type === 'mousedown' || e.type === 'dragstart') {
 282       // These events are removed manually.
 283       Dygraph.addEvent(topElem, 'mousemove', onZoom);
 284       Dygraph.addEvent(topElem, 'mouseup', onZoomEnd);
 285     }
 286     self.fgcanvas_.style.cursor = 'col-resize';
 287     tarp.cover();
 288     return true;
 289   };
 290
 291   onZoom = function(e) {
 292     if (!isZooming) {
 293       return false;
 294     }
 295     Dygraph.cancelEvent(e);
 296
 297     var delX = e.clientX - clientXLast;
 298     if (Math.abs(delX) < 4) {
 299       return true;
 300     }
 301     clientXLast = e.clientX;
 302
 303     // Move handle.
 304     var zoomHandleStatus = self.getZoomHandleStatus_();
 305     var newPos;
 306     if (handle == self.leftZoomHandle_) {
 307       newPos = zoomHandleStatus.leftHandlePos + delX;
 308       newPos = Math.min(newPos, zoomHandleStatus.rightHandlePos - handle.width - 3);
 309       newPos = Math.max(newPos, self.canvasRect_.x);
 310     } else {
 311       newPos = zoomHandleStatus.rightHandlePos + delX;
 312       newPos = Math.min(newPos, self.canvasRect_.x + self.canvasRect_.w);
 313       newPos = Math.max(newPos, zoomHandleStatus.leftHandlePos + handle.width + 3);
 314     }
 315     var halfHandleWidth = handle.width/2;
 316     handle.style.left = (newPos - halfHandleWidth) + 'px';
 317     self.drawInteractiveLayer_();
 318
 319     // Zoom on the fly.
 320     if (dynamic) {
 321       doZoom();
 322     }
 323     return true;
 324   };
 325
 326   onZoomEnd = function(e) {
 327     if (!isZooming) {
 328       return false;
 329     }
 330     isZooming = false;
 331     tarp.uncover();
 332     Dygraph.removeEvent(topElem, 'mousemove', onZoom);
 333     Dygraph.removeEvent(topElem, 'mouseup', onZoomEnd);
 334     self.fgcanvas_.style.cursor = 'default';
 335
 336     // If on a slower device, zoom now.
 337     if (!dynamic) {
 338       doZoom();
 339     }
 340     return true;
 341   };
 342
 343   doZoom = function() {
 344     try {
 345       var zoomHandleStatus = self.getZoomHandleStatus_();
 346       self.isChangingRange_ = true;
 347       if (!zoomHandleStatus.isZoomed) {
 348         self.dygraph_.resetZoom();
 349       } else {
 350         var xDataWindow = toXDataWindow(zoomHandleStatus);
 351         self.dygraph_.doZoomXDates_(xDataWindow[0], xDataWindow[1]);
 352       }
 353     } finally {
 354       self.isChangingRange_ = false;
 355     }
 356   };
 357
 358   isMouseInPanZone = function(e) {
 359     var rect = self.leftZoomHandle_.getBoundingClientRect();
 360     var leftHandleClientX = rect.left + rect.width/2;
 361     rect = self.rightZoomHandle_.getBoundingClientRect();
 362     var rightHandleClientX = rect.left + rect.width/2;
 363     return (e.clientX > leftHandleClientX && e.clientX < rightHandleClientX);
 364   };
 365
 366   onPanStart = function(e) {
 367     if (!isPanning && isMouseInPanZone(e) && self.getZoomHandleStatus_().isZoomed) {
 368       Dygraph.cancelEvent(e);
 369       isPanning = true;
 370       clientXLast = e.clientX;
 371       if (e.type === 'mousedown') {
 372         // These events are removed manually.
 373         Dygraph.addEvent(topElem, 'mousemove', onPan);
 374         Dygraph.addEvent(topElem, 'mouseup', onPanEnd);
 375       }
 376       return true;
 377     }
 378     return false;
 379   };
 380
 381   onPan = function(e) {
 382     if (!isPanning) {
 383       return false;
 384     }
 385     Dygraph.cancelEvent(e);
 386
 387     var delX = e.clientX - clientXLast;
 388     if (Math.abs(delX) < 4) {
 389       return true;
 390     }
 391     clientXLast = e.clientX;
 392
 393     // Move range view
 394     var zoomHandleStatus = self.getZoomHandleStatus_();
 395     var leftHandlePos = zoomHandleStatus.leftHandlePos;
 396     var rightHandlePos = zoomHandleStatus.rightHandlePos;
 397     var rangeSize = rightHandlePos - leftHandlePos;
 398     if (leftHandlePos + delX <= self.canvasRect_.x) {
 399       leftHandlePos = self.canvasRect_.x;
 400       rightHandlePos = leftHandlePos + rangeSize;
 401     } else if (rightHandlePos + delX >= self.canvasRect_.x + self.canvasRect_.w) {
 402       rightHandlePos = self.canvasRect_.x + self.canvasRect_.w;
 403       leftHandlePos = rightHandlePos - rangeSize;
 404     } else {
 405       leftHandlePos += delX;
 406       rightHandlePos += delX;
 407     }
 408     var halfHandleWidth = self.leftZoomHandle_.width/2;
 409     self.leftZoomHandle_.style.left = (leftHandlePos - halfHandleWidth) + 'px';
 410     self.rightZoomHandle_.style.left = (rightHandlePos - halfHandleWidth) + 'px';
 411     self.drawInteractiveLayer_();
 412
 413     // Do pan on the fly.
 414     if (dynamic) {
 415       doPan();
 416     }
 417     return true;
 418   };
 419
 420   onPanEnd = function(e) {
 421     if (!isPanning) {
 422       return false;
 423     }
 424     isPanning = false;
 425     Dygraph.removeEvent(topElem, 'mousemove', onPan);
 426     Dygraph.removeEvent(topElem, 'mouseup', onPanEnd);
 427     // If on a slower device, do pan now.
 428     if (!dynamic) {
 429       doPan();
 430     }
 431     return true;
 432   };
 433
 434   doPan = function() {
 435     try {
 436       self.isChangingRange_ = true;
 437       self.dygraph_.dateWindow_ = toXDataWindow(self.getZoomHandleStatus_());
 438       self.dygraph_.drawGraph_(false);
 439     } finally {
 440       self.isChangingRange_ = false;
 441     }
 442   };
 443
 444   onCanvasHover = function(e) {
 445     if (isZooming || isPanning) {
 446       return;
 447     }
 448     var cursor = isMouseInPanZone(e) ? 'move' : 'default';
 449     if (cursor != self.fgcanvas_.style.cursor) {
 450       self.fgcanvas_.style.cursor = cursor;
 451     }
 452   };
 453
 454   onZoomHandleTouchEvent = function(e) {
 455     if (e.type == 'touchstart' && e.targetTouches.length == 1) {
 456       if (onZoomStart(e.targetTouches[0])) {
 457         Dygraph.cancelEvent(e);
 458       }
 459     } else if (e.type == 'touchmove' && e.targetTouches.length == 1) {
 460       if (onZoom(e.targetTouches[0])) {
 461         Dygraph.cancelEvent(e);
 462       }
 463     } else {
 464       onZoomEnd(e);
 465     }
 466   };
 467
 468   onCanvasTouchEvent = function(e) {
 469     if (e.type == 'touchstart' && e.targetTouches.length == 1) {
 470       if (onPanStart(e.targetTouches[0])) {
 471         Dygraph.cancelEvent(e);
 472       }
 473     } else if (e.type == 'touchmove' && e.targetTouches.length == 1) {
 474       if (onPan(e.targetTouches[0])) {
 475         Dygraph.cancelEvent(e);
 476       }
 477     } else {
 478       onPanEnd(e);
 479     }
 480   };
 481
 482   addTouchEvents = function(elem, fn) {
 483     var types = ['touchstart', 'touchend', 'touchmove', 'touchcancel'];
 484     for (var i = 0; i < types.length; i++) {
 485       self.dygraph_.addAndTrackEvent(elem, types[i], fn);
 486     }
 487   };
 488
 489   this.setDefaultOption_('interactionModel', Dygraph.Interaction.dragIsPanInteractionModel);
 490   this.setDefaultOption_('panEdgeFraction', 0.0001);
 491
 492   var dragStartEvent = window.opera ? 'mousedown' : 'dragstart';
 493   this.dygraph_.addAndTrackEvent(this.leftZoomHandle_, dragStartEvent, onZoomStart);
 494   this.dygraph_.addAndTrackEvent(this.rightZoomHandle_, dragStartEvent, onZoomStart);
 495
 496   this.dygraph_.addAndTrackEvent(this.fgcanvas_, 'mousedown', onPanStart);
 497   this.dygraph_.addAndTrackEvent(this.fgcanvas_, 'mousemove', onCanvasHover);
 498
 499   // Touch events
 500   if (this.hasTouchInterface_) {
 501     addTouchEvents(this.leftZoomHandle_, onZoomHandleTouchEvent);
 502     addTouchEvents(this.rightZoomHandle_, onZoomHandleTouchEvent);
 503     addTouchEvents(this.fgcanvas_, onCanvasTouchEvent);
 504   }
 505 };
 506
 507 /**
 508  * @private
 509  * Draws the static layer in the background canvas.
 510  */
 511 rangeSelector.prototype.drawStaticLayer_ = function() {
 512   var ctx = this.bgcanvas_ctx_;
 513   ctx.clearRect(0, 0, this.canvasRect_.w, this.canvasRect_.h);
 514   try {
 515     this.drawMiniPlot_();
 516   } catch(ex) {
 517     console.warn(ex);
 518   }
 519
 520   var margin = 0.5;
 521   this.bgcanvas_ctx_.lineWidth = this.getOption_('rangeSelectorBackgroundLineWidth');
 522   ctx.strokeStyle = this.getOption_('rangeSelectorBackgroundStrokeColor');
 523   ctx.beginPath();
 524   ctx.moveTo(margin, margin);
 525   ctx.lineTo(margin, this.canvasRect_.h-margin);
 526   ctx.lineTo(this.canvasRect_.w-margin, this.canvasRect_.h-margin);
 527   ctx.lineTo(this.canvasRect_.w-margin, margin);
 528   ctx.stroke();
 529 };
 530
 531
 532 /**
 533  * @private
 534  * Draws the mini plot in the background canvas.
 535  */
 536 rangeSelector.prototype.drawMiniPlot_ = function() {
 537   var fillStyle = this.getOption_('rangeSelectorPlotFillColor');
 538   var fillGradientStyle = this.getOption_('rangeSelectorPlotFillGradientColor');
 539   var strokeStyle = this.getOption_('rangeSelectorPlotStrokeColor');
 540   if (!fillStyle && !strokeStyle) {
 541     return;
 542   }
 543
 544   var stepPlot = this.getOption_('stepPlot');
 545
 546   var combinedSeriesData = this.computeCombinedSeriesAndLimits_();
 547   var yRange = combinedSeriesData.yMax - combinedSeriesData.yMin;
 548
 549   // Draw the mini plot.
 550   var ctx = this.bgcanvas_ctx_;
 551   var margin = 0.5;
 552
 553   var xExtremes = this.dygraph_.xAxisExtremes();
 554   var xRange = Math.max(xExtremes[1] - xExtremes[0], 1.e-30);
 555   var xFact = (this.canvasRect_.w - margin)/xRange;
 556   var yFact = (this.canvasRect_.h - margin)/yRange;
 557   var canvasWidth = this.canvasRect_.w - margin;
 558   var canvasHeight = this.canvasRect_.h - margin;
 559
 560   var prevX = null, prevY = null;
 561
 562   ctx.beginPath();
 563   ctx.moveTo(margin, canvasHeight);
 564   for (var i = 0; i < combinedSeriesData.data.length; i++) {
 565     var dataPoint = combinedSeriesData.data[i];
 566     var x = ((dataPoint[0] !== null) ? ((dataPoint[0] - xExtremes[0])*xFact) : NaN);
 567     var y = ((dataPoint[1] !== null) ? (canvasHeight - (dataPoint[1] - combinedSeriesData.yMin)*yFact) : NaN);
 568
 569     // Skip points that don't change the x-value. Overly fine-grained points
 570     // can cause major slowdowns with the ctx.fill() call below.
 571     if (!stepPlot && prevX !== null && Math.round(x) == Math.round(prevX)) {
 572       continue;
 573     }
 574
 575     if (isFinite(x) && isFinite(y)) {
 576       if(prevX === null) {
 577         ctx.lineTo(x, canvasHeight);
 578       }
 579       else if (stepPlot) {
 580         ctx.lineTo(x, prevY);
 581       }
 582       ctx.lineTo(x, y);
 583       prevX = x;
 584       prevY = y;
 585     }
 586     else {
 587       if(prevX !== null) {
 588         if (stepPlot) {
 589           ctx.lineTo(x, prevY);
 590           ctx.lineTo(x, canvasHeight);
 591         }
 592         else {
 593           ctx.lineTo(prevX, canvasHeight);
 594         }
 595       }
 596       prevX = prevY = null;
 597     }
 598   }
 599   ctx.lineTo(canvasWidth, canvasHeight);
 600   ctx.closePath();
 601
 602   if (fillStyle) {
 603     var lingrad = this.bgcanvas_ctx_.createLinearGradient(0, 0, 0, canvasHeight);
 604     if (fillGradientStyle) {
 605       lingrad.addColorStop(0, fillGradientStyle);
 606     }
 607     lingrad.addColorStop(1, fillStyle);
 608     this.bgcanvas_ctx_.fillStyle = lingrad;
 609     ctx.fill();
 610   }
 611
 612   if (strokeStyle) {
 613     this.bgcanvas_ctx_.strokeStyle = strokeStyle;
 614     this.bgcanvas_ctx_.lineWidth = this.getOption_('rangeSelectorPlotLineWidth');
 615     ctx.stroke();
 616   }
 617 };
 618
 619 /**
 620  * @private
 621  * Computes and returns the combined series data along with min/max for the mini plot.
 622  * The combined series consists of averaged values for all series.
 623  * When series have error bars, the error bars are ignored.
 624  * @return {Object} An object containing combined series array, ymin, ymax.
 625  */
 626 rangeSelector.prototype.computeCombinedSeriesAndLimits_ = function() {
 627   var g = this.dygraph_;
 628   var logscale = this.getOption_('logscale');
 629   var i;
 630
 631   // Select series to combine. By default, all series are combined.
 632   var numColumns = g.numColumns();
 633   var labels = g.getLabels();
 634   var includeSeries = new Array(numColumns);
 635   var anySet = false;
 636   for (i = 1; i < numColumns; i++) {
 637     var include = this.getOption_('showInRangeSelector', labels[i]);
 638     includeSeries[i] = include;
 639     if (include !== null) anySet = true;  // it's set explicitly for this series
 640   }
 641   if (!anySet) {
 642     for (i = 0; i < includeSeries.length; i++) includeSeries[i] = true;
 643   }
 644
 645   // Create a combined series (average of selected series values).
 646   // TODO(danvk): short-circuit if there's only one series.
 647   var rolledSeries = [];
 648   var dataHandler = g.dataHandler_;
 649   var options = g.attributes_;
 650   for (i = 1; i < g.numColumns(); i++) {
 651     if (!includeSeries[i]) continue;
 652     var series = dataHandler.extractSeries(g.rawData_, i, options);
 653     if (g.rollPeriod() > 1) {
 654       series = dataHandler.rollingAverage(series, g.rollPeriod(), options);
 655     }
 656
 657     rolledSeries.push(series);
 658   }
 659
 660   var combinedSeries = [];
 661   for (i = 0; i < rolledSeries[0].length; i++) {
 662     var sum = 0;
 663     var count = 0;
 664     for (var j = 0; j < rolledSeries.length; j++) {
 665       var y = rolledSeries[j][i][1];
 666       if (y === null || isNaN(y)) continue;
 667       count++;
 668       sum += y;
 669     }
 670     combinedSeries.push([rolledSeries[0][i][0], sum / count]);
 671   }
 672
 673   // Compute the y range.
 674   var yMin = Number.MAX_VALUE;
 675   var yMax = -Number.MAX_VALUE;
 676   for (i = 0; i < combinedSeries.length; i++) {
 677     var yVal = combinedSeries[i][1];
 678     if (yVal !== null && isFinite(yVal) && (!logscale || yVal > 0)) {
 679       yMin = Math.min(yMin, yVal);
 680       yMax = Math.max(yMax, yVal);
 681     }
 682   }
 683
 684   // Convert Y data to log scale if needed.
 685   // Also, expand the Y range to compress the mini plot a little.
 686   var extraPercent = 0.25;
 687   if (logscale) {
 688     yMax = Dygraph.log10(yMax);
 689     yMax += yMax*extraPercent;
 690     yMin = Dygraph.log10(yMin);
 691     for (i = 0; i < combinedSeries.length; i++) {
 692       combinedSeries[i][1] = Dygraph.log10(combinedSeries[i][1]);
 693     }
 694   } else {
 695     var yExtra;
 696     var yRange = yMax - yMin;
 697     if (yRange <= Number.MIN_VALUE) {
 698       yExtra = yMax*extraPercent;
 699     } else {
 700       yExtra = yRange*extraPercent;
 701     }
 702     yMax += yExtra;
 703     yMin -= yExtra;
 704   }
 705
 706   return {data: combinedSeries, yMin: yMin, yMax: yMax};
 707 };
 708
 709 /**
 710  * @private
 711  * Places the zoom handles in the proper position based on the current X data window.
 712  */
 713 rangeSelector.prototype.placeZoomHandles_ = function() {
 714   var xExtremes = this.dygraph_.xAxisExtremes();
 715   var xWindowLimits = this.dygraph_.xAxisRange();
 716   var xRange = xExtremes[1] - xExtremes[0];
 717   var leftPercent = Math.max(0, (xWindowLimits[0] - xExtremes[0])/xRange);
 718   var rightPercent = Math.max(0, (xExtremes[1] - xWindowLimits[1])/xRange);
 719   var leftCoord = this.canvasRect_.x + this.canvasRect_.w*leftPercent;
 720   var rightCoord = this.canvasRect_.x + this.canvasRect_.w*(1 - rightPercent);
 721   var handleTop = Math.max(this.canvasRect_.y, this.canvasRect_.y + (this.canvasRect_.h - this.leftZoomHandle_.height)/2);
 722   var halfHandleWidth = this.leftZoomHandle_.width/2;
 723   this.leftZoomHandle_.style.left = (leftCoord - halfHandleWidth) + 'px';
 724   this.leftZoomHandle_.style.top = handleTop + 'px';
 725   this.rightZoomHandle_.style.left = (rightCoord - halfHandleWidth) + 'px';
 726   this.rightZoomHandle_.style.top = this.leftZoomHandle_.style.top;
 727
 728   this.leftZoomHandle_.style.visibility = 'visible';
 729   this.rightZoomHandle_.style.visibility = 'visible';
 730 };
 731
 732 /**
 733  * @private
 734  * Draws the interactive layer in the foreground canvas.
 735  */
 736 rangeSelector.prototype.drawInteractiveLayer_ = function() {
 737   var ctx = this.fgcanvas_ctx_;
 738   ctx.clearRect(0, 0, this.canvasRect_.w, this.canvasRect_.h);
 739   var margin = 1;
 740   var width = this.canvasRect_.w - margin;
 741   var height = this.canvasRect_.h - margin;
 742   var zoomHandleStatus = this.getZoomHandleStatus_();
 743
 744   ctx.strokeStyle = this.getOption_('rangeSelectorForegroundStrokeColor');
 745   ctx.lineWidth = this.getOption_('rangeSelectorForegroundLineWidth');
 746   if (!zoomHandleStatus.isZoomed) {
 747     ctx.beginPath();
 748     ctx.moveTo(margin, margin);
 749     ctx.lineTo(margin, height);
 750     ctx.lineTo(width, height);
 751     ctx.lineTo(width, margin);
 752     ctx.stroke();
 753   } else {
 754     var leftHandleCanvasPos = Math.max(margin, zoomHandleStatus.leftHandlePos - this.canvasRect_.x);
 755     var rightHandleCanvasPos = Math.min(width, zoomHandleStatus.rightHandlePos - this.canvasRect_.x);
 756
 757     ctx.fillStyle = 'rgba(240, 240, 240, ' + this.getOption_('rangeSelectorAlpha').toString() + ')';
 758     ctx.fillRect(0, 0, leftHandleCanvasPos, this.canvasRect_.h);
 759     ctx.fillRect(rightHandleCanvasPos, 0, this.canvasRect_.w - rightHandleCanvasPos, this.canvasRect_.h);
 760
 761     ctx.beginPath();
 762     ctx.moveTo(margin, margin);
 763     ctx.lineTo(leftHandleCanvasPos, margin);
 764     ctx.lineTo(leftHandleCanvasPos, height);
 765     ctx.lineTo(rightHandleCanvasPos, height);
 766     ctx.lineTo(rightHandleCanvasPos, margin);
 767     ctx.lineTo(width, margin);
 768     ctx.stroke();
 769   }
 770 };
 771
 772 /**
 773  * @private
 774  * Returns the current zoom handle position information.
 775  * @return {Object} The zoom handle status.
 776  */
 777 rangeSelector.prototype.getZoomHandleStatus_ = function() {
 778   var halfHandleWidth = this.leftZoomHandle_.width/2;
 779   var leftHandlePos = parseFloat(this.leftZoomHandle_.style.left) + halfHandleWidth;
 780   var rightHandlePos = parseFloat(this.rightZoomHandle_.style.left) + halfHandleWidth;
 781   return {
 782       leftHandlePos: leftHandlePos,
 783       rightHandlePos: rightHandlePos,
 784       isZoomed: (leftHandlePos - 1 > this.canvasRect_.x || rightHandlePos + 1 < this.canvasRect_.x+this.canvasRect_.w)
 785   };
 786 };
 787
 788 return rangeSelector;
 789
 790 })();