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88e95c46 DV |
1 | /** |
2 | * @license | |
3 | * Copyright 2006 Dan Vanderkam (danvdk@gmail.com) | |
4 | * MIT-licensed (http://opensource.org/licenses/MIT) | |
5 | */ | |
6a1aa64f DV |
6 | |
7 | /** | |
74a5af31 DV |
8 | * @fileoverview Based on PlotKit.CanvasRenderer, but modified to meet the |
9 | * needs of dygraphs. | |
10 | * | |
3df0ccf0 | 11 | * In particular, support for: |
0abfbd7e | 12 | * - grid overlays |
3df0ccf0 DV |
13 | * - error bars |
14 | * - dygraphs attribute system | |
6a1aa64f DV |
15 | */ |
16 | ||
6a1aa64f | 17 | /** |
423f5ed3 DV |
18 | * The DygraphCanvasRenderer class does the actual rendering of the chart onto |
19 | * a canvas. It's based on PlotKit.CanvasRenderer. | |
6a1aa64f | 20 | * @param {Object} element The canvas to attach to |
2cf95fff RK |
21 | * @param {Object} elementContext The 2d context of the canvas (injected so it |
22 | * can be mocked for testing.) | |
285a6bda | 23 | * @param {Layout} layout The DygraphLayout object for this graph. |
74a5af31 | 24 | * @constructor |
6a1aa64f | 25 | */ |
c0f54d4f | 26 | |
758a629f DV |
27 | /*jshint globalstrict: true */ |
28 | /*global Dygraph:false,RGBColor:false */ | |
c0f54d4f DV |
29 | "use strict"; |
30 | ||
79253bd0 | 31 | |
8cfe592f DV |
32 | /** |
33 | * @constructor | |
34 | * | |
35 | * This gets called when there are "new points" to chart. This is generally the | |
36 | * case when the underlying data being charted has changed. It is _not_ called | |
37 | * in the common case that the user has zoomed or is panning the view. | |
38 | * | |
39 | * The chart canvas has already been created by the Dygraph object. The | |
40 | * renderer simply gets a drawing context. | |
41 | * | |
42 | * @param {Dyraph} dygraph The chart to which this renderer belongs. | |
43 | * @param {Canvas} element The <canvas> DOM element on which to draw. | |
44 | * @param {CanvasRenderingContext2D} elementContext The drawing context. | |
45 | * @param {DygraphLayout} layout The chart's DygraphLayout object. | |
46 | * | |
47 | * TODO(danvk): remove the elementContext property. | |
48 | */ | |
c0f54d4f | 49 | var DygraphCanvasRenderer = function(dygraph, element, elementContext, layout) { |
9317362d | 50 | this.dygraph_ = dygraph; |
fbe31dc8 | 51 | |
fbe31dc8 | 52 | this.layout = layout; |
b0c3b730 | 53 | this.element = element; |
2cf95fff | 54 | this.elementContext = elementContext; |
fbe31dc8 DV |
55 | this.container = this.element.parentNode; |
56 | ||
fbe31dc8 DV |
57 | this.height = this.element.height; |
58 | this.width = this.element.width; | |
59 | ||
60 | // --- check whether everything is ok before we return | |
61 | if (!this.isIE && !(DygraphCanvasRenderer.isSupported(this.element))) | |
62 | throw "Canvas is not supported."; | |
63 | ||
64 | // internal state | |
758a629f DV |
65 | this.xlabels = []; |
66 | this.ylabels = []; | |
fbe31dc8 | 67 | |
70be5ed1 | 68 | this.area = layout.getPlotArea(); |
423f5ed3 DV |
69 | this.container.style.position = "relative"; |
70 | this.container.style.width = this.width + "px"; | |
71 | ||
72 | // Set up a clipping area for the canvas (and the interaction canvas). | |
73 | // This ensures that we don't overdraw. | |
920208fb PF |
74 | if (this.dygraph_.isUsingExcanvas_) { |
75 | this._createIEClipArea(); | |
76 | } else { | |
971870e5 DV |
77 | // on Android 3 and 4, setting a clipping area on a canvas prevents it from |
78 | // displaying anything. | |
79 | if (!Dygraph.isAndroid()) { | |
80 | var ctx = this.dygraph_.canvas_ctx_; | |
81 | ctx.beginPath(); | |
82 | ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h); | |
83 | ctx.clip(); | |
920208fb | 84 | |
971870e5 DV |
85 | ctx = this.dygraph_.hidden_ctx_; |
86 | ctx.beginPath(); | |
87 | ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h); | |
88 | ctx.clip(); | |
89 | } | |
920208fb | 90 | } |
423f5ed3 DV |
91 | }; |
92 | ||
93 | DygraphCanvasRenderer.prototype.attr_ = function(x) { | |
94 | return this.dygraph_.attr_(x); | |
95 | }; | |
96 | ||
8cfe592f DV |
97 | /** |
98 | * Clears out all chart content and DOM elements. | |
99 | * This is called immediately before render() on every frame, including | |
100 | * during zooms and pans. | |
101 | * @private | |
102 | */ | |
fbe31dc8 | 103 | DygraphCanvasRenderer.prototype.clear = function() { |
758a629f | 104 | var context; |
fbe31dc8 DV |
105 | if (this.isIE) { |
106 | // VML takes a while to start up, so we just poll every this.IEDelay | |
107 | try { | |
108 | if (this.clearDelay) { | |
109 | this.clearDelay.cancel(); | |
110 | this.clearDelay = null; | |
111 | } | |
758a629f | 112 | context = this.elementContext; |
fbe31dc8 DV |
113 | } |
114 | catch (e) { | |
76171648 | 115 | // TODO(danvk): this is broken, since MochiKit.Async is gone. |
758a629f DV |
116 | // this.clearDelay = MochiKit.Async.wait(this.IEDelay); |
117 | // this.clearDelay.addCallback(bind(this.clear, this)); | |
fbe31dc8 DV |
118 | return; |
119 | } | |
120 | } | |
121 | ||
758a629f | 122 | context = this.elementContext; |
fbe31dc8 DV |
123 | context.clearRect(0, 0, this.width, this.height); |
124 | ||
758a629f DV |
125 | function removeArray(ary) { |
126 | for (var i = 0; i < ary.length; i++) { | |
127 | var el = ary[i]; | |
128 | if (el.parentNode) el.parentNode.removeChild(el); | |
129 | } | |
ce49c2fa | 130 | } |
758a629f DV |
131 | |
132 | removeArray(this.xlabels); | |
133 | removeArray(this.ylabels); | |
758a629f | 134 | |
758a629f DV |
135 | this.xlabels = []; |
136 | this.ylabels = []; | |
fbe31dc8 DV |
137 | }; |
138 | ||
8cfe592f DV |
139 | /** |
140 | * Checks whether the browser supports the <canvas> tag. | |
141 | * @private | |
142 | */ | |
fbe31dc8 DV |
143 | DygraphCanvasRenderer.isSupported = function(canvasName) { |
144 | var canvas = null; | |
145 | try { | |
758a629f | 146 | if (typeof(canvasName) == 'undefined' || canvasName === null) { |
b0c3b730 | 147 | canvas = document.createElement("canvas"); |
758a629f | 148 | } else { |
b0c3b730 | 149 | canvas = canvasName; |
758a629f DV |
150 | } |
151 | canvas.getContext("2d"); | |
fbe31dc8 DV |
152 | } |
153 | catch (e) { | |
154 | var ie = navigator.appVersion.match(/MSIE (\d\.\d)/); | |
155 | var opera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1); | |
156 | if ((!ie) || (ie[1] < 6) || (opera)) | |
157 | return false; | |
158 | return true; | |
159 | } | |
160 | return true; | |
6a1aa64f | 161 | }; |
6a1aa64f DV |
162 | |
163 | /** | |
600d841a DV |
164 | * @param { [String] } colors Array of color strings. Should have one entry for |
165 | * each series to be rendered. | |
166 | */ | |
167 | DygraphCanvasRenderer.prototype.setColors = function(colors) { | |
168 | this.colorScheme_ = colors; | |
169 | }; | |
170 | ||
171 | /** | |
8cfe592f DV |
172 | * This method is responsible for drawing everything on the chart, including |
173 | * lines, error bars, fills and axes. | |
174 | * It is called immediately after clear() on every frame, including during pans | |
175 | * and zooms. | |
176 | * @private | |
6a1aa64f | 177 | */ |
285a6bda | 178 | DygraphCanvasRenderer.prototype.render = function() { |
528ce7e5 DV |
179 | // Draw the new X/Y grid. Lines appear crisper when pixels are rounded to |
180 | // half-integers. This prevents them from drawing in two rows/cols. | |
2cf95fff | 181 | var ctx = this.elementContext; |
758a629f DV |
182 | function halfUp(x) { return Math.round(x) + 0.5; } |
183 | function halfDown(y){ return Math.round(y) - 0.5; } | |
e7746234 | 184 | |
423f5ed3 | 185 | if (this.attr_('underlayCallback')) { |
1e41bd2d DV |
186 | // NOTE: we pass the dygraph object to this callback twice to avoid breaking |
187 | // users who expect a deprecated form of this callback. | |
423f5ed3 | 188 | this.attr_('underlayCallback')(ctx, this.area, this.dygraph_, this.dygraph_); |
e7746234 EC |
189 | } |
190 | ||
758a629f | 191 | var x, y, i, ticks; |
423f5ed3 | 192 | if (this.attr_('drawYGrid')) { |
758a629f | 193 | ticks = this.layout.yticks; |
bbba718a | 194 | // TODO(konigsberg): I don't think these calls to save() have a corresponding restore(). |
6a1aa64f | 195 | ctx.save(); |
423f5ed3 | 196 | ctx.strokeStyle = this.attr_('gridLineColor'); |
990d6a35 | 197 | ctx.lineWidth = this.attr_('gridLineWidth'); |
758a629f | 198 | for (i = 0; i < ticks.length; i++) { |
880a574f | 199 | // TODO(danvk): allow secondary axes to draw a grid, too. |
758a629f DV |
200 | if (ticks[i][0] !== 0) continue; |
201 | x = halfUp(this.area.x); | |
202 | y = halfDown(this.area.y + ticks[i][1] * this.area.h); | |
6a1aa64f DV |
203 | ctx.beginPath(); |
204 | ctx.moveTo(x, y); | |
205 | ctx.lineTo(x + this.area.w, y); | |
206 | ctx.closePath(); | |
207 | ctx.stroke(); | |
208 | } | |
6bf4df7f | 209 | ctx.restore(); |
6a1aa64f DV |
210 | } |
211 | ||
423f5ed3 | 212 | if (this.attr_('drawXGrid')) { |
758a629f | 213 | ticks = this.layout.xticks; |
6a1aa64f | 214 | ctx.save(); |
423f5ed3 | 215 | ctx.strokeStyle = this.attr_('gridLineColor'); |
990d6a35 | 216 | ctx.lineWidth = this.attr_('gridLineWidth'); |
758a629f DV |
217 | for (i=0; i<ticks.length; i++) { |
218 | x = halfUp(this.area.x + ticks[i][0] * this.area.w); | |
219 | y = halfDown(this.area.y + this.area.h); | |
6a1aa64f | 220 | ctx.beginPath(); |
880a574f | 221 | ctx.moveTo(x, y); |
6a1aa64f DV |
222 | ctx.lineTo(x, this.area.y); |
223 | ctx.closePath(); | |
224 | ctx.stroke(); | |
225 | } | |
6bf4df7f | 226 | ctx.restore(); |
6a1aa64f | 227 | } |
2ce09b19 DV |
228 | |
229 | // Do the ordinary rendering, as before | |
2ce09b19 | 230 | this._renderLineChart(); |
f8540c66 | 231 | // this._renderAxis(); |
fbe31dc8 DV |
232 | }; |
233 | ||
920208fb PF |
234 | DygraphCanvasRenderer.prototype._createIEClipArea = function() { |
235 | var className = 'dygraph-clip-div'; | |
236 | var graphDiv = this.dygraph_.graphDiv; | |
237 | ||
238 | // Remove old clip divs. | |
239 | for (var i = graphDiv.childNodes.length-1; i >= 0; i--) { | |
240 | if (graphDiv.childNodes[i].className == className) { | |
241 | graphDiv.removeChild(graphDiv.childNodes[i]); | |
242 | } | |
243 | } | |
244 | ||
245 | // Determine background color to give clip divs. | |
246 | var backgroundColor = document.bgColor; | |
247 | var element = this.dygraph_.graphDiv; | |
248 | while (element != document) { | |
249 | var bgcolor = element.currentStyle.backgroundColor; | |
250 | if (bgcolor && bgcolor != 'transparent') { | |
251 | backgroundColor = bgcolor; | |
252 | break; | |
253 | } | |
254 | element = element.parentNode; | |
255 | } | |
256 | ||
257 | function createClipDiv(area) { | |
758a629f | 258 | if (area.w === 0 || area.h === 0) { |
920208fb PF |
259 | return; |
260 | } | |
261 | var elem = document.createElement('div'); | |
262 | elem.className = className; | |
263 | elem.style.backgroundColor = backgroundColor; | |
264 | elem.style.position = 'absolute'; | |
265 | elem.style.left = area.x + 'px'; | |
266 | elem.style.top = area.y + 'px'; | |
267 | elem.style.width = area.w + 'px'; | |
268 | elem.style.height = area.h + 'px'; | |
269 | graphDiv.appendChild(elem); | |
270 | } | |
271 | ||
272 | var plotArea = this.area; | |
273 | // Left side | |
758a629f DV |
274 | createClipDiv({ |
275 | x:0, y:0, | |
276 | w:plotArea.x, | |
277 | h:this.height | |
278 | }); | |
279 | ||
920208fb | 280 | // Top |
758a629f DV |
281 | createClipDiv({ |
282 | x: plotArea.x, y: 0, | |
283 | w: this.width - plotArea.x, | |
284 | h: plotArea.y | |
285 | }); | |
286 | ||
920208fb | 287 | // Right side |
758a629f DV |
288 | createClipDiv({ |
289 | x: plotArea.x + plotArea.w, y: 0, | |
290 | w: this.width-plotArea.x - plotArea.w, | |
291 | h: this.height | |
292 | }); | |
293 | ||
920208fb | 294 | // Bottom |
758a629f DV |
295 | createClipDiv({ |
296 | x: plotArea.x, | |
297 | y: plotArea.y + plotArea.h, | |
298 | w: this.width - plotArea.x, | |
299 | h: this.height - plotArea.h - plotArea.y | |
300 | }); | |
301 | }; | |
fbe31dc8 DV |
302 | |
303 | DygraphCanvasRenderer.prototype._renderAxis = function() { | |
423f5ed3 | 304 | if (!this.attr_('drawXAxis') && !this.attr_('drawYAxis')) return; |
fbe31dc8 | 305 | |
528ce7e5 | 306 | // Round pixels to half-integer boundaries for crisper drawing. |
758a629f DV |
307 | function halfUp(x) { return Math.round(x) + 0.5; } |
308 | function halfDown(y){ return Math.round(y) - 0.5; } | |
528ce7e5 | 309 | |
2cf95fff | 310 | var context = this.elementContext; |
fbe31dc8 | 311 | |
758a629f DV |
312 | var label, x, y, tick, i; |
313 | ||
34fedff8 | 314 | var labelStyle = { |
423f5ed3 DV |
315 | position: "absolute", |
316 | fontSize: this.attr_('axisLabelFontSize') + "px", | |
317 | zIndex: 10, | |
318 | color: this.attr_('axisLabelColor'), | |
319 | width: this.attr_('axisLabelWidth') + "px", | |
74a5af31 | 320 | // height: this.attr_('axisLabelFontSize') + 2 + "px", |
758a629f | 321 | lineHeight: "normal", // Something other than "normal" line-height screws up label positioning. |
423f5ed3 | 322 | overflow: "hidden" |
34fedff8 | 323 | }; |
48e614ac | 324 | var makeDiv = function(txt, axis, prec_axis) { |
34fedff8 DV |
325 | var div = document.createElement("div"); |
326 | for (var name in labelStyle) { | |
85b99f0b DV |
327 | if (labelStyle.hasOwnProperty(name)) { |
328 | div.style[name] = labelStyle[name]; | |
329 | } | |
fbe31dc8 | 330 | } |
ba451526 | 331 | var inner_div = document.createElement("div"); |
48e614ac DV |
332 | inner_div.className = 'dygraph-axis-label' + |
333 | ' dygraph-axis-label-' + axis + | |
334 | (prec_axis ? ' dygraph-axis-label-' + prec_axis : ''); | |
3bdf7140 | 335 | inner_div.innerHTML=txt; |
ba451526 | 336 | div.appendChild(inner_div); |
34fedff8 | 337 | return div; |
fbe31dc8 DV |
338 | }; |
339 | ||
340 | // axis lines | |
341 | context.save(); | |
423f5ed3 DV |
342 | context.strokeStyle = this.attr_('axisLineColor'); |
343 | context.lineWidth = this.attr_('axisLineWidth'); | |
fbe31dc8 | 344 | |
423f5ed3 | 345 | if (this.attr_('drawYAxis')) { |
8b7a0cc3 | 346 | if (this.layout.yticks && this.layout.yticks.length > 0) { |
48e614ac | 347 | var num_axes = this.dygraph_.numAxes(); |
758a629f DV |
348 | for (i = 0; i < this.layout.yticks.length; i++) { |
349 | tick = this.layout.yticks[i]; | |
fbe31dc8 | 350 | if (typeof(tick) == "function") return; |
758a629f | 351 | x = this.area.x; |
880a574f | 352 | var sgn = 1; |
48e614ac | 353 | var prec_axis = 'y1'; |
880a574f DV |
354 | if (tick[0] == 1) { // right-side y-axis |
355 | x = this.area.x + this.area.w; | |
356 | sgn = -1; | |
48e614ac | 357 | prec_axis = 'y2'; |
9012dd21 | 358 | } |
758a629f | 359 | y = this.area.y + tick[1] * this.area.h; |
920208fb PF |
360 | |
361 | /* Tick marks are currently clipped, so don't bother drawing them. | |
fbe31dc8 | 362 | context.beginPath(); |
528ce7e5 | 363 | context.moveTo(halfUp(x), halfDown(y)); |
0e23cfc6 | 364 | context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y)); |
fbe31dc8 DV |
365 | context.closePath(); |
366 | context.stroke(); | |
920208fb | 367 | */ |
fbe31dc8 | 368 | |
758a629f | 369 | label = makeDiv(tick[2], 'y', num_axes == 2 ? prec_axis : null); |
423f5ed3 | 370 | var top = (y - this.attr_('axisLabelFontSize') / 2); |
fbe31dc8 DV |
371 | if (top < 0) top = 0; |
372 | ||
423f5ed3 | 373 | if (top + this.attr_('axisLabelFontSize') + 3 > this.height) { |
fbe31dc8 DV |
374 | label.style.bottom = "0px"; |
375 | } else { | |
376 | label.style.top = top + "px"; | |
377 | } | |
758a629f | 378 | if (tick[0] === 0) { |
423f5ed3 | 379 | label.style.left = (this.area.x - this.attr_('yAxisLabelWidth') - this.attr_('axisTickSize')) + "px"; |
9012dd21 DV |
380 | label.style.textAlign = "right"; |
381 | } else if (tick[0] == 1) { | |
382 | label.style.left = (this.area.x + this.area.w + | |
423f5ed3 | 383 | this.attr_('axisTickSize')) + "px"; |
9012dd21 DV |
384 | label.style.textAlign = "left"; |
385 | } | |
423f5ed3 | 386 | label.style.width = this.attr_('yAxisLabelWidth') + "px"; |
b0c3b730 | 387 | this.container.appendChild(label); |
fbe31dc8 | 388 | this.ylabels.push(label); |
2160ed4a | 389 | } |
fbe31dc8 DV |
390 | |
391 | // The lowest tick on the y-axis often overlaps with the leftmost | |
392 | // tick on the x-axis. Shift the bottom tick up a little bit to | |
393 | // compensate if necessary. | |
394 | var bottomTick = this.ylabels[0]; | |
423f5ed3 | 395 | var fontSize = this.attr_('axisLabelFontSize'); |
758a629f | 396 | var bottom = parseInt(bottomTick.style.top, 10) + fontSize; |
fbe31dc8 | 397 | if (bottom > this.height - fontSize) { |
758a629f | 398 | bottomTick.style.top = (parseInt(bottomTick.style.top, 10) - |
fbe31dc8 DV |
399 | fontSize / 2) + "px"; |
400 | } | |
401 | } | |
402 | ||
528ce7e5 | 403 | // draw a vertical line on the left to separate the chart from the labels. |
f4b87da2 KW |
404 | var axisX; |
405 | if (this.attr_('drawAxesAtZero')) { | |
406 | var r = this.dygraph_.toPercentXCoord(0); | |
407 | if (r > 1 || r < 0) r = 0; | |
408 | axisX = halfUp(this.area.x + r * this.area.w); | |
409 | } else { | |
410 | axisX = halfUp(this.area.x); | |
411 | } | |
fbe31dc8 | 412 | context.beginPath(); |
f4b87da2 KW |
413 | context.moveTo(axisX, halfDown(this.area.y)); |
414 | context.lineTo(axisX, halfDown(this.area.y + this.area.h)); | |
fbe31dc8 DV |
415 | context.closePath(); |
416 | context.stroke(); | |
c1dbeb10 | 417 | |
528ce7e5 | 418 | // if there's a secondary y-axis, draw a vertical line for that, too. |
c1dbeb10 DV |
419 | if (this.dygraph_.numAxes() == 2) { |
420 | context.beginPath(); | |
528ce7e5 DV |
421 | context.moveTo(halfDown(this.area.x + this.area.w), halfDown(this.area.y)); |
422 | context.lineTo(halfDown(this.area.x + this.area.w), halfDown(this.area.y + this.area.h)); | |
c1dbeb10 DV |
423 | context.closePath(); |
424 | context.stroke(); | |
425 | } | |
fbe31dc8 DV |
426 | } |
427 | ||
423f5ed3 | 428 | if (this.attr_('drawXAxis')) { |
fbe31dc8 | 429 | if (this.layout.xticks) { |
758a629f DV |
430 | for (i = 0; i < this.layout.xticks.length; i++) { |
431 | tick = this.layout.xticks[i]; | |
432 | x = this.area.x + tick[0] * this.area.w; | |
433 | y = this.area.y + this.area.h; | |
920208fb PF |
434 | |
435 | /* Tick marks are currently clipped, so don't bother drawing them. | |
fbe31dc8 | 436 | context.beginPath(); |
528ce7e5 | 437 | context.moveTo(halfUp(x), halfDown(y)); |
423f5ed3 | 438 | context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize'))); |
fbe31dc8 DV |
439 | context.closePath(); |
440 | context.stroke(); | |
920208fb | 441 | */ |
fbe31dc8 | 442 | |
758a629f | 443 | label = makeDiv(tick[1], 'x'); |
fbe31dc8 | 444 | label.style.textAlign = "center"; |
423f5ed3 | 445 | label.style.top = (y + this.attr_('axisTickSize')) + 'px'; |
fbe31dc8 | 446 | |
423f5ed3 DV |
447 | var left = (x - this.attr_('axisLabelWidth')/2); |
448 | if (left + this.attr_('axisLabelWidth') > this.width) { | |
449 | left = this.width - this.attr_('xAxisLabelWidth'); | |
fbe31dc8 DV |
450 | label.style.textAlign = "right"; |
451 | } | |
452 | if (left < 0) { | |
453 | left = 0; | |
454 | label.style.textAlign = "left"; | |
455 | } | |
456 | ||
457 | label.style.left = left + "px"; | |
423f5ed3 | 458 | label.style.width = this.attr_('xAxisLabelWidth') + "px"; |
b0c3b730 | 459 | this.container.appendChild(label); |
fbe31dc8 | 460 | this.xlabels.push(label); |
2160ed4a | 461 | } |
fbe31dc8 DV |
462 | } |
463 | ||
464 | context.beginPath(); | |
f4b87da2 KW |
465 | var axisY; |
466 | if (this.attr_('drawAxesAtZero')) { | |
467 | var r = this.dygraph_.toPercentYCoord(0, 0); | |
468 | if (r > 1 || r < 0) r = 1; | |
469 | axisY = halfDown(this.area.y + r * this.area.h); | |
470 | } else { | |
471 | axisY = halfDown(this.area.y + this.area.h); | |
472 | } | |
473 | context.moveTo(halfUp(this.area.x), axisY); | |
474 | context.lineTo(halfUp(this.area.x + this.area.w), axisY); | |
fbe31dc8 DV |
475 | context.closePath(); |
476 | context.stroke(); | |
477 | } | |
478 | ||
479 | context.restore(); | |
6a1aa64f DV |
480 | }; |
481 | ||
fbe31dc8 | 482 | |
ccb0001c | 483 | /** |
8722284b RK |
484 | * Returns a predicate to be used with an iterator, which will |
485 | * iterate over points appropriately, depending on whether | |
486 | * connectSeparatedPoints is true. When it's false, the predicate will | |
487 | * skip over points with missing yVals. | |
ccb0001c | 488 | */ |
8722284b RK |
489 | DygraphCanvasRenderer._getIteratorPredicate = function(connectSeparatedPoints) { |
490 | return connectSeparatedPoints ? DygraphCanvasRenderer._predicateThatSkipsEmptyPoints : null; | |
491 | } | |
492 | ||
493 | DygraphCanvasRenderer._predicateThatSkipsEmptyPoints = | |
494 | function(array, idx) { return array[idx].yval !== null; } | |
04c104d7 | 495 | |
857a6931 | 496 | DygraphCanvasRenderer.prototype._drawStyledLine = function( |
5469113b KW |
497 | ctx, i, setName, color, strokeWidth, strokePattern, drawPoints, |
498 | drawPointCallback, pointSize) { | |
99a77a04 | 499 | // TODO(konigsberg): Compute attributes outside this method call. |
857a6931 KW |
500 | var stepPlot = this.attr_("stepPlot"); |
501 | var firstIndexInSet = this.layout.setPointsOffsets[i]; | |
502 | var setLength = this.layout.setPointsLengths[i]; | |
857a6931 | 503 | var points = this.layout.points; |
857a6931 KW |
504 | if (!Dygraph.isArrayLike(strokePattern)) { |
505 | strokePattern = null; | |
506 | } | |
a5a50727 | 507 | var drawGapPoints = this.dygraph_.attr_('drawGapEdgePoints', setName); |
857a6931 | 508 | |
b843b52c | 509 | ctx.save(); |
7d1afbb9 | 510 | |
7d1afbb9 | 511 | var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, |
8722284b | 512 | DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); |
7d1afbb9 | 513 | |
31f8e58b RK |
514 | var pointsOnLine; |
515 | var strategy; | |
516 | if (!strokePattern || strokePattern.length <= 1) { | |
517 | strategy = trivialStrategy(ctx, color, strokeWidth); | |
b843b52c | 518 | } else { |
31f8e58b | 519 | strategy = nonTrivialStrategy(this, ctx, color, strokeWidth, strokePattern); |
b843b52c | 520 | } |
31f8e58b RK |
521 | pointsOnLine = this._drawSeries(ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, stepPlot, strategy); |
522 | this._drawPointsOnLine(ctx, pointsOnLine, drawPointCallback, setName, color, pointSize); | |
523 | ||
b843b52c RK |
524 | ctx.restore(); |
525 | }; | |
526 | ||
31f8e58b RK |
527 | var nonTrivialStrategy = function(renderer, ctx, color, strokeWidth, strokePattern) { |
528 | return new function() { | |
529 | this.init = function() { }; | |
530 | this.finish = function() { }; | |
531 | this.startSegment = function() { | |
532 | ctx.beginPath(); | |
533 | ctx.strokeStyle = color; | |
534 | ctx.lineWidth = strokeWidth; | |
535 | }; | |
536 | this.endSegment = function() { | |
537 | ctx.stroke(); // should this include closePath? | |
538 | }; | |
539 | this.drawLine = function(x1, y1, x2, y2) { | |
540 | renderer._dashedLine(ctx, x1, y1, x2, y2, strokePattern); | |
541 | }; | |
542 | this.skipPixel = function(prevX, prevY, curX, curY) { | |
543 | // TODO(konigsberg): optimize with http://jsperf.com/math-round-vs-hack/6 ? | |
544 | return (Math.round(prevX) == Math.round(curX) && | |
545 | Math.round(prevY) == Math.round(curY)); | |
546 | }; | |
547 | }; | |
548 | }; | |
549 | ||
550 | var trivialStrategy = function(ctx, color, strokeWidth) { | |
551 | return new function() { | |
552 | this.init = function() { | |
553 | ctx.beginPath(); | |
554 | ctx.strokeStyle = color; | |
555 | ctx.lineWidth = strokeWidth; | |
556 | }; | |
557 | this.finish = function() { | |
558 | ctx.stroke(); // should this include closePath? | |
559 | }; | |
560 | this.startSegment = function() { }; | |
561 | this.endSegment = function() { }; | |
562 | this.drawLine = function(x1, y1, x2, y2) { | |
563 | ctx.moveTo(x1, y1); | |
564 | ctx.lineTo(x2, y2); | |
565 | }; | |
566 | // don't skip pixels. | |
567 | this.skipPixel = function() { | |
568 | return false; | |
569 | }; | |
570 | }; | |
571 | }; | |
572 | ||
a401ca8a RK |
573 | DygraphCanvasRenderer.prototype._drawPointsOnLine = function(ctx, pointsOnLine, drawPointCallback, setName, color, pointSize) { |
574 | for (var idx = 0; idx < pointsOnLine.length; idx++) { | |
575 | var cb = pointsOnLine[idx]; | |
576 | ctx.save(); | |
577 | drawPointCallback( | |
578 | this.dygraph_, setName, ctx, cb[0], cb[1], color, pointSize); | |
579 | ctx.restore(); | |
580 | } | |
581 | } | |
582 | ||
31f8e58b RK |
583 | DygraphCanvasRenderer.prototype._drawSeries = function( |
584 | ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, | |
585 | stepPlot, strategy) { | |
586 | ||
31f8e58b RK |
587 | var prevCanvasX = null; |
588 | var prevCanvasY = null; | |
589 | var nextCanvasY = null; | |
590 | var isIsolated; // true if this point is isolated (no line segments) | |
591 | var point; // the point being processed in the while loop | |
b843b52c | 592 | var pointsOnLine = []; // Array of [canvasx, canvasy] pairs. |
31f8e58b RK |
593 | var first = true; // the first cycle through the while loop |
594 | ||
595 | strategy.init(); | |
596 | ||
7d1afbb9 RK |
597 | while(iter.hasNext()) { |
598 | point = iter.next(); | |
a02978e2 | 599 | if (point.canvasy === null || point.canvasy != point.canvasy) { |
31f8e58b | 600 | if (stepPlot && prevCanvasX !== null) { |
857a6931 | 601 | // Draw a horizontal line to the start of the missing data |
31f8e58b RK |
602 | strategy.startSegment(); |
603 | strategy.drawLine(prevX, prevY, point.canvasx, prevY); | |
604 | strategy.endSegment(); | |
857a6931 | 605 | } |
31f8e58b | 606 | prevCanvasX = prevCanvasY = null; |
857a6931 | 607 | } else { |
31f8e58b | 608 | nextCanvasY = iter.hasNext() ? iter.peek().canvasy : null; |
a02978e2 RK |
609 | // TODO: we calculate isNullOrNaN for this point, and the next, and then, when |
610 | // we iterate, test for isNullOrNaN again. Why bother? | |
611 | var isNextCanvasYNullOrNaN = nextCanvasY === null || nextCanvasY != nextCanvasY; | |
612 | isIsolated = (!prevCanvasX && isNextCanvasYNullOrNaN); | |
19b84fe7 | 613 | if (drawGapPoints) { |
31f8e58b | 614 | // Also consider a point to be "isolated" if it's adjacent to a |
19b84fe7 | 615 | // null point, excluding the graph edges. |
31f8e58b | 616 | if ((!first && !prevCanvasX) || |
a02978e2 | 617 | (iter.hasNext() && isNextCanvasYNullOrNaN)) { |
19b84fe7 KW |
618 | isIsolated = true; |
619 | } | |
620 | } | |
31f8e58b RK |
621 | if (prevCanvasX !== null) { |
622 | if (strategy.skipPixel(prevCanvasX, prevCanvasY, point.canvasx, point.canvasy)) { | |
857a6931 KW |
623 | continue; |
624 | } | |
857a6931 | 625 | if (strokeWidth) { |
31f8e58b | 626 | strategy.startSegment(); |
857a6931 | 627 | if (stepPlot) { |
31f8e58b RK |
628 | strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, prevCanvasY); |
629 | prevCanvasX = point.canvasx; | |
857a6931 | 630 | } |
31f8e58b RK |
631 | strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, point.canvasy); |
632 | strategy.endSegment(); | |
b843b52c RK |
633 | } |
634 | } | |
b843b52c RK |
635 | if (drawPoints || isIsolated) { |
636 | pointsOnLine.push([point.canvasx, point.canvasy]); | |
637 | } | |
31f8e58b RK |
638 | prevCanvasX = point.canvasx; |
639 | prevCanvasY = point.canvasy; | |
b843b52c | 640 | } |
7d1afbb9 | 641 | first = false; |
b843b52c | 642 | } |
31f8e58b RK |
643 | strategy.finish(); |
644 | return pointsOnLine; | |
857a6931 KW |
645 | }; |
646 | ||
647 | DygraphCanvasRenderer.prototype._drawLine = function(ctx, i) { | |
648 | var setNames = this.layout.setNames; | |
649 | var setName = setNames[i]; | |
650 | ||
651 | var strokeWidth = this.dygraph_.attr_("strokeWidth", setName); | |
652 | var borderWidth = this.dygraph_.attr_("strokeBorderWidth", setName); | |
5469113b KW |
653 | var drawPointCallback = this.dygraph_.attr_("drawPointCallback", setName) || |
654 | Dygraph.Circles.DEFAULT; | |
99a77a04 | 655 | |
857a6931 | 656 | if (borderWidth && strokeWidth) { |
5469113b | 657 | this._drawStyledLine(ctx, i, setName, |
857a6931 KW |
658 | this.dygraph_.attr_("strokeBorderColor", setName), |
659 | strokeWidth + 2 * borderWidth, | |
660 | this.dygraph_.attr_("strokePattern", setName), | |
661 | this.dygraph_.attr_("drawPoints", setName), | |
5469113b | 662 | drawPointCallback, |
857a6931 KW |
663 | this.dygraph_.attr_("pointSize", setName)); |
664 | } | |
665 | ||
5469113b | 666 | this._drawStyledLine(ctx, i, setName, |
857a6931 KW |
667 | this.colors[setName], |
668 | strokeWidth, | |
669 | this.dygraph_.attr_("strokePattern", setName), | |
670 | this.dygraph_.attr_("drawPoints", setName), | |
5469113b | 671 | drawPointCallback, |
857a6931 KW |
672 | this.dygraph_.attr_("pointSize", setName)); |
673 | }; | |
ce49c2fa | 674 | |
6a1aa64f | 675 | /** |
758a629f DV |
676 | * Actually draw the lines chart, including error bars. |
677 | * TODO(danvk): split this into several smaller functions. | |
678 | * @private | |
6a1aa64f | 679 | */ |
285a6bda | 680 | DygraphCanvasRenderer.prototype._renderLineChart = function() { |
44c6bc29 | 681 | // TODO(danvk): use this.attr_ for many of these. |
857a6931 | 682 | var ctx = this.elementContext; |
423f5ed3 | 683 | var fillAlpha = this.attr_('fillAlpha'); |
e4182459 | 684 | var errorBars = this.attr_("errorBars") || this.attr_("customBars"); |
44c6bc29 | 685 | var fillGraph = this.attr_("fillGraph"); |
b2c9222a DV |
686 | var stackedGraph = this.attr_("stackedGraph"); |
687 | var stepPlot = this.attr_("stepPlot"); | |
c3e1495b AR |
688 | var points = this.layout.points; |
689 | var pointsLength = points.length; | |
8722284b | 690 | var point, i, prevX, prevY, prevYs, color, setName, newYs, err_color, rgb, yscale, axis; |
21d3323f | 691 | |
82c6fe4d | 692 | var setNames = this.layout.setNames; |
21d3323f | 693 | var setCount = setNames.length; |
6a1aa64f | 694 | |
ee53deb9 | 695 | this.colors = this.dygraph_.colorsMap_; |
f032c51d | 696 | |
ff00d3e2 DV |
697 | // Update Points |
698 | // TODO(danvk): here | |
b843b52c RK |
699 | // |
700 | // TODO(bhs): this loop is a hot-spot for high-point-count charts. These | |
701 | // transformations can be pushed into the canvas via linear transformation | |
702 | // matrices. | |
758a629f DV |
703 | for (i = pointsLength; i--;) { |
704 | point = points[i]; | |
6a1aa64f DV |
705 | point.canvasx = this.area.w * point.x + this.area.x; |
706 | point.canvasy = this.area.h * point.y + this.area.y; | |
707 | } | |
6a1aa64f DV |
708 | |
709 | // create paths | |
80aaae18 | 710 | if (errorBars) { |
857a6931 | 711 | ctx.save(); |
6a834bbb DV |
712 | if (fillGraph) { |
713 | this.dygraph_.warn("Can't use fillGraph option with error bars"); | |
714 | } | |
715 | ||
758a629f DV |
716 | for (i = 0; i < setCount; i++) { |
717 | setName = setNames[i]; | |
718 | axis = this.dygraph_.axisPropertiesForSeries(setName); | |
719 | color = this.colors[setName]; | |
6a1aa64f | 720 | |
04c104d7 KW |
721 | var firstIndexInSet = this.layout.setPointsOffsets[i]; |
722 | var setLength = this.layout.setPointsLengths[i]; | |
04c104d7 | 723 | |
8722284b RK |
724 | var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, |
725 | DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); | |
04c104d7 | 726 | |
6a1aa64f | 727 | // setup graphics context |
758a629f DV |
728 | prevX = NaN; |
729 | prevY = NaN; | |
730 | prevYs = [-1, -1]; | |
731 | yscale = axis.yscale; | |
f474c2a3 | 732 | // should be same color as the lines but only 15% opaque. |
758a629f DV |
733 | rgb = new RGBColor(color); |
734 | err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + | |
43af96e7 | 735 | fillAlpha + ')'; |
f474c2a3 | 736 | ctx.fillStyle = err_color; |
05c9d0c4 | 737 | ctx.beginPath(); |
8722284b RK |
738 | while (iter.hasNext()) { |
739 | point = iter.next(); | |
04c104d7 | 740 | if (point.name == setName) { // TODO(klausw): this is always true |
e9fe4a2f | 741 | if (!Dygraph.isOK(point.y)) { |
56623f3b | 742 | prevX = NaN; |
ae85914a | 743 | continue; |
5011e7a1 | 744 | } |
ce49c2fa | 745 | |
3637724f | 746 | // TODO(danvk): here |
afdc483f | 747 | if (stepPlot) { |
758a629f | 748 | newYs = [ point.y_bottom, point.y_top ]; |
afdc483f NN |
749 | prevY = point.y; |
750 | } else { | |
758a629f | 751 | newYs = [ point.y_bottom, point.y_top ]; |
afdc483f | 752 | } |
6a1aa64f DV |
753 | newYs[0] = this.area.h * newYs[0] + this.area.y; |
754 | newYs[1] = this.area.h * newYs[1] + this.area.y; | |
56623f3b | 755 | if (!isNaN(prevX)) { |
afdc483f | 756 | if (stepPlot) { |
47600757 | 757 | ctx.moveTo(prevX, newYs[0]); |
afdc483f | 758 | } else { |
47600757 | 759 | ctx.moveTo(prevX, prevYs[0]); |
afdc483f | 760 | } |
5954ef32 DV |
761 | ctx.lineTo(point.canvasx, newYs[0]); |
762 | ctx.lineTo(point.canvasx, newYs[1]); | |
afdc483f | 763 | if (stepPlot) { |
47600757 | 764 | ctx.lineTo(prevX, newYs[1]); |
afdc483f | 765 | } else { |
47600757 | 766 | ctx.lineTo(prevX, prevYs[1]); |
afdc483f | 767 | } |
5954ef32 DV |
768 | ctx.closePath(); |
769 | } | |
354e15ab | 770 | prevYs = newYs; |
5954ef32 DV |
771 | prevX = point.canvasx; |
772 | } | |
773 | } | |
774 | ctx.fill(); | |
775 | } | |
857a6931 | 776 | ctx.restore(); |
5954ef32 | 777 | } else if (fillGraph) { |
857a6931 | 778 | ctx.save(); |
349dd9ba DW |
779 | var baseline = {}; // for stacked graphs: baseline for filling |
780 | var currBaseline; | |
354e15ab DE |
781 | |
782 | // process sets in reverse order (needed for stacked graphs) | |
758a629f DV |
783 | for (i = setCount - 1; i >= 0; i--) { |
784 | setName = setNames[i]; | |
785 | color = this.colors[setName]; | |
786 | axis = this.dygraph_.axisPropertiesForSeries(setName); | |
ea4942ed DV |
787 | var axisY = 1.0 + axis.minyval * axis.yscale; |
788 | if (axisY < 0.0) axisY = 0.0; | |
789 | else if (axisY > 1.0) axisY = 1.0; | |
790 | axisY = this.area.h * axisY + this.area.y; | |
04c104d7 KW |
791 | var firstIndexInSet = this.layout.setPointsOffsets[i]; |
792 | var setLength = this.layout.setPointsLengths[i]; | |
04c104d7 | 793 | |
8722284b RK |
794 | var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, |
795 | DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); | |
5954ef32 DV |
796 | |
797 | // setup graphics context | |
758a629f DV |
798 | prevX = NaN; |
799 | prevYs = [-1, -1]; | |
800 | yscale = axis.yscale; | |
5954ef32 | 801 | // should be same color as the lines but only 15% opaque. |
758a629f DV |
802 | rgb = new RGBColor(color); |
803 | err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + | |
43af96e7 | 804 | fillAlpha + ')'; |
5954ef32 DV |
805 | ctx.fillStyle = err_color; |
806 | ctx.beginPath(); | |
8722284b RK |
807 | while(iter.hasNext()) { |
808 | point = iter.next(); | |
04c104d7 | 809 | if (point.name == setName) { // TODO(klausw): this is always true |
e9fe4a2f | 810 | if (!Dygraph.isOK(point.y)) { |
56623f3b | 811 | prevX = NaN; |
5954ef32 DV |
812 | continue; |
813 | } | |
354e15ab | 814 | if (stackedGraph) { |
349dd9ba DW |
815 | currBaseline = baseline[point.canvasx]; |
816 | var lastY; | |
817 | if (currBaseline === undefined) { | |
818 | lastY = axisY; | |
819 | } else { | |
820 | if(stepPlot) { | |
821 | lastY = currBaseline[0]; | |
822 | } else { | |
823 | lastY = currBaseline; | |
824 | } | |
825 | } | |
354e15ab | 826 | newYs = [ point.canvasy, lastY ]; |
b843b52c | 827 | |
349dd9ba DW |
828 | if(stepPlot) { |
829 | // Step plots must keep track of the top and bottom of | |
830 | // the baseline at each point. | |
831 | if(prevYs[0] === -1) { | |
832 | baseline[point.canvasx] = [ point.canvasy, axisY ]; | |
833 | } else { | |
834 | baseline[point.canvasx] = [ point.canvasy, prevYs[0] ]; | |
835 | } | |
836 | } else { | |
837 | baseline[point.canvasx] = point.canvasy; | |
838 | } | |
b843b52c | 839 | |
354e15ab DE |
840 | } else { |
841 | newYs = [ point.canvasy, axisY ]; | |
842 | } | |
56623f3b | 843 | if (!isNaN(prevX)) { |
05c9d0c4 | 844 | ctx.moveTo(prevX, prevYs[0]); |
b843b52c | 845 | |
afdc483f | 846 | if (stepPlot) { |
47600757 | 847 | ctx.lineTo(point.canvasx, prevYs[0]); |
349dd9ba DW |
848 | if(currBaseline) { |
849 | // Draw to the bottom of the baseline | |
850 | ctx.lineTo(point.canvasx, currBaseline[1]); | |
851 | } else { | |
852 | ctx.lineTo(point.canvasx, newYs[1]); | |
853 | } | |
afdc483f | 854 | } else { |
47600757 | 855 | ctx.lineTo(point.canvasx, newYs[0]); |
349dd9ba | 856 | ctx.lineTo(point.canvasx, newYs[1]); |
afdc483f | 857 | } |
b843b52c | 858 | |
05c9d0c4 DV |
859 | ctx.lineTo(prevX, prevYs[1]); |
860 | ctx.closePath(); | |
6a1aa64f | 861 | } |
354e15ab | 862 | prevYs = newYs; |
6a1aa64f DV |
863 | prevX = point.canvasx; |
864 | } | |
05c9d0c4 | 865 | } |
6a1aa64f DV |
866 | ctx.fill(); |
867 | } | |
857a6931 | 868 | ctx.restore(); |
80aaae18 DV |
869 | } |
870 | ||
f9414b11 | 871 | // Drawing the lines. |
758a629f | 872 | for (i = 0; i < setCount; i += 1) { |
857a6931 | 873 | this._drawLine(ctx, i); |
80aaae18 | 874 | } |
6a1aa64f | 875 | }; |
79253bd0 | 876 | |
877 | /** | |
878 | * This does dashed lines onto a canvas for a given pattern. You must call | |
879 | * ctx.stroke() after to actually draw it, much line ctx.lineTo(). It remembers | |
880 | * the state of the line in regards to where we left off on drawing the pattern. | |
881 | * You can draw a dashed line in several function calls and the pattern will be | |
882 | * continous as long as you didn't call this function with a different pattern | |
883 | * in between. | |
884 | * @param ctx The canvas 2d context to draw on. | |
885 | * @param x The start of the line's x coordinate. | |
886 | * @param y The start of the line's y coordinate. | |
887 | * @param x2 The end of the line's x coordinate. | |
888 | * @param y2 The end of the line's y coordinate. | |
889 | * @param pattern The dash pattern to draw, an array of integers where even | |
890 | * index is drawn and odd index is not drawn (Ex. [10, 2, 5, 2], 10 is drawn 5 | |
891 | * is drawn, 2 is the space between.). A null pattern, array of length one, or | |
892 | * empty array will do just a solid line. | |
893 | * @private | |
894 | */ | |
895 | DygraphCanvasRenderer.prototype._dashedLine = function(ctx, x, y, x2, y2, pattern) { | |
896 | // Original version http://stackoverflow.com/questions/4576724/dotted-stroke-in-canvas | |
897 | // Modified by Russell Valentine to keep line history and continue the pattern | |
898 | // where it left off. | |
899 | var dx, dy, len, rot, patternIndex, segment; | |
900 | ||
901 | // If we don't have a pattern or it is an empty array or of size one just | |
902 | // do a solid line. | |
903 | if (!pattern || pattern.length <= 1) { | |
904 | ctx.moveTo(x, y); | |
905 | ctx.lineTo(x2, y2); | |
906 | return; | |
907 | } | |
908 | ||
909 | // If we have a different dash pattern than the last time this was called we | |
910 | // reset our dash history and start the pattern from the begging | |
911 | // regardless of state of the last pattern. | |
912 | if (!Dygraph.compareArrays(pattern, this._dashedLineToHistoryPattern)) { | |
913 | this._dashedLineToHistoryPattern = pattern; | |
914 | this._dashedLineToHistory = [0, 0]; | |
915 | } | |
916 | ctx.save(); | |
917 | ||
918 | // Calculate transformation parameters | |
919 | dx = (x2-x); | |
920 | dy = (y2-y); | |
921 | len = Math.sqrt(dx*dx + dy*dy); | |
922 | rot = Math.atan2(dy, dx); | |
923 | ||
924 | // Set transformation | |
925 | ctx.translate(x, y); | |
926 | ctx.moveTo(0, 0); | |
927 | ctx.rotate(rot); | |
928 | ||
929 | // Set last pattern index we used for this pattern. | |
930 | patternIndex = this._dashedLineToHistory[0]; | |
931 | x = 0; | |
932 | while (len > x) { | |
933 | // Get the length of the pattern segment we are dealing with. | |
934 | segment = pattern[patternIndex]; | |
935 | // If our last draw didn't complete the pattern segment all the way we | |
936 | // will try to finish it. Otherwise we will try to do the whole segment. | |
937 | if (this._dashedLineToHistory[1]) { | |
938 | x += this._dashedLineToHistory[1]; | |
939 | } else { | |
940 | x += segment; | |
941 | } | |
942 | if (x > len) { | |
943 | // We were unable to complete this pattern index all the way, keep | |
944 | // where we are the history so our next draw continues where we left off | |
945 | // in the pattern. | |
946 | this._dashedLineToHistory = [patternIndex, x-len]; | |
947 | x = len; | |
948 | } else { | |
949 | // We completed this patternIndex, we put in the history that we are on | |
950 | // the beginning of the next segment. | |
951 | this._dashedLineToHistory = [(patternIndex+1)%pattern.length, 0]; | |
952 | } | |
953 | ||
954 | // We do a line on a even pattern index and just move on a odd pattern index. | |
955 | // The move is the empty space in the dash. | |
956 | if(patternIndex % 2 === 0) { | |
957 | ctx.lineTo(x, 0); | |
958 | } else { | |
959 | ctx.moveTo(x, 0); | |
960 | } | |
961 | // If we are not done, next loop process the next pattern segment, or the | |
962 | // first segment again if we are at the end of the pattern. | |
963 | patternIndex = (patternIndex+1) % pattern.length; | |
964 | } | |
965 | ctx.restore(); | |
966 | }; |