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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 = []; | |
67 | this.annotations = []; | |
fbe31dc8 | 68 | |
70be5ed1 | 69 | this.area = layout.getPlotArea(); |
423f5ed3 DV |
70 | this.container.style.position = "relative"; |
71 | this.container.style.width = this.width + "px"; | |
72 | ||
73 | // Set up a clipping area for the canvas (and the interaction canvas). | |
74 | // This ensures that we don't overdraw. | |
920208fb PF |
75 | if (this.dygraph_.isUsingExcanvas_) { |
76 | this._createIEClipArea(); | |
77 | } else { | |
971870e5 DV |
78 | // on Android 3 and 4, setting a clipping area on a canvas prevents it from |
79 | // displaying anything. | |
80 | if (!Dygraph.isAndroid()) { | |
81 | var ctx = this.dygraph_.canvas_ctx_; | |
82 | ctx.beginPath(); | |
83 | ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h); | |
84 | ctx.clip(); | |
920208fb | 85 | |
971870e5 DV |
86 | ctx = this.dygraph_.hidden_ctx_; |
87 | ctx.beginPath(); | |
88 | ctx.rect(this.area.x, this.area.y, this.area.w, this.area.h); | |
89 | ctx.clip(); | |
90 | } | |
920208fb | 91 | } |
423f5ed3 DV |
92 | }; |
93 | ||
94 | DygraphCanvasRenderer.prototype.attr_ = function(x) { | |
95 | return this.dygraph_.attr_(x); | |
96 | }; | |
97 | ||
8cfe592f DV |
98 | /** |
99 | * Clears out all chart content and DOM elements. | |
100 | * This is called immediately before render() on every frame, including | |
101 | * during zooms and pans. | |
102 | * @private | |
103 | */ | |
fbe31dc8 | 104 | DygraphCanvasRenderer.prototype.clear = function() { |
758a629f | 105 | var context; |
fbe31dc8 DV |
106 | if (this.isIE) { |
107 | // VML takes a while to start up, so we just poll every this.IEDelay | |
108 | try { | |
109 | if (this.clearDelay) { | |
110 | this.clearDelay.cancel(); | |
111 | this.clearDelay = null; | |
112 | } | |
758a629f | 113 | context = this.elementContext; |
fbe31dc8 DV |
114 | } |
115 | catch (e) { | |
76171648 | 116 | // TODO(danvk): this is broken, since MochiKit.Async is gone. |
758a629f DV |
117 | // this.clearDelay = MochiKit.Async.wait(this.IEDelay); |
118 | // this.clearDelay.addCallback(bind(this.clear, this)); | |
fbe31dc8 DV |
119 | return; |
120 | } | |
121 | } | |
122 | ||
758a629f | 123 | context = this.elementContext; |
fbe31dc8 DV |
124 | context.clearRect(0, 0, this.width, this.height); |
125 | ||
758a629f DV |
126 | function removeArray(ary) { |
127 | for (var i = 0; i < ary.length; i++) { | |
128 | var el = ary[i]; | |
129 | if (el.parentNode) el.parentNode.removeChild(el); | |
130 | } | |
ce49c2fa | 131 | } |
758a629f DV |
132 | |
133 | removeArray(this.xlabels); | |
134 | removeArray(this.ylabels); | |
135 | removeArray(this.annotations); | |
136 | ||
758a629f DV |
137 | this.xlabels = []; |
138 | this.ylabels = []; | |
139 | this.annotations = []; | |
fbe31dc8 DV |
140 | }; |
141 | ||
8cfe592f DV |
142 | /** |
143 | * Checks whether the browser supports the <canvas> tag. | |
144 | * @private | |
145 | */ | |
fbe31dc8 DV |
146 | DygraphCanvasRenderer.isSupported = function(canvasName) { |
147 | var canvas = null; | |
148 | try { | |
758a629f | 149 | if (typeof(canvasName) == 'undefined' || canvasName === null) { |
b0c3b730 | 150 | canvas = document.createElement("canvas"); |
758a629f | 151 | } else { |
b0c3b730 | 152 | canvas = canvasName; |
758a629f DV |
153 | } |
154 | canvas.getContext("2d"); | |
fbe31dc8 DV |
155 | } |
156 | catch (e) { | |
157 | var ie = navigator.appVersion.match(/MSIE (\d\.\d)/); | |
158 | var opera = (navigator.userAgent.toLowerCase().indexOf("opera") != -1); | |
159 | if ((!ie) || (ie[1] < 6) || (opera)) | |
160 | return false; | |
161 | return true; | |
162 | } | |
163 | return true; | |
6a1aa64f | 164 | }; |
6a1aa64f DV |
165 | |
166 | /** | |
600d841a DV |
167 | * @param { [String] } colors Array of color strings. Should have one entry for |
168 | * each series to be rendered. | |
169 | */ | |
170 | DygraphCanvasRenderer.prototype.setColors = function(colors) { | |
171 | this.colorScheme_ = colors; | |
172 | }; | |
173 | ||
174 | /** | |
8cfe592f DV |
175 | * This method is responsible for drawing everything on the chart, including |
176 | * lines, error bars, fills and axes. | |
177 | * It is called immediately after clear() on every frame, including during pans | |
178 | * and zooms. | |
179 | * @private | |
6a1aa64f | 180 | */ |
285a6bda | 181 | DygraphCanvasRenderer.prototype.render = function() { |
528ce7e5 DV |
182 | // Draw the new X/Y grid. Lines appear crisper when pixels are rounded to |
183 | // half-integers. This prevents them from drawing in two rows/cols. | |
2cf95fff | 184 | var ctx = this.elementContext; |
758a629f DV |
185 | function halfUp(x) { return Math.round(x) + 0.5; } |
186 | function halfDown(y){ return Math.round(y) - 0.5; } | |
e7746234 | 187 | |
423f5ed3 | 188 | if (this.attr_('underlayCallback')) { |
1e41bd2d DV |
189 | // NOTE: we pass the dygraph object to this callback twice to avoid breaking |
190 | // users who expect a deprecated form of this callback. | |
423f5ed3 | 191 | this.attr_('underlayCallback')(ctx, this.area, this.dygraph_, this.dygraph_); |
e7746234 EC |
192 | } |
193 | ||
758a629f | 194 | var x, y, i, ticks; |
423f5ed3 | 195 | if (this.attr_('drawYGrid')) { |
758a629f | 196 | ticks = this.layout.yticks; |
bbba718a | 197 | // TODO(konigsberg): I don't think these calls to save() have a corresponding restore(). |
6a1aa64f | 198 | ctx.save(); |
423f5ed3 | 199 | ctx.strokeStyle = this.attr_('gridLineColor'); |
990d6a35 | 200 | ctx.lineWidth = this.attr_('gridLineWidth'); |
758a629f | 201 | for (i = 0; i < ticks.length; i++) { |
880a574f | 202 | // TODO(danvk): allow secondary axes to draw a grid, too. |
758a629f DV |
203 | if (ticks[i][0] !== 0) continue; |
204 | x = halfUp(this.area.x); | |
205 | y = halfDown(this.area.y + ticks[i][1] * this.area.h); | |
6a1aa64f DV |
206 | ctx.beginPath(); |
207 | ctx.moveTo(x, y); | |
208 | ctx.lineTo(x + this.area.w, y); | |
209 | ctx.closePath(); | |
210 | ctx.stroke(); | |
211 | } | |
6bf4df7f | 212 | ctx.restore(); |
6a1aa64f DV |
213 | } |
214 | ||
423f5ed3 | 215 | if (this.attr_('drawXGrid')) { |
758a629f | 216 | ticks = this.layout.xticks; |
6a1aa64f | 217 | ctx.save(); |
423f5ed3 | 218 | ctx.strokeStyle = this.attr_('gridLineColor'); |
990d6a35 | 219 | ctx.lineWidth = this.attr_('gridLineWidth'); |
758a629f DV |
220 | for (i=0; i<ticks.length; i++) { |
221 | x = halfUp(this.area.x + ticks[i][0] * this.area.w); | |
222 | y = halfDown(this.area.y + this.area.h); | |
6a1aa64f | 223 | ctx.beginPath(); |
880a574f | 224 | ctx.moveTo(x, y); |
6a1aa64f DV |
225 | ctx.lineTo(x, this.area.y); |
226 | ctx.closePath(); | |
227 | ctx.stroke(); | |
228 | } | |
6bf4df7f | 229 | ctx.restore(); |
6a1aa64f | 230 | } |
2ce09b19 DV |
231 | |
232 | // Do the ordinary rendering, as before | |
2ce09b19 | 233 | this._renderLineChart(); |
fbe31dc8 DV |
234 | this._renderAxis(); |
235 | }; | |
236 | ||
920208fb PF |
237 | DygraphCanvasRenderer.prototype._createIEClipArea = function() { |
238 | var className = 'dygraph-clip-div'; | |
239 | var graphDiv = this.dygraph_.graphDiv; | |
240 | ||
241 | // Remove old clip divs. | |
242 | for (var i = graphDiv.childNodes.length-1; i >= 0; i--) { | |
243 | if (graphDiv.childNodes[i].className == className) { | |
244 | graphDiv.removeChild(graphDiv.childNodes[i]); | |
245 | } | |
246 | } | |
247 | ||
248 | // Determine background color to give clip divs. | |
249 | var backgroundColor = document.bgColor; | |
250 | var element = this.dygraph_.graphDiv; | |
251 | while (element != document) { | |
252 | var bgcolor = element.currentStyle.backgroundColor; | |
253 | if (bgcolor && bgcolor != 'transparent') { | |
254 | backgroundColor = bgcolor; | |
255 | break; | |
256 | } | |
257 | element = element.parentNode; | |
258 | } | |
259 | ||
260 | function createClipDiv(area) { | |
758a629f | 261 | if (area.w === 0 || area.h === 0) { |
920208fb PF |
262 | return; |
263 | } | |
264 | var elem = document.createElement('div'); | |
265 | elem.className = className; | |
266 | elem.style.backgroundColor = backgroundColor; | |
267 | elem.style.position = 'absolute'; | |
268 | elem.style.left = area.x + 'px'; | |
269 | elem.style.top = area.y + 'px'; | |
270 | elem.style.width = area.w + 'px'; | |
271 | elem.style.height = area.h + 'px'; | |
272 | graphDiv.appendChild(elem); | |
273 | } | |
274 | ||
275 | var plotArea = this.area; | |
276 | // Left side | |
758a629f DV |
277 | createClipDiv({ |
278 | x:0, y:0, | |
279 | w:plotArea.x, | |
280 | h:this.height | |
281 | }); | |
282 | ||
920208fb | 283 | // Top |
758a629f DV |
284 | createClipDiv({ |
285 | x: plotArea.x, y: 0, | |
286 | w: this.width - plotArea.x, | |
287 | h: plotArea.y | |
288 | }); | |
289 | ||
920208fb | 290 | // Right side |
758a629f DV |
291 | createClipDiv({ |
292 | x: plotArea.x + plotArea.w, y: 0, | |
293 | w: this.width-plotArea.x - plotArea.w, | |
294 | h: this.height | |
295 | }); | |
296 | ||
920208fb | 297 | // Bottom |
758a629f DV |
298 | createClipDiv({ |
299 | x: plotArea.x, | |
300 | y: plotArea.y + plotArea.h, | |
301 | w: this.width - plotArea.x, | |
302 | h: this.height - plotArea.h - plotArea.y | |
303 | }); | |
304 | }; | |
fbe31dc8 DV |
305 | |
306 | DygraphCanvasRenderer.prototype._renderAxis = function() { | |
423f5ed3 | 307 | if (!this.attr_('drawXAxis') && !this.attr_('drawYAxis')) return; |
fbe31dc8 | 308 | |
528ce7e5 | 309 | // Round pixels to half-integer boundaries for crisper drawing. |
758a629f DV |
310 | function halfUp(x) { return Math.round(x) + 0.5; } |
311 | function halfDown(y){ return Math.round(y) - 0.5; } | |
528ce7e5 | 312 | |
2cf95fff | 313 | var context = this.elementContext; |
fbe31dc8 | 314 | |
758a629f DV |
315 | var label, x, y, tick, i; |
316 | ||
34fedff8 | 317 | var labelStyle = { |
423f5ed3 DV |
318 | position: "absolute", |
319 | fontSize: this.attr_('axisLabelFontSize') + "px", | |
320 | zIndex: 10, | |
321 | color: this.attr_('axisLabelColor'), | |
322 | width: this.attr_('axisLabelWidth') + "px", | |
74a5af31 | 323 | // height: this.attr_('axisLabelFontSize') + 2 + "px", |
758a629f | 324 | lineHeight: "normal", // Something other than "normal" line-height screws up label positioning. |
423f5ed3 | 325 | overflow: "hidden" |
34fedff8 | 326 | }; |
48e614ac | 327 | var makeDiv = function(txt, axis, prec_axis) { |
34fedff8 DV |
328 | var div = document.createElement("div"); |
329 | for (var name in labelStyle) { | |
85b99f0b DV |
330 | if (labelStyle.hasOwnProperty(name)) { |
331 | div.style[name] = labelStyle[name]; | |
332 | } | |
fbe31dc8 | 333 | } |
ba451526 | 334 | var inner_div = document.createElement("div"); |
48e614ac DV |
335 | inner_div.className = 'dygraph-axis-label' + |
336 | ' dygraph-axis-label-' + axis + | |
337 | (prec_axis ? ' dygraph-axis-label-' + prec_axis : ''); | |
3bdf7140 | 338 | inner_div.innerHTML=txt; |
ba451526 | 339 | div.appendChild(inner_div); |
34fedff8 | 340 | return div; |
fbe31dc8 DV |
341 | }; |
342 | ||
343 | // axis lines | |
344 | context.save(); | |
423f5ed3 DV |
345 | context.strokeStyle = this.attr_('axisLineColor'); |
346 | context.lineWidth = this.attr_('axisLineWidth'); | |
fbe31dc8 | 347 | |
423f5ed3 | 348 | if (this.attr_('drawYAxis')) { |
8b7a0cc3 | 349 | if (this.layout.yticks && this.layout.yticks.length > 0) { |
48e614ac | 350 | var num_axes = this.dygraph_.numAxes(); |
758a629f DV |
351 | for (i = 0; i < this.layout.yticks.length; i++) { |
352 | tick = this.layout.yticks[i]; | |
fbe31dc8 | 353 | if (typeof(tick) == "function") return; |
758a629f | 354 | x = this.area.x; |
880a574f | 355 | var sgn = 1; |
48e614ac | 356 | var prec_axis = 'y1'; |
880a574f DV |
357 | if (tick[0] == 1) { // right-side y-axis |
358 | x = this.area.x + this.area.w; | |
359 | sgn = -1; | |
48e614ac | 360 | prec_axis = 'y2'; |
9012dd21 | 361 | } |
758a629f | 362 | y = this.area.y + tick[1] * this.area.h; |
920208fb PF |
363 | |
364 | /* Tick marks are currently clipped, so don't bother drawing them. | |
fbe31dc8 | 365 | context.beginPath(); |
528ce7e5 | 366 | context.moveTo(halfUp(x), halfDown(y)); |
0e23cfc6 | 367 | context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y)); |
fbe31dc8 DV |
368 | context.closePath(); |
369 | context.stroke(); | |
920208fb | 370 | */ |
fbe31dc8 | 371 | |
758a629f | 372 | label = makeDiv(tick[2], 'y', num_axes == 2 ? prec_axis : null); |
423f5ed3 | 373 | var top = (y - this.attr_('axisLabelFontSize') / 2); |
fbe31dc8 DV |
374 | if (top < 0) top = 0; |
375 | ||
423f5ed3 | 376 | if (top + this.attr_('axisLabelFontSize') + 3 > this.height) { |
fbe31dc8 DV |
377 | label.style.bottom = "0px"; |
378 | } else { | |
379 | label.style.top = top + "px"; | |
380 | } | |
758a629f | 381 | if (tick[0] === 0) { |
423f5ed3 | 382 | label.style.left = (this.area.x - this.attr_('yAxisLabelWidth') - this.attr_('axisTickSize')) + "px"; |
9012dd21 DV |
383 | label.style.textAlign = "right"; |
384 | } else if (tick[0] == 1) { | |
385 | label.style.left = (this.area.x + this.area.w + | |
423f5ed3 | 386 | this.attr_('axisTickSize')) + "px"; |
9012dd21 DV |
387 | label.style.textAlign = "left"; |
388 | } | |
423f5ed3 | 389 | label.style.width = this.attr_('yAxisLabelWidth') + "px"; |
b0c3b730 | 390 | this.container.appendChild(label); |
fbe31dc8 | 391 | this.ylabels.push(label); |
2160ed4a | 392 | } |
fbe31dc8 DV |
393 | |
394 | // The lowest tick on the y-axis often overlaps with the leftmost | |
395 | // tick on the x-axis. Shift the bottom tick up a little bit to | |
396 | // compensate if necessary. | |
397 | var bottomTick = this.ylabels[0]; | |
423f5ed3 | 398 | var fontSize = this.attr_('axisLabelFontSize'); |
758a629f | 399 | var bottom = parseInt(bottomTick.style.top, 10) + fontSize; |
fbe31dc8 | 400 | if (bottom > this.height - fontSize) { |
758a629f | 401 | bottomTick.style.top = (parseInt(bottomTick.style.top, 10) - |
fbe31dc8 DV |
402 | fontSize / 2) + "px"; |
403 | } | |
404 | } | |
405 | ||
528ce7e5 | 406 | // draw a vertical line on the left to separate the chart from the labels. |
f4b87da2 KW |
407 | var axisX; |
408 | if (this.attr_('drawAxesAtZero')) { | |
409 | var r = this.dygraph_.toPercentXCoord(0); | |
410 | if (r > 1 || r < 0) r = 0; | |
411 | axisX = halfUp(this.area.x + r * this.area.w); | |
412 | } else { | |
413 | axisX = halfUp(this.area.x); | |
414 | } | |
fbe31dc8 | 415 | context.beginPath(); |
f4b87da2 KW |
416 | context.moveTo(axisX, halfDown(this.area.y)); |
417 | context.lineTo(axisX, halfDown(this.area.y + this.area.h)); | |
fbe31dc8 DV |
418 | context.closePath(); |
419 | context.stroke(); | |
c1dbeb10 | 420 | |
528ce7e5 | 421 | // if there's a secondary y-axis, draw a vertical line for that, too. |
c1dbeb10 DV |
422 | if (this.dygraph_.numAxes() == 2) { |
423 | context.beginPath(); | |
528ce7e5 DV |
424 | context.moveTo(halfDown(this.area.x + this.area.w), halfDown(this.area.y)); |
425 | context.lineTo(halfDown(this.area.x + this.area.w), halfDown(this.area.y + this.area.h)); | |
c1dbeb10 DV |
426 | context.closePath(); |
427 | context.stroke(); | |
428 | } | |
fbe31dc8 DV |
429 | } |
430 | ||
423f5ed3 | 431 | if (this.attr_('drawXAxis')) { |
fbe31dc8 | 432 | if (this.layout.xticks) { |
758a629f DV |
433 | for (i = 0; i < this.layout.xticks.length; i++) { |
434 | tick = this.layout.xticks[i]; | |
435 | x = this.area.x + tick[0] * this.area.w; | |
436 | y = this.area.y + this.area.h; | |
920208fb PF |
437 | |
438 | /* Tick marks are currently clipped, so don't bother drawing them. | |
fbe31dc8 | 439 | context.beginPath(); |
528ce7e5 | 440 | context.moveTo(halfUp(x), halfDown(y)); |
423f5ed3 | 441 | context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize'))); |
fbe31dc8 DV |
442 | context.closePath(); |
443 | context.stroke(); | |
920208fb | 444 | */ |
fbe31dc8 | 445 | |
758a629f | 446 | label = makeDiv(tick[1], 'x'); |
fbe31dc8 | 447 | label.style.textAlign = "center"; |
423f5ed3 | 448 | label.style.top = (y + this.attr_('axisTickSize')) + 'px'; |
fbe31dc8 | 449 | |
423f5ed3 DV |
450 | var left = (x - this.attr_('axisLabelWidth')/2); |
451 | if (left + this.attr_('axisLabelWidth') > this.width) { | |
452 | left = this.width - this.attr_('xAxisLabelWidth'); | |
fbe31dc8 DV |
453 | label.style.textAlign = "right"; |
454 | } | |
455 | if (left < 0) { | |
456 | left = 0; | |
457 | label.style.textAlign = "left"; | |
458 | } | |
459 | ||
460 | label.style.left = left + "px"; | |
423f5ed3 | 461 | label.style.width = this.attr_('xAxisLabelWidth') + "px"; |
b0c3b730 | 462 | this.container.appendChild(label); |
fbe31dc8 | 463 | this.xlabels.push(label); |
2160ed4a | 464 | } |
fbe31dc8 DV |
465 | } |
466 | ||
467 | context.beginPath(); | |
f4b87da2 KW |
468 | var axisY; |
469 | if (this.attr_('drawAxesAtZero')) { | |
470 | var r = this.dygraph_.toPercentYCoord(0, 0); | |
471 | if (r > 1 || r < 0) r = 1; | |
472 | axisY = halfDown(this.area.y + r * this.area.h); | |
473 | } else { | |
474 | axisY = halfDown(this.area.y + this.area.h); | |
475 | } | |
476 | context.moveTo(halfUp(this.area.x), axisY); | |
477 | context.lineTo(halfUp(this.area.x + this.area.w), axisY); | |
fbe31dc8 DV |
478 | context.closePath(); |
479 | context.stroke(); | |
480 | } | |
481 | ||
482 | context.restore(); | |
6a1aa64f DV |
483 | }; |
484 | ||
fbe31dc8 | 485 | |
ccb0001c | 486 | /** |
8722284b RK |
487 | * Returns a predicate to be used with an iterator, which will |
488 | * iterate over points appropriately, depending on whether | |
489 | * connectSeparatedPoints is true. When it's false, the predicate will | |
490 | * skip over points with missing yVals. | |
ccb0001c | 491 | */ |
8722284b RK |
492 | DygraphCanvasRenderer._getIteratorPredicate = function(connectSeparatedPoints) { |
493 | return connectSeparatedPoints ? DygraphCanvasRenderer._predicateThatSkipsEmptyPoints : null; | |
494 | } | |
495 | ||
496 | DygraphCanvasRenderer._predicateThatSkipsEmptyPoints = | |
497 | function(array, idx) { return array[idx].yval !== null; } | |
04c104d7 | 498 | |
857a6931 | 499 | DygraphCanvasRenderer.prototype._drawStyledLine = function( |
5469113b KW |
500 | ctx, i, setName, color, strokeWidth, strokePattern, drawPoints, |
501 | drawPointCallback, pointSize) { | |
99a77a04 | 502 | // TODO(konigsberg): Compute attributes outside this method call. |
857a6931 KW |
503 | var stepPlot = this.attr_("stepPlot"); |
504 | var firstIndexInSet = this.layout.setPointsOffsets[i]; | |
505 | var setLength = this.layout.setPointsLengths[i]; | |
857a6931 | 506 | var points = this.layout.points; |
857a6931 KW |
507 | if (!Dygraph.isArrayLike(strokePattern)) { |
508 | strokePattern = null; | |
509 | } | |
a5a50727 | 510 | var drawGapPoints = this.dygraph_.attr_('drawGapEdgePoints', setName); |
857a6931 | 511 | |
b843b52c | 512 | ctx.save(); |
7d1afbb9 | 513 | |
7d1afbb9 | 514 | var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, |
8722284b | 515 | DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); |
7d1afbb9 | 516 | |
31f8e58b RK |
517 | var pointsOnLine; |
518 | var strategy; | |
519 | if (!strokePattern || strokePattern.length <= 1) { | |
520 | strategy = trivialStrategy(ctx, color, strokeWidth); | |
b843b52c | 521 | } else { |
31f8e58b | 522 | strategy = nonTrivialStrategy(this, ctx, color, strokeWidth, strokePattern); |
b843b52c | 523 | } |
31f8e58b RK |
524 | pointsOnLine = this._drawSeries(ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, stepPlot, strategy); |
525 | this._drawPointsOnLine(ctx, pointsOnLine, drawPointCallback, setName, color, pointSize); | |
526 | ||
b843b52c RK |
527 | ctx.restore(); |
528 | }; | |
529 | ||
31f8e58b RK |
530 | var nonTrivialStrategy = function(renderer, ctx, color, strokeWidth, strokePattern) { |
531 | return new function() { | |
532 | this.init = function() { }; | |
533 | this.finish = function() { }; | |
534 | this.startSegment = function() { | |
535 | ctx.beginPath(); | |
536 | ctx.strokeStyle = color; | |
537 | ctx.lineWidth = strokeWidth; | |
538 | }; | |
539 | this.endSegment = function() { | |
540 | ctx.stroke(); // should this include closePath? | |
541 | }; | |
542 | this.drawLine = function(x1, y1, x2, y2) { | |
543 | renderer._dashedLine(ctx, x1, y1, x2, y2, strokePattern); | |
544 | }; | |
545 | this.skipPixel = function(prevX, prevY, curX, curY) { | |
546 | // TODO(konigsberg): optimize with http://jsperf.com/math-round-vs-hack/6 ? | |
547 | return (Math.round(prevX) == Math.round(curX) && | |
548 | Math.round(prevY) == Math.round(curY)); | |
549 | }; | |
550 | }; | |
551 | }; | |
552 | ||
553 | var trivialStrategy = function(ctx, color, strokeWidth) { | |
554 | return new function() { | |
555 | this.init = function() { | |
556 | ctx.beginPath(); | |
557 | ctx.strokeStyle = color; | |
558 | ctx.lineWidth = strokeWidth; | |
559 | }; | |
560 | this.finish = function() { | |
561 | ctx.stroke(); // should this include closePath? | |
562 | }; | |
563 | this.startSegment = function() { }; | |
564 | this.endSegment = function() { }; | |
565 | this.drawLine = function(x1, y1, x2, y2) { | |
566 | ctx.moveTo(x1, y1); | |
567 | ctx.lineTo(x2, y2); | |
568 | }; | |
569 | // don't skip pixels. | |
570 | this.skipPixel = function() { | |
571 | return false; | |
572 | }; | |
573 | }; | |
574 | }; | |
575 | ||
a401ca8a RK |
576 | DygraphCanvasRenderer.prototype._drawPointsOnLine = function(ctx, pointsOnLine, drawPointCallback, setName, color, pointSize) { |
577 | for (var idx = 0; idx < pointsOnLine.length; idx++) { | |
578 | var cb = pointsOnLine[idx]; | |
579 | ctx.save(); | |
580 | drawPointCallback( | |
581 | this.dygraph_, setName, ctx, cb[0], cb[1], color, pointSize); | |
582 | ctx.restore(); | |
583 | } | |
584 | } | |
585 | ||
31f8e58b RK |
586 | DygraphCanvasRenderer.prototype._drawSeries = function( |
587 | ctx, iter, strokeWidth, pointSize, drawPoints, drawGapPoints, | |
588 | stepPlot, strategy) { | |
589 | ||
31f8e58b RK |
590 | var prevCanvasX = null; |
591 | var prevCanvasY = null; | |
592 | var nextCanvasY = null; | |
593 | var isIsolated; // true if this point is isolated (no line segments) | |
594 | var point; // the point being processed in the while loop | |
b843b52c | 595 | var pointsOnLine = []; // Array of [canvasx, canvasy] pairs. |
31f8e58b RK |
596 | var first = true; // the first cycle through the while loop |
597 | ||
598 | strategy.init(); | |
599 | ||
7d1afbb9 RK |
600 | while(iter.hasNext()) { |
601 | point = iter.next(); | |
a02978e2 | 602 | if (point.canvasy === null || point.canvasy != point.canvasy) { |
31f8e58b | 603 | if (stepPlot && prevCanvasX !== null) { |
857a6931 | 604 | // Draw a horizontal line to the start of the missing data |
31f8e58b RK |
605 | strategy.startSegment(); |
606 | strategy.drawLine(prevX, prevY, point.canvasx, prevY); | |
607 | strategy.endSegment(); | |
857a6931 | 608 | } |
31f8e58b | 609 | prevCanvasX = prevCanvasY = null; |
857a6931 | 610 | } else { |
31f8e58b | 611 | nextCanvasY = iter.hasNext() ? iter.peek().canvasy : null; |
a02978e2 RK |
612 | // TODO: we calculate isNullOrNaN for this point, and the next, and then, when |
613 | // we iterate, test for isNullOrNaN again. Why bother? | |
614 | var isNextCanvasYNullOrNaN = nextCanvasY === null || nextCanvasY != nextCanvasY; | |
615 | isIsolated = (!prevCanvasX && isNextCanvasYNullOrNaN); | |
19b84fe7 | 616 | if (drawGapPoints) { |
31f8e58b | 617 | // Also consider a point to be "isolated" if it's adjacent to a |
19b84fe7 | 618 | // null point, excluding the graph edges. |
31f8e58b | 619 | if ((!first && !prevCanvasX) || |
a02978e2 | 620 | (iter.hasNext() && isNextCanvasYNullOrNaN)) { |
19b84fe7 KW |
621 | isIsolated = true; |
622 | } | |
623 | } | |
31f8e58b RK |
624 | if (prevCanvasX !== null) { |
625 | if (strategy.skipPixel(prevCanvasX, prevCanvasY, point.canvasx, point.canvasy)) { | |
857a6931 KW |
626 | continue; |
627 | } | |
857a6931 | 628 | if (strokeWidth) { |
31f8e58b | 629 | strategy.startSegment(); |
857a6931 | 630 | if (stepPlot) { |
31f8e58b RK |
631 | strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, prevCanvasY); |
632 | prevCanvasX = point.canvasx; | |
857a6931 | 633 | } |
31f8e58b RK |
634 | strategy.drawLine(prevCanvasX, prevCanvasY, point.canvasx, point.canvasy); |
635 | strategy.endSegment(); | |
b843b52c RK |
636 | } |
637 | } | |
b843b52c RK |
638 | if (drawPoints || isIsolated) { |
639 | pointsOnLine.push([point.canvasx, point.canvasy]); | |
640 | } | |
31f8e58b RK |
641 | prevCanvasX = point.canvasx; |
642 | prevCanvasY = point.canvasy; | |
b843b52c | 643 | } |
7d1afbb9 | 644 | first = false; |
b843b52c | 645 | } |
31f8e58b RK |
646 | strategy.finish(); |
647 | return pointsOnLine; | |
857a6931 KW |
648 | }; |
649 | ||
650 | DygraphCanvasRenderer.prototype._drawLine = function(ctx, i) { | |
651 | var setNames = this.layout.setNames; | |
652 | var setName = setNames[i]; | |
653 | ||
654 | var strokeWidth = this.dygraph_.attr_("strokeWidth", setName); | |
655 | var borderWidth = this.dygraph_.attr_("strokeBorderWidth", setName); | |
5469113b KW |
656 | var drawPointCallback = this.dygraph_.attr_("drawPointCallback", setName) || |
657 | Dygraph.Circles.DEFAULT; | |
99a77a04 | 658 | |
857a6931 | 659 | if (borderWidth && strokeWidth) { |
5469113b | 660 | this._drawStyledLine(ctx, i, setName, |
857a6931 KW |
661 | this.dygraph_.attr_("strokeBorderColor", setName), |
662 | strokeWidth + 2 * borderWidth, | |
663 | this.dygraph_.attr_("strokePattern", setName), | |
664 | this.dygraph_.attr_("drawPoints", setName), | |
5469113b | 665 | drawPointCallback, |
857a6931 KW |
666 | this.dygraph_.attr_("pointSize", setName)); |
667 | } | |
668 | ||
5469113b | 669 | this._drawStyledLine(ctx, i, setName, |
857a6931 KW |
670 | this.colors[setName], |
671 | strokeWidth, | |
672 | this.dygraph_.attr_("strokePattern", setName), | |
673 | this.dygraph_.attr_("drawPoints", setName), | |
5469113b | 674 | drawPointCallback, |
857a6931 KW |
675 | this.dygraph_.attr_("pointSize", setName)); |
676 | }; | |
ce49c2fa | 677 | |
6a1aa64f | 678 | /** |
758a629f DV |
679 | * Actually draw the lines chart, including error bars. |
680 | * TODO(danvk): split this into several smaller functions. | |
681 | * @private | |
6a1aa64f | 682 | */ |
285a6bda | 683 | DygraphCanvasRenderer.prototype._renderLineChart = function() { |
44c6bc29 | 684 | // TODO(danvk): use this.attr_ for many of these. |
857a6931 | 685 | var ctx = this.elementContext; |
423f5ed3 | 686 | var fillAlpha = this.attr_('fillAlpha'); |
e4182459 | 687 | var errorBars = this.attr_("errorBars") || this.attr_("customBars"); |
44c6bc29 | 688 | var fillGraph = this.attr_("fillGraph"); |
b2c9222a DV |
689 | var stackedGraph = this.attr_("stackedGraph"); |
690 | var stepPlot = this.attr_("stepPlot"); | |
c3e1495b AR |
691 | var points = this.layout.points; |
692 | var pointsLength = points.length; | |
8722284b | 693 | var point, i, prevX, prevY, prevYs, color, setName, newYs, err_color, rgb, yscale, axis; |
21d3323f | 694 | |
82c6fe4d | 695 | var setNames = this.layout.setNames; |
21d3323f | 696 | var setCount = setNames.length; |
6a1aa64f | 697 | |
ee53deb9 | 698 | this.colors = this.dygraph_.colorsMap_; |
f032c51d | 699 | |
ff00d3e2 DV |
700 | // Update Points |
701 | // TODO(danvk): here | |
b843b52c RK |
702 | // |
703 | // TODO(bhs): this loop is a hot-spot for high-point-count charts. These | |
704 | // transformations can be pushed into the canvas via linear transformation | |
705 | // matrices. | |
758a629f DV |
706 | for (i = pointsLength; i--;) { |
707 | point = points[i]; | |
6a1aa64f DV |
708 | point.canvasx = this.area.w * point.x + this.area.x; |
709 | point.canvasy = this.area.h * point.y + this.area.y; | |
710 | } | |
6a1aa64f DV |
711 | |
712 | // create paths | |
80aaae18 | 713 | if (errorBars) { |
857a6931 | 714 | ctx.save(); |
6a834bbb DV |
715 | if (fillGraph) { |
716 | this.dygraph_.warn("Can't use fillGraph option with error bars"); | |
717 | } | |
718 | ||
758a629f DV |
719 | for (i = 0; i < setCount; i++) { |
720 | setName = setNames[i]; | |
721 | axis = this.dygraph_.axisPropertiesForSeries(setName); | |
722 | color = this.colors[setName]; | |
6a1aa64f | 723 | |
04c104d7 KW |
724 | var firstIndexInSet = this.layout.setPointsOffsets[i]; |
725 | var setLength = this.layout.setPointsLengths[i]; | |
04c104d7 | 726 | |
8722284b RK |
727 | var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, |
728 | DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); | |
04c104d7 | 729 | |
6a1aa64f | 730 | // setup graphics context |
758a629f DV |
731 | prevX = NaN; |
732 | prevY = NaN; | |
733 | prevYs = [-1, -1]; | |
734 | yscale = axis.yscale; | |
f474c2a3 | 735 | // should be same color as the lines but only 15% opaque. |
758a629f DV |
736 | rgb = new RGBColor(color); |
737 | err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + | |
43af96e7 | 738 | fillAlpha + ')'; |
f474c2a3 | 739 | ctx.fillStyle = err_color; |
05c9d0c4 | 740 | ctx.beginPath(); |
8722284b RK |
741 | while (iter.hasNext()) { |
742 | point = iter.next(); | |
04c104d7 | 743 | if (point.name == setName) { // TODO(klausw): this is always true |
e9fe4a2f | 744 | if (!Dygraph.isOK(point.y)) { |
56623f3b | 745 | prevX = NaN; |
ae85914a | 746 | continue; |
5011e7a1 | 747 | } |
ce49c2fa | 748 | |
3637724f | 749 | // TODO(danvk): here |
afdc483f | 750 | if (stepPlot) { |
758a629f | 751 | newYs = [ point.y_bottom, point.y_top ]; |
afdc483f NN |
752 | prevY = point.y; |
753 | } else { | |
758a629f | 754 | newYs = [ point.y_bottom, point.y_top ]; |
afdc483f | 755 | } |
6a1aa64f DV |
756 | newYs[0] = this.area.h * newYs[0] + this.area.y; |
757 | newYs[1] = this.area.h * newYs[1] + this.area.y; | |
56623f3b | 758 | if (!isNaN(prevX)) { |
afdc483f | 759 | if (stepPlot) { |
47600757 | 760 | ctx.moveTo(prevX, newYs[0]); |
afdc483f | 761 | } else { |
47600757 | 762 | ctx.moveTo(prevX, prevYs[0]); |
afdc483f | 763 | } |
5954ef32 DV |
764 | ctx.lineTo(point.canvasx, newYs[0]); |
765 | ctx.lineTo(point.canvasx, newYs[1]); | |
afdc483f | 766 | if (stepPlot) { |
47600757 | 767 | ctx.lineTo(prevX, newYs[1]); |
afdc483f | 768 | } else { |
47600757 | 769 | ctx.lineTo(prevX, prevYs[1]); |
afdc483f | 770 | } |
5954ef32 DV |
771 | ctx.closePath(); |
772 | } | |
354e15ab | 773 | prevYs = newYs; |
5954ef32 DV |
774 | prevX = point.canvasx; |
775 | } | |
776 | } | |
777 | ctx.fill(); | |
778 | } | |
857a6931 | 779 | ctx.restore(); |
5954ef32 | 780 | } else if (fillGraph) { |
857a6931 | 781 | ctx.save(); |
349dd9ba DW |
782 | var baseline = {}; // for stacked graphs: baseline for filling |
783 | var currBaseline; | |
354e15ab DE |
784 | |
785 | // process sets in reverse order (needed for stacked graphs) | |
758a629f DV |
786 | for (i = setCount - 1; i >= 0; i--) { |
787 | setName = setNames[i]; | |
788 | color = this.colors[setName]; | |
789 | axis = this.dygraph_.axisPropertiesForSeries(setName); | |
ea4942ed DV |
790 | var axisY = 1.0 + axis.minyval * axis.yscale; |
791 | if (axisY < 0.0) axisY = 0.0; | |
792 | else if (axisY > 1.0) axisY = 1.0; | |
793 | axisY = this.area.h * axisY + this.area.y; | |
04c104d7 KW |
794 | var firstIndexInSet = this.layout.setPointsOffsets[i]; |
795 | var setLength = this.layout.setPointsLengths[i]; | |
04c104d7 | 796 | |
8722284b RK |
797 | var iter = Dygraph.createIterator(points, firstIndexInSet, setLength, |
798 | DygraphCanvasRenderer._getIteratorPredicate(this.attr_("connectSeparatedPoints"))); | |
5954ef32 DV |
799 | |
800 | // setup graphics context | |
758a629f DV |
801 | prevX = NaN; |
802 | prevYs = [-1, -1]; | |
803 | yscale = axis.yscale; | |
5954ef32 | 804 | // should be same color as the lines but only 15% opaque. |
758a629f DV |
805 | rgb = new RGBColor(color); |
806 | err_color = 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ',' + | |
43af96e7 | 807 | fillAlpha + ')'; |
5954ef32 DV |
808 | ctx.fillStyle = err_color; |
809 | ctx.beginPath(); | |
8722284b RK |
810 | while(iter.hasNext()) { |
811 | point = iter.next(); | |
04c104d7 | 812 | if (point.name == setName) { // TODO(klausw): this is always true |
e9fe4a2f | 813 | if (!Dygraph.isOK(point.y)) { |
56623f3b | 814 | prevX = NaN; |
5954ef32 DV |
815 | continue; |
816 | } | |
354e15ab | 817 | if (stackedGraph) { |
349dd9ba DW |
818 | currBaseline = baseline[point.canvasx]; |
819 | var lastY; | |
820 | if (currBaseline === undefined) { | |
821 | lastY = axisY; | |
822 | } else { | |
823 | if(stepPlot) { | |
824 | lastY = currBaseline[0]; | |
825 | } else { | |
826 | lastY = currBaseline; | |
827 | } | |
828 | } | |
354e15ab | 829 | newYs = [ point.canvasy, lastY ]; |
b843b52c | 830 | |
349dd9ba DW |
831 | if(stepPlot) { |
832 | // Step plots must keep track of the top and bottom of | |
833 | // the baseline at each point. | |
834 | if(prevYs[0] === -1) { | |
835 | baseline[point.canvasx] = [ point.canvasy, axisY ]; | |
836 | } else { | |
837 | baseline[point.canvasx] = [ point.canvasy, prevYs[0] ]; | |
838 | } | |
839 | } else { | |
840 | baseline[point.canvasx] = point.canvasy; | |
841 | } | |
b843b52c | 842 | |
354e15ab DE |
843 | } else { |
844 | newYs = [ point.canvasy, axisY ]; | |
845 | } | |
56623f3b | 846 | if (!isNaN(prevX)) { |
05c9d0c4 | 847 | ctx.moveTo(prevX, prevYs[0]); |
b843b52c | 848 | |
afdc483f | 849 | if (stepPlot) { |
47600757 | 850 | ctx.lineTo(point.canvasx, prevYs[0]); |
349dd9ba DW |
851 | if(currBaseline) { |
852 | // Draw to the bottom of the baseline | |
853 | ctx.lineTo(point.canvasx, currBaseline[1]); | |
854 | } else { | |
855 | ctx.lineTo(point.canvasx, newYs[1]); | |
856 | } | |
afdc483f | 857 | } else { |
47600757 | 858 | ctx.lineTo(point.canvasx, newYs[0]); |
349dd9ba | 859 | ctx.lineTo(point.canvasx, newYs[1]); |
afdc483f | 860 | } |
b843b52c | 861 | |
05c9d0c4 DV |
862 | ctx.lineTo(prevX, prevYs[1]); |
863 | ctx.closePath(); | |
6a1aa64f | 864 | } |
354e15ab | 865 | prevYs = newYs; |
6a1aa64f DV |
866 | prevX = point.canvasx; |
867 | } | |
05c9d0c4 | 868 | } |
6a1aa64f DV |
869 | ctx.fill(); |
870 | } | |
857a6931 | 871 | ctx.restore(); |
80aaae18 DV |
872 | } |
873 | ||
f9414b11 | 874 | // Drawing the lines. |
758a629f | 875 | for (i = 0; i < setCount; i += 1) { |
857a6931 | 876 | this._drawLine(ctx, i); |
80aaae18 | 877 | } |
6a1aa64f | 878 | }; |
79253bd0 | 879 | |
880 | /** | |
881 | * This does dashed lines onto a canvas for a given pattern. You must call | |
882 | * ctx.stroke() after to actually draw it, much line ctx.lineTo(). It remembers | |
883 | * the state of the line in regards to where we left off on drawing the pattern. | |
884 | * You can draw a dashed line in several function calls and the pattern will be | |
885 | * continous as long as you didn't call this function with a different pattern | |
886 | * in between. | |
887 | * @param ctx The canvas 2d context to draw on. | |
888 | * @param x The start of the line's x coordinate. | |
889 | * @param y The start of the line's y coordinate. | |
890 | * @param x2 The end of the line's x coordinate. | |
891 | * @param y2 The end of the line's y coordinate. | |
892 | * @param pattern The dash pattern to draw, an array of integers where even | |
893 | * index is drawn and odd index is not drawn (Ex. [10, 2, 5, 2], 10 is drawn 5 | |
894 | * is drawn, 2 is the space between.). A null pattern, array of length one, or | |
895 | * empty array will do just a solid line. | |
896 | * @private | |
897 | */ | |
898 | DygraphCanvasRenderer.prototype._dashedLine = function(ctx, x, y, x2, y2, pattern) { | |
899 | // Original version http://stackoverflow.com/questions/4576724/dotted-stroke-in-canvas | |
900 | // Modified by Russell Valentine to keep line history and continue the pattern | |
901 | // where it left off. | |
902 | var dx, dy, len, rot, patternIndex, segment; | |
903 | ||
904 | // If we don't have a pattern or it is an empty array or of size one just | |
905 | // do a solid line. | |
906 | if (!pattern || pattern.length <= 1) { | |
907 | ctx.moveTo(x, y); | |
908 | ctx.lineTo(x2, y2); | |
909 | return; | |
910 | } | |
911 | ||
912 | // If we have a different dash pattern than the last time this was called we | |
913 | // reset our dash history and start the pattern from the begging | |
914 | // regardless of state of the last pattern. | |
915 | if (!Dygraph.compareArrays(pattern, this._dashedLineToHistoryPattern)) { | |
916 | this._dashedLineToHistoryPattern = pattern; | |
917 | this._dashedLineToHistory = [0, 0]; | |
918 | } | |
919 | ctx.save(); | |
920 | ||
921 | // Calculate transformation parameters | |
922 | dx = (x2-x); | |
923 | dy = (y2-y); | |
924 | len = Math.sqrt(dx*dx + dy*dy); | |
925 | rot = Math.atan2(dy, dx); | |
926 | ||
927 | // Set transformation | |
928 | ctx.translate(x, y); | |
929 | ctx.moveTo(0, 0); | |
930 | ctx.rotate(rot); | |
931 | ||
932 | // Set last pattern index we used for this pattern. | |
933 | patternIndex = this._dashedLineToHistory[0]; | |
934 | x = 0; | |
935 | while (len > x) { | |
936 | // Get the length of the pattern segment we are dealing with. | |
937 | segment = pattern[patternIndex]; | |
938 | // If our last draw didn't complete the pattern segment all the way we | |
939 | // will try to finish it. Otherwise we will try to do the whole segment. | |
940 | if (this._dashedLineToHistory[1]) { | |
941 | x += this._dashedLineToHistory[1]; | |
942 | } else { | |
943 | x += segment; | |
944 | } | |
945 | if (x > len) { | |
946 | // We were unable to complete this pattern index all the way, keep | |
947 | // where we are the history so our next draw continues where we left off | |
948 | // in the pattern. | |
949 | this._dashedLineToHistory = [patternIndex, x-len]; | |
950 | x = len; | |
951 | } else { | |
952 | // We completed this patternIndex, we put in the history that we are on | |
953 | // the beginning of the next segment. | |
954 | this._dashedLineToHistory = [(patternIndex+1)%pattern.length, 0]; | |
955 | } | |
956 | ||
957 | // We do a line on a even pattern index and just move on a odd pattern index. | |
958 | // The move is the empty space in the dash. | |
959 | if(patternIndex % 2 === 0) { | |
960 | ctx.lineTo(x, 0); | |
961 | } else { | |
962 | ctx.moveTo(x, 0); | |
963 | } | |
964 | // If we are not done, next loop process the next pattern segment, or the | |
965 | // first segment again if we are at the end of the pattern. | |
966 | patternIndex = (patternIndex+1) % pattern.length; | |
967 | } | |
968 | ctx.restore(); | |
969 | }; |