Commit | Line | Data |
---|---|---|
cbe41be1 DV |
1 | /** |
2 | * @license | |
3 | * Copyright 2012 Dan Vanderkam (danvdk@gmail.com) | |
4 | * MIT-licensed (http://opensource.org/licenses/MIT) | |
5 | */ | |
6 | ||
7 | Dygraph.Plugins.Grid = (function() { | |
8 | ||
9 | /* | |
10 | ||
11 | Current bits of jankiness: | |
12 | ||
13 | */ | |
14 | ||
15 | "use strict"; | |
16 | ||
17 | ||
18 | /** | |
19 | * Draws the gridlines, i.e. the gray horizontal & vertical lines running the | |
20 | * length of the chart. | |
21 | * | |
22 | * @constructor | |
23 | */ | |
24 | var grid = function() { | |
25 | }; | |
26 | ||
27 | grid.prototype.toString = function() { | |
28 | return "Gridline Plugin"; | |
29 | }; | |
30 | ||
31 | grid.prototype.activate = function(g) { | |
32 | return { | |
98eb4713 | 33 | willDrawChart: this.willDrawChart |
cbe41be1 DV |
34 | }; |
35 | }; | |
36 | ||
98eb4713 | 37 | grid.prototype.willDrawChart = function(e) { |
cbe41be1 DV |
38 | // Draw the new X/Y grid. Lines appear crisper when pixels are rounded to |
39 | // half-integers. This prevents them from drawing in two rows/cols. | |
40 | var g = e.dygraph; | |
41 | var ctx = e.drawingContext; | |
42 | var layout = g.layout_; | |
43 | var area = e.dygraph.plotter_.area; | |
44 | ||
45 | function halfUp(x) { return Math.round(x) + 0.5; } | |
46 | function halfDown(y){ return Math.round(y) - 0.5; } | |
47 | ||
48 | var x, y, i, ticks; | |
49 | if (g.getOption('drawYGrid')) { | |
50 | ticks = layout.yticks; | |
51 | ctx.save(); | |
52 | ctx.strokeStyle = g.getOption('gridLineColor'); | |
53 | ctx.lineWidth = g.getOption('gridLineWidth'); | |
54 | for (i = 0; i < ticks.length; i++) { | |
55 | // TODO(danvk): allow secondary axes to draw a grid, too. | |
56 | if (ticks[i][0] !== 0) continue; | |
57 | x = halfUp(area.x); | |
58 | y = halfDown(area.y + ticks[i][1] * area.h); | |
59 | ctx.beginPath(); | |
60 | ctx.moveTo(x, y); | |
61 | ctx.lineTo(x + area.w, y); | |
62 | ctx.closePath(); | |
63 | ctx.stroke(); | |
64 | } | |
65 | ctx.restore(); | |
66 | } | |
67 | ||
68 | if (g.getOption('drawXGrid')) { | |
69 | ticks = layout.xticks; | |
70 | ctx.save(); | |
71 | ctx.strokeStyle = g.getOption('gridLineColor'); | |
72 | ctx.lineWidth = g.getOption('gridLineWidth'); | |
73 | for (i = 0; i < ticks.length; i++) { | |
74 | x = halfUp(area.x + ticks[i][0] * area.w); | |
75 | y = halfDown(area.y + area.h); | |
76 | ctx.beginPath(); | |
77 | ctx.moveTo(x, y); | |
78 | ctx.lineTo(x, area.y); | |
79 | ctx.closePath(); | |
80 | ctx.stroke(); | |
81 | } | |
82 | ctx.restore(); | |
83 | } | |
84 | } | |
85 | ||
86 | grid.prototype.destroy = function() { | |
87 | }; | |
88 | ||
89 | return grid; | |
90 | ||
91 | })(); |