1 /**
  2  * @license
  3  * Copyright 2012 Dan Vanderkam (danvdk@gmail.com)
  4  * MIT-licenced: https://opensource.org/licenses/MIT
  5  */
  6 
  7 /*global Dygraph:false */
  8 
  9 'use strict';
 10 
 11 /*
 12 Bits of jankiness:
 13 - Direct layout access
 14 - Direct area access
 15 - Should include calculation of ticks, not just the drawing.
 16 
 17 Options left to make axis-friendly.
 18   ('drawAxesAtZero')
 19   ('xAxisHeight')
 20 */
 21 
 22 import * as utils from '../dygraph-utils';
 23 
 24 /**
 25  * Draws the axes. This includes the labels on the x- and y-axes, as well
 26  * as the tick marks on the axes.
 27  * It does _not_ draw the grid lines which span the entire chart.
 28  */
 29 var axes = function() {
 30   this.xlabels_ = [];
 31   this.ylabels_ = [];
 32 };
 33 
 34 axes.prototype.toString = function() {
 35   return 'Axes Plugin';
 36 };
 37 
 38 axes.prototype.activate = function(g) {
 39   return {
 40     layout: this.layout,
 41     clearChart: this.clearChart,
 42     willDrawChart: this.willDrawChart
 43   };
 44 };
 45 
 46 axes.prototype.layout = function(e) {
 47   var g = e.dygraph;
 48 
 49   if (g.getOptionForAxis('drawAxis', 'y')) {
 50     var w = g.getOptionForAxis('axisLabelWidth', 'y') + 2 * g.getOptionForAxis('axisTickSize', 'y');
 51     e.reserveSpaceLeft(w);
 52   }
 53 
 54   if (g.getOptionForAxis('drawAxis', 'x')) {
 55     var h;
 56     // NOTE: I think this is probably broken now, since g.getOption() now
 57     // hits the dictionary. (That is, g.getOption('xAxisHeight') now always
 58     // has a value.)
 59     if (g.getOption('xAxisHeight')) {
 60       h = g.getOption('xAxisHeight');
 61     } else {
 62       h = g.getOptionForAxis('axisLabelFontSize', 'x') + 2 * g.getOptionForAxis('axisTickSize', 'x');
 63     }
 64     e.reserveSpaceBottom(h);
 65   }
 66 
 67   if (g.numAxes() == 2) {
 68     if (g.getOptionForAxis('drawAxis', 'y2')) {
 69       var w = g.getOptionForAxis('axisLabelWidth', 'y2') + 2 * g.getOptionForAxis('axisTickSize', 'y2');
 70       e.reserveSpaceRight(w);
 71     }
 72   } else if (g.numAxes() > 2) {
 73     g.error('Only two y-axes are supported at this time. (Trying ' +
 74             'to use ' + g.numAxes() + ')');
 75   }
 76 };
 77 
 78 axes.prototype.detachLabels = function() {
 79   function removeArray(ary) {
 80     for (var i = 0; i < ary.length; i++) {
 81       var el = ary[i];
 82       if (el.parentNode) el.parentNode.removeChild(el);
 83     }
 84   }
 85 
 86   removeArray(this.xlabels_);
 87   removeArray(this.ylabels_);
 88   this.xlabels_ = [];
 89   this.ylabels_ = [];
 90 };
 91 
 92 axes.prototype.clearChart = function(e) {
 93   this.detachLabels();
 94 };
 95 
 96 axes.prototype.willDrawChart = function(e) {
 97   var g = e.dygraph;
 98 
 99   if (!g.getOptionForAxis('drawAxis', 'x') &&
100       !g.getOptionForAxis('drawAxis', 'y') &&
101       !g.getOptionForAxis('drawAxis', 'y2')) {
102     return;
103   }
104 
105   // Round pixels to half-integer boundaries for crisper drawing.
106   function halfUp(x)  { return Math.round(x) + 0.5; }
107   function halfDown(y){ return Math.round(y) - 0.5; }
108 
109   var context = e.drawingContext;
110   var containerDiv = e.canvas.parentNode;
111   var canvasWidth = g.width_;  // e.canvas.width is affected by pixel ratio.
112   var canvasHeight = g.height_;
113 
114   var label, x, y, tick, i;
115 
116   var makeLabelStyle = function(axis) {
117     return {
118       position: 'absolute',
119       fontSize: g.getOptionForAxis('axisLabelFontSize', axis) + 'px',
120       width: g.getOptionForAxis('axisLabelWidth', axis) + 'px',
121     };
122   };
123 
124   var labelStyles = {
125     x: makeLabelStyle('x'),
126     y: makeLabelStyle('y'),
127     y2: makeLabelStyle('y2')
128   };
129 
130   var makeDiv = function(txt, axis, prec_axis) {
131     /*
132      * This seems to be called with the following three sets of axis/prec_axis:
133      * x: undefined
134      * y: y1
135      * y: y2
136      */
137     var div = document.createElement('div');
138     var labelStyle = labelStyles[prec_axis == 'y2' ? 'y2' : axis];
139     utils.update(div.style, labelStyle);
140     // TODO: combine outer & inner divs
141     var inner_div = document.createElement('div');
142     inner_div.className = 'dygraph-axis-label' +
143                           ' dygraph-axis-label-' + axis +
144                           (prec_axis ? ' dygraph-axis-label-' + prec_axis : '');
145     inner_div.innerHTML = txt;
146     div.appendChild(inner_div);
147     return div;
148   };
149 
150   // axis lines
151   context.save();
152 
153   var layout = g.layout_;
154   var area = e.dygraph.plotter_.area;
155 
156   // Helper for repeated axis-option accesses.
157   var makeOptionGetter = function(axis) {
158     return function(option) {
159       return g.getOptionForAxis(option, axis);
160     };
161   };
162 
163   if (g.getOptionForAxis('drawAxis', 'y')) {
164     if (layout.yticks && layout.yticks.length > 0) {
165       var num_axes = g.numAxes();
166       var getOptions = [makeOptionGetter('y'), makeOptionGetter('y2')];
167       layout.yticks.forEach(tick => {
168         if (tick.label === undefined) return;  // this tick only has a grid line.
169         x = area.x;
170         var sgn = 1;
171         var prec_axis = 'y1';
172         var getAxisOption = getOptions[0];
173         if (tick.axis == 1) {  // right-side y-axis
174           x = area.x + area.w;
175           sgn = -1;
176           prec_axis = 'y2';
177           getAxisOption = getOptions[1];
178         }
179         var fontSize = getAxisOption('axisLabelFontSize');
180         y = area.y + tick.pos * area.h;
181 
182         /* Tick marks are currently clipped, so don't bother drawing them.
183         context.beginPath();
184         context.moveTo(halfUp(x), halfDown(y));
185         context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y));
186         context.closePath();
187         context.stroke();
188         */
189 
190         label = makeDiv(tick.label, 'y', num_axes == 2 ? prec_axis : null);
191         var top = (y - fontSize / 2);
192         if (top < 0) top = 0;
193 
194         if (top + fontSize + 3 > canvasHeight) {
195           label.style.bottom = '0';
196         } else {
197           label.style.top = top + 'px';
198         }
199         // TODO: replace these with css classes?
200         if (tick.axis === 0) {
201           label.style.left = (area.x - getAxisOption('axisLabelWidth') - getAxisOption('axisTickSize')) + 'px';
202           label.style.textAlign = 'right';
203         } else if (tick.axis == 1) {
204           label.style.left = (area.x + area.w +
205                               getAxisOption('axisTickSize')) + 'px';
206           label.style.textAlign = 'left';
207         }
208         label.style.width = getAxisOption('axisLabelWidth') + 'px';
209         containerDiv.appendChild(label);
210         this.ylabels_.push(label);
211       });
212 
213       // The lowest tick on the y-axis often overlaps with the leftmost
214       // tick on the x-axis. Shift the bottom tick up a little bit to
215       // compensate if necessary.
216       var bottomTick = this.ylabels_[0];
217       // Interested in the y2 axis also?
218       var fontSize = g.getOptionForAxis('axisLabelFontSize', 'y');
219       var bottom = parseInt(bottomTick.style.top, 10) + fontSize;
220       if (bottom > canvasHeight - fontSize) {
221         bottomTick.style.top = (parseInt(bottomTick.style.top, 10) -
222             fontSize / 2) + 'px';
223       }
224     }
225 
226     // draw a vertical line on the left to separate the chart from the labels.
227     var axisX;
228     if (g.getOption('drawAxesAtZero')) {
229       var r = g.toPercentXCoord(0);
230       if (r > 1 || r < 0 || isNaN(r)) r = 0;
231       axisX = halfUp(area.x + r * area.w);
232     } else {
233       axisX = halfUp(area.x);
234     }
235 
236     context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y');
237     context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y');
238 
239     context.beginPath();
240     context.moveTo(axisX, halfDown(area.y));
241     context.lineTo(axisX, halfDown(area.y + area.h));
242     context.closePath();
243     context.stroke();
244 
245     // if there's a secondary y-axis, draw a vertical line for that, too.
246     if (g.numAxes() == 2) {
247       context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y2');
248       context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y2');
249       context.beginPath();
250       context.moveTo(halfDown(area.x + area.w), halfDown(area.y));
251       context.lineTo(halfDown(area.x + area.w), halfDown(area.y + area.h));
252       context.closePath();
253       context.stroke();
254     }
255   }
256 
257   if (g.getOptionForAxis('drawAxis', 'x')) {
258     if (layout.xticks) {
259       var getAxisOption = makeOptionGetter('x');
260       layout.xticks.forEach(tick => {
261         if (tick.label === undefined) return;  // this tick only has a grid line.
262         x = area.x + tick.pos * area.w;
263         y = area.y + area.h;
264 
265         /* Tick marks are currently clipped, so don't bother drawing them.
266         context.beginPath();
267         context.moveTo(halfUp(x), halfDown(y));
268         context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize')));
269         context.closePath();
270         context.stroke();
271         */
272 
273         label = makeDiv(tick.label, 'x');
274         label.style.textAlign = 'center';
275         label.style.top = (y + getAxisOption('axisTickSize')) + 'px';
276 
277         var left = (x - getAxisOption('axisLabelWidth')/2);
278         if (left + getAxisOption('axisLabelWidth') > canvasWidth) {
279           left = canvasWidth - getAxisOption('axisLabelWidth');
280           label.style.textAlign = 'right';
281         }
282         if (left < 0) {
283           left = 0;
284           label.style.textAlign = 'left';
285         }
286 
287         label.style.left = left + 'px';
288         label.style.width = getAxisOption('axisLabelWidth') + 'px';
289         containerDiv.appendChild(label);
290         this.xlabels_.push(label);
291       });
292     }
293 
294     context.strokeStyle = g.getOptionForAxis('axisLineColor', 'x');
295     context.lineWidth = g.getOptionForAxis('axisLineWidth', 'x');
296     context.beginPath();
297     var axisY;
298     if (g.getOption('drawAxesAtZero')) {
299       var r = g.toPercentYCoord(0, 0);
300       if (r > 1 || r < 0) r = 1;
301       axisY = halfDown(area.y + r * area.h);
302     } else {
303       axisY = halfDown(area.y + area.h);
304     }
305     context.moveTo(halfUp(area.x), axisY);
306     context.lineTo(halfUp(area.x + area.w), axisY);
307     context.closePath();
308     context.stroke();
309   }
310 
311   context.restore();
312 };
313 
314 export default axes;
315