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') || g.getOptionForAxis('drawAxis', 'y2')) {
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         if (!getAxisOption('drawAxis')) return;
180         var fontSize = getAxisOption('axisLabelFontSize');
181         y = area.y + tick.pos * area.h;
182 
183         /* Tick marks are currently clipped, so don't bother drawing them.
184         context.beginPath();
185         context.moveTo(halfUp(x), halfDown(y));
186         context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y));
187         context.closePath();
188         context.stroke();
189         */
190 
191         label = makeDiv(tick.label, 'y', num_axes == 2 ? prec_axis : null);
192         var top = (y - fontSize / 2);
193         if (top < 0) top = 0;
194 
195         if (top + fontSize + 3 > canvasHeight) {
196           label.style.bottom = '0';
197         } else {
198           // The lowest tick on the y-axis often overlaps with the leftmost
199           // tick on the x-axis. Shift the bottom tick up a little bit to
200           // compensate if necessary.
201           label.style.top = Math.min(top, canvasHeight - (2 * fontSize)) + 'px';
202         }
203         // TODO: replace these with css classes?
204         if (tick.axis === 0) {
205           label.style.left = (area.x - getAxisOption('axisLabelWidth') - getAxisOption('axisTickSize')) + 'px';
206           label.style.textAlign = 'right';
207         } else if (tick.axis == 1) {
208           label.style.left = (area.x + area.w +
209                               getAxisOption('axisTickSize')) + 'px';
210           label.style.textAlign = 'left';
211         }
212         label.style.width = getAxisOption('axisLabelWidth') + 'px';
213         containerDiv.appendChild(label);
214         this.ylabels_.push(label);
215       });
216     }
217 
218     // draw a vertical line on the left to separate the chart from the labels.
219     var axisX;
220     if (g.getOption('drawAxesAtZero')) {
221       var r = g.toPercentXCoord(0);
222       if (r > 1 || r < 0 || isNaN(r)) r = 0;
223       axisX = halfUp(area.x + r * area.w);
224     } else {
225       axisX = halfUp(area.x);
226     }
227 
228     context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y');
229     context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y');
230 
231     context.beginPath();
232     context.moveTo(axisX, halfDown(area.y));
233     context.lineTo(axisX, halfDown(area.y + area.h));
234     context.closePath();
235     context.stroke();
236 
237     // if there's a secondary y-axis, draw a vertical line for that, too.
238     if (g.numAxes() == 2 && g.getOptionForAxis('drawAxis', 'y2')) {
239       context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y2');
240       context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y2');
241       context.beginPath();
242       context.moveTo(halfDown(area.x + area.w), halfDown(area.y));
243       context.lineTo(halfDown(area.x + area.w), halfDown(area.y + area.h));
244       context.closePath();
245       context.stroke();
246     }
247   }
248 
249   if (g.getOptionForAxis('drawAxis', 'x')) {
250     if (layout.xticks) {
251       var getAxisOption = makeOptionGetter('x');
252       layout.xticks.forEach(tick => {
253         if (tick.label === undefined) return;  // this tick only has a grid line.
254         x = area.x + tick.pos * area.w;
255         y = area.y + area.h;
256 
257         /* Tick marks are currently clipped, so don't bother drawing them.
258         context.beginPath();
259         context.moveTo(halfUp(x), halfDown(y));
260         context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize')));
261         context.closePath();
262         context.stroke();
263         */
264 
265         label = makeDiv(tick.label, 'x');
266         label.style.textAlign = 'center';
267         label.style.top = (y + getAxisOption('axisTickSize')) + 'px';
268 
269         var left = (x - getAxisOption('axisLabelWidth')/2);
270         if (left + getAxisOption('axisLabelWidth') > canvasWidth) {
271           left = canvasWidth - getAxisOption('axisLabelWidth');
272           label.style.textAlign = 'right';
273         }
274         if (left < 0) {
275           left = 0;
276           label.style.textAlign = 'left';
277         }
278 
279         label.style.left = left + 'px';
280         label.style.width = getAxisOption('axisLabelWidth') + 'px';
281         containerDiv.appendChild(label);
282         this.xlabels_.push(label);
283       });
284     }
285 
286     context.strokeStyle = g.getOptionForAxis('axisLineColor', 'x');
287     context.lineWidth = g.getOptionForAxis('axisLineWidth', 'x');
288     context.beginPath();
289     var axisY;
290     if (g.getOption('drawAxesAtZero')) {
291       var r = g.toPercentYCoord(0, 0);
292       if (r > 1 || r < 0) r = 1;
293       axisY = halfDown(area.y + r * area.h);
294     } else {
295       axisY = halfDown(area.y + area.h);
296     }
297     context.moveTo(halfUp(area.x), axisY);
298     context.lineTo(halfUp(area.x + area.w), axisY);
299     context.closePath();
300     context.stroke();
301   }
302 
303   context.restore();
304 };
305 
306 export default axes;
307