dcos-dygraphs
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dygraphs is a fast, flexible open source JavaScript charting library.
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JavaScript
/**
* @license
* Copyright 2012 Dan Vanderkam (danvdk@gmail.com)
* MIT-licensed (http://opensource.org/licenses/MIT)
*/
/*global Dygraph:false */
;
/*
Bits of jankiness:
- Direct layout access
- Direct area access
- Should include calculation of ticks, not just the drawing.
Options left to make axis-friendly.
('drawAxesAtZero')
('xAxisHeight')
*/
/**
* Draws the axes. This includes the labels on the x- and y-axes, as well
* as the tick marks on the axes.
* It does _not_ draw the grid lines which span the entire chart.
*/
var axes = function() {
this.xlabels_ = [];
this.ylabels_ = [];
};
axes.prototype.toString = function() {
return 'Axes Plugin';
};
axes.prototype.activate = function(g) {
return {
layout: this.layout,
clearChart: this.clearChart,
willDrawChart: this.willDrawChart
};
};
axes.prototype.layout = function(e) {
var g = e.dygraph;
if (g.getOptionForAxis('drawAxis', 'y')) {
var w = g.getOptionForAxis('axisLabelWidth', 'y') + 2 * g.getOptionForAxis('axisTickSize', 'y');
e.reserveSpaceLeft(w);
}
if (g.getOptionForAxis('drawAxis', 'x')) {
var h;
// NOTE: I think this is probably broken now, since g.getOption() now
// hits the dictionary. (That is, g.getOption('xAxisHeight') now always
// has a value.)
if (g.getOption('xAxisHeight')) {
h = g.getOption('xAxisHeight');
} else {
h = g.getOptionForAxis('axisLabelFontSize', 'x') + 2 * g.getOptionForAxis('axisTickSize', 'x');
}
e.reserveSpaceBottom(h);
}
if (g.numAxes() == 2) {
if (g.getOptionForAxis('drawAxis', 'y2')) {
var w = g.getOptionForAxis('axisLabelWidth', 'y2') + 2 * g.getOptionForAxis('axisTickSize', 'y2');
e.reserveSpaceRight(w);
}
} else if (g.numAxes() > 2) {
g.error('Only two y-axes are supported at this time. (Trying ' +
'to use ' + g.numAxes() + ')');
}
};
axes.prototype.detachLabels = function() {
function removeArray(ary) {
for (var i = 0; i < ary.length; i++) {
var el = ary[i];
if (el.parentNode) el.parentNode.removeChild(el);
}
}
removeArray(this.xlabels_);
removeArray(this.ylabels_);
this.xlabels_ = [];
this.ylabels_ = [];
};
axes.prototype.clearChart = function(e) {
this.detachLabels();
};
axes.prototype.willDrawChart = function(e) {
var g = e.dygraph;
if (!g.getOptionForAxis('drawAxis', 'x') &&
!g.getOptionForAxis('drawAxis', 'y') &&
!g.getOptionForAxis('drawAxis', 'y2')) {
return;
}
// Round pixels to half-integer boundaries for crisper drawing.
function halfUp(x) { return Math.round(x) + 0.5; }
function halfDown(y){ return Math.round(y) - 0.5; }
var context = e.drawingContext;
var containerDiv = e.canvas.parentNode;
var canvasWidth = g.width_; // e.canvas.width is affected by pixel ratio.
var canvasHeight = g.height_;
var label, x, y, tick, i;
var makeLabelStyle = function(axis) {
return {
position: 'absolute',
fontSize: g.getOptionForAxis('axisLabelFontSize', axis) + 'px',
zIndex: 10,
color: g.getOptionForAxis('axisLabelColor', axis),
width: g.getOptionForAxis('axisLabelWidth', axis) + 'px',
// height: g.getOptionForAxis('axisLabelFontSize', 'x') + 2 + "px",
lineHeight: 'normal', // Something other than "normal" line-height screws up label positioning.
overflow: 'hidden'
};
};
var labelStyles = {
x : makeLabelStyle('x'),
y : makeLabelStyle('y'),
y2 : makeLabelStyle('y2')
};
var makeDiv = function(txt, axis, prec_axis) {
/*
* This seems to be called with the following three sets of axis/prec_axis:
* x: undefined
* y: y1
* y: y2
*/
var div = document.createElement('div');
var labelStyle = labelStyles[prec_axis == 'y2' ? 'y2' : axis];
for (var name in labelStyle) {
if (labelStyle.hasOwnProperty(name)) {
div.style[name] = labelStyle[name];
}
}
var inner_div = document.createElement('div');
inner_div.className = 'dygraph-axis-label' +
' dygraph-axis-label-' + axis +
(prec_axis ? ' dygraph-axis-label-' + prec_axis : '');
inner_div.innerHTML = txt;
div.appendChild(inner_div);
return div;
};
// axis lines
context.save();
var layout = g.layout_;
var area = e.dygraph.plotter_.area;
// Helper for repeated axis-option accesses.
var makeOptionGetter = function(axis) {
return function(option) {
return g.getOptionForAxis(option, axis);
};
};
if (g.getOptionForAxis('drawAxis', 'y')) {
if (layout.yticks && layout.yticks.length > 0) {
var num_axes = g.numAxes();
var getOptions = [makeOptionGetter('y'), makeOptionGetter('y2')];
for (i = 0; i < layout.yticks.length; i++) {
tick = layout.yticks[i];
if (typeof(tick) == 'function') return; // <-- when would this happen?
x = area.x;
var sgn = 1;
var prec_axis = 'y1';
var getAxisOption = getOptions[0];
if (tick[0] == 1) { // right-side y-axis
x = area.x + area.w;
sgn = -1;
prec_axis = 'y2';
getAxisOption = getOptions[1];
}
var fontSize = getAxisOption('axisLabelFontSize');
y = area.y + tick[1] * area.h;
/* Tick marks are currently clipped, so don't bother drawing them.
context.beginPath();
context.moveTo(halfUp(x), halfDown(y));
context.lineTo(halfUp(x - sgn * this.attr_('axisTickSize')), halfDown(y));
context.closePath();
context.stroke();
*/
label = makeDiv(tick[2], 'y', num_axes == 2 ? prec_axis : null);
var top = (y - fontSize / 2);
if (top < 0) top = 0;
if (top + fontSize + 3 > canvasHeight) {
label.style.bottom = '0';
} else {
label.style.top = top + 'px';
}
if (tick[0] === 0) {
label.style.left = (area.x - getAxisOption('axisLabelWidth') - getAxisOption('axisTickSize')) + 'px';
label.style.textAlign = 'right';
} else if (tick[0] == 1) {
label.style.left = (area.x + area.w +
getAxisOption('axisTickSize')) + 'px';
label.style.textAlign = 'left';
}
label.style.width = getAxisOption('axisLabelWidth') + 'px';
containerDiv.appendChild(label);
this.ylabels_.push(label);
}
// The lowest tick on the y-axis often overlaps with the leftmost
// tick on the x-axis. Shift the bottom tick up a little bit to
// compensate if necessary.
var bottomTick = this.ylabels_[0];
// Interested in the y2 axis also?
var fontSize = g.getOptionForAxis('axisLabelFontSize', 'y');
var bottom = parseInt(bottomTick.style.top, 10) + fontSize;
if (bottom > canvasHeight - fontSize) {
bottomTick.style.top = (parseInt(bottomTick.style.top, 10) -
fontSize / 2) + 'px';
}
}
// draw a vertical line on the left to separate the chart from the labels.
var axisX;
if (g.getOption('drawAxesAtZero')) {
var r = g.toPercentXCoord(0);
if (r > 1 || r < 0 || isNaN(r)) r = 0;
axisX = halfUp(area.x + r * area.w);
} else {
axisX = halfUp(area.x);
}
context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y');
context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y');
context.beginPath();
context.moveTo(axisX, halfDown(area.y));
context.lineTo(axisX, halfDown(area.y + area.h));
context.closePath();
context.stroke();
// if there's a secondary y-axis, draw a vertical line for that, too.
if (g.numAxes() == 2) {
context.strokeStyle = g.getOptionForAxis('axisLineColor', 'y2');
context.lineWidth = g.getOptionForAxis('axisLineWidth', 'y2');
context.beginPath();
context.moveTo(halfDown(area.x + area.w), halfDown(area.y));
context.lineTo(halfDown(area.x + area.w), halfDown(area.y + area.h));
context.closePath();
context.stroke();
}
}
if (g.getOptionForAxis('drawAxis', 'x')) {
if (layout.xticks) {
var getAxisOption = makeOptionGetter('x');
for (i = 0; i < layout.xticks.length; i++) {
tick = layout.xticks[i];
x = area.x + tick[0] * area.w;
y = area.y + area.h;
/* Tick marks are currently clipped, so don't bother drawing them.
context.beginPath();
context.moveTo(halfUp(x), halfDown(y));
context.lineTo(halfUp(x), halfDown(y + this.attr_('axisTickSize')));
context.closePath();
context.stroke();
*/
label = makeDiv(tick[1], 'x');
label.style.textAlign = 'center';
label.style.top = (y + getAxisOption('axisTickSize')) + 'px';
var left = (x - getAxisOption('axisLabelWidth')/2);
if (left + getAxisOption('axisLabelWidth') > canvasWidth) {
left = canvasWidth - getAxisOption('axisLabelWidth');
label.style.textAlign = 'right';
}
if (left < 0) {
left = 0;
label.style.textAlign = 'left';
}
label.style.left = left + 'px';
label.style.width = getAxisOption('axisLabelWidth') + 'px';
containerDiv.appendChild(label);
this.xlabels_.push(label);
}
}
context.strokeStyle = g.getOptionForAxis('axisLineColor', 'x');
context.lineWidth = g.getOptionForAxis('axisLineWidth', 'x');
context.beginPath();
var axisY;
if (g.getOption('drawAxesAtZero')) {
var r = g.toPercentYCoord(0, 0);
if (r > 1 || r < 0) r = 1;
axisY = halfDown(area.y + r * area.h);
} else {
axisY = halfDown(area.y + area.h);
}
context.moveTo(halfUp(area.x), axisY);
context.lineTo(halfUp(area.x + area.w), axisY);
context.closePath();
context.stroke();
}
context.restore();
};
export default axes;