// MIT License:
//
// Copyright (c) 2010-2013, Joe Walnes
// 2013-2014, Drew Noakes
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
/**
* Smoothie Charts - http://smoothiecharts.org/
* (c) 2010-2013, Joe Walnes
* 2013-2014, Drew Noakes
*
* v1.0: Main charting library, by Joe Walnes
* v1.1: Auto scaling of axis, by Neil Dunn
* v1.2: fps (frames per second) option, by Mathias Petterson
* v1.3: Fix for divide by zero, by Paul Nikitochkin
* v1.4: Set minimum, top-scale padding, remove timeseries, add optional timer to reset bounds, by Kelley Reynolds
* v1.5: Set default frames per second to 50... smoother.
* .start(), .stop() methods for conserving CPU, by Dmitry Vyal
* options.interpolation = 'bezier' or 'line', by Dmitry Vyal
* options.maxValue to fix scale, by Dmitry Vyal
* v1.6: minValue/maxValue will always get converted to floats, by Przemek Matylla
* v1.7: options.grid.fillStyle may be a transparent color, by Dmitry A. Shashkin
* Smooth rescaling, by Kostas Michalopoulos
* v1.8: Set max length to customize number of live points in the dataset with options.maxDataSetLength, by Krishna Narni
* v1.9: Display timestamps along the bottom, by Nick and Stev-io
* (https://groups.google.com/forum/?fromgroups#!topic/smoothie-charts/-Ywse8FCpKI%5B1-25%5D)
* Refactored by Krishna Narni, to support timestamp formatting function
* v1.10: Switch to requestAnimationFrame, removed the now obsoleted options.fps, by Gergely Imreh
* v1.11: options.grid.sharpLines option added, by @drewnoakes
* Addressed warning seen in Firefox when seriesOption.fillStyle undefined, by @drewnoakes
* v1.12: Support for horizontalLines added, by @drewnoakes
* Support for yRangeFunction callback added, by @drewnoakes
* v1.13: Fixed typo (#32), by @alnikitich
* v1.14: Timer cleared when last TimeSeries removed (#23), by @davidgaleano
* Fixed diagonal line on chart at start/end of data stream, by @drewnoakes
* v1.15: Support for npm package (#18), by @dominictarr
* Fixed broken removeTimeSeries function (#24) by @davidgaleano
* Minor performance and tidying, by @drewnoakes
* v1.16: Bug fix introduced in v1.14 relating to timer creation/clearance (#23), by @drewnoakes
* TimeSeries.append now deals with out-of-order timestamps, and can merge duplicates, by @zacwitte (#12)
* Documentation and some local variable renaming for clarity, by @drewnoakes
* v1.17: Allow control over font size (#10), by @drewnoakes
* Timestamp text won't overlap, by @drewnoakes
* v1.18: Allow control of max/min label precision, by @drewnoakes
* Added 'borderVisible' chart option, by @drewnoakes
* Allow drawing series with fill but no stroke (line), by @drewnoakes
* v1.19: Avoid unnecessary repaints, and fixed flicker in old browsers having multiple charts in document (#40), by @asbai
* v1.20: Add SmoothieChart.getTimeSeriesOptions and SmoothieChart.bringToFront functions, by @drewnoakes
* v1.21: Add 'step' interpolation mode, by @drewnoakes
* v1.22: Add support for different pixel ratios. Also add optional y limit formatters, by @copacetic
* v1.23: Fix bug introduced in v1.22 (#44), by @drewnoakes
* v1.24: Fix bug introduced in v1.23, re-adding parseFloat to y-axis formatter defaults, by @siggy_sf
* v1.25: Fix bug seen when adding a data point to TimeSeries which is older than the current data, by @Nking92
* Draw time labels on top of series, by @comolosabia
* Add TimeSeries.clear function, by @drewnoakes
* v1.26: Add support for resizing on high device pixel ratio screens, by @copacetic
* v1.27: Fix bug introduced in v1.26 for non whole number devicePixelRatio values, by @zmbush
* v1.28: Add 'minValueScale' option, by @megawac
*/
;(function(exports) {
var Util = {
extend: function() {
arguments[0] = arguments[0] || {};
for (var i = 1; i < arguments.length; i++)
{
for (var key in arguments[i])
{
if (arguments[i].hasOwnProperty(key))
{
if (typeof(arguments[i][key]) === 'object') {
if (arguments[i][key] instanceof Array) {
arguments[0][key] = arguments[i][key];
} else {
arguments[0][key] = Util.extend(arguments[0][key], arguments[i][key]);
}
} else {
arguments[0][key] = arguments[i][key];
}
}
}
}
return arguments[0];
}
};
/**
* Initialises a new TimeSeries with optional data options.
*
* Options are of the form (defaults shown):
*
*
* {
* resetBounds: true, // enables/disables automatic scaling of the y-axis
* resetBoundsInterval: 3000 // the period between scaling calculations, in millis
* }
*
*
* Presentation options for TimeSeries are specified as an argument to SmoothieChart.addTimeSeries.
*
* @constructor
*/
function TimeSeries(options) {
this.options = Util.extend({}, TimeSeries.defaultOptions, options);
this.clear();
}
TimeSeries.defaultOptions = {
resetBoundsInterval: 3000,
resetBounds: true
};
/**
* Clears all data and state from this TimeSeries object.
*/
TimeSeries.prototype.clear = function() {
this.data = [];
this.maxValue = Number.NaN; // The maximum value ever seen in this TimeSeries.
this.minValue = Number.NaN; // The minimum value ever seen in this TimeSeries.
};
/**
* Recalculate the min/max values for this TimeSeries object.
*
* This causes the graph to scale itself in the y-axis.
*/
TimeSeries.prototype.resetBounds = function() {
if (this.data.length) {
// Walk through all data points, finding the min/max value
this.maxValue = this.data[0][1];
this.minValue = this.data[0][1];
for (var i = 1; i < this.data.length; i++) {
var value = this.data[i][1];
if (value > this.maxValue) {
this.maxValue = value;
}
if (value < this.minValue) {
this.minValue = value;
}
}
} else {
// No data exists, so set min/max to NaN
this.maxValue = Number.NaN;
this.minValue = Number.NaN;
}
};
/**
* Adds a new data point to the TimeSeries, preserving chronological order.
*
* @param timestamp the position, in time, of this data point
* @param value the value of this data point
* @param sumRepeatedTimeStampValues if timestamp has an exact match in the series, this flag controls
* whether it is replaced, or the values summed (defaults to false.)
*/
TimeSeries.prototype.append = function(timestamp, value, sumRepeatedTimeStampValues) {
// Rewind until we hit an older timestamp
var i = this.data.length - 1;
while (i >= 0 && this.data[i][0] > timestamp) {
i--;
}
if (i === -1) {
// This new item is the oldest data
this.data.splice(0, 0, [timestamp, value]);
} else if (this.data.length > 0 && this.data[i][0] === timestamp) {
// Update existing values in the array
if (sumRepeatedTimeStampValues) {
// Sum this value into the existing 'bucket'
this.data[i][1] += value;
value = this.data[i][1];
} else {
// Replace the previous value
this.data[i][1] = value;
}
} else if (i < this.data.length - 1) {
// Splice into the correct position to keep timestamps in order
this.data.splice(i + 1, 0, [timestamp, value]);
} else {
// Add to the end of the array
this.data.push([timestamp, value]);
}
this.maxValue = isNaN(this.maxValue) ? value : Math.max(this.maxValue, value);
this.minValue = isNaN(this.minValue) ? value : Math.min(this.minValue, value);
};
TimeSeries.prototype.dropOldData = function(oldestValidTime, maxDataSetLength) {
// We must always keep one expired data point as we need this to draw the
// line that comes into the chart from the left, but any points prior to that can be removed.
var removeCount = 0;
while (this.data.length - removeCount >= maxDataSetLength && this.data[removeCount + 1][0] < oldestValidTime) {
removeCount++;
}
if (removeCount !== 0) {
this.data.splice(0, removeCount);
}
};
/**
* Initialises a new SmoothieChart.
*
* Options are optional, and should be of the form below. Just specify the values you
* need and the rest will be given sensible defaults as shown:
*
*
* {
* minValue: undefined, // specify to clamp the lower y-axis to a given value
* maxValue: undefined, // specify to clamp the upper y-axis to a given value
* maxValueScale: 1, // allows proportional padding to be added above the chart. for 10% padding, specify 1.1.
* minValueScale: 1, // allows proportional padding to be added below the chart. for 10% padding, specify 1.1.
* yRangeFunction: function(value) { // function({min: , max: }) { return {min: , max: }; }
* return value)
* }
* valueTransformFunction: undefinde // function(value) { return value; }
* scaleSmoothing: 0.125, // controls the rate at which y-value zoom animation occurs
* millisPerPixel: 20, // sets the speed at which the chart pans by
* enableDpiScaling: true, // support rendering at different DPI depending on the device
* yMinFormatter: function(min, precision) { // callback function that formats the min y value label
* return parseFloat(min).toFixed(precision);
* },
* yMaxFormatter: function(max, precision) { // callback function that formats the max y value label
* return parseFloat(max).toFixed(precision);
* },
* maxDataSetLength: 2,
* interpolation: 'bezier' // one of 'bezier', 'linear', or 'step'
* timestampFormatter: null, // optional function to format time stamps for bottom of chart
* // you may use SmoothieChart.timeFormatter, or your own: function(date) { return ''; }
* scrollBackwards: false, // reverse the scroll direction of the chart
* horizontalLines: [], // [ { value: 0, color: '#ffffff', lineWidth: 1 } ]
* grid:
* {
* fillStyle: '#000000', // the background colour of the chart
* lineWidth: 1, // the pixel width of grid lines
* strokeStyle: '#777777', // colour of grid lines
* millisPerLine: 1000, // distance between vertical grid lines
* sharpLines: false, // controls whether grid lines are 1px sharp, or softened
* verticalSections: 2, // number of vertical sections marked out by horizontal grid lines
* borderVisible: true // whether the grid lines trace the border of the chart or not
* },
* labels
* {
* disabled: false, // enables/disables labels showing the min/max values
* fillStyle: '#ffffff', // colour for text of labels,
* fontSize: 15,
* fontFamily: 'sans-serif',
* precision: 2
* }
* }
*
*
* @constructor
*/
function SmoothieChart(options) {
this.options = Util.extend({}, SmoothieChart.defaultChartOptions, options);
this.seriesSet = [];
this.currentValueRange = 1;
this.currentVisMinValue = 0;
this.lastRenderTimeMillis = 0;
}
SmoothieChart.defaultChartOptions = {
millisPerPixel: 20,
enableDpiScaling: true,
yMinFormatter: function(min, precision) {
return parseFloat(min).toFixed(precision);
},
yMaxFormatter: function(max, precision) {
return parseFloat(max).toFixed(precision);
},
maxValueScale: 1,
minValueScale: 1,
valueTransformFunction: function (value) {
return value;
},
interpolation: 'bezier',
scaleSmoothing: 0.125,
maxDataSetLength: 2,
scrollBackwards: false,
grid: {
fillStyle: '#000000',
strokeStyle: '#777777',
lineWidth: 1,
sharpLines: false,
millisPerLine: 1000,
verticalSections: 2,
borderVisible: true
},
labels: {
fillStyle: '#ffffff',
disabled: false,
fontSize: 10,
fontFamily: 'monospace',
precision: 2
},
horizontalLines: []
};
// Based on http://inspirit.github.com/jsfeat/js/compatibility.js
SmoothieChart.AnimateCompatibility = (function() {
var requestAnimationFrame = function(callback, element) {
var requestAnimationFrame =
window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback) {
return window.setTimeout(function() {
callback(new Date().getTime());
}, 16);
};
return requestAnimationFrame.call(window, callback, element);
},
cancelAnimationFrame = function(id) {
var cancelAnimationFrame =
window.cancelAnimationFrame ||
function(id) {
clearTimeout(id);
};
return cancelAnimationFrame.call(window, id);
};
return {
requestAnimationFrame: requestAnimationFrame,
cancelAnimationFrame: cancelAnimationFrame
};
})();
SmoothieChart.defaultSeriesPresentationOptions = {
lineWidth: 1,
strokeStyle: '#ffffff'
};
/**
* Adds a TimeSeries to this chart, with optional presentation options.
*
* Presentation options should be of the form (defaults shown):
*
*
* {
* lineWidth: 1,
* strokeStyle: '#ffffff',
* fillStyle: undefined
* }
*
*/
SmoothieChart.prototype.addTimeSeries = function(timeSeries, options) {
this.seriesSet.push({timeSeries: timeSeries, options: Util.extend({}, SmoothieChart.defaultSeriesPresentationOptions, options)});
if (timeSeries.options.resetBounds && timeSeries.options.resetBoundsInterval > 0) {
timeSeries.resetBoundsTimerId = setInterval(
function() {
timeSeries.resetBounds();
},
timeSeries.options.resetBoundsInterval
);
}
};
/**
* Removes the specified TimeSeries from the chart.
*/
SmoothieChart.prototype.removeTimeSeries = function(timeSeries) {
// Find the correct timeseries to remove, and remove it
var numSeries = this.seriesSet.length;
for (var i = 0; i < numSeries; i++) {
if (this.seriesSet[i].timeSeries === timeSeries) {
this.seriesSet.splice(i, 1);
break;
}
}
// If a timer was operating for that timeseries, remove it
if (timeSeries.resetBoundsTimerId) {
// Stop resetting the bounds, if we were
clearInterval(timeSeries.resetBoundsTimerId);
}
};
/**
* Gets render options for the specified TimeSeries.
*
* As you may use a single TimeSeries in multiple charts with different formatting in each usage,
* these settings are stored in the chart.
*/
SmoothieChart.prototype.getTimeSeriesOptions = function(timeSeries) {
// Find the correct timeseries to remove, and remove it
var numSeries = this.seriesSet.length;
for (var i = 0; i < numSeries; i++) {
if (this.seriesSet[i].timeSeries === timeSeries) {
return this.seriesSet[i].options;
}
}
};
/**
* Brings the specified TimeSeries to the top of the chart. It will be rendered last.
*/
SmoothieChart.prototype.bringToFront = function(timeSeries) {
// Find the correct timeseries to remove, and remove it
var numSeries = this.seriesSet.length;
for (var i = 0; i < numSeries; i++) {
if (this.seriesSet[i].timeSeries === timeSeries) {
var set = this.seriesSet.splice(i, 1);
this.seriesSet.push(set[0]);
break;
}
}
};
/**
* Instructs the SmoothieChart to start rendering to the provided canvas, with specified delay.
*
* @param canvas the target canvas element
* @param delayMillis an amount of time to wait before a data point is shown. This can prevent the end of the series
* from appearing on screen, with new values flashing into view, at the expense of some latency.
*/
SmoothieChart.prototype.streamTo = function(canvas, delayMillis) {
this.canvas = canvas;
this.delay = delayMillis;
this.start();
};
/**
* Make sure the canvas has the optimal resolution for the device's pixel ratio.
*/
SmoothieChart.prototype.resize = function() {
// TODO this function doesn't handle the value of enableDpiScaling changing during execution
if (!this.options.enableDpiScaling || !window || window.devicePixelRatio === 1)
return;
var dpr = window.devicePixelRatio;
var width = parseInt(this.canvas.getAttribute('width'));
var height = parseInt(this.canvas.getAttribute('height'));
if (!this.originalWidth || (Math.floor(this.originalWidth * dpr) !== width)) {
this.originalWidth = width;
this.canvas.setAttribute('width', (Math.floor(width * dpr)).toString());
this.canvas.style.width = width + 'px';
this.canvas.getContext('2d').scale(dpr, dpr);
}
if (!this.originalHeight || (Math.floor(this.originalHeight * dpr) !== height)) {
this.originalHeight = height;
this.canvas.setAttribute('height', (Math.floor(height * dpr)).toString());
this.canvas.style.height = height + 'px';
this.canvas.getContext('2d').scale(dpr, dpr);
}
};
/**
* Starts the animation of this chart.
*/
SmoothieChart.prototype.start = function() {
if (this.frame) {
// We're already running, so just return
return;
}
// Renders a frame, and queues the next frame for later rendering
var animate = function() {
this.frame = SmoothieChart.AnimateCompatibility.requestAnimationFrame(function() {
this.render();
animate();
}.bind(this));
}.bind(this);
animate();
};
/**
* Stops the animation of this chart.
*/
SmoothieChart.prototype.stop = function() {
if (this.frame) {
SmoothieChart.AnimateCompatibility.cancelAnimationFrame(this.frame);
delete this.frame;
}
};
SmoothieChart.prototype.updateValueRange = function() {
// Calculate the current scale of the chart, from all time series.
var chartOptions = this.options,
chartMaxValue = Number.NaN,
chartMinValue = Number.NaN;
for (var d = 0; d < this.seriesSet.length; d++) {
// TODO(ndunn): We could calculate / track these values as they stream in.
var timeSeries = this.seriesSet[d].timeSeries;
if (!isNaN(timeSeries.maxValue)) {
chartMaxValue = !isNaN(chartMaxValue) ? Math.max(chartMaxValue, timeSeries.maxValue) : timeSeries.maxValue;
}
if (!isNaN(timeSeries.minValue)) {
chartMinValue = !isNaN(chartMinValue) ? Math.min(chartMinValue, timeSeries.minValue) : timeSeries.minValue;
}
}
// Scale the chartMaxValue to add padding at the top if required
if (chartOptions.maxValue != null) {
chartMaxValue = chartOptions.maxValue;
} else {
chartMaxValue *= chartOptions.maxValueScale;
}
// Set the minimum if we've specified one
if (chartOptions.minValue != null) {
chartMinValue = chartOptions.minValue;
} else {
chartMinValue -= Math.abs(chartMinValue * chartOptions.minValueScale - chartMinValue);
}
// If a custom range function is set, call it
if (this.options.yRangeFunction) {
var range = this.options.yRangeFunction({min: chartMinValue, max: chartMaxValue});
chartMinValue = range.min;
chartMaxValue = range.max;
}
if (!isNaN(chartMaxValue) && !isNaN(chartMinValue)) {
var targetValueRange = chartMaxValue - chartMinValue;
var valueRangeDiff = (targetValueRange - this.currentValueRange);
var minValueDiff = (chartMinValue - this.currentVisMinValue);
this.isAnimatingScale = Math.abs(valueRangeDiff) > 0.1 || Math.abs(minValueDiff) > 0.1;
this.currentValueRange += chartOptions.scaleSmoothing * valueRangeDiff;
this.currentVisMinValue += chartOptions.scaleSmoothing * minValueDiff;
}
this.valueRange = { min: chartMinValue, max: chartMaxValue };
};
SmoothieChart.prototype.render = function(canvas, time) {
var nowMillis = new Date().getTime();
if (!this.isAnimatingScale) {
// We're not animating. We can use the last render time and the scroll speed to work out whether
// we actually need to paint anything yet. If not, we can return immediately.
// Render at least every 1/6th of a second. The canvas may be resized, which there is
// no reliable way to detect.
var maxIdleMillis = Math.min(1000/6, this.options.millisPerPixel);
if (nowMillis - this.lastRenderTimeMillis < maxIdleMillis) {
return;
}
}
this.resize();
this.lastRenderTimeMillis = nowMillis;
canvas = canvas || this.canvas;
time = time || nowMillis - (this.delay || 0);
// Round time down to pixel granularity, so motion appears smoother.
time -= time % this.options.millisPerPixel;
var context = canvas.getContext('2d'),
chartOptions = this.options,
dimensions = { top: 0, left: 0, width: canvas.clientWidth, height: canvas.clientHeight },
// Calculate the threshold time for the oldest data points.
oldestValidTime = time - (dimensions.width * chartOptions.millisPerPixel),
valueToYPixel = function(value) {
var offset = this.options.valueTransformFunction(value - this.currentVisMinValue);
return this.currentValueRange === 0
? dimensions.height
: dimensions.height - (Math.round((offset / this.options.valueTransformFunction(this.currentValueRange)) * dimensions.height));
}.bind(this),
timeToXPixel = function(t) {
if(chartOptions.scrollBackwards) {
return Math.round((time - t) / chartOptions.millisPerPixel);
}
return Math.round(dimensions.width - ((time - t) / chartOptions.millisPerPixel));
};
this.updateValueRange();
context.font = chartOptions.labels.fontSize + 'px ' + chartOptions.labels.fontFamily;
// Save the state of the canvas context, any transformations applied in this method
// will get removed from the stack at the end of this method when .restore() is called.
context.save();
// Move the origin.
context.translate(dimensions.left, dimensions.top);
// Create a clipped rectangle - anything we draw will be constrained to this rectangle.
// This prevents the occasional pixels from curves near the edges overrunning and creating
// screen cheese (that phrase should need no explanation).
context.beginPath();
context.rect(0, 0, dimensions.width, dimensions.height);
context.clip();
// Clear the working area.
context.save();
context.fillStyle = chartOptions.grid.fillStyle;
context.clearRect(0, 0, dimensions.width, dimensions.height);
context.fillRect(0, 0, dimensions.width, dimensions.height);
context.restore();
// Grid lines...
context.save();
context.lineWidth = chartOptions.grid.lineWidth;
context.strokeStyle = chartOptions.grid.strokeStyle;
// Vertical (time) dividers.
if (chartOptions.grid.millisPerLine > 0) {
context.beginPath();
for (var t = time - (time % chartOptions.grid.millisPerLine);
t >= oldestValidTime;
t -= chartOptions.grid.millisPerLine) {
var gx = timeToXPixel(t);
if (chartOptions.grid.sharpLines) {
gx -= 0.5;
}
context.moveTo(gx, 0);
context.lineTo(gx, dimensions.height);
}
context.stroke();
context.closePath();
}
// Horizontal (value) dividers.
for (var v = 1; v < chartOptions.grid.verticalSections; v++) {
var gy = Math.round(v * dimensions.height / chartOptions.grid.verticalSections);
if (chartOptions.grid.sharpLines) {
gy -= 0.5;
}
context.beginPath();
context.moveTo(0, gy);
context.lineTo(dimensions.width, gy);
context.stroke();
context.closePath();
}
// Bounding rectangle.
if (chartOptions.grid.borderVisible) {
context.beginPath();
context.strokeRect(0, 0, dimensions.width, dimensions.height);
context.closePath();
}
context.restore();
// Draw any horizontal lines...
if (chartOptions.horizontalLines && chartOptions.horizontalLines.length) {
for (var hl = 0; hl < chartOptions.horizontalLines.length; hl++) {
var line = chartOptions.horizontalLines[hl],
hly = Math.round(valueToYPixel(line.value)) - 0.5;
context.strokeStyle = line.color || '#ffffff';
context.lineWidth = line.lineWidth || 1;
context.beginPath();
context.moveTo(0, hly);
context.lineTo(dimensions.width, hly);
context.stroke();
context.closePath();
}
}
// For each data set...
for (var d = 0; d < this.seriesSet.length; d++) {
context.save();
var timeSeries = this.seriesSet[d].timeSeries,
dataSet = timeSeries.data,
seriesOptions = this.seriesSet[d].options;
// Delete old data that's moved off the left of the chart.
timeSeries.dropOldData(oldestValidTime, chartOptions.maxDataSetLength);
// Set style for this dataSet.
context.lineWidth = seriesOptions.lineWidth;
context.strokeStyle = seriesOptions.strokeStyle;
// Draw the line...
context.beginPath();
// Retain lastX, lastY for calculating the control points of bezier curves.
var firstX = 0, lastX = 0, lastY = 0;
for (var i = 0; i < dataSet.length && dataSet.length !== 1; i++) {
var x = timeToXPixel(dataSet[i][0]),
y = valueToYPixel(dataSet[i][1]);
if (i === 0) {
firstX = x;
context.moveTo(x, y);
} else {
switch (chartOptions.interpolation) {
case "linear":
case "line": {
context.lineTo(x,y);
break;
}
case "bezier":
default: {
// Great explanation of Bezier curves: http://en.wikipedia.org/wiki/Bezier_curve#Quadratic_curves
//
// Assuming A was the last point in the line plotted and B is the new point,
// we draw a curve with control points P and Q as below.
//
// A---P
// |
// |
// |
// Q---B
//
// Importantly, A and P are at the same y coordinate, as are B and Q. This is
// so adjacent curves appear to flow as one.
//
context.bezierCurveTo( // startPoint (A) is implicit from last iteration of loop
Math.round((lastX + x) / 2), lastY, // controlPoint1 (P)
Math.round((lastX + x)) / 2, y, // controlPoint2 (Q)
x, y); // endPoint (B)
break;
}
case "step": {
context.lineTo(x,lastY);
context.lineTo(x,y);
break;
}
}
}
lastX = x; lastY = y;
}
if (dataSet.length > 1) {
if (seriesOptions.fillStyle) {
// Close up the fill region.
context.lineTo(dimensions.width + seriesOptions.lineWidth + 1, lastY);
context.lineTo(dimensions.width + seriesOptions.lineWidth + 1, dimensions.height + seriesOptions.lineWidth + 1);
context.lineTo(firstX, dimensions.height + seriesOptions.lineWidth);
context.fillStyle = seriesOptions.fillStyle;
context.fill();
}
if (seriesOptions.strokeStyle && seriesOptions.strokeStyle !== 'none') {
context.stroke();
}
context.closePath();
}
context.restore();
}
// Draw the axis values on the chart.
if (!chartOptions.labels.disabled && !isNaN(this.valueRange.min) && !isNaN(this.valueRange.max)) {
var maxValueString = chartOptions.yMaxFormatter(this.valueRange.max, chartOptions.labels.precision),
minValueString = chartOptions.yMinFormatter(this.valueRange.min, chartOptions.labels.precision),
maxLabelPos = chartOptions.scrollBackwards ? 0 : dimensions.width - context.measureText(maxValueString).width - 2;
minLabelPos = chartOptions.scrollBackwards ? 0 : dimensions.width - context.measureText(minValueString).width - 2;
context.fillStyle = chartOptions.labels.fillStyle;
context.fillText(maxValueString, maxLabelPos, chartOptions.labels.fontSize);
context.fillText(minValueString, minLabelPos, dimensions.height - 2);
}
// Display timestamps along x-axis at the bottom of the chart.
if (chartOptions.timestampFormatter && chartOptions.grid.millisPerLine > 0) {
var textUntilX = chartOptions.scrollBackwards
? context.measureText(minValueString).width
: dimensions.width - context.measureText(minValueString).width + 4;
for (var t = time - (time % chartOptions.grid.millisPerLine);
t >= oldestValidTime;
t -= chartOptions.grid.millisPerLine) {
var gx = timeToXPixel(t);
// Only draw the timestamp if it won't overlap with the previously drawn one.
if ((!chartOptions.scrollBackwards && gx < textUntilX) || (chartOptions.scrollBackwards && gx > textUntilX)) {
// Formats the timestamp based on user specified formatting function
// SmoothieChart.timeFormatter function above is one such formatting option
var tx = new Date(t),
ts = chartOptions.timestampFormatter(tx),
tsWidth = context.measureText(ts).width;
textUntilX = chartOptions.scrollBackwards
? gx + tsWidth + 2
: gx - tsWidth - 2;
context.fillStyle = chartOptions.labels.fillStyle;
if(chartOptions.scrollBackwards) {
context.fillText(ts, gx, dimensions.height - 2);
} else {
context.fillText(ts, gx - tsWidth, dimensions.height - 2);
}
}
}
}
context.restore(); // See .save() above.
};
// Sample timestamp formatting function
SmoothieChart.timeFormatter = function(date) {
function pad2(number) { return (number < 10 ? '0' : '') + number }
return pad2(date.getHours()) + ':' + pad2(date.getMinutes()) + ':' + pad2(date.getSeconds());
};
exports.TimeSeries = TimeSeries;
exports.SmoothieChart = SmoothieChart;
})(typeof exports === 'undefined' ? this : exports);