d3-line-chart

A d3.js library to help you draw line charts easily.

How to use it

• include d3.js, d3-line-char.js

<script type="text/javascript" src="./d3.js" charset="utf-8"></script>
<script type="text/javascript" src="./d3-line-chart.js" charset="utf-8"></script>

• simplest way to draw the graph

	var data = {
		name: 'series',
		values: [{x: 1, y: 2}, {x: 2, y : 4}, {x:3, y: 3}]
	};
	new LineChart().for([data]).plot();

This library uses UMD to export a single name to the browser window: "LineChart". It has a single dependency on d3 and expects it to be exported to the browser window as well, include d3 using the <script> tag and you will be fine.

If you ever use this on nodejs, you can use require as such

var LineChart = require('./d3-line-chart.js');

API

d3-line-chart actually provides a lot more options for drawing line chart, you can customize the following things.

• id of the svg chart, defaults to no id
• parent of the chart, defaults to body
• all_series an array of series that will be plotted
• graph-width, width of the entire graph, defaults to 960
• graph-height, height of the entire graph, defaults to 500
• margin, margins around the chart, this can be used to draw axis and legent, defaults to (20, 100, 30, 60)
• x_axis_text text that is printed beside the x-axis
• y_axis_text text that is printed beside the y-axis
• x_parse function that is used to parse the x values of each data point, defaults to identity function
• y_parse function that is used to parse the y values of each data point, defaults to identity function
• x_scale scale function for x values, defaults to d3.scale.linear()
• y_scale scale function for y values, defaults to d3.scale.linear()
• width the maximum width the line chart can appear in, equals to graph_width - margin.left - margin.right, defaults to 960 - 100 - 60
• height the maximum height the line chart can appear in, equals to graph_height - margin.right - margin.bottom, defaults to 500 - 20 - 30
• tooltip a function that is called with the tooltip div and the current data point that is hovered to allow you to display your custom div

More advanced stuff

Specify colours

The color for reach series is taken from d3.scale.category10(), which is used to provide a mapping from the name of a series to one of ten available colours. If more colours are needed, you need to edit the source, to use d3.scale.category20() perhaps.

Tooltips on hover

By default tooltips are shown on hover, with some simple styling. x-axis values are underlined, followed by y-axis values.

You can display your own custom tooltip by providing a function called tooltip to the constructor. This function must take in 2 parameters, div, which is the div of the tooltip, and point which is the point that is hovered over.

Date on the x axis

You can specify other scales besides d3.scale.linear() by passing the function into LineChart()

lc = new LineChart({
	x_scale: d3.time.scale()
});
var data = {
	name: 'series',
	values: [{x: new Date(2014, 4, 1, 0, 0, 0, 0), y: 9},
	{x: new Date(2014, 4, 3, 0, 0, 0, 0), y: 2},
	{x: new Date(2014, 4, 9, 0, 0, 0, 0), y: 3}]
};
lc.for([data]).plot();