D3-Transform

d3-transform makes it easy to define and reuse functions that produce
transform attribute strings for SVG elements. Using d3-transform reduces
repetition, allows you to compose multiple transforms, and eliminates ugly
string-interpolation from your d3 visualization code.

Installation

Include d3-transform in your web page using a script tag any time after you've
included d3:

``html


`

Usage

d3-transform replaces the manual construction of transform attribute strings
for SVG elements. For example, if you want to translate, rotate, and scale a
group element depending on the data bound to that element, you'd write
something like this without d3-transform:

`javascript
d3.select('svg').selectAll('g')
.data([{ size: 5 }, { size: 10 }])
.enter().append('g')
.attr('transform', function(d, i) {
return "translate(20," + d.size * 10 + ") rotate (40) scale(" + ( d.size + 2 ) + ")");
});
`

With d3-transform, you can rewrite the above code like this:

`javascript
var transform = d3.transform()
.translate(function(d) { return [20, d.size * 10] })
.rotate(40)
.scale(function(d) { return d.size + 2 });

var svg = d3.select('svg').selectAll('g')
.data([{ size: 5 }, { size: 10 }])
.enter()
.append('g')
.attr('transform', transform);
`

In both cases the resulting document will look the same:

`html




`

You can specify arguments for these operations by either providing positional
arguments to the corresponding method of the transform object, or by providing
a function that will return an array of arguments that are interpreted as
positional arguments. In the special case where an operation only takes one
argument, your function can return a number.

All of the SVG 1.1 transform operations are supported: matrix, rotate,
translate, scale, skewX, and skewY. See the SVG 1.1 Specification
or MDN for further details on the arguments of each operation.

When using node.js, calls to require('d3-transform') return a direct reference to the "transform" method.

`javascript
var d3 = require('d3');
var d3Transform = require('d3-transform');

var transform = d3Transform()
.translate(function(d) { return [20, d.size * 10] })
.rotate(40)
.scale(function(d) { return d.size + 2 });

var svg = d3.select('svg.example1').selectAll('g')
.data([{ size: 5 }, { size: 10 }])
.enter()
.append('g')
.attr('transform', transform);
`

$3

If you want to extend one transform with another set of operations, pass the
initial transform object into the d3.transform() function:

`javascript
var transform1 = d3.transform()
.translate(10,20);

var transform2 = d3.transform(transform1)
.scale(function(d) { return [d.size];})

d3.select('svg.example2').selectAll('g')
.data([{ size: 5 }, { size: 10 }])
.enter().append('g')
.attr('transform', transform2);
`

Another way to compose multiple transform objects is to use the seq
operation:

`javascript
var transform1 = d3.transform()
.translate(10,20);

var transform2 = d3.transform()
.scale(function(d) { return [d.size];})

var transform =
transform1.seq(transform2);
`

With either of these approaches, the result is a document that looks like this:

`html




``

Contributors

* Erik Cunningham @trinary
* Spiros Eliopoulos @seliopou
* Micah Stubbs @micahstubbs