transform-2d

A module to keep track of and perform common mutations on a matrix describing a 2d affine transform.

In other words, you can use to do things to images like:

• [x] zooming
• [x] panning
• [ ] rotations
• [ ] sheering

Usage

var Transform2D = require('transform-2d');

var t = new Transform2D();

// [10, 10] -> [5, 5]
t.panStart([10, 10]).pan([5, 5]).panEnd();

// Zoom in a little centered at [5, 5]
t.zoom(3, [5, 5]);

API

transform = new Transform2D([options])

options = { // defaults
  zoomLevel: 1, // initial zoom level
  zoomScale: 0.1, // scaling factor per zoom step
  minZoomLevel: 0.1, // minimum zoom level
  maxZoomLevel: 10 // maximum zoom level
}

transform.zoom(steps : number, point : Array<number>)

zoom steps steps around a point. Returns this.

transform.panStart(point : Array<number>)

Initiate panning from a particular point, as if the image were pulled at that location. Returns this.

transform.pan(point : Array<number>)

Pan to a particular point. Returns this.

transform.panEnd()

Terminate panning.

transform.getCTM()

Returns the current transformation matrix in the form [a, c, b, d, x, y] corresponding to the 2d augmented matrix [[a, b, x], [c, d, y]].