monkey patch CanvasRenderingContext2D to include a getTransform method
npm install ctx-get-transformcxt.getTransform() is one of the missing bits of functionality in CanvasRenderingContext2D. This module will monkey patch a ctx to track the current transformation stack and allows retrieval of the current matrix.
npm install ctx-get-transform
``javascript
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
require('ctx-get-transform')(ctx);
console.log(ctx.getTransform) // outputs: function tGetTransform() ...
ctx.getTransform() // returns a gl-matrix style mat3
`
there is only a single method added to the passed ctx, but every method that manipulates the transformation matrix is wrapped.
The awesome method (and purpose of this library):
ctx.getTransform - return a gl-matrix style mat3 (just a 9 element Array)
_note_: the returned array is not a copy of the tracked matrix. Changing it can result in weird issues! Utilize mat3.clone(ctx.getTransform()) if you need a copy.
ctx.pointToWorld(out, point) - project a point ([0, 0]) (e.g. mouse position) into world coords. out` needs to be a 2 component array and the result of the operation will be applied to it.
MIT (see LICENSE.txt)