- http://fabricjs.com/ - has a lot of plugins and open-source modifications. Possible to achieve most of businnes requirements. Has ability to manage data throught JSON or SVG. Touch devices support. Possible to run under Node.js
- https://www.createjs.com/easeljs - games oriented library. Is a part of CreateJS framework. Has a lot of profitable functionality around animation, sounds integration and performance.
- http://paperjs.org/ - animation oriented library. Good performance optimization.
- https://konvajs.github.io/ - canvas extender like FabricJS. Good performance even on the mobile. Support layers and stages. Possible to redraw image by layers. Has ability to manage Stage from\to JSON.
- http://pixijs.io/ - it is a flexible 2D WebGL renderer. Unbeatable performance, intuitive API, globally used. Complex framework.
- https://threejs.org/ - popular framework for games and complex animation in the Web.
- https://codepen.io/osublake/pen/gGLLOa - draggable\sizing implementation.
- https://github.com/kangax/fabric.js/blob/master/lib/aligning_guidelines.js - add aligning guidelines to the canvas.
- http://pomax.nihongoresources.com/pages/Font.js/ - get few information about font. Cons: old library.
- https://www.npmjs.com/package/measure-font - all required info about font. Need to be checked in live demo.
- https://developer.mozilla.org/en-US/docs/Web/API/TextMetrics - native API for measure text, but isn't supported in all moder browsers
- https://fontforge.github.io/en-US/ - measure font attributes. (Windows application)