drawing-tool
v2.3.2
Published
HTML5 Drawing Tool
Downloads
27
Readme
HTML5 Drawing Tool
Demo: https://models-resources.concord.org/drawing-tool/branch/master/examples/index.html
Using as a library
npm install drawing-tool
In myComponent.js:
import DrawingTool from "drawing-tool";
import 'drawing-tool/dist/drawing-tool.css';
const drawingTool = new DrawingTool("#drawing-tool-container");
Development
- Install (if you don't have them):
- Node.js :
brew install node
on OS X - Live server :
npm install -g live-server
- Node.js :
- Run:
npm install
to install dependencies.webpack --watch
-- Automatically compiles sources to./dist
live-server .
-- starts a web server on http://localhost:8080/- Open http://localhost:8080/examples/.
- Code!!
- Before you commit, run
webpack
to updatedist
directory and add it to git index.
Undo / redo feature
If you are planning to add new feature that will be exposed in UI or via main API, you should consider whether this action should be saved in history (so undo and redo is possible) or not.
If so, all you need to do is to call DrawingTool.pushToHistory
method.
The current convention is that everything that modifies canvas should be saved in history, e.g.:
- new object created
- object removed
- object stroke color changed
- canvas dimensions changed
However state of the drawing tool itself is not tracked, so e.g. following events are not saved:
- tool changed
- current stroke color changed
- current fill color changed
If an action is async and callback can be provided, callback should be invoked after history is updated
(see DrawingTool.setBackgroundImage
). It gives us more flexibility, as the client code can reset history
after action is complete so user won't be able to undo it (sometimes it is useful).
JSON state converter
Drawing Tool state can be serialized to JSON. If you're introducing non-backward compatible change, update version in DrawingTool#save
method and add approperiate conversion to convert-state.js
.