Canvas Drawing Example

ReactCanvasDrawing.js

/** @jsx React.DOM */

var Graphic = React.createClass({ 

  componentDidMount: function() {
    var context = this.getDOMNode().getContext('2d');
    this.paint(context);
  },

  componentDidUpdate: function() {
    var context = this.getDOMNode().getContext('2d');
    context.clearRect(0, 0, 200, 200);
    this.paint(context);
  },

  paint: function(context) {
    context.save();
    context.translate(100, 100);
    context.rotate(this.props.rotation, 100, 100);
    context.fillStyle = '#F00';
    context.fillRect(-50, -50, 100, 100);
    context.restore();
  },

  render: function() {
    return <canvas width={200} height={200} />;
  }

});

var App = React.createClass({

  getInitialState: function() {
    return { rotation: 0 };
  },

  componentDidMount: function() {
    requestAnimationFrame(this.tick);
  },

  tick: function() {
    this.setState({ rotation: this.state.rotation + .01 });
    requestAnimationFrame(this.tick);
  },

  render: function() {
    return <div><Graphic rotation={this.state.rotation} /></div>
  }

});

React.renderComponent(<App />, document.body);

It is really helpful, thanks!

Very helpful, appreciate it.

very good, thx again

Note that getDOMNode is deprecated, use findDOMNode now.

And you may have to use the syntax ReactDOM.findDOMNode(this).getContext('2d) instead, depending on your React implementation.

How to view this output in node js ?

Where will you run this program?