#Js sketchpad online how to
#Js sketchpad online update
#Js sketchpad online android
#Js sketchpad online code

The lower-level API keeps OrbiterMicro's file size small, making OrbiterMicro usable in bandwidth-limited environments, such as mobile devices. Unlike Orbiter and Reactor, OrbiterMicro applications send raw UPC messages directly. The list of available UPC ('Union Procedure Call') messages is documented in the UPC Specification. MsgManager.addMessageListener(UPC.CLIENT_ATTR_UPDATE, clientAttributeUpdateListener, this) To be notified of attribute changes received from other clients, each client registers a message listener for CLIENT_ATTR_UPDATE messages, as follows:

#Js sketchpad online code

For example, the following code changes the attribute named 'thickness': To change an attribute, clients use the MessageManager's sendUPC() command to send a SET_CLIENT_ATTR message to the server. When a client changes its 'color' attribute to, say, '#666666', all other clients in the 'examples.uniondraw' room are instantly notified of the change. The attributes are named, appropriately, 'thickness' and 'color'. UnionDraw's client attributes specify each user's current line thickness and color. For example, a UnionDraw client never receives the position of the ball in the Union Pong room, which also runs on. Because users join 'examples.uniondraw', and not any other room, they automatically ignore traffic generated by other applications on the server.

#Js sketchpad online update

For example, a user might receive an update such as: 'user 236 drew a line from 40,45 to 65, 50'. Upon joining the 'examples.uniondraw' room, users automatically begin receiving updates relevant to the drawing application. It gives users a place in which to share information, such as drawing commands and line styles. UnionDraw's room is named 'examples.uniondraw'. The multiuser aspects of the shared drawing program rely on three key Union platform features: rooms, client attributes, and room messages.

In this example, we connect to the public test server. UnionDraw requires access to a Union Server. UnionDraw is broken into two files: an HTML wrapper that provides the drawing canvas and basic user interface, and a JavaScript file that implements the application logic. Stripped of comments and line breaks, the code is about 350 lines of client-side JavaScript, and requires no server-side programming. Support for in Internet Explorer 8 is provided by Google's ExplorerCanvas.

#Js sketchpad online android

The drawing pad works in Firefox 3+, Chrome 1+, Safari 4+, iPad, iPhone 3+, Android 2.1+, Internet Explorer 8+, and Opera 9.5+.

Where WebSocket is not supported, OrbiterMicro automatically falls back to Union platform's binary request model for responsive two-way communication over traditional HTTP. For maximum speed, the connection to Union Server is made over WebSocket in browsers that support it. To manage communication between users, the JavaScript code uses OrbiterMicro, which connects to Union Server. The drawing pad updates in realtime when any connected user draws a line.

#Js sketchpad online how to

This example shows how to create a simple multiuser drawing pad (aka shared whiteboard, multiuser sketchpad, or collaborative painting tool) using pure JavaScript and HTML5's tag. Lastly we need to add the script tag for our script at the bottom of the body.OrbiterMicro Examples Multiuser Drawing Pad Built with Pure JavaScript/HTML5/Canvas It will be a canvas element, but for layouting purposes we'll wrap it into a div. The next thing we have to add in our html is the actual drawing board. Lastly I'll add a button with the id of clear and this will be used to clear the drawing board. Don't forget to add the corresponding labels for these input fields. For the color input I add the id of stroke as it will define the color of the stroke and for the number input I'll add the id of lineWidth. Below that we'll add two input fields: one for color and one for the with of the line. Inside the toolbar we'll add a title for our app in an h1. I also set an id of toolbar for it so it will be easier to work with it in javascript. Inside that we create a div which will hold our toolbar. This will be used to align the toolbar and the drawing board. We'll start by wrapping the whole app into a section with the class of container. If you would watch a detailed step-by-step video instead you can check out the video I made covering this project on my Youtube Channel:

To do that we will use vanilla JS and the Canvas API.Īfter this tutorial you'll have a great overview of the canvas API and event handling in javascript. In this tutorial we will create a simple drawing app in the browser.