Canvas API offers extensions and global parameters to configure the user experience in a per client basis. To set up your configuration options is to include a Cx.Canvas.Config.js file after Canvas scripts has been loaded (this may improve later when Canvas starts offering head.js based loading tools).

<!-- Load Canvas Scripts -->
...
<!-- End Canvas Scripts section -->
<script type="text/javascript" src="Cx.Canvas.Config.js"></script>

In this file, you will define the configuration of Canvas just as you would do with a Web.Config file in ASP.Net.

User defined typed metadata for figures

It is very useful to be able to attach metadata to each figure in a document when implementing the client logic. Things like “Fabric”, “Material” or “HighQualityPrinting” may only have meaning in the particular context of a certain application. The approach that Canvas takes, it to give clients the basic properties that are common when building graphic application and offer an extension point for user defined properties.

In you Cx.Canvas.Config.js file you can call the function:

Cx.Figure.setupClientProperties({
    fabricType          : { type: 'string', def: 'Cotton' }
  , highQualityPrinting : { type: 'boolean', def: false, dropDef:true }
  // , ... other properties
});

Once this is inplace your client can use their own defined properties in the same way it uses the normal figures properties (like “pin, “layer”, etc).

// In the client code
// getter
var ft = figure.fabricType() ; 
// setter
figure.fabricType('Linen');

For each property, the type config option let the system do automatic parsing into the real representation of your properties. You can select ‘string’, ‘number’, ‘integer’, ‘boolean’, ‘point’, ‘color’, ‘brush’, etc. For a complete list read this non existent documentation (?). This is very useful to avoid writing code like parseInt( figure.charLimit() ) in your code base that can lead to subtle bugs.

The def config set up a default value for figures where the property has not been yet defined and dropDef controls if the value is going to be dropped from the CDL in the case it is the default. This is useful for metadata that has a clear default that will not change in the future. For example, the Text columnCount property is dropped if its value is 1.

You can check a real configuration file used by Kiosk4 here: Cx.Canvas.Config.js

Properties defined by one client and stored in Cx servers are not going to be dropped, even if other clients will open these documents. All the metadata will be kept safe as an internal key-value dictionary in the figures.

Because other clients may later use the same names, it is convenient to use some kind of namespace when naming your client defined properties. For TX project we are using properties with names like “txName”.

Global parameters

Canvas exposed several global parameters that control optimizations, general user interface related strategies and debugging modes. To change a particular variable use:

Cx.Global.configurationVariableName = enabled; // true-or-false

This is a (probably) incomplete list of configuration variables. Look directly in the source code to check an up-to-date version of it.