Working with Variables

Variables are at the center of dynamic movies. They provide an interface to supply dynamic content into the dynamic movie. Dynamic content can be text, files, or URLs to fetch content from other servers.

Creating a Dynamic Text Object

The following ImageProvider will use the text supplied via the parameter mytext and display it a 40 pixel red default font.

var text = new sdl.ImageProvider({
    type: "textsimple",
    color: {red: 255, alpha: 255},
    fontsize: 40,    
    text: {
        type: "map"
        key: "mytext"
        defaultvalue: "Some text"
    }
}) 

StringVariables

The text property of the ImageProvider is of type StringVariable. A StringVariable can get its content from various sources. The following table lists the most common sources:

Type	Description
constant	Constant. Use value directly
map	Fetch value via parameter named key
http	Fetch value via HTTP from URL specified in source
structureddata	Get value from a structured data source, e.g. JSON object
datasource	Get value from a datasource (CSV, Excel, etc.)

Creating a Dynamic Image Object

The following ImageProvider will render an image supplied from a HTTP server. The URL of the image is constructed using a fixed server URL and a user-supplied parameter. The token $variable is substituted with the value of the StringVariable:

var image = new sdl.ImageProvider({
    type: "http",
    source: {
        path: "http://my.server.com/images/$variable.jpg"
        variable: {
            type: "map"
            key: "username"
            defaultvalue: "unknown-user"
        }
    }
}) 

The source property of the ImageProvider is a FileLocation. To learn more about FileLocations, see the the SDL Reference.