Scripting hierarchy The scriptable functionality of Canvas is presented in a hierarchical structure as it is common for Automation on Windows. A similar hierarchy is used by Apple Computer’s AppleScript. The hierarchy is organized in a way that mirrors the layout of Canvas. Objects in the scripting hierarchy represent items of Canvas. The application object is on the highest level. Objects for open documents, which contain page objects, are below the application object. The page objects hold layer objects, which contain the drawing objects that are present in Canvas. A script’s hierarchy is a snapshot of the current state of Canvas. Each object in the hierarchy provides a certain functionality of Canvas that is associated with a particular item. For example, the layer object has functionality for setting and retrieving its name, accessing the draw- ing objects that reside on it, retrieving the page object it resides on, etc. The user can use this functionality to control Canvas through a scripting language. For example, that user could go to the fifth layer and change its name. Methods and properties Each object in the scripting hierarchy has properties and methods. A property represents a certain characteristic of the object and has a specific type (For example: Integer or String). A property can be set by assigning it a value. It can also be accessed to check its current state. For example, Width is a property of drawing objects. You can set it to 144 pixels (all distances in scripting for Canvas are measured in pixels): drawingObject.Width = 144 or you can check whether it is wider than 72 pixel: if (drawingObject.Width > 72) Then ... End If Methods represent operations that can be performed with the object. They can have multiple parameters as input. In addition, methods can produce multiple output values. For example, moving a drawing object is an operation performed by the Move method. Move takes the x and y offsets as parameters. The following line moves a draw- ing object by 300 pixels over to the right and by 90 pixels down: drawingObject.Move 300, 90
Canvas 8 Help: Writing Scripts for Canvas (3 of 16)                                                 Page #745