Scripting Reference Introduction

The Scripting Reference is organized by classes. For example, it contains a section on the DAImage class. Each class contains a description of its functions, including syntax, returned values, and how to use the function. At the end of each class, there is a list of functions that, while relevant to that particular class, are included in the DAStatics library. This library is very large, and it might be easier to familiarize yourself with its contents by looking at specific classes and seeing what DAStatics functions are pertinent. When parameters are described as animated numbers, this means they must be of type DANumber, not that they must necessarily change over time.

All of the methods and properties in the Scripting Reference are accessible through C++. For information, see Using the Scripting Reference in C++ Programming.

This introduction contains the following topics.

Differences between VBScript and JScript
The PixelLibrary and the MeterLibrary

Differences between VBScript and JScript

Syntax and terminology found in this reference are based on Microsoft® Visual Basic® Scripting Edition (VBScript) conventions. However, there are only a few simple differences between VBScript and Microsoft JScript™. Those differences that pertain directly to Microsoft DirectAnimation® are:

VBScript uses functions which return values; uses subroutines which do not return values; and also uses properties.
JScript™ distinguishes between methods which are always associated with objects; functions which are not always associated with objects; and properties which are analagous to Microsoft Visual Basic® properties.
The syntax differs only in that JScript™ ends with a semicolon while VBScript does not.
If you don't want to use an optional parameter in one of the scripting functions, use the word null as a placeholder for JScript and the word Null as a placeholder for VBScript. The placeholders null and Null have no quotes around them.
The syntax for creating a new object is different. The following example shows how to create new objects both in VBScript and JScript™:

// This is VBScript
Set myPt = CreateObject("DirectAnimation.DAPoint2")

// This is JScript
myPt = new ActiveXObject("DirectAnimation.DAPoint2");

The PixelLibrary and the MeterLibrary

The MeterLibrary and the PixelLibrary set the unit of measurement to meters or pixels respectively. Both return the DAStatics object, so, to gain access to that library, one of these libraries must be chosen. There are two important differences between the libraries (other than the obvious one of different units of measurement). They are:

The MeterLibrary considers positive-y to be up and the origin to be in the center of the view. The PixelLibrary considers positive-y to be down.
If the PixelLibrary is chosen, pixels are the unit of measurement only when something is being constructed. Returned values are always in meters. For example, if you construct a DAPoint2 object in pixels and then ask for its x-coordinate, the value will be returned in meters.