String Variable Support

In QuickTime 4 sprite track variables may contain either strings or floating point numbers. These variables may be used for all action and operand parameters that accept strings, such as GotoURL . Additionally, they may be concatenated together to create new string variables.

The new kActionSpriteTrackSetVariableToString action has been introduced to allow you to set a variable to a string value. You still use the kActionSpriteTrackSetVariable action to set a variable to a floating-point number.

When a sprite track variable is retrieved and used via the kOperandSpriteTrackVariable operand, it will be coerced to the required type. If it is used as part of an expression and it is a string, it will be converted to a floating-point number. If used as a string parameter, it will be converted to a C or Pascal string as needed from a floating-point number or string variable.

When a floating point number which does not contain an integer value is coerced to a string, a format of up to five digits before the decimal point and three digits afterwards is used.

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