You want to specify the dimensions of a Projector.
Use SWF Studio to create the Projector (Windows only). Set the size settings prior to building the project.
If you are creating a Windows Projector, you can use SWF Studio to set the dimensions of the movie. Follow the steps in Recipe 2.10, substituting the following tasks for step 6:
Choose the first item from the Project Tree. If you have saved your project, the item has the same name as your project; otherwise, the item is labeled Untitled.
On the right, the Project Options pane appears, and the Output tab is selected by default. You can leave the output settings at their default values.
Select the Window tab.
In the Window tab, choose one of the following options:
This option forces the Projector to full screen, matching the monitor resolution at runtime.
If you select this option, you must specify the dimensions (in pixels) to use for the Projector. The default is 500 x 400.
This option scales the Projector to fit a percentage of the user's desktop. Because users can have different resolution settings on their computers, choosing a percentage can have different results than using Fixed Size.
This option leaves the movie's dimensions as they are.
See Recipe 2.10 for more information on how to use SWF Studio.