Start the Flash program. Click "New" from the File menu on the main Flash menu bar. Click the file type "Flash File(ActionScript 3.0)" from the New Document dialog box that appears. Click the "OK" button to close the dialog box.
Click the "File" option from the main Flash menu bar, then click the "Import" option and then the "Import to Stage" option to display the Flash file directory dialog box. Select a JPEG, GIF or PNG graphic file to import onto the Flash Stage. Click the graphic file you want to import, then click the "OPEN" button to import the graphic file onto the stage.
Click the "Convert to Symbol" option from the Modify menu on the main Flash menu bar. Check the "Export for ActionScript" check box, then click the "OK" button to close the dialog box. Click the "OK" button on the next dialog box that appears.
Click the "Properties" option from the Window menu on the main Flash menu bar to open the Property Inspector. Type in "goddess" in the Instance Name text box for the name of the graphic you imported and to use as the name of the object to mask within the ActionScript 3 code.
Select the "Actions" option from the Window menu on the main Flash menu bar to open the Actions editor. Position your mouse cursor on the first line of the Actions editor. Click your mouse button and type in the code below to create and place on the stage an instance of the Sprite class that is a circle positioned at the Flash stage coordinates (200, 250) with a radius of 50 to be used as a circular cutout to view a circular region of graphic you imported:
var circleMask:Sprite = new Sprite();
circleMask.graphics.lineStyle(1);
circleMask.graphics.beginFill(0xfd3434, 1);
circleMask.graphics.drawCircle(200,200,50);
addChild(circleMask);
Type the code below, starting at the next line in the Actions editor to apply the mask and the circle cutout on the mask over the object to be masked, the graphic you imported and named "goddess":
goddess.mask = circleMask;
Copy and paste the code below into the Actions editor if you want to ensure that your ActionScript 3 mask program has no errors and runs correctly:
var circleMask:Sprite = new Sprite();
circleMask.graphics.lineStyle(1);
circleMask.graphics.beginFill(0xfd3434, 1);
circleMask.graphics.drawCircle(200,200,50);
addChild(circleMask);
goddess.mask = circleMask;
Click the "TestMovie" option in the Control menu on the main Flash menu bar to view your masked graphic. Observe that the entire contents of your graphic is invisible (masked out) except for the circular area you specified as the mask cutout.