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Places a solid or patterned background behind the application's windows, hiding any other applications.Syntax:

set the backdrop to {<colorName> | <RGBColor> | <patternNumber> | <imageID> | none}


set the backdrop to "black"
set the backdrop to "140,30,30"
set the backdrop to none -- removes the backdrop

Use the backdrop property to create a kiosk mode, or to limit distractions during a movie or similar presentation.

Hiding other applications from the user is usually not recommended, since users may need or want to see other windows on their system. However, the ability to do this can be very useful for some applications (such as kiosk systems or games) or at times when you want to reduce distractions (such as during the playing of a movie).

Setting the backdrop property to "none" eliminates the backdrop and lets other windows be seen.

Pattern images can be color or black-and-white.

To be used as a pattern on Mac OS
systems, an image must be 128x128 pixels or less, and both its

height and width must be a power of 2. To be used on Windows and Unix systems, height and width must be divisible by 8. To be used as a fully cross-platform pattern, both an image's dimensions should be one of 8, 16, 32, 64, or 128.

On Mac OS systems, if you use the

launch or open process commands to start up another application, or if the user brings another application to the front, its windows appear in front of the backdrop. (The backdrop remains visible even if the application is in the background.) Bringing the application to the front again hides the other application behind the backdrop. On Unix and Windows systems, any windows you open after setting the backdrop property remain in front of the backdrop, even if they belong to an application that is in the background.

If the system has multiple screens connected, the backdrop property affects only the main screen.

Changes: The backdrop pattern option was introduced in version 1.1. In previous versions, the backdrop could be a solid color, but not a pattern.

See also: clickStack (function),stacks (function),mouseUpInBackdrop (message),raiseWindows (property),height (property),pixels (property),width (property),