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Appendix C - Keyboard Resources / About the Keyboard Resources

What the Keyboard Resources Are

The keyboard resources fall into two categories: those that are hardware-dependent
(and script-independent) and those that are script-dependent (and hardware-independent). It is this division that allows many different physical keyboards to work correctly with many different script systems. Table C-3 lists the keyboard resources and their resource types, and gives a capsule description of their contents. More complete descriptions follow.

The keyboard resources

Name	Resource type	Contents
Key map	'KMAP'	Tables to map raw key codes to virtual key codes
Key remap	'itlk'	Tables to remap virtual key codes for certain key combinations
Keyboard layout	'KCHR'	Tables to map virtual key codes to character codes
Keyboard icons	'kcs#'	Keyboard icon (1-bit; black-and-white)
	'kcs4'	Keyboard icon (4-bit)
	'kcs8'	Keyboard icon (8-bit)
Keyboard swap	'KSWP'	Table specifying key combinations for changing keyboard script or input method
Key caps	'KCAP'	Data that determines keyboard display

• Key-map resource. Maps the raw key codes that have been generated by a specific keyboard microprocessor into hardware-independent standard virtual key codes. There is a maximum of one key-map resource per physical keyboard (several keyboards can share a single key-map resource).
• Key-remap resource. Remaps the virtual key codes for certain key combinations on certain keyboards to other virtual key codes, to allow a single keyboard-layout resource to work with all keyboards. This resource is optional; it is provided with certain keyboard-layout resources.
• Keyboard-layout resource. Maps virtual key codes to character codes. The keyboard-layout resource implements the character set for a script system. It is with different keyboard-layout resources that text input for different script systems and localized versions of system software is enabled. A script system has one or more keyboard-layout resources.
• Keyboard icon family. Implements keyboard icons--small icons that represent a keyboard script or input method--for screens of different bit depths (black-and white, 4-bit, and 8-bit, respectively). These icons are used in the Keyboard menu and in the Keyboard control panel. There is one icon family per keyboard-layout resource (or input method).
• Keyboard-swap resource. Lists modifier-plus-key combinations that can be used to change the keyboard script, or the keyboard layout or input method within a script. There is one keyboard-swap resource per version of system software.
• Key-caps resource. Specifies the physical arrangement of keys on a keyboard and is used to display the characters produced by each keypress. The key-caps resource is independent of any script system, but the Key Caps desk accessory uses it along with the keyboard-layout resource of the current script system--and a font in the current script system--to display the characters corresponding to each keypress or combination of keypresses.There is one key-caps resource per physical keyboard.

Keyboard resources and localized system software

When Macintosh system software is localized for a non-U.S. market,
it contains replacements for or modifications to some of the U.S. versions of the keyboard resources. See the discussion of U.S. international resources and keyboard resources in the appendix
"Built-in Script Support" for a list of resources that may be replaced
during localization.