SetupDesignGuide.pdf - Firmware Encoding Index

Setup Design Guide
DRAFT
accent keys that do not advance the cursor and in essence are a type of modifier key in that they
maintain some level of state.
The way a person uses a dead key is that the dead key that maybe has the function of overlaying an
umlaut (two dots) onto whatever the next character might be. The user presses the umlaut dead key and
follows it with a capital A. This yields a “Ä”
//
// If it’s a dead key, we need to pass a list of physical key
// names… each with a unicode, shifted, altgr, shiftedaltgr
// value. Each key name will have a Modifier value of
// DEAD_KEY_MODIFIER for first entry, and then the list of
// DEAD_KEY_DEPENDENCY_MODIFIER physical key descriptions.
// This eventually will lead to the next normal non-dead-key
// definition.
//
// This requires defining an additional Modifier value of
// DEAD_KEY_DEPENDENCY_MODIFIER to signify DEAD_KEY_MODIFIER
// children definitions.
//
// The keyboard driver (consumer of the layouts) will know that
// any key definitions with the DEAD_KEY_DEPENDENCY_MODIFIER
// modifier do not redefine the value of the specified EFI_KEY.
// They are simply used as a special case augmentation to the
// original DEAD_KEY_MODIFIER.
//
// It is an error condition to define a DEAD_KEY_MODIFIER
// without having all the DEAD_KEY_DEPENDENCY_MODIFIER
// keys defined serially.
//
Layout = {
EfiKeyE0, 0, 0, 0, 0, DEAD_KEY_MODIFIER,
EfiKeyC1, 0x00E2, 0x00C2, 0, 0, DEAD_KEY_DEPENDENCY_MODIFIER,
EfiKeyD3, 0x00EA, 0x00CA, 0, 0, DEAD_KEY_DEPENDENCY_MODIFIER,
EfiKeyD8, 0x00EC, 0x00CC, 0, 0, DEAD_KEY_DEPENDENCY_MODIFIER,
EfiKeyD9, 0x00F4, 0x00D4, 0, 0, DEAD_KEY_DEPENDENCY_MODIFIER,
EfiKeyD7, 0x00FB, 0x00CB, 0, 0, DEAD_KEY_DEPENDENCY_MODIFIER,
}
In the above example, a key located at E0 is designated as a Dead Key. Using a common German
keyboard layout as the example, at the E0 location a circumflex accent “^” is defined as a dead key.
The valid keys that can be pressed after the dead key which will produce valid printable characters are
the A, E, I, O, and U characters. These are located at C1, D3, D8, D9, and D7 respectively.
The results of the Layout definition provided above would allow for the production of the following
characters: âÂêÊîÎôÔûÛ.
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