57 lines
2.2 KiB
Markdown
57 lines
2.2 KiB
Markdown
# Compatibility
|
|
|
|
Relative to the XKB 1.0 specification implemented in current X servers,
|
|
xkbcommon has removed support for some parts of the specification which
|
|
introduced unnecessary complications. Many of these removals were in fact
|
|
not implemented, or half-implemented at best, as well as being totally
|
|
unused in the standard dataset.
|
|
|
|
Notable removals:
|
|
- geometry support
|
|
+ there were very few geometry definitions available, and while
|
|
xkbcommon was responsible for parsing this insanely complex format,
|
|
it never actually did anything with it
|
|
+ hopefully someone will develop a companion library which supports
|
|
keyboard geometries in a more useful format
|
|
- KcCGST (keycodes/compat/geometry/symbols/types) API
|
|
+ use RMLVO instead; KcCGST is now an implementation detail
|
|
+ including pre-defined keymap files
|
|
- XKM support
|
|
+ may come in an optional X11 support/compatibility library
|
|
- around half of the interpret actions
|
|
+ pointer device, message and redirect actions in particular
|
|
- non-virtual modifiers
|
|
+ core and virtual modifiers have been collapsed into the same
|
|
namespace, with a 'significant' flag that largely parallels the
|
|
core/virtual split
|
|
- radio groups
|
|
+ completely unused in current keymaps, never fully implemented
|
|
- overlays
|
|
+ almost completely unused in current keymaps
|
|
- key behaviors
|
|
+ used to implement radio groups and overlays, and to deal with things
|
|
like keys that physically lock; unused in current keymaps
|
|
- indicator behaviours such as LED-controls-key
|
|
+ the only supported LED behaviour is key-controls-LED; again this
|
|
was never really used in current keymaps
|
|
|
|
On the other hand, some features and extensions were added.
|
|
|
|
Notable additions:
|
|
- 32-bit keycodes
|
|
- extended number of modifiers (planned)
|
|
- extended number of groups (planned)
|
|
- multiple keysyms per level
|
|
+ such levels are ignored by x11/xkbcomp.
|
|
- key names (e.g. `<AE11>`) can be longer than 4 characters.
|
|
|
|
## Compose support
|
|
|
|
Relative to the standard implementation in libX11 (described in the
|
|
Compose(5) man-page), some features are not supported:
|
|
|
|
- the (! MODIFIER) syntax
|
|
+ parsed correctly but ignored.
|
|
- using modifier keysyms in Compose sequences
|
|
- several interactions with Braille keysyms
|