Katzenpfote

Introduction

Katzenpfote is a variante of the classic Dvorak keyboard layout but tailored to non-staggered or grid keyboards. Examples of such keyboards are the Kinesis Advantage Ergonomic, the Maltron Ergonomic 3d, the Key64, the ErgoDox, or the TypeMatrix. The Dvorak layout itself is probably most famous for its arrangement of keys on the home row. In fact, around 70% of keyboard strokes are happening on the home row when typing a typical English text.

ESC	7	5	3	1	9	0	2	4	6	8	TAB
ü	:	,	.	p	y	f	g	c	r	l	ö
SHIFT	a	o	e	u	i	d	h	t	n	s	SHIFT
ä	’	q	j	k	x	b	m	w	v	z	ß

Note how easy it is to type bigrams, such as th, eu, and en in the layout. But also trigrams, such as ous, are a bliss to type. If this makes you a faster typist is another question, but, in general, many people say that typing feels more natural in this layout than on common QWERTZ. The order of the numericals on the top row follow Benford’s law such that the most frequent digits are pressed with your most strongest fingers. The side effect that the odd numbers are on the left and the even numbers are on the right makes it also very easy to touch-type long colons of numbers, e.g., when entering data.

Another motivation: the Katzenpfote layout allows you to write formulas, such as:

P(α ≤ X ≤ β) = Φ(β) - Φ(α) = ∫_α^β Φ(x) dx

directly into your TeX-documents, and, as most modern TeX distribution support UTF-8, they will be rendered correctly. It looks nicer and it is much more readable than the equivalent:

P(\alpha \leq X \leq \beta) = \Phi(\beta) - \Phi(\alpha) = \int_{\alpha}^{\beta} \Phi(x) dx

Katzenpfote is the standard keyboard layout of Seebrise.

Layout

The above table shows the alpha-numeric layer of the grid: note the SHIFT-keys, which lie on the home-row of the layout, as we can safely assume that you are much more likely in the need to press SHIFT than CAPS-LOCK. Also, the ESCAPE-key has moved to a more prominent position, and it is now on the same level as the numeric keys. It is much more convenient to have the TABULATOR-key on the right side of the board and close to the numerics, too, which is why it moved there. A side effect of the layout: when entering long rows of digital numbers, it is nice to have , and . right below the numericals and, thus, in easy reach.

When pressing SHIFT, it yields the shifted or capital layer:

ESC	ℍ	𝔹	𝕍	𝔼	𝔽	ℂ	ℝ	ℕ	ℤ	ℚ	TAB
Ü	;	!	?	P	Y	F	G	C	R	L	Ö
SHIFT	A	O	E	U	I	D	H	T	N	S	SHIFT
Ä	”	Q	J	K	X	B	M	W	V	Z	𝟙

The symbol layer looks as follows:

ESC	d¨	d˛	d¸	´	d´	d`	`	€	¢	£	TAB
	∪	+	$	[	@	%	]	\	&	∩	ø
SHIFT	~	<	-	(	±	_	)	/	>	^	SHIFT
å	“	«	=	{	#	*	}	\|	»	”	§

Symbols prefixed with ‘d’ are dead keys. Note how easy it is to press combinations such as <- or ~/ or []. When additionally pressing SHIFT, it yields a shifted symbol layer, which is full of more common UTF-8 characters:

ESC	7	5	3	1	9	0	2	4	6	8	TAB
	⋃	∨	…	⊊	⨉	°	⊆	∙	∧	⋂	Ø
SHIFT	≈	≤	∅	∉	∓	∞	∈	∘	≥	∝	SHIFT
Å	∃	∥	≠	∫	∇	∆	⊤	⋅	⊥	∀

When using the Katzenpfote layout, you have also access to a greek layer. This layer is particularly useful, when writing mathematical text in TeX, as most TeX-dialects, such as ConTeXt and LaTeX, understand UTF-8.

ESC	7	5	3	1	9	0	2	4	6	8	TAB
				π	υ	φ	γ	χ	ρ	λ
SHIFT	α	ο	ε	ψ	ι	δ	η	τ	ν	σ	SHIFT
				κ	ξ	β	μ	ω	θ	ζ

When additionally pressing SHIFT, it yields the capital greek layer:

ESC	7	5	3	1	9	0	2	4	6	8	TAB
				Π	Υ	Φ	Γ	Χ	Ρ	Λ
SHIFT	Α	Ο	Ε	Ψ	Ι	Δ	Η	Τ	Ν	Σ	SHIFT
				Κ	Ξ	Β	Μ	Ω	Θ	Ζ

In grid layouts, the thumbs can do a lot more than just pressing space:

left thumb	right thumb
symbol	space
Control	enter
WM	greek

Pressing symbol or greek will enter the symbol or greek layer respectively. The window manager is controlled by pressing WM.

Installation of Katzenpfote

The keyboard layout descriptions reside in /usr/share/X11/xkb/symbols/ on most Linux distributions. The idea is to simply copy the layout description to this folder.

% git clone https://github.com/00tau/katzenpfote.git ~/.config/katzenpfote
# cd /usr/share/X11/xkb/symbols/
# ln -s ~/.config/katzenpfote/kp kp

Then apply the layout on a Kinesis Advantage Ergonomic:

% setxkbmap kp kinesis

Then apply the layout on a TypeMatrix:

% setxkbmap kp typematrix

Meta keys

The X system has its own keyboard handling layer, in which scan codes are send from your keyboard to X, these scan codes are mapped to key codes, who are then mapped to key symbols, which are then send to your program for interpretation.

The layout description residing in the file kp has been tested for the Kinesis Advantage, the Kinesis Advantage 2, and the TypeMatrix. Katzenpfote builds on top of the X server key code table, i.e., it alters the keycode-keysym-table.

This way you will likely not have any difficulties when using a different non-staggered keyboard. In case you need to tweak the description, however, here is the mapping of the meta keys to keycodes and keysyms in kp in the case of the Kinesis:

interpretation	`keycode`	`keysym`
symbol	BKSP	ISO_Level3_Shift
greek	PGDN	ISO_Level5_Shift
WM	END	Super_L

And in cases of the TypeMatrix:

interpretation	`keycode`	`keysym`
symbol	ALTL	ISO_Level3_Shift
greek	ALTR	ISO_Level5_Shift

Trivia

Katzenpfote is German. It would literally translate to: “the paw of a cat”. However, Katzenpfote is also a nautical term used by German sailors to describe the characteristic pattern that a light sea breeze draws on calm see. Katzenpfote is the standard keyboard layout in Seebrise.

katzenpfote