kitty Documentation

File: 3rdparty/base64/README.md Copy Chapter

Fast Base64 stream encoder/decoder

This is an implementation of a base64 stream encoding/decoding library in C99
with SIMD (AVX2, AVX512, NEON, AArch64/NEON, SSSE3, SSE4.1, SSE4.2, AVX) and
OpenMP acceleration. It also contains wrapper functions
to encode/decode simple length-delimited strings. This library aims to be:

• FAST;
• easy to use;
• elegant.

On x86, the library does runtime feature detection. The first time it's called,
the library will determine the appropriate encoding/decoding routines for the
machine. It then remembers them for the lifetime of the program. If your
processor supports AVX2, SSSE3, SSE4.1, SSE4.2 or AVX instructions, the library
will pick an optimized codec that lets it encode/decode 12 or 24 bytes at a
time, which gives a speedup of four or more times compared to the "plain"
bytewise codec.

AVX512 support is only for encoding at present, utilizing the AVX512 VL and VBMI
instructions. Decoding part reused AVX2 implementations. For CPUs later than
Cannonlake (manufactured in 2018) supports these instructions.

NEON support is hardcoded to on or off at compile time, because portable
runtime feature detection is unavailable on ARM.

Even if your processor does not support SIMD instructions, this is a very fast
library. The fallback routine can process 32 or 64 bits of input in one round,
depending on your processor's word width, which still makes it significantly
faster than naive bytewise implementations. On some 64-bit machines, the 64-bit
routines even outperform the SSSE3 ones.

To the author's knowledge, at the time of original release, this was the only
Base64 library to offer SIMD acceleration. The author wrote
an article explaining one
possible SIMD approach to encoding/decoding Base64. The article can help figure
out what the code is doing, and why.

Notable features:

• Really fast on x86 and ARM systems by using SIMD vector processing;
• Can use OpenMP for even more parallel speedups;
• Really fast on other 32 or 64-bit platforms through optimized routines;
• Reads/writes blocks of streaming data;
• Does not dynamically allocate memory;
• Valid C99 that compiles with pedantic options on;
• Re-entrant and threadsafe;
• Unit tested;
• Uses Duff's Device.

Acknowledgements Copy Chapter

The original AVX2, NEON and Aarch64/NEON codecs were generously contributed by
Inkymail, who, in their fork, also
implemented some additional features. Their work is slowly being backported
into this project.

The SSSE3 and AVX2 codecs were substantially improved by using some very clever
optimizations described by Wojciech Muła in a
series of
articles.
His own code is here.

The AVX512 encoder is based on code from Wojciech Muła's
base64simd library.

The OpenMP implementation was added by Ferry Toth (@htot) from Exalon Delft.

Building Copy Chapter

The lib directory contains the code for the actual library.
Typing make in the toplevel directory will build lib/libbase64.o and bin/base64.
The first is a single, self-contained object file that you can link into your own project.
The second is a standalone test binary that works similarly to the base64 system utility.

The matching header file needed to use this library is in include/libbase64.h.

To compile just the "plain" library without SIMD codecs, type:

make lib/libbase64.o

Optional SIMD codecs can be included by specifying the AVX2_CFLAGS, AVX512_CFLAGS,
NEON32_CFLAGS, NEON64_CFLAGS, SSSE3_CFLAGS, SSE41_CFLAGS, SSE42_CFLAGS and/or AVX_CFLAGS environment variables.
A typical build invocation on x86 looks like this:

AVX2_CFLAGS=-mavx2 SSSE3_CFLAGS=-mssse3 SSE41_CFLAGS=-msse4.1 SSE42_CFLAGS=-msse4.2 AVX_CFLAGS=-mavx make lib/libbase64.o

AVX2 Copy Section

To build and include the AVX2 codec, set the AVX2_CFLAGS environment variable to a value that will turn on AVX2 support in your compiler, typically -mavx2.
Example:

AVX2_CFLAGS=-mavx2 make

AVX512 Copy Section

To build and include the AVX512 codec, set the AVX512_CFLAGS environment variable to a value that will turn on AVX512 support in your compiler, typically -mavx512vl -mavx512vbmi.
Example:

AVX512_CFLAGS="-mavx512vl -mavx512vbmi" make

The codec will only be used if runtime feature detection shows that the target machine supports AVX2.

SSSE3 Copy Section

To build and include the SSSE3 codec, set the SSSE3_CFLAGS environment variable to a value that will turn on SSSE3 support in your compiler, typically -mssse3.
Example:

SSSE3_CFLAGS=-mssse3 make

The codec will only be used if runtime feature detection shows that the target machine supports SSSE3.

NEON Copy Section

This library includes two NEON codecs: one for regular 32-bit ARM and one for the 64-bit AArch64 with NEON, which has double the amount of SIMD registers and can do full 64-byte table lookups.
These codecs encode in 48-byte chunks and decode in massive 64-byte chunks, so they had to be augmented with an uint32/64 codec to stay fast on smaller inputs!

Use LLVM/Clang for compiling the NEON codecs.
The code generation of at least GCC 4.6 (the version shipped with Raspbian and used for testing) contains a bug when compiling vstq4_u8(), and the generated assembly code is of low quality.
NEON intrinsics are a known weak area of GCC.
Clang does a better job.

NEON support can unfortunately not be portably detected at runtime from userland (the mrc instruction is privileged), so the default value for using the NEON codec is determined at compile-time.
But you can do your own runtime detection.
You can include the NEON codec and make it the default, then do a runtime check if the CPU has NEON support, and if not, force a downgrade to non-NEON with BASE64_FORCE_PLAIN.

These are your options:

1. Don't include NEON support;
2. build NEON support and make it the default, but build all other code without NEON flags so that you can override the default at runtime with BASE64_FORCE_PLAIN;
3. build everything with NEON support and make it the default;
4. build everything with NEON support, but don't make it the default (which makes no sense).

For option 1, simply don't specify any NEON-specific compiler flags at all, like so:

CC=clang CFLAGS="-march=armv6" make

For option 2, keep your CFLAGS plain, but set the NEON32_CFLAGS environment variable to a value that will build NEON support.
The line below, for instance, will build all the code at ARMv6 level, except for the NEON codec, which is built at ARMv7.
It will also make the NEON codec the default.
For ARMv6 platforms, override that default at runtime with the BASE64_FORCE_PLAIN flag.
No ARMv7/NEON code will then be touched.

CC=clang CFLAGS="-march=armv6" NEON32_CFLAGS="-march=armv7 -mfpu=neon" make

For option 3, put everything in your CFLAGS and use a stub, but non-empty, NEON32_CFLAGS.
This example works for the Raspberry Pi 2B V1.1, which has NEON support:

CC=clang CFLAGS="-march=armv7 -mtune=cortex-a7" NEON32_CFLAGS="-mfpu=neon" make

To build and include the NEON64 codec, use CFLAGS as usual to define the platform and set NEON64_CFLAGS to a nonempty stub.
(The AArch64 target has mandatory NEON64 support.)
Example:

CC=clang CFLAGS="--target=aarch64-linux-gnu -march=armv8-a" NEON64_CFLAGS=" " make

OpenMP Copy Section

To enable OpenMP on GCC you need to build with -fopenmp. This can be by setting the OPENMP environment variable to 1.

Example:

OPENMP=1 make

This will let the compiler define _OPENMP, which in turn will include the OpenMP optimized lib_openmp.c into lib.c.

By default the number of parallel threads will be equal to the number of cores of the processor.
On a quad core with hyperthreading eight cores will be detected, but hyperthreading will not increase the performance.

To get verbose information about OpenMP start the program with OMP_DISPLAY_ENV=VERBOSE, for instance

OMP_DISPLAY_ENV=VERBOSE test/benchmark

To put a limit on the number of threads, start the program with OMP_THREAD_LIMIT=n, for instance

OMP_THREAD_LIMIT=2 test/benchmark

An example of running a benchmark with OpenMP, SSSE3 and AVX2 enabled:

make clean && OPENMP=1 SSSE3_CFLAGS=-mssse3 AVX2_CFLAGS=-mavx2 make && OPENMP=1 make -C test

API reference Copy Chapter

Strings are represented as a pointer and a length; they are not
zero-terminated. This was a conscious design decision. In the decoding step,
relying on zero-termination would make no sense since the output could contain
legitimate zero bytes. In the encoding step, returning the length saves the
overhead of calling strlen() on the output. If you insist on the trailing
zero, you can easily add it yourself at the given offset.

Flags Copy Section

Some API calls take a flags argument.
That argument can be used to force the use of a specific codec, even if that codec is a no-op in the current build.
Mainly there for testing purposes, this is also useful on ARM where the only way to do runtime NEON detection is to ask the OS if it's available.
The following constants can be used:

• BASE64_FORCE_AVX2
• BASE64_FORCE_AVX512
• BASE64_FORCE_NEON32
• BASE64_FORCE_NEON64
• BASE64_FORCE_PLAIN
• BASE64_FORCE_SSSE3
• BASE64_FORCE_SSE41
• BASE64_FORCE_SSE42
• BASE64_FORCE_AVX

Set flags to 0 for the default behavior, which is runtime feature detection on x86, a compile-time fixed codec on ARM, and the plain codec on other platforms.

Encoding Copy Section

base64_encode

void base64_encode
    ( const char  *src
    , size_t       srclen
    , char        *out
    , size_t      *outlen
    , int          flags
    ) ;

Wrapper function to encode a plain string of given length.
Output is written to out without trailing zero.
Output length in bytes is written to outlen.
The buffer in out has been allocated by the caller and is at least 4/3 the size of the input.

base64_stream_encode_init

void base64_stream_encode_init
    ( struct base64_state  *state
    , int                   flags
    ) ;

Call this before calling base64_stream_encode() to init the state.

base64_stream_encode

void base64_stream_encode
    ( struct base64_state  *state
    , const char           *src
    , size_t                srclen
    , char                 *out
    , size_t               *outlen
    ) ;

Encodes the block of data of given length at src, into the buffer at out.
Caller is responsible for allocating a large enough out-buffer; it must be at least 4/3 the size of the in-buffer, but take some margin.
Places the number of new bytes written into outlen (which is set to zero when the function starts).
Does not zero-terminate or finalize the output.

base64_stream_encode_final

void base64_stream_encode_final
    ( struct base64_state  *state
    , char                 *out
    , size_t               *outlen
    ) ;

Finalizes the output begun by previous calls to base64_stream_encode().
Adds the required end-of-stream markers if appropriate.
outlen is modified and will contain the number of new bytes written at out (which will quite often be zero).

Decoding Copy Section

base64_decode

int base64_decode
    ( const char  *src
    , size_t       srclen
    , char        *out
    , size_t      *outlen
    , int          flags
    ) ;

Wrapper function to decode a plain string of given length.
Output is written to out without trailing zero. Output length in bytes is written to outlen.
The buffer in out has been allocated by the caller and is at least 3/4 the size of the input.
Returns 1 for success, and 0 when a decode error has occured due to invalid input.
Returns -1 if the chosen codec is not included in the current build.

base64_stream_decode_init

void base64_stream_decode_init
    ( struct base64_state  *state
    , int                   flags
    ) ;

Call this before calling base64_stream_decode() to init the state.

base64_stream_decode

int base64_stream_decode
    ( struct base64_state  *state
    , const char           *src
    , size_t                srclen
    , char                 *out
    , size_t               *outlen
    ) ;

Decodes the block of data of given length at src, into the buffer at out.
Caller is responsible for allocating a large enough out-buffer; it must be at least 3/4 the size of the in-buffer, but take some margin.
Places the number of new bytes written into outlen (which is set to zero when the function starts).
Does not zero-terminate the output.
Returns 1 if all is well, and 0 if a decoding error was found, such as an invalid character.
Returns -1 if the chosen codec is not included in the current build.
Used by the test harness to check whether a codec is available for testing.

Examples Copy Chapter

A simple example of encoding a static string to base64 and printing the output
to stdout:

#include <stdio.h>	/* fwrite */
#include "libbase64.h"

int main ()
{
	char src[] = "hello world";
	char out[20];
	size_t srclen = sizeof(src) - 1;
	size_t outlen;

	base64_encode(src, srclen, out, &outlen, 0);

	fwrite(out, outlen, 1, stdout);

	return 0;
}

A simple example (no error checking, etc) of stream encoding standard input to
standard output:

#include <stdio.h>
#include "libbase64.h"

int main ()
{
	size_t nread, nout;
	char buf[12000], out[16000];
	struct base64_state state;

	// Initialize stream encoder:
	base64_stream_encode_init(&state, 0);

	// Read contents of stdin into buffer:
	while ((nread = fread(buf, 1, sizeof(buf), stdin)) > 0) {

		// Encode buffer:
		base64_stream_encode(&state, buf, nread, out, &nout);

		// If there's output, print it to stdout:
		if (nout) {
			fwrite(out, nout, 1, stdout);
		}

		// If an error occurred, exit the loop:
		if (feof(stdin)) {
			break;
		}
	}

	// Finalize encoding:
	base64_stream_encode_final(&state, out, &nout);

	// If the finalizing resulted in extra output bytes, print them:
	if (nout) {
		fwrite(out, nout, 1, stdout);
	}

	return 0;
}

Also see bin/base64.c for a simple re-implementation of the base64 utility.
A file or standard input is fed through the encoder/decoder, and the output is
written to standard output.

Tests Copy Chapter

See tests/ for a small test suite. Testing is automated with
GitHub Actions, which builds and
tests the code across various architectures.

Benchmarks Copy Chapter

Benchmarks can be run with the built-in benchmark program as follows:

make -C test benchmark  && test/benchmark

It will run an encoding and decoding benchmark for all of the compiled-in codecs.

The tables below contain some results on random machines. All numbers measured with a 10MB buffer in MB/sec, rounded to the nearest integer.

*: Update needed

x86 processors

ARM processors

PowerPC processors

Benchmarks on i7-4770 @ 3.4 GHz DDR1600 with varrying buffer sizes:

Note: optimal buffer size to take advantage of the cache is in the range of 100 kB to 1 MB, leading to 12x faster AVX encoding/decoding compared to Plain, or a throughput of 24/27GB/sec.
Also note the performance degradation when the buffer size is less than 10 kB due to thread creation overhead.
To prevent this from happening lib_openmp.c defines OMP_THRESHOLD 20000, requiring at least a 20000 byte buffer to enable multithreading.

License Copy Chapter

This repository is licensed under the
BSD 2-clause License. See the
LICENSE file.

File: docs/kittens/broadcast.rst Copy Chapter

broadcast

.. only:: man

Overview
--------------

Type text in all kitty windows simultaneously

The broadcast kitten can be used to type text simultaneously in all
:term:kitty windows <window> (or a subset as desired).

To use it, simply create a mapping in :file:kitty.conf such as::

map f1 launch --allow-remote-control kitten broadcast

Then press the :kbd:F1 key and whatever you type in the newly created window
will be sent to all kitty windows.

You can use the options described below to control which windows are selected.

For example, only broadcast to other windows in the current tab::

map f1 launch --allow-remote-control kitten broadcast --match-tab state:focused

.. program:: kitty +kitten broadcast

.. include:: /generated/cli-kitten-broadcast.rst

File: docs/kittens/choose-fonts.rst Copy Chapter

Changing kitty fonts

.. only:: man

Overview
--------------

Terminal aficionados spend all day staring at text, as such, getting text
rendering just right is very important. kitty has extremely powerful facilities
for fine-tuning text rendering. It supports OpenType features <https://en.wikipedia.org/wiki/List_of_typographic_features>__ to select
alternate glyph shapes, and Variable fonts <https://en.wikipedia.org/wiki/Variable_font>__ to control the weight or
spacing of a font precisely. You can also :opt:select which font is used to render particular unicode codepoints <symbol_map> and you can :opt:modify font metrics <modify_font> and even :opt:adjust the gamma curves <text_composition_strategy> used for rendering text onto the background color.

The first step is to select the font faces kitty will use for rendering
regular, bold and italic text. kitty comes with a convenient UI for choosing fonts,
in the form of the choose-fonts kitten. Simply run::

kitten choose-fonts

and follow the on screen prompts.

First, choose the family you want, the list of families can be easily filtered by
typing a few letters from the family name you are looking for. The family
selection screen shows you a preview of how the family looks.

.. image:: ../screenshots/family-selection.png
:alt: Choosing a family with the choose fonts kitten
:width: 600

Once you select a family by pressing the :kbd:Enter key, you
are shown previews of what the regular, bold and italic faces look like
for that family. You can choose to fine tune any of the faces. Start with
fine-tuning the regular face by pressing the :kbd:R key. The other styles
will be automatically adjusted based on what you select for the regular face.

.. image:: ../screenshots/font-fine-tune.png
:alt: Fine tune a font by choosing a precise weight and features
:width: 600

You can choose a specific style or font feature by clicking on it. A precise
value for any variable axes can be selected using the slider, in the screenshot
above, the font supports precise weight adjustment. If you are lucky the font
designer has included descriptive names for font features, which will be
displayed, if not, consult the documentation of the font to see what each feature does.

.. _font_spec_syntax:

The font specification syntax Copy Chapter

If you don't like the choose fonts kitten or simply want to understand and
write font selection options into :file:kitty.conf yourself, read on.

There are four font face selection keys: font_family, bold_font,
italic_font and bold_italic_font. Each of these supports the syntax
described below. Their values can be of three types, either a
font family name, the keyword auto or an extended key=value syntax
for specifying font selection precisely.

If a font family name is specified kitty will use Operating System APIs to
search for a matching font. The keyword auto means kitty will choose a font
completely automatically, typically this is used for automatically selecting
bold/italic variants once the :opt:font_family is set. The bold and italic
variants will then automatically use the same set of features as the main face.

To specify font face selection more precisely, a key=value syntax is used.
First, let's look at a few examples::

# Select by family only, actual face selection is automatic
font_family family="Fira Code"
# Select an exact face by Postscript name
font_family postscript_name=FiraCode
# Select an exact face by family with features and variable weight
font_family family=SourceCodeVF variable_name=SourceCodeUpright features="+zero cv01=2" wght=380

The following are the known keys, any other keys are names of variable axes,
that is, they are used to set the variable value for some font characteristic.

family
A font family name. A family typically has multiple actual font faces, such
as bold and italic variants. One or more of the faces can even be variable,
allowing fine tuning of font characteristics.

style
A style name to choose a particular font from a given family. Useful only
with the family key, when no more precise methods for face selection
are specified. Can also be used to specify a named variable style for
variable fonts.

postscript_name
The actual postscript name for a font face. This allows selecting a
particular variant within a font family. But note that postscript names
are usually insufficient for selecting variable fonts.

full_name
This can be used to select a particular font face in a family. However, it
is less precise than postscript_name and should not generally be used.

variable_name
Some families with variable fonts actually contain multiple font files. For
example, a family could have variable weights with one font file containing
upright variable weight faces and another containing italic variable weight
faces. Well designed fonts use a variable name to distinguish between
such files. Should be used in conjunction with family to select a
particular variable font file.

features
A space separated list of OpenType font features to enable/disable or
select a value of, for this font. Consult the documentation for the font
family to see what features it supports and their effects. The exact syntax
for specifying features is documented by HarfBuzz <https://harfbuzz.github.io/harfbuzz-hb-common.html#hb-feature-from-string>__

system
This can be used to pass an arbitrary string, usually a family or full name
to the OS font selection APIs. Should not be used in conjunction with any
other keys. Is the same as specifying just the font name without any keys.

In addition to these keys, any four letter key is treated as the name of a
variable characteristic of the font. Its value is used to set the value for
the name.

File: docs/kittens/clipboard.rst Copy Chapter

clipboard

.. only:: man

Overview
--------------

*Copy/paste to the system clipboard from shell scripts*

.. highlight:: sh

The clipboard kitten can be used to read or write to the system clipboard
from the shell. It even works over SSH. Using it is as simple as::

echo hooray | kitten clipboard

All text received on :file:STDIN is copied to the clipboard.

To get text from the clipboard::

kitten clipboard --get-clipboard

The text will be written to :file:STDOUT. Note that by default kitty asks for
permission when a program attempts to read the clipboard. This can be
controlled via :opt:clipboard_control.

.. versionadded:: 0.27.0
Support for copying arbitrary data types

The clipboard kitten can be used to send/receive
more than just plain text from the system clipboard. You can transfer arbitrary
data types. Best illustrated with some examples::

# Copy an image to the clipboard:
kitten clipboard picture.png

# Copy an image and some text to the clipboard:
kitten clipboard picture.jpg text.txt

# Copy text from STDIN and an image to the clipboard:
echo hello | kitten clipboard picture.png /dev/stdin

# Copy any raster image available on the clipboard to a PNG file:
kitten clipboard -g picture.png

# Copy an image to a file and text to STDOUT:
kitten clipboard -g picture.png /dev/stdout

# List the formats available on the system clipboard
kitten clipboard -g -m . /dev/stdout

Normally, the kitten guesses MIME types based on the file names. To control the
MIME types precisely, use the :option:--mime <kitty +kitten clipboard --mime> option.

This kitten uses a new protocol developed by kitty to function, for details,
see :doc:/clipboard.

.. program:: kitty +kitten clipboard

.. include:: /generated/cli-kitten-clipboard.rst

File: docs/kittens/custom.rst Copy Chapter

Custom kittens

You can easily create your own kittens to extend kitty. They are just terminal
programs written in Python. When launching a kitten, kitty will open an overlay
window over the current window and optionally pass the contents of the current
window/scrollback to the kitten over its :file:STDIN. The kitten can then
perform whatever actions it likes, just as a normal terminal program. After
execution of the kitten is complete, it has access to the running kitty instance
so it can perform arbitrary actions such as closing windows, pasting text, etc.

Let's see a simple example of creating a kitten. It will ask the user for some
input and paste it into the terminal window.

Create a file in the kitty config directory, :file:~/.config/kitty/mykitten.py
(you might need to adjust the path to wherever the :ref:kitty config directory <confloc> is on your machine).

.. code-block:: python

from kitty.boss import Boss

def main(args: list[str]) -> str:
    # this is the main entry point of the kitten, it will be executed in
    # the overlay window when the kitten is launched
    answer = input('Enter some text: ')
    # whatever this function returns will be available in the
    # handle_result() function
    return answer

def handle_result(args: list[str], answer: str, target_window_id: int, boss: Boss) -> None:
    # get the kitty window into which to paste answer
    w = boss.window_id_map.get(target_window_id)
    if w is not None:
        w.paste_text(answer)

Now in :file:kitty.conf add the lines::

map ctrl+k kitten mykitten.py

Start kitty and press :kbd:Ctrl+K and you should see the kitten running.
The best way to develop your own kittens is to modify one of the built-in
kittens. Look in the :repo_folder:kittens sub-directory <kittens> of the kitty source
code for those. Or see below for a list of :ref:third-party kittens <external_kittens>, that other kitty users have created.

kitty API to use with kittens Copy Chapter

Kittens have full access to internal kitty APIs. However these are neither
entirely stable nor documented. You can instead use the kitty
:doc:Remote control API </remote-control>. Simply call
:code:boss.call_remote_control(), with the same arguments you
would pass to kitten @. For example:

.. code-block:: python

def handle_result(args: list[str], answer: str, target_window_id: int, boss: Boss) -> None:
    # get the kitty window to which to send text
    w = boss.window_id_map.get(target_window_id)
    if w is not None:
        boss.call_remote_control(w, ('send-text', f'--match=id:{w.id}', 'hello world'))

.. note::
Inside handle_result() the active window is still the window in which the
kitten was run, therefore when using call_remote_control() be sure to pass
the appropriate option to select the target window, usually --match as
shown above or --self.

Run, kitten @ --help in a kitty terminal, to see all the remote control
commands available to you.

Passing arguments to kittens Copy Chapter

You can pass arguments to kittens by defining them in the map directive in
:file:kitty.conf. For example::

map ctrl+k kitten mykitten.py arg1 arg2

These will be available as the args parameter in the main() and
handle_result() functions. Note also that the current working directory
of the kitten is set to the working directory of whatever program is running in
the active kitty window. The special argument @selection is replaced by the
currently selected text in the active kitty window.

Passing the contents of the screen to the kitten Copy Chapter

If you would like your kitten to have access to the contents of the screen
and/or the scrollback buffer, you just need to add an annotation to the
handle_result() function, telling kitty what kind of input your kitten would
like. For example:

.. code-block:: py

from kitty.boss import Boss

# in main, STDIN is for the kitten process and will contain
# the contents of the screen
def main(args: list[str]) -> str:
    return sys.stdin.read()

# in handle_result, STDIN is for the kitty process itself, rather
# than the kitten process and should not be read from.
from kittens.tui.handler import result_handler
@result_handler(type_of_input='text')
def handle_result(args: list[str], stdin_data: str, target_window_id: int, boss: Boss) -> None:
    pass

This will send the plain text of the active window to the kitten's
:file:STDIN. There are many other types of input you can ask for, described in
the table below:

.. table:: Types of input to kittens
:align: left

=========================== ========================================================================================
Keyword                     Type of :file:`STDIN` input
=========================== ========================================================================================
``text``                    Plain text of active window
``ansi``                    Formatted text of active window
``screen``                  Plain text of active window with line wrap markers
``screen-ansi``             Formatted text of active window with line wrap markers

``history``                 Plain text of active window and its scrollback
``ansi-history``            Formatted text of active window and its scrollback
``screen-history``          Plain text of active window and its scrollback with line wrap markers
``screen-ansi-history``     Formatted text of active window and its scrollback with line wrap markers

``output``                  Plain text of the output from the last run command
``output-screen``           Plain text of the output from the last run command with wrap markers
``output-ansi``             Formatted text of the output from the last run command
``output-screen-ansi``      Formatted text of the output from the last run command with wrap markers

``selection``               The text currently selected with the mouse
=========================== ========================================================================================

In addition to output, that gets the output of the last run command,
last_visited_output gives the output of the command last jumped to
and first_output gives the output of the first command currently on screen.
These can also be combined with screen and ansi for formatting.

.. note::
For the types based on the output of a command, :ref:shell_integration is
required.

Using kittens to script kitty, without any terminal UI Copy Chapter

If you would like your kitten to script kitty, without bothering to write a
terminal program, you can tell the kittens system to run the handle_result()
function without first running the main() function.

For example, here is a kitten that "zooms in/zooms out" the current terminal
window by switching to the stack layout or back to the previous layout. This is
equivalent to the builtin :ac:toggle_layout action.

Create a Python file in the :ref:kitty config directory <confloc>,
:file:~/.config/kitty/zoom_toggle.py

.. code-block:: py

from kitty.boss import Boss

def main(args: list[str]) -> str:
    pass

from kittens.tui.handler import result_handler
@result_handler(no_ui=True)
def handle_result(args: list[str], answer: str, target_window_id: int, boss: Boss) -> None:
    tab = boss.active_tab
    if tab is not None:
        if tab.current_layout.name == 'stack':
            tab.last_used_layout()
        else:
            tab.goto_layout('stack')

Now in :file:kitty.conf add::

map f11 kitten zoom_toggle.py

Pressing :kbd:F11 will now act as a zoom toggle function. You can get even
more fancy, switching the kitty OS window to fullscreen as well as changing the
layout, by simply adding the line::

boss.toggle_fullscreen()

to the handle_result() function, above.

.. _send_mouse_event:

Sending mouse events Copy Chapter

If the program running in a window is receiving mouse events, you can simulate
those using::

from kitty.fast_data_types import send_mouse_event
send_mouse_event(screen, x, y, button, action, mods)

screen is the screen attribute of the window you want to send the event
to. x and y are the 0-indexed coordinates. button is a number using
the same numbering as X11 (left: 1, middle: 2, right: 3, scroll up:
4, scroll down: 5, scroll left: 6, scroll right: 7, back:
8, forward: 9). action is one of PRESS, RELEASE, DRAG
or MOVE. mods is a bitmask of GLFW_MOD_{mod} where {mod} is one
of SHIFT, CONTROL or ALT. All the mentioned constants are imported
from kitty.fast_data_types.

For example, to send a left click at position x: 2, y: 3 to the active window::

from kitty.fast_data_types import send_mouse_event, PRESS
send_mouse_event(boss.active_window.screen, 2, 3, 1, PRESS, 0)

The function will only send the event if the program is receiving events of
that type, and will return True if it sent the event, and False if not.

.. _kitten_main_rc:

Using remote control inside the main() kitten function Copy Chapter

You can use kitty's remote control features inside the main() function of a
kitten, even without enabling remote control. This is useful if you want to
probe kitty for more information before presenting some UI to the user or if
you want the user to be able to control kitty from within your kitten's UI
rather than after it has finished running. To enable it, simply tell kitty your kitten
requires remote control, as shown in the example below::

import json
import sys
from pprint import pprint

from kittens.tui.handler import kitten_ui

@kitten_ui(allow_remote_control=True)
def main(args: list[str]) -> str:
    # get the result of running kitten @ ls
    cp = main.remote_control(['ls'], capture_output=True)
    if cp.returncode != 0:
        sys.stderr.buffer.write(cp.stderr)
        raise SystemExit(cp.returncode)
    output = json.loads(cp.stdout)
    pprint(output)
    # open a new tab with a title specified by the user
    title = input('Enter the name of tab: ')
    window_id = main.remote_control(['launch', '--type=tab', '--tab-title', title], check=True, capture_output=True).stdout.decode()
    return window_id

:code:allow_remote_control=True tells kitty to run this kitten with remote
control enabled, regardless of whether it is enabled globally or not.
To run a remote control command use the :code:main.remote_control() function
which is a thin wrapper around Python's :code:subprocess.run function. Note
that by default, for security, child processes launched by your kitten cannot use remote
control, thus it is necessary to use :code:main.remote_control(). If you wish
to enable child processes to use remote control, call
:code:main.allow_indiscriminate_remote_control().

Remote control access can be further secured by using
:code:kitten_ui(allow_remote_control=True, remote_control_password='ls set-colors').
This will use a secure generated password to restrict remote control.
You can specify a space separated list of remote control commands to allow, see
:opt:remote_control_password for details. The password value is accessible
as :code:main.password and is used by :code:main.remote_control()
automatically.

Debugging kittens Copy Chapter

The part of the kitten that runs in main() is just a normal program and the
output of print statements will be visible in the kitten window. Or alternately,
you can use::

from kittens.tui.loop import debug
debug('whatever')

The debug() function is just like print() except that the output will
appear in the STDOUT of the kitty process inside which the kitten is
running.

The handle_result() part of the kitten runs inside the kitty process.
The output of print statements will go to the STDOUT of the kitty process.
So if you run kitty from another kitty instance, the output will be visible
in the first kitty instance.

Developing builtin kittens for inclusion with kitty Copy Chapter

There is documentation for :doc:developing-builtin-kittens which are written in the Go
language.

.. _external_kittens:

Kittens created by kitty users Copy Chapter

vim-kitty-navigator <https://github.com/knubie/vim-kitty-navigator>_
Allows you to navigate seamlessly between vim and kitty splits using a
consistent set of hotkeys.

smart-scroll <https://github.com/yurikhan/kitty-smart-scroll>_
Makes the kitty scroll bindings work in full screen applications

kitty-tab-switcher <https://github.com/OsiPog/kitty-tab-switcher>__
Fuzzy finder for kitty tabs with previews

gattino <https://github.com/salvozappa/gattino>__
Integrate kitty with an LLM to convert plain language prompts into shell commands.

:iss:insert password <1222>
Insert a password from a CLI password manager, taking care to only do it at
a password prompt.

weechat-hints <https://github.com/GermainZ/kitty-weechat-hints>_
URL hints kitten for WeeChat that works without having to use WeeChat's
raw-mode.

pdf-kitten <https://github.com/gelaechter/pdf-kitten>__
Allows you to export kitty's output to PDF, making use of weasyprint.

kitty-action-menu <https://github.com/olispeedy/kitty-action-menu>__
A pop-up action menu (copy selection, copy link/path, paste, new tab, split,
close) opened by right-click or any mapping.

File: docs/kittens/developing-builtin-kittens.rst Copy Chapter

Developing builtin kittens

Builtin kittens in kitty are written in the Go language, with small Python
wrapper scripts to define command line options and handle UI integration.

Getting started Copy Chapter

To get started with creating a builtin kitten, one that will become part of kitty
and be available as kitten my-kitten, create a directory named
:file:my_kitten in the :file:kittens directory. Then, in this directory
add three files: :file:__init__.py (an empty file), :file:main.py and
:file:main.go.

Template for main.py
^^^^^^^^^^^^^^^^^^^^^^

The file :file:main.py contains the command line option definitions for your kitten. Change the actual options and help text below as needed.

.. code-block:: python

#!/usr/bin/env python
# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>

import sys

# See the file kitty/cli.py in the kitty sourcecode for more examples of
# the syntax for defining options
OPTIONS = r'''
--some-string-option -s
default=my_default_value
Help text for a simple option taking a string value.


--some-boolean-option -b
type=bool-set
Help text for a boolean option defaulting to false.


--some-inverted-boolean-option
type=bool-unset
Help text for a boolean option defaulting to true.


--an-integer-option
type=int
default=13
bla bla


--an-enum-option
choices=a,b,c,d
default=a
This option can only take the values a, b, c, or d
'''.format

help_text = '''\
The introductory help text for your kitten.

Can contain multiple paragraphs with :bold:`bold`
:green:`colored`, :code:`code`, :link:`links <http://url>` etc.
formatting.

Option help strings can also use this formatting.
'''

# The usage string for your kitten
usage = 'TITLE [BODY ...]'
short_description = 'A short description of your kitten'

if __name__ == '__main__':
    raise SystemExit('This should be run as kitten my-kitten')
elif __name__ == '__doc__':
    cd = sys.cli_docs  # type: ignore
    cd['usage'] = usage
    cd['options'] = OPTIONS
    cd['help_text'] = help_text
    cd['short_desc'] = short_description

Template for main.go
^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: go

package my_kitten

import (
    "fmt"

    "github.com/kovidgoyal/kitty/tools/cli"
)

var _ = fmt.Print

func main(_ *cli.Command, opts *Options, args []string) (rc int, err error) {
    // Here rc is the exit code for the kitten which should be 1 or higher if err is not nil
    fmt.Println("Hello world!")
    fmt.Println(args)
    fmt.Println(fmt.Sprintf("%#v", opts))
    return
}

func EntryPoint(parent *cli.Command) {
    create_cmd(parent, main)
}

Edit :file:tools/cmd/tool/main.go
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Add the entry point of the kitten into :file:tools/cmd/tool/main.go.

First, import the kitten into this file. To do this, add :code:"github.com/kovidgoyal/kitty/kittens/my_kitten" into the :code:import ( ... ) section at the top.
Then, add my_kitten.EntryPoint(root) into func KittyToolEntryPoints(root *cli.Command) and you are done. After running make you should
be able to test your kitten by running::

kitten my-kitten

File: docs/kittens/diff.rst Copy Chapter

kitty-diff

A fast side-by-side diff tool with syntax highlighting and images

.. highlight:: sh

Major Features Copy Chapter

.. container:: major-features

* Displays diffs side-by-side in the kitty terminal

* Does syntax highlighting of the displayed diffs, asynchronously, for
  maximum speed

* Displays images as well as text diffs, even over SSH

* Does recursive directory diffing

.. figure:: ../screenshots/diff.png
:alt: Screenshot, showing a sample diff
:align: center
:width: 100%

Screenshot, showing a sample diff

Installation Copy Chapter

Simply :ref:install kitty <quickstart>.

Usage Copy Chapter

In the kitty terminal, run::

kitten diff file1 file2

to see the diff between :file:file1 and :file:file2.

Create an alias in your shell's startup file to shorten the command, for
example:

.. code-block:: sh

alias d="kitten diff"

Now all you need to do to diff two files is::

d file1 file2

You can also pass directories instead of files to see the recursive diff of the
directory contents.

Keyboard controls Copy Chapter

=========================== ===========================
Action Shortcut
=========================== ===========================
Quit :kbd:Q
Scroll line up :kbd:K, :kbd:Up
Scroll line down :kbd:J, :kbd:Down
Scroll page up :kbd:PgUp
Scroll page down :kbd:PgDn
Scroll to top :kbd:Home
Scroll to bottom :kbd:End
Scroll to next page :kbd:Space, :kbd:PgDn, :kbd:Ctrl+F
Scroll to previous page :kbd:PgUp, :kbd:Ctrl+B
Scroll down half page :kbd:Ctrl+D
Scroll up half page :kbd:Ctrl+U
Scroll to next change :kbd:N
Scroll to previous change :kbd:P
Increase lines of context :kbd:+
Decrease lines of context :kbd:-
All lines of context :kbd:A
Restore default context :kbd:=
Search forwards :kbd:/
Search backwards :kbd:?
Clear search or exit :kbd:Esc
Scroll to next match :kbd:>, :kbd:.
Scroll to previous match :kbd:<, :kbd:,
Copy selection to clipboard :kbd:y
Copy selection or exit :kbd:Ctrl+C
=========================== ===========================

Integrating with git Copy Chapter

Add the following to :file:~/.gitconfig:

.. code-block:: ini

[diff]
    tool = kitty
    guitool = kitty.gui
[difftool]
    prompt = false
    trustExitCode = true
[difftool "kitty"]
    cmd = kitten diff $LOCAL $REMOTE
[difftool "kitty.gui"]
    cmd = kitten diff $LOCAL $REMOTE

Now to use kitty-diff to view git diffs, you can simply do::

git difftool --no-symlinks --dir-diff

Once again, creating an alias for this command is useful.

Alternatively, git-kitten-diff <https://github.com/eureka-cpu/kitty-diff-git>__
is a git plugin that forwards git diff arguments to kitty-diff without
needing any :file:~/.gitconfig changes. Once installed, simply run::

git kitten diff

Why does this work only in kitty? Copy Chapter

The diff kitten makes use of various features that are :doc:kitty only , such as the :doc:kitty graphics protocol </graphics-protocol>, the :doc:extended keyboard protocol </keyboard-protocol>, etc. It also leverages terminal program infrastructure
I created for all of kitty's other kittens to reduce the amount of code needed
(the entire implementation is under 3000 lines of code).

And fundamentally, it's kitty only because I wrote it for myself, and I am
highly unlikely to use any other terminals :)

Configuration Copy Chapter

You can configure the colors used, keyboard shortcuts, the diff implementation,
the default lines of context, etc. by creating a :file:diff.conf file in your
:ref:kitty config folder <confloc>. See below for the supported configuration
directives.

.. include:: /generated/conf-kitten-diff.rst

.. include:: /generated/cli-kitten-diff.rst

Sample diff.conf Copy Chapter

You can download a sample :file:diff.conf file with all default settings and
comments describing each setting by clicking: :download:sample diff.conf </generated/conf/diff.conf>.

File: docs/kittens/hints.rst Copy Chapter

Hints

.. only:: man

Overview
--------------

|kitty| has a hints mode to select and act on arbitrary text snippets
currently visible on the screen. For example, you can press :sc:open_url
to choose any URL visible on the screen and then open it using your default web
browser.

.. figure:: ../screenshots/hints_mode.png
:alt: URL hints mode
:align: center
:width: 100%

URL hints mode

Similarly, you can press :sc:insert_selected_path to select anything that
looks like a path or filename and then insert it into the terminal, very useful
for picking files from the output of a :program:git or :program:ls command
and adding them to the command line for the next command.

You can also press :sc:goto_file_line to select anything that looks like a
path or filename followed by a colon and a line number and open the file in
your default editor at the specified line number (opening at line number will
work only if your editor supports the +linenum command line syntax or is a
"known" editor). The patterns and editor to be used can be modified using
options passed to the kitten. For example::

map ctrl+g kitten hints --type=linenum --linenum-action=tab nvim +{line} {path}

will open the selected file in a new tab inside Neovim <https://neovim.io/>__
when you press :kbd:Ctrl+G.

Pressing :sc:open_selected_hyperlink will open :term:hyperlinks, i.e. a URL
that has been marked as such by the program running in the terminal,
for example, by ls --hyperlink=auto. If :program:ls comes with your OS
does not support hyperlink, you may need to install GNU Coreutils <https://www.gnu.org/software/coreutils/>__.

You can also :doc:customize what actions are taken for different types of URLs <../open_actions>.

.. note:: If there are more hints than letters, hints will use multiple
letters. In this case, when you press the first letter, only hints
starting with that letter are displayed. Pressing the second letter will
select that hint or press :kbd:Enter or :kbd:Space to select the empty
hint.

For mouse lovers, the hints kitten also allows you to click on any matched text to
select it instead of typing the hint character.

The hints kitten is very powerful to see more detailed help on its various
options and modes of operation, see below. You can use these options to
create mappings in :file:kitty.conf to select various different text
snippets. See :sc:insert_selected_path for examples.

Completely customizing the matching and actions of the kitten Copy Chapter

The hints kitten supports writing simple Python scripts that can be used to
completely customize how it finds matches and what happens when a match is
selected. This allows the hints kitten to provide the user interface, while you
can provide the logic for finding matches and performing actions on them. This
is best illustrated with an example. Create the file :file:custom-hints.py in
the :ref:kitty config directory <confloc> with the following contents:

.. code-block:: python

import re

def mark(text, args, Mark, extra_cli_args, *a):
    # This function is responsible for finding all
    # matching text. extra_cli_args are any extra arguments
    # passed on the command line when invoking the kitten.
    # We mark all individual word for potential selection
    for idx, m in enumerate(re.finditer(r'\w+', text)):
        start, end = m.span()
        mark_text = text[start:end].replace('\n', '').replace('\0', '')
        # The empty dictionary below will be available as groupdicts
        # in handle_result() and can contain string keys and arbitrary JSON
        # serializable values.
        yield Mark(idx, start, end, mark_text, {})


def handle_result(args, data, target_window_id, boss, extra_cli_args, *a):
    # This function is responsible for performing some
    # action on the selected text.
    # matches is a list of the selected entries and groupdicts contains
    # the arbitrary data associated with each entry in mark() above
    matches, groupdicts = [], []
    for m, g in zip(data['match'], data['groupdicts']):
        if m:
            matches.append(m), groupdicts.append(g)
    for word, match_data in zip(matches, groupdicts):
        # Lookup the word in a dictionary, the open_url function
        # will open the provided url in the system browser
        boss.open_url(f'https://www.google.com/search?q=define:{word}')

Now run kitty with::

kitty -o 'map f1 kitten hints --customize-processing custom-hints.py'

When you press the :kbd:F1 key you will be able to select a word to
look it up in the Google dictionary.

.. include:: ../generated/cli-kitten-hints.rst

.. note::

To avoid having to specify the same command line options on every
invocation, you can use the :opt:`action_alias` option in
:file:`kitty.conf`, creating aliases that have common sets of options.
For example::

    action_alias myhints kitten hints --alphabet qfjdkslaureitywovmcxzpq1234567890
    map f1 myhints --customize-processing custom-hints.py

File: docs/kittens/hyperlinked_grep.rst Copy Chapter

Hyperlinked grep

.. only:: man

Overview
--------------

.. note::

As of ripgrep versions newer than 13.0 it supports hyperlinks
natively so you can just add the following alias in your shell rc file:
alias rg="rg --hyperlink-format=kitty" no need to use this kitten.
But, see below for instructions on how to customize kitty to have it open
the hyperlinks from ripgrep in your favorite editor.

This kitten allows you to search your files using ripgrep <https://github.com/BurntSushi/ripgrep>__ and open the results directly in your
favorite editor in the terminal, at the line containing the search result,
simply by clicking on the result you want.

.. versionadded:: 0.19.0

To set it up, first create :file:~/.config/kitty/open-actions.conf with the
following contents:

.. code:: conf

# Open any file with a fragment in vim, fragments are generated
# by the hyperlink-grep kitten and nothing else so far.
protocol file
fragment_matches [0-9]+
action launch --type=overlay --cwd=current vim +${FRAGMENT} -- ${FILE_PATH}

# Open text files without fragments in the editor
protocol file
mime text/*
action launch --type=overlay --cwd=current -- ${EDITOR} -- ${FILE_PATH}

Now, run a search with::

kitten hyperlinked-grep something

Hold down the :kbd:Ctrl+Shift keys and click on any of the result lines, to
open the file in :program:vim at the matching line. If you use some editor
other than :program:vim, you should adjust the :file:open-actions.conf file
accordingly. To open links with the keyboard instead, use
:sc:open_selected_hyperlink.

Finally, add an alias to your shell's rc files to invoke the kitten as
:command:hg::

alias hg="kitten hyperlinked-grep"

You can now run searches with::

hg some-search-term

To learn more about kitty's powerful framework for customizing URL click
actions, see :doc:here </open_actions>.

By default, this kitten adds hyperlinks for several parts of ripgrep output:
the per-file header, match context lines, and match lines. You can control
which items are linked with a :code:--kitten hyperlink flag. For example,
:code:--kitten hyperlink=matching_lines will only add hyperlinks to the
match lines. :code:--kitten hyperlink=file_headers,context_lines will link
file headers and context lines but not match lines. :code:--kitten hyperlink=none will cause the command line to be passed directly to
:command:rg so no hyperlinking will be performed. :code:--kitten hyperlink
may be specified multiple times.

Hopefully, someday this functionality will make it into some upstream grep <https://github.com/BurntSushi/ripgrep/issues/665>__ program directly removing
the need for this kitten.

.. note::
While you can pass any of ripgrep's command line options to the kitten and
they will be forwarded to :program:rg, do not use options that change the
output formatting as the kitten works by parsing the output from ripgrep.
The unsupported options are: :code:--context-separator,
:code:--field-context-separator, :code:--field-match-separator,
:code:--json, :code:-I --no-filename, :code:-0 --null,
:code:--null-data, :code:--path-separator. If you specify options via
configuration file, then any changes to the default output format will not be
supported, not just the ones listed.