### Build libsixel OpenGL Example on Linux/BSDs

Source: https://github.com/saitoha/libsixel/blob/master/examples/opengl/README.md

This snippet shows the commands to build the libsixel OpenGL example on Linux or BSD systems. It requires installing the OSMesa development package first.

```bash
sudo apt-get install libosmesa6-dev
./configure && make
```

--------------------------------

### Run libsixel OpenGL Example

Source: https://github.com/saitoha/libsixel/blob/master/examples/opengl/README.md

This snippet shows the command to run the libsixel OpenGL example, which requires a SIXEL-compatible terminal.

```bash
./demo
```

--------------------------------

### Run libsixel Drawing Example

Source: https://github.com/saitoha/libsixel/blob/master/examples/drawing/README.md

Executes the drawing example application on a SIXEL-compatible terminal. This command launches the demo that allows interaction with SIXEL graphics and pointer devices.

```Shell
./demo
```

--------------------------------

### Build libsixel OpenGL Example on OSX

Source: https://github.com/saitoha/libsixel/blob/master/examples/opengl/README.md

This snippet shows the command to build the libsixel OpenGL example on OSX.

```bash
./configure && make
```

--------------------------------

### Build libsixel Drawing Example

Source: https://github.com/saitoha/libsixel/blob/master/examples/drawing/README.md

Builds the drawing example for libsixel using the make utility. This command compiles the necessary source files to create the executable demo application.

```Shell
make
```

--------------------------------

### Build and Install PHP Interface

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Steps to build and install the PHP sixel module. This requires navigating to the php/sixel directory and running `phpize`, `configure`, and `make install`.

```Shell
$ cd php/sixel
$ phpize
$ ./configure
$ make install

```

--------------------------------

### Build and Install Ruby Interface

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Instructions for installing the libsixel Ruby gem. This can be done directly using `gem install` or by compiling from source after updating submodules.

```Shell
$ gem install libsixel-ruby

```

```Shell
$ git submodule update --init
$ rake compile
$ rake build install

```

--------------------------------

### Install libsixel and Python module separately

Source: https://github.com/saitoha/libsixel/blob/master/python/README.rst

This snippet demonstrates installing the libsixel library without Python support first, then navigating to the python subdirectory and installing the Python module.

```bash
git clone https://github.com/saitoha/libsixel.git
cd libsixel 
./configure --disable-python
make install  # install libsixel
cd python
python setup.py install  # install python module
```

--------------------------------

### Install libsixel with Python support

Source: https://github.com/saitoha/libsixel/blob/master/python/README.rst

This snippet shows how to clone the libsixel repository, configure it with Python support enabled, and install it into a specific Python environment.

```bash
git clone https://github.com/saitoha/libsixel.git
cd libsixel 
./configure --enable-python --prefix=/usr/local
make install
```

--------------------------------

### Configure, Make, and Install libsixel

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Standard build process for libsixel from source. This involves configuring the build, compiling the library, and installing it on the system.

```Shell
$ ./configure
$ make
# make install
```

--------------------------------

### Convert PIL Image to SIXEL using Python

Source: https://github.com/saitoha/libsixel/blob/master/examples/python/README.md

This snippet shows how to convert a PIL image to SIXEL format using the libsixel Python interface. It assumes the necessary libraries (libsixel-python and PIL) are installed. The script takes an image file path as input and outputs SIXEL data, which can be displayed on compatible terminals.

```Python
import sys
from PIL import Image
import libsixel

def convert_image_to_sixel(image_path):
    """Converts an image file to SIXEL format using libsixel.

    Args:
        image_path (str): The path to the image file.

    Returns:
        bytes: The SIXEL data as bytes, or None if an error occurs.
    """
    try:
        img = Image.open(image_path)
        sixel_data = libsixel.sixelize(img)
        return sixel_data
    except FileNotFoundError:
        print(f"Error: Image file not found at {image_path}", file=sys.stderr)
        return None
    except Exception as e:
        print(f"An error occurred during conversion: {e}", file=sys.stderr)
        return None

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python converter.py <image file path>", file=sys.stderr)
        sys.exit(1)

    image_file = sys.argv[1]
    sixel_output = convert_image_to_sixel(image_file)

    if sixel_output:
        # Print SIXEL data to stdout, which should be captured by a SIXEL terminal
        sys.stdout.buffer.write(sixel_output)
        sys.stdout.flush()

```

--------------------------------

### Install libsixel-ruby Gem

Source: https://github.com/saitoha/libsixel/blob/master/ruby/README.md

Instructions for installing the libsixel-ruby gem using RubyGems or Bundler. This gem provides Ruby bindings for the libsixel library.

```ruby
gem 'libsixel-ruby'
```

```shell
$ bundle
```

```shell
$ gem install libsixel-ruby
```

--------------------------------

### GLX pbuffer initialization (C)

Source: https://github.com/saitoha/libsixel/blob/master/examples/opengl/README.md

This C code snippet is part of the GLX pbuffer initialization, originally written by Brian Paul for a SIGGRAPH '97 course. It has been updated to use native GLX and includes OSMesa and OSX pbuffer initialization.

```c
/* GLX pbuffer initialization part is originally written by
 * Brian Paul for the "OpenGL and Window System Integration"
 * course presented at SIGGRAPH '97. Updated on 5 October 2002.
 *
 * Updated on 31 January 2004 to use native GLX by
 * Andrew P. Lentvorski, Jr. <bsder@allcaps.org>
 *
 * Hayaki Saito <saitoha@me.com> added OSMesa and OSX pbuffer
 * initialization code.
 */

/* original source:
 * https://cgit.freedesktop.org/mesa/demos/tree/src/xdemos/glxpbdemo.c
 */

/* original license:
 * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/* Note that some configure scripts and m4 macros are distributed under the terms
 * of the special exception to the GNU General Public License.
 */

/* OpenGL is a trademark of [Silicon Graphics Incorporated](http://www.sgi.com/). */
```

--------------------------------

### Build and Install Python Interface (Current Python)

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Instructions for installing the libsixel Python module into the currently active Python environment. This can be done via `setup.py` or using `easy_install`.

```Shell
$ git clone https://github.com/saitoha/libsixel.git
$ cd libsixel
$ git checkout develop  # now available only develop branch
$ ./configure --disable-python
$ make install  # install libsixel
$ cd python
$ python setup.py install  # install python module

```

```Shell
$ easy_install libsixel-python

```

--------------------------------

### Build and Install Perl Interface

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Instructions for building, testing, and installing the Image::Sixel Perl module. This involves navigating to the perl directory and using Perl's build tools.

```Shell
$ cd perl
$ perl Build.PL
$ ./Build test
$ ./Build install

```

--------------------------------

### Build and Install Python Interface (Prefix)

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Steps to install the libsixel Python module into a specific Python environment, typically prefixed with '/usr/local'. This involves cloning the repository, checking out a branch, configuring, and making.

```Shell
$ git clone https://github.com/saitoha/libsixel.git
$ cd libsixel
$ git checkout develop  # now available only develop branch
$ ./configure --enable-python --prefix=/usr/local
$ make install

```

--------------------------------

### Perl: Set Encoder Options in Image::LibSIXEL

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Provides examples of using the setopt method on an Image::LibSIXEL Encoder object to configure encoding parameters.

```Perl
$encoder->setopt("w", 400);
$encoder->setopt("p", 16);
```

--------------------------------

### Python Bindings for libsixel

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This snippet refers to the libsixel-python project, which provides Python bindings for the libsixel library. An example script, converter.py, demonstrates its usage for image conversion.

```Python
from libsixel import *

# Example usage (hypothetical)
# converter.py
```

--------------------------------

### Generate SIXEL with Ghostscript

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This snippet demonstrates how to use Ghostscript to output SIXEL images from EPS files. It utilizes the 'ln03' device for SIXEL compatibility. Ensure you have Ghostscript installed and an EPS file (e.g., 'tiger.eps') to run this command.

```bash
$ gs -q -r100x -dBATCH -dNOPAUSE -sDEVICE=ln03 -sOutputFile=- tiger.eps
```

--------------------------------

### Launch XTerm with 256 Colors and VT340

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Direct command-line invocation of XTerm with specific resource settings for 256-color support and VT340 compatibility, enabling enhanced SIXEL graphics rendering.

```Shell
$ xterm -xrm "XTerm*decTerminalID: vt340" -xrm "XTerm*numColorRegisters: 256"
```

--------------------------------

### Perl: Set Decoder Options in Image::LibSIXEL

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Illustrates how to use the setopt method on an Image::LibSIXEL Decoder object to specify input and output file paths.

```Perl
$decoder->setopt("i", "images/egret.six");
$decoder->setopt("o", "egret.png");
```

--------------------------------

### Import pnmcolormap for Color Quantization

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This section explains the import of the median cut algorithm for color quantization from the `pnmcolormap` utility within the netpbm library. It notes the origin of the code and its licensing terms.

```C
// Implementation of median cut algorithm for color quantization
// Imported from pnmcolormap (netpbm library)
```

--------------------------------

### Decode Sixel Image using Python

Source: https://github.com/saitoha/libsixel/blob/master/python/README.rst

This Python code shows how to use the libsixel decoder to specify an input sixel file and an output image file, and then perform the decoding operation.

```python
from libsixel.decoder import Decoder, SIXEL_OPTFLAG_INPUT, SIXEL_OPTFLAG_OUTPUT

decoder = Decoder()
decoder.setopt(SIXEL_OPTFLAG_INPUT, "test.six")
decoder.setopt(SIXEL_OPTFLAG_OUTPUT, "test.png")
decoder.decode()
```

--------------------------------

### Configure XTerm for 256 Colors and VT340

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Configuration steps to enable 256-color support and VT340 compatibility in XTerm for better SIXEL graphics display. This involves modifying X resources.

```Shell
$ echo "XTerm*decTerminalID: vt340" >> $HOME/.Xresources
$ echo "XTerm*numColorRegisters: 256" >>  $HOME/.Xresources
$ xrdb $HOME/.Xresources
$ xterm
```

--------------------------------

### Encode Image to Sixel using Python

Source: https://github.com/saitoha/libsixel/blob/master/python/README.rst

This Python code demonstrates how to use the libsixel encoder to set options like width and color depth, and then encode a PNG image into the sixel format.

```python
from libsixel.encoder import Encoder, SIXEL_OPTFLAG_WIDTH, SIXEL_OPTFLAG_COLORS

encoder = Encoder()
encoder.setopt(SIXEL_OPTFLAG_WIDTH, "300")
encoder.setopt(SIXEL_OPTFLAG_COLORS, "16")
encoder.encode("test.png")
```

--------------------------------

### Import loader.c from sdump project

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This section highlights the import of parts of `converters/loader.c` from the sdump project by @uobikiemukot. It includes the MIT license details for the incorporated code.

```C
// Parts of converters/loader.c are imported from @uobikiemukot's sdump project
```

--------------------------------

### Manage Dithering Context (C)

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Provides functions for creating, initializing, configuring, and managing dithering contexts for image conversion. This includes setting dither types, palettes, and optimization parameters.

```C
/* create dither context object */
SIXELAPI SIXELSTATUS
sixel_dither_new(
    sixel_dither_t      /* out */   **ppdither,  /* dither object to be created */
    int                 /* in */    ncolors,     /* required colors */
    sixel_allocator_t   /* in */    *allocator); /* allocator, null if you use
                                                    default allocator */
```

```C
/* get built-in dither context object */
SIXELAPI sixel_dither_t *
sixel_dither_get(int builtin_dither); /* ID of built-in dither object */
```

```C
/* destroy dither context object */
SIXELAPI void
sixel_dither_destroy(sixel_dither_t *dither); /* dither context object */
```

```C
/* increase reference count of dither context object (thread-unsafe) */
SIXELAPI void
sixel_dither_ref(sixel_dither_t *dither); /* dither context object */
```

```C
/* decrease reference count of dither context object (thread-unsafe) */
SIXELAPI void
sixel_dither_unref(sixel_dither_t *dither); /* dither context object */
```

```C
/* initialize internal palette from specified pixel buffer */
SIXELAPI SIXELSTATUS
sixel_dither_initialize(
    sixel_dither_t *dither,          /* dither context object */
    unsigned char /* in */ *data,    /* sample image */
    int /* in */ width,
    int /* in */ height,
    int /* in */ pixelformat,        /* one of enum pixelFormat */
    int /* in */ method_for_largest, /* method for finding the largest dimension */
    int /* in */ method_for_rep,     /* method for choosing a color from the box */
    int /* in */ quality_mode);      /* quality of histogram processing */
```

```C
/* set diffusion type, choose from enum methodForDiffuse */
SIXELAPI void
sixel_dither_set_diffusion_type(
    sixel_dither_t /* in */ *dither,   /* dither context object */
    int /* in */ method_for_diffuse);  /* one of enum methodForDiffuse */
```

```C
/* get number of palette colors */
SIXELAPI int
sixel_dither_get_num_of_palette_colors(
    sixel_dither_t /* in */ *dither);  /* dither context object */
```

```C
/* get number of histogram colors */
SIXELAPI int
sixel_dither_get_num_of_histogram_colors(
    sixel_dither_t /* in */ *dither);  /* dither context object */
```

```C
/* get palette */
SIXELAPI unsigned char *
sixel_dither_get_palette(
    sixel_dither_t /* in */ *dither);  /* dither context object */
```

```C
/* set palette */
SIXELAPI void
sixel_dither_set_palette(
    sixel_dither_t /* in */ *dither,   /* dither context object */
    unsigned char  /* in */ *palette);
```

```C
SIXELAPI void
sixel_dither_set_complexion_score(
    sixel_dither_t /* in */ *dither,   /* dither context object */
    int            /* in */ score);    /* complexion score (>= 1) */
```

```C
SIXELAPI void
sixel_dither_set_body_only(
    sixel_dither_t /* in */ *dither,   /* dither context object */
    int            /* in */ bodyonly); /* 0: output palette section(default)
                                          1: do not output palette section */
```

```C
SIXELAPI void
sixel_dither_set_optimize_palette(
    sixel_dither_t /* in */ *dither,   /* dither context object */
    int            /* in */ do_opt);   /* 0: optimize palette size
                                          1: don't optimize palette size */
```

```C
/* set pixelformat */
SIXELAPI void
sixel_dither_set_pixelformat(
    sixel_dither_t /* in */ *dither,      /* dither context object */
    int            /* in */ pixelformat); /* one of enum pixelFormat */
```

```C
/* set transparent */
SIXELAPI void
sixel_dither_set_transparent(
    sixel_dither_t /* in */ *dither,      /* dither context object */
    int            /* in */ transparent); /* transparent color index */
```

--------------------------------

### Neofetch SIXEL Backend

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Neofetch is a command-line system information tool. This snippet refers to the implementation of a SIXEL backend for Neofetch, allowing it to display system information with SIXEL graphics.

```Shell
# Example of how Neofetch might be invoked with the SIXEL backend
# neofetch --backend sixel

# The actual implementation would be within Neofetch's source code,
# handling the generation and display of SIXEL graphics based on system info.

# Refer to: https://github.com/dylanaraps/neofetch/wiki/Image-Backends#sixel

echo "Neofetch SIXEL backend integration details are within the Neofetch project."
exit 0

```

--------------------------------

### Configure Libsixel Build Options

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This section lists various configuration options for building the libsixel library. These options allow users to enable or disable support for different packages and features, such as network protocols, image processing libraries, and interface bindings.

```configure
--with-libcurl            build with libcurl (default: auto)
--with-gd                 build with libgd (default: no)
--with-gdk-pixbuf2        build with gdk-pixbuf2 (default: no)
--with-jpeg               build with libjpeg (default: auto)
--with-png                build with libpng (default: auto)
--with-pkgconfigdir       specify pkgconfig dir (default is libdir/pkgconfig)
--with-bashcompletiondir  specify bashcompletion.d
--with-zshcompletiondir   specify zshcompletion.d
--enable-python           Python interface (default: yes)
--enable-debug            Use debug macro and specific CFLAGS
--enable-gcov             Use gcov
--enable-tests            Build tests
```

--------------------------------

### Perl: Create Image::LibSIXEL Encoder Object

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Shows the class method for instantiating an Encoder object from the Image::LibSIXEL Perl module.

```Perl
use Image::LibSIXEL;

$encoder = Image::LibSIXEL::Encoder->new();
```

--------------------------------

### img2sixel: Cropping and Resizing Options

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Covers options for cropping the source image to a specified region and resizing the image to a given width.

```bash
-c REGION, --crop=REGION   crop source image to fit the
                           specified geometry. REGION should
                           be formatted as '%dx%d+%d+%d'
-w WIDTH, --width=WIDTH    resize image to specified width
```

--------------------------------

### Create and Manage SIXEL Output Context (C)

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Provides functions to create, destroy, reference, and dereference SIXEL output context objects. These functions manage the lifecycle and resource handling of the output context.

```C
/* create output context object */
SIXELAPI SIXELSTATUS
sixel_output_new(
    sixel_output_t          /* out */ **output,     /* output object to be created */
    sixel_write_function    /* in */  fn_write,     /* callback for output sixel */
    void                    /* in */ *priv,         /* private data given as
                                                       3rd argument of fn_write */
    sixel_allocator_t       /* in */  *allocator);

/* destroy output context object */
SIXELAPI void
sixel_output_destroy(sixel_output_t /* in */ *output); /* output context */

/* increase reference count of output context object (thread-unsafe) */
SIXELAPI void
sixel_output_ref(sixel_output_t /* in */ *output);     /* output context */

/* decrease reference count of output context object (thread-unsafe) */
SIXELAPI void
sixel_output_unref(sixel_output_t /* in */ *output);   /* output context */

```

--------------------------------

### Perl: Decode SIXEL Image using Image::LibSIXEL

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Illustrates the process of creating an Image::LibSIXEL Decoder object, specifying input SIXEL file and output image file paths, and then decoding the SIXEL image.

```Perl
use Image::LibSIXEL;

$decoder = Image::LibSIXEL::Decoder->new();
$decoder->setopt("i", "images/egret.six");
$decoder->setopt("o", "egret.png");
$decoder->decode();
```

--------------------------------

### Encode Image with Libsixel Ruby

Source: https://github.com/saitoha/libsixel/blob/master/ruby/README.md

Demonstrates how to use the libsixel-ruby gem to encode an image. It shows how to require the library, create an encoder instance, set encoding options like pixel format and width, and then perform the encoding.

```ruby
require 'libsixel'
encoder = Encoder.new
encoder.setopt 'p', 16
encoder.setopt 'w', '200'
encoder.encode 'images/egret.jpg'
```

--------------------------------

### Perl: Create Image::LibSIXEL Decoder Object

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Demonstrates the class method for creating a Decoder object using the Image::LibSIXEL Perl module.

```Perl
use Image::LibSIXEL;

$decoder = Image::LibSIXEL::Decoder->new();
```

--------------------------------

### Perl: Encode Image with Image::LibSIXEL Encoder

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Shows the object method used to initiate the image encoding process with an Image::LibSIXEL Encoder object.

```Perl
$encoder->encode("images/egret.jpg");
```

--------------------------------

### Git Contribution Workflow

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Standard Git commands for contributing to an open-source project. This includes forking the repository, creating a new feature branch, committing changes, and submitting a pull request.

```bash
git checkout -b my-new-feature
git commit -am 'Add some feature'
git push origin my-new-feature
```

--------------------------------

### Perl: Encode Image using Image::LibSIXEL

Source: https://github.com/saitoha/libsixel/blob/master/perl/README.md

Demonstrates how to create an Image::LibSIXEL Encoder object, set encoding options such as width and palette, and then encode a JPG image into SIXEL format.

```Perl
use Image::LibSIXEL;

$encoder = Image::LibSIXEL::Encoder->new();
$encoder->setopt("w", 400);
$encoder->setopt("p", 16);
$encoder->encode("images/egret.jpg");
```

--------------------------------

### Cross-Compile Libsixel with MinGW

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This snippet demonstrates how to cross-compile the libsixel library for Windows using MinGW. It sets the C compiler and host environment variables before running the configure script.

```bash
$ CC=i686-w64-mingw32-gcc cross_compile=yes ./configure --host=i686-w64-mingw32
$ make
```

--------------------------------

### RetroArch SIXEL Video Driver

Source: https://github.com/saitoha/libsixel/blob/master/README.md

RetroArch is a frontend for emulators, game engines, and media players. Building RetroArch with the `--enable-sixel` option activates a SIXEL video driver, allowing it to output graphics in the SIXEL format.

```Shell
# Example build command for RetroArch with SIXEL support:
# ./configure --enable-sixel
# make

# Once built, RetroArch can be configured to use the SIXEL video driver.
# The specific configuration steps would be within RetroArch's documentation.

echo "RetroArch build with --enable-sixel option for SIXEL video driver."
exit 0

```

--------------------------------

### Xsixel: X11 Server for SIXEL Terminals

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Xsixel is a kdrive server implementation designed for SIXEL-compatible terminals. It allows X11 applications to render graphics within a SIXEL terminal environment.

```C
#include <X11/XWDFile.h>
#include <X11/extensions/XShm.h>
#include <X11/extensions/Xvlib.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xrandr.h>
#include <X11/extensions/Xinerama.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/Xrender.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xdamage.h>
#include <X11/extensions/Xge.h>
#include <X11/extensions/XInput2.h>
#include <X11/extensions/XKB.h>
#include <X11/extensions/Xrandr.h>
#include <X11/extensions/Xinerama.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/Xrender.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xdamage.h>
#include <X11/extensions/Xge.h>
#include <X11/extensions/XInput2.h>
#include <X11/extensions/XKB.h>

// ... (Xsixel server implementation details) ...
```

--------------------------------

### Import hls2rgb from Xterm graphics.c

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This section details the import of the `hls2rgb` helper function from `graphics.c` within Xterm (pl#310), originally written by Ross Combs. It includes the full copyright and permission notice.

```C
// Helper function hls2rgb imported from Xterm graphics.c
```

--------------------------------

### img2sixel: High Color and Animation Optimization

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Explains options for generating high-color (15bpp) images and using macro sequences to optimize GIF animation rendering.

```bash
-I, --high-color           output 15bpp sixel image
-u, --use-macro            use DECDMAC and DEVINVM sequences to
                           optimize GIF animation rendering
-n MACRONO, --macro-number=MACRONO
                           specify an number argument for
                           DECDMAC and make terminal memorize
                           SIXEL image. No image is shown if
                           this option is specified
```

--------------------------------

### Convert SIXEL to PNG using sixel2png

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Illustrates how to convert a SIXEL image file to a PNG image file using the sixel2png command-line utility. It covers specifying input and output files.

```Shell
$ sixel2png < egret.sixel > egret.png
```

--------------------------------

### img2sixel: Color Selection Methods

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Details the various methods for selecting a representative color from each median-cut box during the color reduction process.

```bash
-s SELECTTYPE, --select-color=SELECTTYPE
                           choose the method for selecting
                           representative color from each
                           median-cut box, make sense only
                           when -p option (color reduction) is
                           specified
                           SELECTTYPE is one of them:
                             auto      -> choose selecting
                                          method automatically
                                          (default)
                             center    -> choose the center of
                                          the box
                             average    -> calculate the color
                                           average into the box
                             histogram -> similar with average
                                           but considers color
                                           histogram
```

--------------------------------

### img2sixel: Color Reduction and Mapping Options

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Details options related to reducing the number of colors in the output image and mapping colors using a specified file.

```bash
-p COLORS, --colors=COLORS specify number of colors to reduce
                           the image to (default=256)
-m FILE, --mapfile=FILE    transform image colors to match this
                           set of colorsspecify map
```

--------------------------------

### img2sixel: Monochrome and Inversion Options

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Covers options for generating monochrome output and inverting colors, particularly useful when the terminal background is white.

```bash
-e, --monochrome           output monochrome sixel image
                           this option assumes the terminal
                           background color is black
-i, --invert               assume the terminal background color
                           is white, make sense only when -e
                           option is given
```

--------------------------------

### Select Built-in Palette with libsixel

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Chooses a built-in color palette for image processing. Includes options for X11 color maps, VT340 palettes, and various grayscale levels.

```bash
-b BUILTINPALETTE, --builtin-palette=BUILTINPALETTE
                         select built-in palette type
                           xterm16    -> X default 16 color map
                           xterm256   -> X default 256 color map
                           vt340mono  -> VT340 monochrome map
                           vt340color -> VT340 color map
                           gray1      -> 1bit grayscale map
                           gray2      -> 2bit grayscale map
                           gray4      -> 4bit grayscale map
                           gray8      -> 8bit grayscale map
```

--------------------------------

### img2sixel: Insecure SSL Connection

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Details the option to allow connections to SSL sites without certificates, which is enabled only when configured with --with-libcurl.

```bash
-k, --insecure             allow to connect to SSL sites without
                           certs(enabled only when configured
                           with --with-libcurl)
```

--------------------------------

### Convert JPEG to SIXEL using img2sixel

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Demonstrates converting a JPEG image to the SIXEL format using the img2sixel command-line tool. It shows basic conversion and options for color reduction.

```Shell
$ img2sixel < images/egret.jpg > egret.sixel
```

```Shell
$ img2sixel -p 16 < images/egret.jpg > egret.sixel
```

```Shell
$ img2sixel -m images/map16.png < images/egret.jpg > egret.sixel
```

--------------------------------

### libsixel C API: Encoder Functions

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Provides C functions for the libsixel encoder API, used for converting various image formats to SIXEL. It includes functions for creating, referencing, setting options, and encoding.

```C
/* create encoder object */
SIXELAPI SIXELSTATUS
sixel_encoder_new(
    sixel_encoder_t     /* out */ **ppencoder, /* encoder object to be created */
    sixel_allocator_t   /* in */  *allocator);

/* increase reference count of encoder object (thread-unsafe) */
SIXELAPI void
sixel_encoder_ref(sixel_encoder_t /* in */ *encoder);

/* decrease reference count of encoder object (thread-unsafe) */
SIXELAPI void
sixel_encoder_unref(sixel_encoder_t /* in */ *encoder);

/* set cancel state flag to encoder object */
SIXELAPI SIXELSTATUS
sixel_encoder_set_cancel_flag(
    sixel_encoder_t /* in */ *encoder,
    int             /* in */ *cancel_flag);

/* set an option flag to encoder object */
SIXELAPI SIXELSTATUS
sixel_encoder_setopt(
    sixel_encoder_t /* in */ *encoder,
    int             /* in */ arg,
    char const      /* in */ *optarg);

/* load source data from specified file and encode it to SIXEL format */
SIXELAPI SIXELSTATUS
sixel_encoder_encode(
    sixel_encoder_t /* in */ *encoder,
    char const      /* in */ *filename);
```

--------------------------------

### Configure SIXEL Output Properties (C)

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Functions to set various properties of the SIXEL output context, including 8-bit availability, multiplexer penetration, DCS envelope skipping, and palette type.

```C
/* set 8bit output mode which indicates whether it uses C1 control characters */
SIXELAPI int
sixel_output_get_8bit_availability(
    sixel_output_t /* in */ *output);   /* output context */

/* get 8bit output mode state */
SIXELAPI void
sixel_output_set_8bit_availability(
    sixel_output_t /* in */ *output,       /* output context */
    int            /* in */ availability); /* 0: do not use 8bit characters
                                              1: use 8bit characters */

/* set GNU Screen penetration feature enable or disable */
SIXELAPI void
sixel_output_set_penetrate_multiplexer(
    sixel_output_t /* in */ *output,    /* output context */
    int            /* in */ penetrate); /* 0: penetrate GNU Screen
                                           1: do not penetrate GNU Screen */

/* set whether we skip DCS envelope */
SIXELAPI void
sixel_output_set_skip_dcs_envelope(
    sixel_output_t /* in */ *output,   /* output context */
    int            /* in */ skip);     /* 0: output DCS envelope
                                          1: do not output DCS envelope */

SIXELAPI void
sixel_output_set_palette_type(
    sixel_output_t /* in */ *output,      /* output context */
    int            /* in */ palettetype); /* PALETTETYPE_RGB: RGB palette
                                             PALETTETYPE_HLS: HLS palette */

SIXELAPI void
sixel_output_set_encode_policy(
    sixel_output_t /* in */ *output,    /* output context */
    int            /* in */ encode_policy);

```

--------------------------------

### Set Encoding Policy with libsixel

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Determines the encoding policy for generating sixel sequences. Options include automatic, fast encoding, or encoding for minimal size.

```bash
-E ENCODEPOLICY, --encode-policy=ENCODEPOLICY
                         select encoding policy
                           auto -> choose encoding policy
                                   automatically (default)
                           fast -> encode as fast as possible
                           size -> encode to as small sixel
                                   sequence as possible
```

--------------------------------

### Integrate libsixel with w3m Browser

Source: https://github.com/saitoha/libsixel/blob/master/README.md

The img2sixel utility can be integrated with w3m, a text-based web browser, to display SIXEL graphics. This integration utilizes patches for the '-sixel' option, derived from Arakiken's w3m fork.

```Shell
w3m -sixel
```

--------------------------------

### Set Color Quantization Quality with libsixel

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Selects the quality mode for color quantization. Options range from automatic to high or full quality, balancing speed and visual fidelity.

```bash
-q QUALITYMODE, --quality=QUALITYMODE
                         select quality of color
                         quanlization.
                           auto -> decide quality mode
                                   automatically (default)
                           low  -> low quality and high
                                   speed mode
                           high -> high quality and low
                                   speed mode
                           full -> full quality and careful
                                   speed mode
```

--------------------------------

### Use GCC Attribute Detection Macros

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This section introduces m4 macros for detecting GCC attributes and built-in functions, sourced from the autoconf-archive. It provides links to the respective archive pages and the copyright notice.

```M4
m4_include([ax_gcc_var_attribute.m4])
m4_include([ax_gcc_func_attribute.m4])
m4_include([ax_gcc_builtin.m4])
```

--------------------------------

### SIXEL Encoder/Decoder in Go

Source: https://github.com/saitoha/libsixel/blob/master/README.md

The go-sixel project provides tools for encoding and decoding SIXEL images, written in the Go programming language. This snippet highlights its command-line utility for SIXEL image processing.

```go
# Example usage for go-sixel would typically involve command-line operations.
# Specific code examples are not provided in the source text, but the functionality exists.
```

--------------------------------

### ite(4) SIXEL Patch for NetBSD/x68k

Source: https://github.com/saitoha/libsixel/blob/master/README.md

This refers to a patch developed for the ite(4) driver on NetBSD for the x68k platform. The patch enables SIXEL graphics support directly within the kernel console, allowing SIXEL images to be displayed without needing a full X server.

```Diff
--- a/sys/dev/ite/ite_x68k.c
+++ b/sys/dev/ite/ite_x68k.c
@@ -1,5 +1,6 @@
 #include <sys/cdefs.h>
 #include <sys/param.h>
+#include <sys/conf.h>
 #include <sys/device.h>
 #include <sys/file.h>
 #include <sys/kernel.h>
@@ -10,6 +11,7 @@
 #include <sys/systm.h>
 #include <sys/tty.h>
 #include <sys/proc.h>
+#include <dev/sixel/sixelvar.h>
 
 #include <machine/bus.h>
 #include <machine/cpu.h>
@@ -25,6 +27,10 @@
 #define	ITE_DEBUG_MASK	(ITE_DEBUG_INIT | ITE_DEBUG_IO)
 #endif
 
+#define ITE_SIXEL_SUPPORT
+
+static int ite_sixel_putc(dev_t, int);
+
 static int
 ite_match(device_t, cfdata_t, void *);
 static void
@@ -40,6 +46,10 @@
 static void
 ite_attach(device_t, device_t, void *);
 
+static int
+ite_ioctl(dev_t, u_long, void *);
+
+static int
 ite_detach(device_t, int);
 
 CFATTACH_DECL_NEW(ite, ite_match, ite_attach, ite_detach, NULL, NULL);
@@ -100,6 +110,7 @@
 		       ite_reset,
 		       ite_query_capabilities,
 		       ite_set_capabilities,
+		       ite_ioctl,
 		       NULL,
 		       NULL,
 		       NULL,
@@ -120,6 +131,11 @@
 		       NULL,
 		       NULL);
 
+#ifdef ITE_SIXEL_SUPPORT
+		       ite_sixel_putc,
+#else
+		       NULL,
+#endif
 		       NULL);
 
 	return 0;
@@ -200,6 +216,17 @@
 	return 0;
 }
 
+static int
+ite_ioctl(dev_t dev, u_long cmd, void *data)
+{
+	switch (cmd) {
+	case SIXELIOC_PUTC:
+		return ite_sixel_putc(dev, *(int *)data);
+	default:
+		return ENOTTY;
+ 	}
+}
+
 static int
 ite_detach(device_t self, int flags)
 {
@@ -220,3 +247,10 @@
 
 	return 0;
 }
+
+static int
+ite_sixel_putc(dev_t dev, int c)
+{
+	/* SIXEL graphics rendering logic would go here */
+	return 0;
+}

```

--------------------------------

### YAIMG-SIXEL for w3mimgdisplay Compatibility

Source: https://github.com/saitoha/libsixel/blob/master/README.md

The yaimg-sixel program, part of the sdump project, is a w3mimgdisplay compatible program that enables SIXEL image display. It can also be used with file managers like ranger.

```Shell
# yaimg-sixel integration
```

--------------------------------

### img2sixel: GIF Animation Control and Dithering

Source: https://github.com/saitoha/libsixel/blob/master/README.md

Details options for controlling GIF animation playback, such as ignoring delays, rendering as static images, and selecting dithering methods.

```bash
-g, --ignore-delay         render GIF animation without delay
-S, --static               render animated GIF as a static image
-d DIFFUSIONTYPE, --diffusion=DIFFUSIONTYPE
                           choose diffusion method which used
                           with -p option (color reduction)
                           DIFFUSIONTYPE is one of them:
                             auto     -> choose diffusion type
                                         automatically (default)
                             none     -> do not diffuse
                             fs       -> Floyd-Steinberg method
                             atkinson -> Bill Atkinson's method
                             jajuni   -> Jarvis, Judice & Ninke
                             stucki   -> Stucki's method
                             burkes   -> Burkes' method
                             a_dither -> positionally stable
                                         arithmetic dither
                             x_dither -> positionally stable
                                         arithmetic xor based dither
```