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Libsixel: The new standard of SIXEL development – graphics in the terminal

libsixel

Libsixel: The new standard of SIXEL development – graphics in the terminal Libsixel: The new standard of SIXEL development – graphics in the terminal

What is this?

This package provides encoder/decoder implementation for DEC SIXEL graphics, and some converter programs.

Libsixel: The new standard of SIXEL development – graphics in the terminal

SIXEL is one of image formats for printer and terminal imaging introduced by Digital Equipment Corp. (DEC). Its data scheme is represented as a terminal-friendly escape sequence. So if you want to view a SIXEL image file, all you have to do is "cat" it to your terminal.

SIXEL Animation

img2sixel(1) can decode GIF animation.

Libsixel: The new standard of SIXEL development – graphics in the terminal

Related projects

Video streaming

Now Youtube video streaming is available over SIXEL protocol byFFmpeg-SIXEL project.

Libsixel: The new standard of SIXEL development – graphics in the terminal

SDL integration: Gaming, Virtualization, …etc.

SDL1.2-SIXEL project makes enable you to operate various GUI applications on the terminal.

You can play " The Battle for Wesnoth " over SIXEL protocol.

Libsixel: The new standard of SIXEL development – graphics in the terminal

You can run QEMU on SIXEL terminals.

Libsixel: The new standard of SIXEL development – graphics in the terminal

SDL1.2-SIXEL can collaborate withXSDL-SIXEL.

Libsixel: The new standard of SIXEL development – graphics in the terminal

X11 on SIXEL terminals

XSIXEL is a kdrive server implementation for SIXEL terminals.

Libsixel: The new standard of SIXEL development – graphics in the terminal

W3M integration

img2sixel(1) can be integrated with Arakiken’s w3m fork(remoteimg branch) .

Libsixel: The new standard of SIXEL development – graphics in the terminal

@uobikiemukot’ssdump project selected another approach. He wrote a w3mimgdisplay compatible programyaimg-sixel. It also works withranger.

Libsixel: The new standard of SIXEL development – graphics in the terminal

GNU Screen integration

Arakiken’s GNU Screen fork(sixel branch) works with SIXEL-supported applications including above products. This project is now in progress. GUI flavored SIXEL applications will integrated with existing terminal applications on it.

Libsixel: The new standard of SIXEL development – graphics in the terminal

Libsixel: The new standard of SIXEL development – graphics in the terminal

Libsixel: The new standard of SIXEL development – graphics in the terminal

See also on youtube .

Twitter client integration

Some NetBSD/OpenBSD users are doing amazing challenges.

arakiken’s mikutterm(mikutterm-sixel)

Now mikutter + mikutterm works with libsixel inline-image extension.

SIXEL works with old powerless machines such as

NetBSD/luna68k (here is OMRON LUNA-II):

Libsixel: The new standard of SIXEL development – graphics in the terminal

NetBSD/hp300 (here is HP9000/425e):

Libsixel: The new standard of SIXEL development – graphics in the terminal

arakiken’s tw(tw-sixel)

arakiken’s tw(tw-sixel) works with libsixel inline-image extension.

SIXEL works with old powerless machines such as OpenBSD/luna88k (here is OMRON LUNA-88K2 MC88100@33MHz):

Libsixel: The new standard of SIXEL development – graphics in the terminal

sayaka-chan

sayaka-chan(PHP version) works with libsixel inline-image extension.

SIXEL works with old powerless machines such as NetBSD/x68k (here is SHARP X68030 with 060turbo):

Libsixel: The new standard of SIXEL development – graphics in the terminal

SIXEL works even in-kernel console.@isaki68k wrotea patch for ite(4).

Libsixel: The new standard of SIXEL development – graphics in the terminal

Highlighted features

Improved compression

Former sixel encoders(such as ppmtosixel ) are mainly designed for dot-matrix printers. They minimize the amount of printer-head movement distance. But nowadays this method did not represent the best performance for displaying sixel data on terminal emulators. SIXEL data for terminals were found in 80’s Usenet, but the technology of how to create them seems to be lost. kmiya’s sixel introduces the encoding method which is re-designed for terminal emulators to optimize the overhead of transporting SIXEL with keeping compatibility with former SIXEL terminal. Now libsixel and ImageMagick’s sixel coder follow it.

@arakiken, known as the maintainer of mlterm, describes about the way to generate high quality SIXEL, which is adopted by libsixel ( http://mlterm.sourceforge.net/libsixel.pdf , in Japanese).

High quality quantization

img2sixel(1) supports color image quantization. It works well even if few number of colors are allowed.

  • ppmtosixel ( netpbm )

    $ jpegtopnm images/snake.jpg | pnmquant 16 | ppmtosixel

    Libsixel: The new standard of SIXEL development – graphics in the terminal

  • ppmtosixel with Floyd–Steinberg dithering ( netpbm )

    $ jpegtopnm images/snake.jpg | pnmquant 16 -floyd | ppmtosixel

    Libsixel: The new standard of SIXEL development – graphics in the terminal

  • kmiya’s sixel

    $ sixel -p16 images/snake.jpg

    Libsixel: The new standard of SIXEL development – graphics in the terminal

  • PySixel ( sixelconv command)

    $ sixelconv -n16 images/snake.jpg

    Libsixel: The new standard of SIXEL development – graphics in the terminal

  • libsixel ( img2sixel command)

    $ img2sixel -p16 images/snake.jpg

    Libsixel: The new standard of SIXEL development – graphics in the terminal

Terminal requirements

If you want to view a SIXEL image, you have to get a terminal which support sixel graphics.

Now SIXEL feature is supported by the following terminals.

Install

Using package managers

You can install libsixel via the following package systems.

Build from source package

$ ./configure $ make # make install 

Build with optional packages

You can configure with the following options

--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 

For more information, see "./configure –help".

Cross compiling with MinGW

You can build a windows binary in cross-build environment.

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

Usage of command line tools

img2sixel

Usage: img2sixel [Options] imagefiles        img2sixel [Options] < imagefile  Options: -o, --outfile              specify output file name.                            (default:stdout) -7, --7bit-mode            generate a sixel image for 7bit                            terminals or printers (default) -8, --8bit-mode            generate a sixel image for 8bit                            terminals or printers -R, --gri-limit            limit arguments of DECGRI('!') to 255 -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 -e, --monochrome           output monochrome sixel image                            this option assumes the terminal                            background color is black -k, --insecure             allow to connect to SSL sites without                            certs(enabled only when configured                            with --with-libcurl) -i, --invert               assume the terminal background color                            is white, make sense only when -e                            option is given -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 -C COMPLEXIONSCORE, --complexion-score=COMPLEXIONSCORE                            specify an number argument for the                            score of complexion correction.                            COMPLEXIONSCORE must be 1 or more. -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 -f FINDTYPE, --find-largest=FINDTYPE                            choose method for finding the largest                            dimension of median cut boxes for                            splitting, make sense only when -p                            option (color reduction) is                            specified                            FINDTYPE is one of them:                              auto -> choose finding method                                      automatically (default)                              norm -> simply comparing the                                      range in RGB space                              lum  -> transforming into                                      luminosities before the                                      comparison -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 -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                            WIDTH is represented by the                            following syntax                              auto       -> preserving aspect                                            ratio (default)                              <number>%  -> scale width with                                            given percentage                              <number>   -> scale width with                                            pixel counts                              <number>px -> scale width with                                            pixel counts -h HEIGHT, --height=HEIGHT resize image to specified height                            HEIGHT is represented by the                            following syntax                              auto       -> preserving aspect                                            ratio (default)                              <number>%  -> scale height with                                            given percentage                              <number>   -> scale height with                                            pixel counts                              <number>px -> scale height with                                            pixel counts -r RESAMPLINGTYPE, --resampling=RESAMPLINGTYPE                            choose resampling filter used                            with -w or -h option (scaling)                            RESAMPLINGTYPE is one of them:                              nearest  -> Nearest-Neighbor                                          method                              gaussian -> Gaussian filter                              hanning  -> Hanning filter                              hamming  -> Hamming filter                              bilinear -> Bilinear filter                                          (default)                              welsh    -> Welsh filter                              bicubic  -> Bicubic filter                              lanczos2 -> Lanczos-2 filter                              lanczos3 -> Lanczos-3 filter                              lanczos4 -> Lanczos-4 filter -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 -l LOOPMODE, --loop-control=LOOPMODE                            select loop control mode for GIF                            animation.                              auto    -> honor the setting of                                         GIF header (default)                              force   -> always enable loop                              disable -> always disable loop -t PALETTETYPE, --palette-type=PALETTETYPE                            select palette color space type                              auto -> choose palette type                                      automatically (default)                              hls  -> use HLS color space                              rgb  -> use RGB color space -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 -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 -B BGCOLOR, --bgcolor=BGCOLOR                            specify background color                            BGCOLOR is represented by the                            following syntax                              #rgb                              #rrggbb                              #rrrgggbbb                              #rrrrggggbbbb                              rgb:r/g/b                              rgb:rr/gg/bb                              rgb:rrr/ggg/bbb                              rgb:rrrr/gggg/bbbb -P, --penetrate            penetrate GNU Screen using DCS                            pass-through sequence -D, --pipe-mode            read source images from stdin                            continuously -v, --verbose              show debugging info -V, --version              show version and license info -H, --help                 show this help  Environment variables: SIXEL_BGCOLOR              specify background color.                            overrided by -B(--bgcolor) option.                            represented by the following                            syntax:                              #rgb                              #rrggbb                              #rrrgggbbb                              #rrrrggggbbbb                              rgb:r/g/b                              rgb:rr/gg/bb                              rgb:rrr/ggg/bbb                              rgb:rrrr/gggg/bbbb 

Convert a jpeg image file into a sixel file

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

Reduce colors to 16:

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

Reduce colors with fixed palette:

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

sixel2png

Usage: sixel2png -i input.sixel -o output.png        sixel2png < input.sixel > output.png  Options: -i, --input     specify input file -o, --output    specify output file -V, --version   show version and license information -H, --help      show this help 

Convert a sixel file into a png image file

$ sixel2png < egret.sixel > egret.png 

The high-level conversion API

The high-livel API provides File-to-File conversion features.

Encoder

The sixel encoder object and related functions provides almost same features as img2sixel .

/* create encoder object */ SIXELAPI SIXELSTATUS sixel_encoder_new(     sixel_encoder_t     /* out */ **ppencoder, /* encoder object to be created */     sixel_allocator_t   /* in */  *allocator); /* allocator, null if you use                                                   default 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);

Decoder

The sixel decoder object and related functions provides almost same features as sixel2png .

/* create decoder object */ SIXELAPI SIXELSTATUS sixel_decoder_new(     sixel_decoder_t    /* out */ **ppdecoder,  /* decoder object to be created */     sixel_allocator_t  /* in */  *allocator);  /* allocator, null if you use                                                   default allocator */  /* increase reference count of decoder object (thread-unsafe) */ SIXELAPI void sixel_decoder_ref(sixel_decoder_t *decoder);  /* decrease reference count of decoder object (thread-unsafe) */ SIXELAPI void sixel_decoder_unref(sixel_decoder_t *decoder);  /* set an option flag to decoder object */ SIXELAPI SIXELSTATUS sixel_decoder_setopt(     sixel_decoder_t /* in */ *decoder,  /* decoder object */     int             /* in */ arg,       /* one of SIXEL_OPTFLAG_*** */     char const      /* in */ *optarg);  /* null or an argument of optflag */  /* load source data from stdin or the file specified with    SIXEL_OPTFLAG_INPUT flag, and decode it */ SIXELAPI SIXELSTATUS sixel_decoder_decode(     sixel_decoder_t /* in */ *decoder);

The low-level conversion API

The low-livel API provides Bytes-to-Bytes conversion features.

The Whole API is describedhere.

Example

A tiny example is availablehere.

Libsixel: The new standard of SIXEL development – graphics in the terminal

Bitmap to SIXEL

sixel_encode function converts bitmap array into SIXEL format.

/* convert pixels into sixel format and write it to output context */ SIXELAPI SIXELSTATUS sixel_encode(     unsigned char  /* in */ *pixels,     /* pixel bytes */     int            /* in */  width,      /* image width */     int            /* in */  height,     /* image height */     int            /* in */  depth,      /* color depth: now unused */     sixel_dither_t /* in */ *dither,     /* dither context */     sixel_output_t /* in */ *context);   /* output context */

To use this function, you have to initialize two objects,

  • sixel_dither_t (dithering context object)
  • sixel_output_t (output context object)

Dithering context

Here is a part of APIs for dithering context manipulation.

/* 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 */  /* get built-in dither context object */ SIXELAPI sixel_dither_t * sixel_dither_get(int builtin_dither); /* ID of built-in dither object */  /* destroy dither context object */ SIXELAPI void sixel_dither_destroy(sixel_dither_t *dither); /* dither context object */  /* increase reference count of dither context object (thread-unsafe) */ SIXELAPI void sixel_dither_ref(sixel_dither_t *dither); /* dither context object */  /* decrease reference count of dither context object (thread-unsafe) */ SIXELAPI void sixel_dither_unref(sixel_dither_t *dither); /* dither context object */  /* 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,              /* image width */     int /* in */ height,             /* image 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 */  /* 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 */  /* get number of palette colors */ SIXELAPI int sixel_dither_get_num_of_palette_colors(     sixel_dither_t /* in */ *dither);  /* dither context object */  /* get number of histogram colors */ SIXELAPI int sixel_dither_get_num_of_histogram_colors(     sixel_dither_t /* in */ *dither);  /* dither context object */  /* get palette */ SIXELAPI unsigned char * sixel_dither_get_palette(     sixel_dither_t /* in */ *dither);  /* dither context object */  /* set palette */ SIXELAPI void sixel_dither_set_palette(     sixel_dither_t /* in */ *dither,   /* dither context object */     unsigned char  /* in */ *palette);  SIXELAPI void sixel_dither_set_complexion_score(     sixel_dither_t /* in */ *dither,   /* dither context object */     int            /* in */ score);    /* complexion score (>= 1) */  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 */ 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 */ /* set pixelformat */ SIXELAPI void sixel_dither_set_pixelformat(     sixel_dither_t /* in */ *dither,      /* dither context object */     int            /* in */ pixelformat); /* one of enum pixelFormat */  /* set transparent */ SIXELAPI void sixel_dither_set_transparent(     sixel_dither_t /* in */ *dither,      /* dither context object */     int            /* in */ transparent); /* transparent color index */

Output context

Here is a part of APIs for output context manipulation.

/* 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);  /* allocator, null if you use                                                        default 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 */  /* 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);

SIXEL to indexed bitmap

sixel_decode function converts SIXEL into indexed bitmap bytes with its palette.

/* convert sixel data into indexed pixel bytes and palette data */ SIXELAPI SIXELSTATUS sixel_decode_raw(     unsigned char       /* in */  *p,           /* sixel bytes */     int                 /* in */  len,          /* size of sixel bytes */     unsigned char       /* out */ **pixels,     /* decoded pixels */     int                 /* out */ *pwidth,      /* image width */     int                 /* out */ *pheight,     /* image height */     unsigned char       /* out */ **palette,    /* ARGB palette */     int                 /* out */ *ncolors,     /* palette size (<= 256) */     sixel_allocator_t   /* in */  *allocator);  /* allocator object */ 

Perl interface

This package includes a perl module Image::Sixel .

Build and install Perl interface

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

Python interface

This package includes a Python module libsixel .

Build and install Python interface

Install into the python prefixed with ‘/usr/local’

$ 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 

Install into only current active python

$ 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 

or

$ easy_install libsixel-python 

PHP interface

This package includes a PHP module sixel .

Build and install PHP interface

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

Ruby interface

Build and install Ruby interface

$ gem install libsixel-ruby 

or

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

Support

This software is provided "as is" without express or implied warranty. The main support channel for this software is the github issue tracker:

https://github.com/saitoha/libsixel/issues

Please post your issue if you have any problems, questions or suggestions.

License

The MIT License (MIT)

Copyright (c) 2014 Hayaki Saito

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 THE AUTHORS OR COPYRIGHT HOLDERS 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.

Contributers and Reviewers

Contributing

  1. Fork it ( https://github.com/saitoha/libsixel/fork/ )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am ‘Add some feature’)
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request

Acknowledgment

This software derives from the following implementations.

sixel 2014-3-2

src/tosixel.c, src/fromsixel.c, and some part of converters/loader.c are derived from kmiya’s " sixel " original version (2014-3-2)

Package: http://nanno.dip.jp/softlib/man/rlogin/sixel.tar.gz

Unofficial repo: https://github.com/saitoha/sixel

This work is written by kmiya@ culti. He distributes it under very permissive license.

The original license text(in Japanese only) is:

このプログラム及びソースコードの使用について個人・商用を問わず  ご自由に使用していただいで結構です。  また、配布・転載・紹介もご連絡の必要もありません。  ソースの改変による配布も自由ですが、どのバージョンの改変かを  明記されることを希望します。  バージョン情報が無い場合は、配布物の年月日を明記されることを  希望します。                    2014/10/05  kmiya 

The unofficial translation:

Anyone is free to use this program for any purpose, commercial or non-commercial, without any restriction.  Anyone is free to distribute, copy, publish, or advertise this software, without any contact.  Anyone is free to distribute with modification of the source code, but I "hope" that its based version or date will be written clearly.                                      2014/10/05 kmiya 

kmiya also said this is compatible with MIT/BSD/GPL.

stbi-2.06

This software includes stbi-2.06 (stb_image.h), public domain JPEG/PNG reader.

https://github.com/nothings/stb

stbiw-0.94

This software includes stbiw-0.94 (stb_image_write.h), public domain PNG/BMP/TGA writer.

https://github.com/nothings/stb

pnmquant.c (netpbm library)

The implementation of median cut algorithm for color quantization in quant.c is imported from pnmcolormap included in netpbm library .

http://netpbm.sourceforge.net/

pnmcolormap was derived from ppmquant , originally written by Jef Poskanzer.

Copyright (C) 1989, 1991 by Jef Poskanzer. Copyright (C) 2001 by Bryan Henderson.

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. This software is provided "as is" without express or implied warranty.

loader.h (@uobikiemukot’s sdump)

Some parts of converters/loader.c are imported from @uobikiemukot’ssdump project

The MIT License (MIT)

Copyright (c) 2014 haru

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 THE AUTHORS OR COPYRIGHT HOLDERS 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.

ax_gcc_var_attribute / ax_gcc_func_attribute

These are useful m4 macros for detecting some GCC attributes.

http://www.gnu.org/software/autoconf-archive/ax_gcc_var_attribute.html http://www.gnu.org/software/autoconf-archive/ax_gcc_func_attribute.html

Copyright (c) 2013 Gabriele Svelto gabriele.svelto@gmail.com

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved. This file is offered as-is, without any warranty.

graphics.c (from Xterm pl#310)

The helper function hls2rgb in src/fromsixel.c is imported from graphics.c in Xterm pl#310 , originally written by Ross Combs.

Copyright 2013,2014 by Ross Combs

                    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 THE ABOVE LISTED COPYRIGHT HOLDER(S) 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.

Except as contained in this notice, the name(s) of the above copyright holders shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization.

test images

http://public-domain-photos.com/

The following test images in "image/" directory came from PUBLIC-DOMAIN-PHOTOS.com.

These are in the public domain .

vimperator3.png (mascot of vimperator)

images/vimperator3.png is in the public domain.

author: @k_wizard url: http://quadrantem.com/~k_wizard/vimprtan/ 

PngSuite

Images under the directory images/pngsuite/ are imported from PngSuite created by Willem van Schaik.

Permission to use, copy, modify and distribute these images for any purpose and without fee is hereby granted.

(c) Willem van Schaik, 1996, 2011

References

ImageMagick

We are greatly inspired by the quality of ImageMagick and added some resampling filters to img2sixel in reference to the line-up of filters of MagickCore’s resize.c.

http://www.imagemagick.org/api/MagickCore/resize_8c_source.html 

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转载本站任何文章请注明:转载至神刀安全网,谢谢神刀安全网 » Libsixel: The new standard of SIXEL development – graphics in the terminal

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