Ubuntu Manpage: timg - A terminal image and video viewer

NAME

       timg - A terminal image and video viewer

SYNOPSIS

       timg [<options> <image/video> [<image/video>...]

DESCRIPTION

Show images, play animated gifs, scroll static images or play videos in the terminal.
Even show PDFs if needed.

Useful if you want to have a quick visual check without leaving the comfort of your shell
and having to start a bulky image viewer. Sometimes this is the only way if your terminal
is connected remotely via ssh. And of course if you don’t need the resolution. While
icons typically fit pixel-perfect, larger images are scaled down to match the resolution.

The command line accepts any number of image/video filenames that it shows in sequence one
per page or in a grid in multiple columns, depending on your choice of --grid. The output
is emitted in-line with minimally messing with your terminal, so you can simply go back in
history using your terminals’ scroll-bar (Or redirecting the output to a file allows you
to later simply cat that file to your terminal. Even less -R seems to be happy with such
output).

The special filename “-” stands for standard input, so you can read an image from a pipe.
If the input from a pipe is a video, use the -V option (see below).

Under the hood, timg uses GraphicsMagick to open and decode a wide range of image formats.
It also uses libav to decode and play videos or images from files and URLs. With -I or -V
you can choose to use only one of these file decoders (GraphicsMagick or libav
respectively).

OPTIONS

General Options
-g <width>x<height>
Output image to fit inside given geometry. By default, the size is determined by
the available space in the terminal. The image is scaled to fit inside the
available box to fill the screen; see -W if you want to fill the width.

It is possible to only partially specify the size before or after the x separator,
like -g<width>x or -gx<height>. The corresponding other value is then derived from
the terminal size.

-p <[h|q|k|i]>, --pixelation=[h|q|k|i]
Choice for pixelation of the content. Value `h' chooses unicode half block
characters, while `q' chooses quarter blocks. The choice `k' chooses kitty-
graphics protocol, `i' the iTerm2 graphics protocol.

Half blocks have a pixel aspect ratio of about 1:1 and allow to represent colors
correctly, but they look more `blocky'.

Quarter blocks will have a pixel aspect ratio of 1:2 (timg will stretch the picture
accordingly, no worries), and can only represent colors approximately, as the four
quadrant sub-pixels can only be foreground or background color. This increases the
spatial resolution in x-direction at expense of slight less color accuracy. It
makes it look less `blocky' and usually better.

There are terminal emulators that allow to display high-resolution pictures. If
timg is detecting to run in a Kitty, iTerm2 or WezTerm, the corresponding mode is
auto-selected. You can choose the modes explicitly with -pk (Kitty) or -pi (iTerm2
protocol, also implemented by WezTerm).

Default is `quarter' unless the terminal is graphics-capable.

--compress
For the graphics modes: this switches on compression for the transmission to the
terminal. This uses more CPU on timg, but is desirable when connected over a slow
network.

-C, --center
Center image(s) and title(s) horizontally.

-W, --fit-width
Scale to fit width of the available space. This means that the height can
overflow, e.g. be longer than the terminal, so might require scrolling to see the
full picture. Default behavior is to fit within the allotted width and height.

--grid=<cols>[x<rows>]
Arrange images in a grid. If only one parameter is given, arranges in a square
grid (e.g. --grid=3 makes a 3x3 grid). Alternatively, you can choose columns and
rows that should fit on one terminal (e.g. --grid=3x2)

-w <seconds>
Wait time between images when multiple images are given on the command line.
Fractional values are allowed, so -w3.1415 would wait approximately π seconds
between images.

-a Switch off anti aliasing. The images are scaled down to show on the minimal amount
of pixels, so some smoothing is applied for best visual effect. This switches off
that smoothing.

-b <background-color>
Set the background color for transparent images. Common HTML/SVG/X11 color strings
are supported, such as purple, *#00ff00 or rgb(0, 0, 255).

As a `special' color, auto is allowed, which attempts to query the terminal for its
background color (Best effort; not all terminals support that). If detection
fails, the fallback is `black'.

The special value none switches off blending background color.

-B <checkerboard-other-color>
Show the background of a transparent image in a checkerboard pattern with the given
color, which alternates with the -b color. Supported color specifications like in
-b.

--pattern-size=<size-factor>
Scale background checkerboard pattern by this factor.

--auto-crop[=<pre-crop>]
Trim same-color pixels around the border of image before displaying. Use this if
there is a boring even-colored space aorund the image which uses too many of our
available few pixels.

The optional pre-crop is number of pixels to unconditionally trim all around the
original image, for instance to remove a thin border. The link in the EXAMPLES
section shows an example how this improves showing an xkcd comic with a border.

--rotate=<exif|off>
If `exif', rotate the image according to the exif data stored in the image. With
`off', no rotation is extracted or applied.

--clear
Clear screen before first image. This places the image at the top of the screen.

There is an optional parameter `every' (--clear=every), which will clean the screen
before every image. This only makes sense if there is no --grid used and if you
allow some time to show the image of course, so good in combination with -w.

-U, --upscale=[i]
Allow Upscaling. If an image is smaller than the terminal size, scale it up to fit
the terminal.

By default, larger images are only scaled down and images smaller than the
available pixels in the terminal are left at the original size (this helps assess
small deliberately pixelated images such as icons in their intended appearance).
This option scales up smaller images to fit available space.

The long option allows for an optional parameter --upscale=i that forces the
upscaling to be in integer increments to keep the `blocky' appearance of an
upscaled image without bilinear scale `fuzzing'.

-V This is a video, directly read the content as video and don’t attempt to probe
image decoding first.

Usually, timg will first attempt to interpret the data as image, but if it that
fails, will fall-back to try interpret the file as video. However, if the file is
coming from stdin, the first bytes used to probe for the image have already been
consumed so the fall-back would fail in that case... Arguably, this should be dealt
with automatically but isn’t :)

Long story short: if you read a video from a pipe, use -V. See link in EXAMPLES
section for a an example.

-I This is an image, don’t attempt to fall back to video decoding. Somewhat the
opposite of -V.

--title=[format-string]
Print title above each image. It is possible to customize the title by giving a
format string. In this string, the following format specifiers are expanded:

• %f = full filename

• %b = basename (filename without path)

• %w = image width

• %h = image height

• %D = internal decoder used (image, video, ...)

If no format string is given, this is just the filename (%f) or, if set, what is
provided in the TIMG_DEFAULT_TITLE environment variable.

-F Behaves like –title="%f", i.e. the filename is printed as title (or, if set, the
TIMG_DEFAULT_TITLE environment variable).

-f <filelist-file>
Read a list of image filenames to show from this file. The list needs to be
newline separated. This option can be supplied multiple times in which case it
appends to the end of the list of images to show. If there are also filenames on
the command line, they will be shown at the very end.

Absolute filenames in the list are used as-is, relative filenames are resolved
relative to the filelist-file itself.

-o <outfile>
Write terminal image to given filename instead of stdout.

-E Don’t hide the cursor while showing images.

--threads=<n>
Run image decoding in parallel with n threads. By default, half the reported CPU-
cores are used.

--color8
Use 8 bit color mode for terminals that don’t support 24 bit color (only shows
6x6x6 = 216 distinct colors instead of 256x256x256 = 16777216).

--version
Print version and exit.

-h, --help
Print command line option help and exit.

For Animations, Scrolling, or Video
Usually, animations are shown in full in an infinite loop. These options limit infinity.

-t<seconds>
Stop an animation after these number of seconds. Fractional values are allowed.

--loops=<num>
Number of loops through a fully cycle of an animation or video. A value of -1
stands for `forever'.

If not set, videos loop once, animated images forever unless there is more than one
file to show. If there are multiple files on the command line, animated images are
only shown once if --loops is not set to prevent the output get stuck on the first
animation.

--frames=<frame-count>
Only render the first frame-count frames in an animation or video. If frame-count
is set to 1, the output behaves like a static image.

Scrolling
--scroll[=<ms>]
Scroll horizontally with an optional delay between updates (default: 60ms). In the
EXAMPLES section is an example how to use ImageMagick to create a text that you
then can scroll with timg over the terminal.

--delta-move=<dx>:<dy>
Scroll with delta x and delta y. The default of 1:0 scrolls it horizontally, but
with this option you can scroll vertically or even diagonally.

RETURN VALUES

       Exit code is

       0      On reading and displaying all images successfully.

       1      If any of the images could not be  read  or  decoded  or  if  there  was  no  image
              provided.

       2      If an invalid option or parameter was provided.

       3      If  timg  could not determine the size of terminal (not a tty?).  Provide -g option
              to provide size of the output to be generated.

       4      Could not write to output file provided with -o.

       5      Could not read file list file provided with -f.

ENVIRONMENT

TIMG_DEFAULT_TITLE
The default format string used for --title. If not given, the default title format
string is "%f".

TIMG_USE_UPPER_BLOCK
If this environment variable is set to the value 1, timg will use the U+2580 -
`Upper Half Block' (▀) Unicode character.

To display pixels, timg uses a Unicode half block and sets the foreground color and
background color to get two vertical pixels. By default, it uses the U+2584 -
`Lower Half Block' (▄) character to achieve this goal. This has been chosen as it
resulted in the best image in all tested terminals (konsole, gnome terminal and
cool-retro-term). So usually, there is no need to change that. But if the
terminal or font result in a funny output, this might be worth a try. This is an
environment variable because if it turns out to yield a better result on your
system, you can set it once in your profile and forget about it.

TIMG_FONT_WIDTH_CORRECT
A floating point stretch factor in width direction to correct for fonts that don’t
produce quite square output.

If you notice that the image displayed is not quite the right aspect ratio because
of the font used, you can modify this factor to make it look correct. Increasing
the visual width by 10% would be setting it to TIMG_FONT_WIDTH_CORRECT=1.1 for
instance.

This is an environment variable, so that you can set it once to best fit your
terminal emulator of choice.

TIMG_ALLOW_FRAME_SKIP
Set this environment variable to 1 if you like to allow timg to drop frames when
play-back is falling behind. This is particularly useful if you are on a very slow
remote terminal connection that can’t keep up with playing videos. Or if you have
a very slow CPU.

EXAMPLES

       Some  example  invocations  including  scrolling text or streaming an online video are put
       together at <https://github.com/hzeller/timg#examples>

KNOWN ISSUES

       This requires a terminal that can deal with Unicode characters and  24  bit  color  escape
       codes.   This  will  be  problematic on really old installations or if you want to display
       images on some limited text console.

       The option -V should not  be  necessary  for  streaming  video  from  stdin;  timg  should
       internally buffer bytes it uses for probing.

BUGS

       Report bugs to <http://github.com/hzeller/timg/issues>

COPYRIGHT

       Copyright (c) 2016..2021 Henner Zeller.  This program is free software, provided under the
       GNU GPL version 2.0 or later <https://gnu.org/licenses/gpl.html>.

AUTHORS

       Henner Zeller.

                                             Feb 2021                                     timg(1)