Difference between revisions of "How to preview images"

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(Link to instructions on integrating Überzug)
(Reorganize general structure and apply some minor updates)
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Starting with 0.8 vifm provides four macros describing preview area that can be used along with external applications to preview images in a terminal, they are:
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Vifm v0.8 onward provides four macros describing preview area that can be used along with external applications to preview images in a terminal, they are:
 
* <code>%px</code> x coordinate of top-left corner of preview area;
 
* <code>%px</code> x coordinate of top-left corner of preview area;
 
* <code>%py</code> y coordinate of top-left corner of preview area;
 
* <code>%py</code> y coordinate of top-left corner of preview area;
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* <code>%ph</code> height of preview area.
 
* <code>%ph</code> height of preview area.
  
Below is a description and an example of making this work using <code>w3m</code> on GNU/Linux.
+
Note that because terminals were built to display text rather than images, making them display images can be problematic. Some solutions work better in some environments than in others and none of them is perfect.
Mind that the support is lacking and you might have trouble making this work in many terminals. <code>xterm</code> without double-buffering tends to work bettern than others.
+
 
See the last section for a way of making it work on OS X with iTerm2.
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== Überzug ==
  
 
For an instruction on how to use [https://github.com/seebye/ueberzug Überzug], which is likely to work better than <code>w3m</code>, see [https://www.youtube.com/watch?v=qgxsduCO1pE this video].
 
For an instruction on how to use [https://github.com/seebye/ueberzug Überzug], which is likely to work better than <code>w3m</code>, see [https://www.youtube.com/watch?v=qgxsduCO1pE this video].
 
The video is based on [https://www.reddit.com/r/linux/comments/aviu08/ueberzug_v1810_released/ehfj0s4/ this thread].
 
The video is based on [https://www.reddit.com/r/linux/comments/aviu08/ueberzug_v1810_released/ehfj0s4/ this thread].
 +
 +
== iTerm2 ==
 +
 +
See [https://github.com/vifm/vifm/issues/299 issue #299 on GitHub] for a command for OS X in iTerm2.
 +
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== w3m ==
 +
 +
Below is a description and an example of making this work using <code>w3m</code> on GNU/Linux.
 +
Mind that the support is lacking and you might have trouble making this work in many terminals. <code>xterm</code> without double-buffering tends to work better than others.
  
 
=== Prerequisites ===
 
=== Prerequisites ===
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Replace "imgt" with path to preview script or just update name if
 
Replace "imgt" with path to preview script or just update name if
 
script is available in your <code>$PATH</code> (which is the case if you put it
 
script is available in your <code>$PATH</code> (which is the case if you put it
under <code>~/.vifm/scripts</code>).
+
under <code>$VIFM/scripts</code>).
  
 
=== Notes ===
 
=== Notes ===
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* [https://github.com/vifm/vifm/issues/82 Issue #82 on GitHub] for similar description and some discussion of some issues.
 
* [https://github.com/vifm/vifm/issues/82 Issue #82 on GitHub] for similar description and some discussion of some issues.
 
* [https://github.com/vifm/vifm/issues/102 Issue #102 on GitHub] for report on image clearing issues.
 
* [https://github.com/vifm/vifm/issues/102 Issue #102 on GitHub] for report on image clearing issues.
* [https://github.com/vifm/vifm/issues/299 Issue #299 on GitHub] for a command for OS X in iTerm2.
 

Revision as of 12:03, 29 September 2020

Vifm v0.8 onward provides four macros describing preview area that can be used along with external applications to preview images in a terminal, they are:

  • %px x coordinate of top-left corner of preview area;
  • %py y coordinate of top-left corner of preview area;
  • %pw width of preview area;
  • %ph height of preview area.

Note that because terminals were built to display text rather than images, making them display images can be problematic. Some solutions work better in some environments than in others and none of them is perfect.

Überzug

For an instruction on how to use Überzug, which is likely to work better than w3m, see this video. The video is based on this thread.

iTerm2

See issue #299 on GitHub for a command for OS X in iTerm2.

w3m

Below is a description and an example of making this work using w3m on GNU/Linux. Mind that the support is lacking and you might have trouble making this work in many terminals. xterm without double-buffering tends to work better than others.

Prerequisites

1. w3mimgdisplay which might be part of w3m package or a separate one.

2. Terminal emulator without double buffering, otherwise w3m will fail to display images properly.

Setup

1. Create script that invokes w3m. w3mimgdisplay executable might reside in different locations depending on the distribution. Below is a sample script, which can be used after correcting several parameters at the top.

#!/bin/bash
#
# Based on script by z3bra -- 2014-01-21

W3MIMGDISPLAY="/usr/libexec/w3m/w3mimgdisplay"
FONTH=15 # Size of one terminal row
FONTW=7 # Size of one terminal column

X=$1
Y=$2
COLUMNS=$3
LINES=$4
FILENAME=$5

read width height <<< `echo "5;$FILENAME" | $W3MIMGDISPLAY`
if [ -z "$width" -o -z "$height" ]; then
    echo 'Error: Failed to obtain image size.'
    exit 1
fi

x=$((FONTW * X))
y=$((FONTH * Y))

max_width=$((FONTW * COLUMNS))
max_height=$((FONTH * LINES))

if [ "$width" -gt "$max_width" ]; then
    height=$((height * max_width / width))
    width=$max_width
fi
if [ "$height" -gt "$max_height" ]; then
    width=$((width * max_height / height))
    height=$max_height
fi

w3m_command="0;1;$x;$y;$width;$height;;;;;$FILENAME\n4;\n3;"

echo -e "$w3m_command" | $W3MIMGDISPLAY

2. Update vifmrc with preview command like the following:

fileviewer *.bmp,*.jpg,*.jpeg,*.png,*.gif,*.xpm
         \ imgt %px %py %pw %ph %c

Replace "imgt" with path to preview script or just update name if script is available in your $PATH (which is the case if you put it under $VIFM/scripts).

Notes

State of terminal support

One should be aware that this is kinda hack as terminals weren't made to display pictures, thus there might be some difficulties (like double buffering or incomplete clearing). That said, it does work in sufficient amount of configurations.

Positioning

When running inside terminal emulators, coordinates known to applications are relative to pane/window position. This should be taken into account, because without applying proper offsets images may appear in unexpected locations.

Clearing

Depending on your terminal this may be enough or require additional script for clearing image leftovers (below), development version of vifm and changed :fileviewer command like this:

fileviewer *.bmp,*.jpg,*.jpeg,*.png,*.gif,*.xpm
         \ imgt %px %py %pw %ph %c
         \ %pc
         \ imgc %px %py %pw %ph

Where imgc is a script that clears background of the terminal (it's configuration is at the top):

#!/bin/bash

W3MIMGDISPLAY="/usr/libexec/w3m/w3mimgdisplay"
FONTH=15 # Size of one terminal row
FONTW=7 # Size of one terminal column

X=$1
Y=$2
COLUMNS=$3
LINES=$4

x=$((FONTW * X))
y=$((FONTH * Y))

erase="6;$x;$y;$(( FONTW*COLUMNS ));$(( FONTH*LINES ))\n3;"
echo -e "$erase" | $W3MIMGDISPLAY

This is the case at least for urxvt.

See also