w3m image preview banding/flickering

[taylorchu]

the image shows in one blink. but xterm works fine.

[ok100]

I have the same issue, but only with st (urxvt works fine).

[devendra-ghate]

I have problem with some images in urxvt. Certain blocks of the images are shown as just white patches. But some images are shown clearly. Don't know how to pin-point the source of the error.

[Adarsh-Barik]

I have the same issue with urxvt (some image previews are shown clearly while some have black patches). However, it runs fine in xterm.
Also, is it possible to make it work in tilda (or gnome-terminal)?

[Edholm]

I resolved this by removing URxvt.depth: 32 from my .Xdefaults file.
(Urxvt never showed images for me)

[Ambrevar]

Been playing a bit with .Xresources, and found out that loading an Xft font caused URxvt to be messy with w3m image preview (random black stripes on preview). Xft fonts work fine with xterm.
My .Xresources:

! Fails
URxvt_font : xft:Dejavu Sans Mono:pixelsize=14
! Works
URxvt_font : --dejavu sans mono-----------iso8859-

! Works
xterm*faceName:DejaVu Sans Mono:pixelsize=12

[taylorchu]

Finally trace down the exact problem:
the anti-aliasing of xft font of urxvt breaks w3m image preview.

I guess we cannot do anything about this in ranger

[Ambrevar]

I wanted to report the urxvt bug upstream. Is it me or is there no bugtraker ?
Besides I do not seem to be able to subscribe to the mailing list (never
received any confirmation mail). And I hate IRC, so...

[ghost]

There was some discussion about this a while back on the suckless mailing list. They were hoping to get it working with st. It looks like it may be a issue with w3m-img.

[Ambrevar]

Funny, I just received the confirmation mail for the urxvt mailing list today! Hell, I subscribed 15 days ago! Well, it's no use anymore.

[ghost]

So did anyone ever find a fix for this? I tried to visit the w3m mailing list archives a few times (as referenced here: http://w3m.sourceforge.net/) but it seems the connection times out. Is there even still any development on w3m?

By the way, seems to me there are two different issues going on here:

• Using an antialiased font breaks the preview completely.
• Having 32bit color depth enabled causes the preview to behave weirdly (jumps sometimes, being only half drawn sometimes, etc.)

[brunal]

This is definitely a w3m problem and not a ranger one: w3mimgdisplay does not handle 32 bit colors. However, the project seems stagnant indeed and we'd have to fix it ouselves. A feature request can be opened on http://sourceforge.net/p/w3m/feature-requests/ but all of them seem to fall in /dev/null.
The source is available on sourceforce, and can be retrieved as a tarball or with cvs (no kidding).
Interesting folder is wm3img/fb/. The Readme seems to hold strange characters... Is it Japanese?
I'm from the generation that does not speak c, but I'll have a go at reading the source this weekend. It's only 46 lines of *.h and 1336 lines of *.c.

Anyone else interested?

[BwackNinja]

w3m was handling visuals and colormaps incorrectly. It always used the default rather than taking it from where it wants to draw to. Here's a patch for it:
https://gist.github.com/BwackNinja/60a344730170f9ce2163

[r8b7xy]

How to apply this patch?
Thanks in advance.

[ghost]

Hi There,

I managed to get it working perfectly by setting:
set draw_borders true

In the ~/.config/ranger/rc.conf

Cheers!

[tats]

w3m was handling visuals and colormaps incorrectly.
https://gist.github.com/BwackNinja/60a344730170f9ce2163

@BwackNinja Thanks for the contribution to w3m.
Merged in the development repository for Debian's w3m.
cf. https://sourceforge.net/p/w3m/patches/72/

[fmthoma]

After applying @BwackNinja's patch I still had problems with resized images not being displayed correctly in urxvt with 32-bit enabled, showing semi-transparent artifacts on resized images. It looks like this is a bug (?) in imlib2, but can be worked around in w3m-img by using a different method for resizing the image. Now image preview in ranger works for me without set draw_borders true, even with background transparency enabled in urxvt.

Here is the patch, should be applied in addition to the one supplied by @BwackNinja: https://gist.github.com/fmthoma/f76a1b44e00d5ca972bb

[tats]

https://gist.github.com/fmthoma/f76a1b44e00d5ca972bb

@fmthoma Merged in Debian's w3m development repo. Thank you.

[noctuid]

@tats @fmthoma Installing w3m from that repo does not fix image display in termite for me. It also breaks ranger's preview (but not using w3m directly) in both xterm and urxvt. Any ideas on why this happens?

[fmthoma]

Does it only break after my patch, or is it broken before? What library do you use for loading images, imlib or imlib2 or gkd-pixbuf? My patch applies only to the imlib2 backend.

I did not test with termite, but it works on xterm (unchanged by my patch, since xterm does not support 32-bit color anyways) and urxvt. In gnome-terminal, ranger's image preview does not work (I don't know why), but w3mimgdisplay works.

Have you tried running w3mimgdisplay separately?
/usr/lib/w3m/w3mimgdisplay <<<$'0;1;100;100;100;100;;;;;/path/to/some/picture\n4;\n3;'

[noctuid]

Installing from that repo, it's broken both before and after the patch. I tried using --with-imagelib=imlib2 without success. I don't have /usr/lib/w3m/w3mimgdisplay (I guess I need to look through the Makefile), but moving the w3mimgdisplay binary there fixes the problem for xterm but not termite. I can view images in termite now using w3m /path/to/image without it opening an external image viewer, but I don't see anything (just the background color; all black).

[fmthoma]

Okay, I did not try to install from the development repo. I just fetch the sources (apt-get source w3m) and apply the patches. For Ubuntu (and probably other Debian based systems) have a look at my dotfiles.

[lcpz]

There's no point using w3m with rxvt as it has it's own method (but bad font handling:-( )

The urxvt method is just rubbing the image on the terminal, without honoring the aspect ratio, plus it requires urxvt to be compiled with a certain non-standard option. Instead, w3mimgdisplay creates a thumbnail.

I don't use a background or transparency, so my banding "stripes" are black.

[vifon]

requires urxvt to be compiled with a certain non-standard option

Sorry for nitpicking but I'm aware of only one Linux distro that supplies urxvt without this option (Arch). I would rather call the lack of this option "non-standard" and file a bug report to the package maintainer.

As for the issue as a whole, not much can be done on our side. The way w3m previews work will always be buggy and it only gets worse with the additional stuff like compositors (e.g. compton).

The urxvt method is just rubbing the image on the terminal, without honoring the aspect ratio

@copycat-killer, I cannot reproduce the aspect ratio issues. Could you provide a confirmed test case?
What do you mean by "rubbing"?

[crocket]

@vifon rubbing means #815 which happens with urxvt image preview method. That's why I don't use urxvt image preview method.

I wonder if SIXEL doesn't have this issue.

[lcpz]

Sorry for nitpicking but I'm aware of only one Linux distro that supplies urxvt without this option (Arch). I would rather call the lack of this option "non-standard" and file a bug report to the package maintainer.

It seems to me improbable that Arch is the only distro without it as standard, anyway there is rxvt-unicode-pixbuf in the AUR.

But enough discussing, let's focus on PySixel. All we have to do is to create a SIXELImageDisplayer class which implement this interface.

[crocket]

I feel that https://github.com/saitoha/PySixel is unmaintained. Perhaps, there is a better sixel binding.

[j-degreef]

Sixel works on a limited number of terminals.
Unless people are ok to switch to another term, which I will not do for functionality reasons (Using i3 I need a term with keyboard navigation as Termite or urxvt have) that will not solve the problem for most.

[noctuid]

Maybe it's not an ideal solution for everyone, but tmux has much better keyboard navigation in my experience (and actually has customizable keybindings). I've not once used termite's keybindings. Regardless, I don't think limited terminal support is any reason not to add support for sixel as a method.

[lcpz]

Yeah, PySixel is unmaintained, and works on a limited number of terminals.

That's why there's libsixel-python.

As soon as I have enough time I'll try to implement the above mentioned displayer.

EDIT: well, urxt seems still unsupported, but I want to play with it anyway.

[vifon]

Sixel support would certainly be nice if you could code it. It's a shame urxvt doesn't support it (personally I don't plan to switch terminals) but a new option is always welcome, as long as it won't be a hard dependency.

[crocket]

st will probably support SIXEL within this year because someone started pushing SIXEL support to st.
If he hears that ranger guys are going to add SIXEL support, he'll definitely push harder.

st is a viable alternative to urxvt and termite if you are willing to compile your configuration from C and accept XIM input method(which ibus supports) instead of the full ibus input method.

The advantage of st is that it supports fontconfig properly while urxvt does only partially.
As a result, there are a lot of unicode characters that st can display and urxvt can't.

Gentoo makes it very easy to compile configurations in programming languages, so I use st along with urxvt on Gentoo Linux.

[WhyNotHugo]

st is a viable alternative to urxvt and termite if you are willing to compile your configuration from C and accept XIM input method(which ibus supports) instead of the full ibus input method.

That's an absurdly huge if. I use a package manager to track that everything is up to date. I've no intention of ever changing that. A great deal of others thing the same. Manually staying up to date on releases and rebuilding is cumbersome and unmaintainable.

[crocket]

@hobarrera I am on gentoo linux. Gentoo's package manager makes it easy to compile st with a configuration file when it installs st. Thus, I can just reinstall the package after changing the configuration.

It takes less than 30 seconds to reinstall st on gentoo.

It seems st is not good on binary linux distributions. Perhaps, you want to check if it's possible to do the same on your linux distribution.

[AeliusSaionji]

You forgot to account for the amount of time it takes to fix your config to match upstream changes.

Even with gentoo, there is more management overhead. You and I are happy to deal with that, but respect that not everyone is.

[WhyNotHugo]

It seems st is not good on binary linux distributions. Perhaps, you want to check if it's possible to do the same on your linux distribution.

You also forgot that I need to subscribe to some for of RSS, and keep an eye on newer releases. Like @Link-Satonaka mentioned, also update the config every time upstream changes.
You might convince some people to do this, but 99% of the people prefer to have updates automated, rather than have to manually patch and install releases.

The idea of manually building from source (even if you build a package) will never be upstream because of the huge overhead. For those who prefer it: go ahead and use that, I've no issue. But don't expect the rest of the world to adopt that.

[crocket]

The idea of manually building from source (even if you build a package) will never be upstream

On Gentoo, you don't build package manually. Gentoo's package manager, emerge, automates compilation although compilation takes time. For example, if you want to compile and install firefox, you just execute emerge -q x11-client/firefox. For system upgrade, I execute emerge -auDN @world. I use gentoo because I want specific customizations to many packages, but if you don't want specific customizations to your linux distribution, you don't want gentoo's compilation overhead. That said, the compilation overhead is acceptable if you have FX-8300 or anything faster and compile everything in tmpfs.

For now, st is convenient only on gentoo systems because gentoo's package manager takes care of compiling st with its configuration file.

st better adopt a model similar to XMonad for configuration.
You can just install XMonad binary package which compiles haskell configuration file with GHC.
Unlike GHC, gcc, which st can use to compile configuration, is not considered as a bloat by many users. Binary linux distribution users have no problem with using XMonad as long as they are willing to live with GHC on their storage devices.

By the way, ordinary text configuration files are just as susceptible to upstream changes, and they can be harder to debug because there is hardly any useful debugging information for ordinary text configuration files. I used to update gitea and gitlab. It was hard to keep up with configuration file changes. At least, with gcc or GHC, compiler helps you find and fix errors.

[steelvelveteen]

Hi, I got rid of the annoying black band across the previews by setting the border for ranger as true
Aprox around line 122 of the rc.conf file
set draw_borders true (it is false by default)
and this solved my problem
Hope it helps

[4drift]

Just wanted to say that there is support for urxvt, but thus far it doesn't compile for me.

https://github.com/saitoha/rxvt-unicode-sixel

[slve]

The only workaround for the banding issue that worked for me is editing
/usr/lib/python3.6/site-packages/ranger/ext/img_display.py
adding import time at the top,
and time.sleep(1/100) just right above self.process.stdin.write(input_gen)
around line 122

btw. I had exactly the same issue with xterm, even though it came up less often

using 1/100 is reliable enough on my pc, still, not much lagging when scrolling through many images,
if you still see some bands on your pc, try increasing it,
using 1/20 not a single band showed up,
but scrolling through a lot of images wasn't as smooth as with 1/100

using this patch, there is no need to set draw_borders true, which is a big plus for me

[wilzbach]

The only workaround for the banding issue that worked for me is editing
/usr/lib/python3.6/site-packages/ranger/ext/img_display.py
adding import time at the top,
and time.sleep(1/100)

Nice! That worked for me too. Is there any chance we could get such a workaround upstream?

[vifon]

@wilzbach Already there. :) #1193

[doa379]

I'm experiencing this in Debian 10 Testing.
I was using w3m to preview images in Xterm and it's been working fine. But after switching to URxvt recently, images are flickering in the Ranger preview.
Clearly whatever fix that was pushed out has not really worked.

[doa379]

I would like to give credence to the theory that it's Xft related because the issue is not present when I start URxvt with a bitmap font instead of an Xft font.

[Ojousama]

[DanielAndreasen]

I had the same flickering problem with st (and tried most things). What in the end worked for me, was to clone this repo and install from source (sudo make install). I made sure ranger.py was in my PATH (I made a link and called it ranger).
After that I tweaked the w3m_delay a bit and ended up with adding this to my config which seems to work in 95% of the cases
set w3m_delay 0.1

[amahmod]

adding w3m_delay to rc.conf solved my problem with st
Thanks to @DanielAndreasen

[thepenguinthatwants]

adding w3m_delay to rc.conf solved my problem with st
Thanks to @DanielAndreasen
Can you show your whole config?

I've being struggling with this for ages.
Pictures show up in ST or alacritty only milliseconds. urxvt and xterm they dont even show up.

set w3m_delay 0.1
didnt help it only delayed showing picture

set preview_files true
set preview_script ~/.config/ranger/scope.sh
set use_preview_script true
set preview_images_method w3m
set draw_borders true

The problem is mostly because of w3m as pictures show there only just milliseconds.

[MarcoDiFrancesco]

set draw_borders true

This solved the problem for me. Thanks!