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Archives For November 30, 1999

Check Contrast between Two Colors in Ubuntu Linux via Kontrast

Last updated: November 2, 2021

For designers want to check color contrast, there are a few handy little tools in Linux Desktop to do the job. Kontrast is the one designed for KDE though works on all Linux desktops.

GNOME has a stylish color contrast tool. Though it’s now in early stage which does not work well and freezes often at least in my case. Here I’ll introduce the KDE’s Kontrast.

This little app displays font color for text and another color as background. Users may change the font and background colors by:

  • manually input a color value.
  • use built-in color picker.
  • drag slider bar to change hue, saturation, and lightness.
  • or use “Randomize” button to generate a pair of colors.

For each color combination, it displays the contrast ratio, and readability (“Perfect”, “Good”, or “Bad”) for normal and large text. There’s also “Invert” button to reverse the two colors. As you can see, it allows to mark color as favorite, though it somehow always fail in my case.

How to Install Kontrast in Ubuntu via apt:

For Ubuntu 21.04 and Ubuntu 21.10, this handy tool has been made into official Ubuntu repositories. Simply press Ctrl+Alt+T on keyboard to open terminal and run command to install it:

sudo apt install kontrast

Though for non-KDE desktop, there will be a lot of dependency libraries also to be installed.

Install Kontrast in Ubuntu 20.04 and older versions:

Ubuntu 20.04, Ubuntu 18.04, and even Ubuntu 16.04 users may install the latest version using the Linux universal flatpak package.

1.) Firstly, press Ctrl+Alt+T on keyboard to open terminal. Then run command to install the flatpak daemon:

sudo apt install flatpak

Ubuntu 18.04 and 16.04 need to add this stable PPA first.

2.) Next, add the flathub repository that hosts the package:

flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

3.) Finally install the color contrast checker app via command:

flatpak install flathub org.kde.kontrast

For first time installing KDE app as flatpak, there are almost 800 MB run-time libraries to be installed:

Once installed, search for and open the tool from activities overview screen and enjoy!

How to Remove Kontrast:

To remove the package installed via apt, use command:

sudo apt remove --autoremove kontrast

For the flatpak, use this command instead to remove it:

flatpak uninstall --delete-data kontrast

And run flatpak uninstall --unused command will delete the unused run-time libraries.

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Linux Kernel 5.15 is Out! Here’s How to Install in Ubuntu

Last updated: November 1, 2021

Linux 5.15 was released yesterday as the new Long Term Support (LTS) kernel release. Here’s what’s new and how to install in Ubuntu.

Linus Torvalds announced the release of Kernel 5.15 on Sunday:

It’s been calm, and I have no excuse to add an extra rc, so here we are, with v5.15 pushed out, and the merge window starting tomorrow.

Which is going to be a bit inconvenient for me, since I also have some conference travel coming up. But it’s only a couple of days and I’ll have my laptop with me. Sometimes the release timing works out, and
sometimes it doesn’t..

…

The new kernel release included following new features:

  • Added the AMD PDTDMA driver
  • An important laptop suspend/resume fix for various AMD models.
  • AMD Zen 3 APU and Yellow Carp APU temperature monitoring support.
  • Initial Intel XeHP and DG2/Alchemist discrete graphics support.
  • New “NTFS3” driver.
  • Added the Apple M1 IOMMU driver
  • New Realtek RTL8188EU WiFi driver
  • Intel “Bz” WiFi hardware support.

How to Install Kernel 5.15 in Ubuntu 21.10:

The Mainline Kernel PPA provides packages for Ubuntu 21.10. However, it does not include any Ubuntu-provided drivers or patches, which are NOT appropriate for production use.

The .deb packages for amd64, arm64, ppc64el and s390x are available to download at the link below:

Download Kernel 5.15

For personal computers, select generic for common system, or lowlatency for a low latency system (e.g. for recording audio):

  • linux-headers-5.15.0-xxxxxx_all.deb
  • linux-headers-5.15.0-xxx-generic(/lowlatency)_xxx_amd64.deb
  • linux-modules-5.15.0-xxx-generic(/lowlatency)_xxx_amd64.deb
  • linux-image-xxx-5.15.0-xxx-generic(/lowlatency)_xxx_amd64.deb

For those familiar with Linux command, open terminal and run commands one by one to download & install the packages:

cd /tmp/

wget -c https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.15/amd64/linux-headers-5.15.0-051500_5.15.0-051500.202110312130_all.deb

wget -c https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.15/amd64/linux-headers-5.15.0-051500-generic_5.15.0-051500.202110312130_amd64.deb

wget -c https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.15/amd64/linux-image-unsigned-5.15.0-051500-generic_5.15.0-051500.202110312130_amd64.deb

wget -c https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.15/amd64/linux-modules-5.15.0-051500-generic_5.15.0-051500.202110312130_amd64.deb

sudo dpkg -i *.deb

Once installed, restart your computer and enjoy!

Uninstall Linux Kernel 5.15:

Restart your machine and select boot with the previous kernel in boot menu ‘Grub2 -> Advanced Option for Ubuntu’. Then run command to remove Linux Kernel 5.15:

sudo dpkg --purge linux-image-unsigned-5.15.0-051500

Kernel 5.15 for Ubuntu 20.04:

The mainline kernel was build against Ubuntu 21.10, so it won’t install in Ubuntu 20.04 LTS. However, for those insist on installing the new kernel, this project is available along with an Ubuntu PPA. Use it at your own risk!

You may run command in terminal to add the PPA:

sudo add-apt-repository ppa:tuxinvader/lts-mainline

Once the Kernel 5.15 package is updated, use command to install it:

sudo apt install linux-generic-5.15
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Gnome Subtitles 1.7.1 Released! How to Install in Ubuntu 20.04 / 21.10

Last updated: October 31, 2021

For adding subtitles to your video, the Gnome Subtitles editor released v1.7.1. Here’s how to install it in Ubuntu 16.04, 18.04, 20.04, 21.10 via PPA.

Gnome Subtitles is a free and open-source subtitle editor for Linux. Without using a heavy video editor app, this simple tool allows to add subtitles & captions to your video with preview, timing synchronization, translation, spell checking support and more.

It has been two years since the last release, Gnome Subtitle 1.7 (and 1.7.1 with quick fixes) was released with support for Enchant 2, AbiWord’s spell-checker with updated API/ABI.

Other changes include:

  • Rewrite GStreamer media playback engine.
  • Fix audio and video playback issues.
  • Update AppData and Desktop files.
  • Subtitle lines displayed on video are now refreshed immediately if changed.
  • And various bug-fixes.

How to Install Gnome Subtitles 1.7.1 in Ubuntu:

NOTE: Due to BUG, the package for Ubuntu 18.04 and Ubuntu 20.04 does not launch though works in Ubuntu 21.10.

1. Add Ubuntu PPA.

The software developer maintains an Ubuntu PPA that contains the latest packages for Ubuntu 16.04, Ubuntu 18.04, Ubuntu 20.04, and Ubuntu 21.10.

Press Ctrl+Alt+T on keyboard to open terminal. Then run the command below to add the PPA:

sudo add-apt-repository ppa:pedrocastro/ppa

Type user password (no visual feedback) when it asks and hit Enter to continue. You may skip the PPA description since it outdated.

2. Update / Install Gnome Subtitles

After adding the PPA, you may run command below one by one to install the software package:

sudo apt update
sudo apt install gnome-subtitles

Or update the package via “Software Updater” if an old version present in your system.

After installation, search for and open the app from activities overview screen and enjoy!

How to Remove Gnome Subtitles & its PPA

To remove the PPA, press Ctrl+Alt+T on keyboard to open terminal and run command:

sudo add-apt-repository --remove ppa:pedrocastro/ppa

And remove the subtitle editor via command:

sudo apt remove --autoremove gnome-subtitles
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How to Install Ksnip Screenshot Tool via PPA in Ubuntu 22.04, 20.04

Last updated: April 24, 2024

For those prefer native DEB to Flatpak and Snap packages, here’s how to install the latest ksnip screenshot tool using PPA in Ubuntu 20.04 and Ubuntu 22.04.

Ksnip is a free and open-source Qt-based screenshot tool with editing feature. I use the app regularly to add annotations (e.g., arrow, rectangle, border and drop shadow) to my images. And, it’s working good in Ubuntu on both Wayland and Xorg session.

The software is available in Ubuntu universe repositories though it’s always old. The developer team maintains the latest packages via Linux universal Snap (available in Ubuntu Software) and Flatpak that run in sandbox.

Native DEB package is also available to download at github releases page. However, the latest version (v1.9.1 so far) does not work on Ubuntu 20.04 due to outdated QT5 library. It will work on Ubuntu 21.10, though users need to manually install the missing “libqt5x11extras5” package.

To add Ubuntu 20.04 support, I uploaded the software package into this unofficial PPA along with packages for Ubuntu 21.04 and Ubuntu 21.10. Though there’s already an Ubuntu PPA so far contains only Ubuntu 20.04 package.

Install Ksnip for Ubuntu PPA:

Firstly, press Ctrl+Alt+T on keyboard to open a terminal window. When it opens, run the commands below one by one.

1. Add Ubuntu PPA.

Copy and paste the command below into terminal and hit Enter.

sudo add-apt-repository ppa:ubuntuhandbook1/ksnip

It will ask for password authentication without visual feedback. After typing user password and hitting Enter, it adds the PPA into system and updates the package cache automatically.

2. Install / Update Ksnip:

After adding the PPA, run command below to install the screenshot tool as well as dependencies:

sudo apt install ksnip

If an old DEB package exist in your system, you may also launch “Software Updater” to upgrade the app.

Uninstall Ksnip & remove PPA:

To remove ksnip, run command in terminal:

sudo apt remove --autoremove ksnip

Also remove the Ubuntu PPA by running command:

sudo add-apt-repository --remove ppa:ubuntuhandbook1/ksnip

Alternatively, remove the repo line using “Software & Updates” under “Other Software” tab.

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How to Record Your Desktop Screen in Ubuntu 21.10 Wayland with Kooha

Last updated: October 28, 2021

Looking for how to record Ubuntu desktop in Wayland session? Here’s how to do it in Ubuntu 21.10 using Kooha.

Ubuntu switched to “Wayland” session since Ubuntu 21.04. However, many apps, e.g., Kazam, Peek and vokoscreen-NG, do not support it. Some apps including OBS-Studio claim to support for Wayland, but either record blank screen or just refuse to work!

The best solution in my opinion is switch back to Xorg session. To do so, simply log out, select your user and then choose “Ubuntu on Xorg” via bottom-right gear button menu. All the apps will work once you login with Xorg.

For those sticking to the default Wayland, Kooha is one of good choices until GNOME’s “in-shell” screenshot & screencast UI is out.

Kooha screen recorder

How to Install Kooha in Ubuntu:

The simple screen recorder allows to capture the full-screen, selected app window, and a selection screen area. It saves video into WebM, MP4, GIF, and MKV formats.

The steps below is only recommended for Ubuntu 21.10 which has properly Pipewire support that is required by Kooha.

1. Setup Flatpak daemon:

The app is available to install as Flatpak package. So you have to first make sure he flatpak daemon is installed. Press Ctrl+Alt+T on keyboard to open terminal, then run command:

sudo apt install flatpak

Next, add the flathub repository by running command in terminal:

flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

2. Install Kooha screen recorder:

After that, run the command below in terminal to install the screencast app:

flatpak install flathub io.github.seadve.Kooha

Upgrade the Pipewire service:

Kooha requires pipewire server, xdg-desktop-portal, and WebRTC (Firefox). There are properly installed and enabled in Ubuntu 21.10 out-of-the-box (at least in my case). The recorder somehow refuses to work with built-in pipewire, but the updated package from this Ubuntu PPA will make it work!

1.) Firstly, press Ctrl+Alt+T to open terminal. Then run command to add the PPA:

sudo add-apt-repository ppa:pipewire-debian/pipewire-upstream

Type user password when it asks (no asterisk feedback) and hit Enter to continue.

2.) Next, either run sudo apt upgrade to upgrade all system packages or use apt command to install the audio & video server:

sudo apt install pipewire

Finally, restart your computer.

Start recording via Kooha:

In the next boot, search for and open Kooha from activities overview screen. When it opens, toggle recording system sound, microphone, mouse cursor, and finally click on “Record” button.

It will pop-up the dialog to either choose full-screen. You need to click the “Built-in display” or other monitor (if any) and then click “Share” to start recording.

Record full-screen – Need to click select display

Or, choose “Single Window” and select between all opened app windows.

Kooha record app window

When recording starts, the app window counts up with button to stop. Though it also has keyboard shortcut Ctrl+R to toggle record.

How to Uninstall Kooha:

To remove the Kooha screen recorder app, open terminal and run command:

flatpak uninstall --delete-data io.github.seadve.Kooha

And to restore the stock pipewire system service, run command to install ppa-purge and purge the Ubuntu PPA will do the trick:

sudo apt install ppa-purge && sudo ppa-purge ppa:pipewire-debian/pipewire-upstream

That’s all. Enjoy!

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Battle for Wesnoth 1.16.0 Released! How to Install in Ubuntu

Last updated: October 26, 2021

After more than 2 years of development, the new major Battle for Wesnoth 1.16.0 was finally available to download.

With Wesnoth 1.15.x development releases, it introduced new campaign: Wings of Victory, an Intermediate level Drake campaign with 11 scenarios. A new new single player or coop survival scenario, Isle of Mists is added.

The add-on World Conquest II (now called World Conquest) has translations support. And users now has ability to add translated titles and descriptions to add-ons.

It has overhauled the Dunefolk to improve balance against the six Default factions. Most of the Dunefolk faction’s units have new and-or updated animations. There is also a new unit called falconer, which is a branch in the skirmisher line.

For multiplayer, it added roll N chat command, new Information button in the lobby to show server related information and ongoing tournaments being held. It’s possible to press F1 to view in-game help in the multiplayer lobby. And, the Private Replay checkbox is available in the game create screen.

It also merged several experimental AI candidate actions (CAs). The campaign AI Controller feature is now deprecated, and has been removed from mainline campaigns.

Other changes in Battle for Wesnoth 1.16.0 include:

  • Many changes to unit stats across the board
  • Several new fauna units added.
  • Many new zombified sprites, monsters, animations, and so forth.
  • Campaign changes and fixes.
  • WML and lua API changes.
  • Require system higher than Windows 7 / macOS 10.11

How to Install Battle for Wesnoth 1.16.0 in Ubuntu Linux:

The Windows EXE, macOS dmg and source tarball are available to download at the link below:

Download Wesnoth 1.16

Linux user may play the game via Steam or itch.io. It’s also available to install separately via the universal Flatpak package in Ubuntu 20.04, Ubuntu 21.10, Ubuntu 18.04 and even older releases. And below will tell you how:

1.) Setup Flatpak daemon.

Firstly, search for and open terminal from start menu (activities overview). When it opens, run command to install the daemon:

sudo apt install flatpak

For old Ubuntu releases, e.g., Ubuntu 16.04 and Ubuntu 18.04, you need to add this PPA first.

Next, add the Flathub repository that hosts the software packages via command:

flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo

2.) Install Battle for Wesnoth as Flatpak.

After setting up the daemon, run the command below in terminal:

flatpak install flathub org.wesnoth.Wesnoth

Both Wesnoth 1.14.x and 1.16 are available in the repository. You need to type number to choose which to install, and type y to confirm.

When everything’s done successfully, launch the game from start menu (searching from activities overview) and enjoy!

Uninstall Wesnoth Flatpak:

For any reason, you may run command in terminal to remove the package:

flatpak uninstall --delete-data org.wesnoth.Wesnoth

And clear unused runtime via flatpak uninstall --unused command.

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This Extension Adds MacBook Style Notch in GNOME 40 in Ubuntu 21.10

Last updated: October 22, 2021

Sounds ridiculous, but it’s true! GNOME now has an extension to add Apple iPhone & MacBook look like but USELESS notch in your screen.

I’m not an Apple fan and don’t know why to add an ugly notch on laptop screen. Though an extension “iNotch” is available to add it in GNOME 40. It does nothing buts add a blank area in top-center, with a camera lens icon as well as tally light.

As Apple’s hardware notch does, it however covers the clock and the cursor disappears when it enters the notch. Though, the drop down calendar menu still works when you click on the area in top-bar.

Notch in Ubuntu 21.10 screen

How to Install iNotch in Ubuntu 21.10:

The extension so far supports only GNOME 40. It’s tested and works in Ubuntu 21.10, and should work on Fedora 34 and Arch Linux.

1.) First, in case you’re first time installing GNOME Extension in Ubuntu 21.10, open terminal by pressing Ctrl+Alt+T on keyboard, and run command to install the required packages:

sudo apt install chrome-gnome-shell gnome-shell-extension-prefs

Note: sudo command will ask for user password authentication while no asterisk feedback.

2.) Next, go to the extension web page and turn on the slider icon to install it:

iNotch Gnome Extension

Don’t see the toggle icon? Install browser extension via ‘click here to install browser extension‘ link and refresh the page!

NOTE: The built-in Firefox in Ubuntu 21.10 is SNAP package that does NOT support installing Gnome Extensions. Use another web browser or install Firefox via classic DEB via command:

sudo apt install firefox

After installing the extension, restart GNOME Shell (Log out and back in if you’re in default Wayland session) to apply change.

How to Remove the Notch:

Search for and open “Gnome Extensions” app from activities overview screen. Then you can turn on / off as well as remove the extension:

That’s all. Enjoy!

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How to Install Anbox to Run Android Apps in Ubuntu 20.04, Ubuntu 21.10

Last updated: December 10, 2023

 

 
ANBOX IS NO LONGER IN ACTIVE DEVELOPMENT! Try the popular Waydroid instead!

Want to run Android apps in Linux? Here’s how to do it using the Anbox container in Ubuntu 20.04 and Ubuntu 21.10.

Anbox, Anbox in a box, is a free and open-source software that runs the full Android system in a container, abstracts hardware access and integrates core system services into a GNU/Linux system.

There’s another solution “Waydroid” to do the similar things in Linux. It’s said to have better performance, though it requires Wayland session. For those stick to Xorg, here’s how to install and use Anbox.

Load Kernel modules:

Anbox requires ashmem_linux and binder_linux kernel modules.

1.) If you have the SecureBoot enabled (check via sudo mokutil --sb-state command), open terminal by pressing Ctrl+Alt+T on keyboard, and run command to sign the kernel module:

sudo kmodsign sha512 /var/lib/shim-signed/mok/MOK.priv /var/lib/shim-signed/mok/MOK.der /lib/modules/`uname -r`/kernel/drivers/staging/android/ashmem_linux.ko

2.) Next load the modules one by one via command:

sudo modprobe ashmem_linux
sudo modprobe binder_linux

3.) Finally verify the kernel modules via command:

lsmod | grep -e ashmem_linux -e binder_linux

Install Anbox:

The software is available to install via official Snap and classic DEB packages, though I recommend the snap package this time. Because, the DEB is not well supported. User needs to manually mount binder, download and load Android image, and troubleshoot other issues. And it ultimately failed to run in my case.

To install Anbox snap, press Ctrl+Alt+T to open terminal, and run command:

snap install anbox --beta --devmode

After installation, you may try to launch Anbox by searching it from activities overview screen. However, it does not launch in my case until installed the Google Play Store. If so, try running the command below in terminal to start it:

anbox launch --package=org.anbox.appmgr --component=org.anbox.appmgr.AppViewActivity

Install Google Play Store:

Anbox has a few built-in applications except Google Play Store, because Google will only permit certified devices to ship with their applications. Thankfully, there’s an installer script to automatically install it for you.

1.) Firstly, open terminal and run command to install some required libraries:

sudo apt install wget curl lzip tar unzip squashfs-tools

2.) Next, download the script via wget command:

wget https://raw.githubusercontent.com/geeks-r-us/anbox-playstore-installer/master/install-playstore.sh

3.) Add executable permission:

chmod u+x install-playstore.sh

4.) And run the script will download the package and install Play Store:

./install-playstore.sh

Now, search for and open Anbox from activities overview screen. When it opens, go to settings and grant all permissions to Google Play Store, and finally open the Play Store to install Android apps.

How to Remove Anbox:

To remove the software, simply run command in terminal:

snap remove --purge anbox

You may also remove the “anbox” and “anbox-work” folders in user’s home directory.

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GIMP 2.99.8 Released with .jxl File Support, How to Install in Ubuntu

Last updated: October 21, 2021

GIMP image editor released new development version 2.99.8 for the next 3.0 series with some great new features.

GIMP 2.99.8 introduced multiple layers support for its Clone, Heal and Perspective Clone tools. There are as well 2 new modes in particular:

When sourcing from multiple selected drawables then cloning into a single drawable, the pixel source is the composited render of source layers.
When cloning while multiple drawables are selected, each drawable clones from itself to itself, i.e. every drawable is both its source and target.

The release added support for loading and exporting JPEG-XL (.jxl) files via the libjxl library. And it supports larger-than-4GiB PSD files and loading up to 99 channels, as well as PSB files with width and height up to 300,000 pixels.

Thanks to Windows Ink support, GIMP now has more more graphics tablets or touch input devices support. Other changes in GIMP 2.99.8 include:

  • Selection cue fixed on Wayland and macOS
  • Clicking anywhere on the toolbox or on Wilber’s drop area now returns the focus to the canvas
  • Dropped the thumbnail icon feature.
  • Memory leak fixes and plug-in improvements.

How to Install GIMP 2.99.8 in Ubuntu Linux:

GIMP rolls out new nightly build of the flatpak package for Linux. After installing flatpak daemon, run the command below will install GIMP nightly build:

flatpak install --user https://nightly.gnome.org/repo/appstream/org.gimp.GIMP.flatpakref

For GIMP 2.99.8 Beta as Flatpak, see this how to install guide.

There are also third-party Ubuntu PPA for those don’t like flatpak. Though it’s not updated at the moment, check HERE.

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How to Remove Trash Icon From Left Dock Panel in Ubuntu 24.04

Last updated: May 4, 2024

This simple tutorial shows how to remove the trash icon from the dock in Ubuntu 24.04 Noble Numbat.

Different to the previous releases, Ubuntu 24.04 puts the trash icon on left dock instead of the desktop. However, I don’t use the trash icon in either location. Instead, I removes files using right-click menu options, and go to trash via file manager left sidebar.

If you also find it useless, then here’s how to remove it either via a single command or by a graphical configuration tool.


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