For people with dyslexia, scopic sensitivity, and related conditions, GNOME has an extension to adds a a translucent colored overlay over your desktop that may help.

It’s ‘ColorTint’ that adds an indicator applet in system tray area. User may click the drop down menu options to enable/disable the overlay, change the color via RGB slider bar, and adjust transparency via the Alpha slider.

How to Install ColorTint:

The extension works on GNOME 40 (Ubuntu 21.10) and GNOME 3.32 (Ubuntu 18.04), however lacks Ubuntu 20.04 support

1.) Firstly, press Ctrl+Alt+T on keyboard to open terminal. When it opens, run command to install the ‘chrome-gnome-shell’ package to enable ability to install Gnome Extension via web broser:

sudo apt install chrome-gnome-shell

2.) Next, go to the link below and turn on the slider icon to install the extension:

Don’t see the toggle icon? Try installing the browser extension via the link in the page and then refresh it.

NOTE: The pre-installed Firefox in Ubuntu 21.10 is a Snap package that so far does not support for installing Gnome Extensions, use another browser or install Firefox as native Deb package via command:

sudo apt install firefox

And, to manage all installed extensions, install ‘Gnome Extensions‘ app either from Ubuntu Software or by running command in terminal:

sudo apt install gnome-shell-extension-prefs

That’s all. Enjoy!

Designers and website developers may sometimes need to check WCAG color contrast to make web content more accessible to people with disabilities.

Without using an online website each time, Linux has a stylish GTK4 app “Contrast” which allows to check whether the contrast between two colors meet the WCAG requirements.

The app has a simple user interface that displays one color as background and another as font color of the text. By clicking on the double arrow icon between two color codes, it reverses background color as text font and font color as background.

User may select color either by clicking on the circle icon before hex code (e.g., #F3F6F9), or by using the color picker tool after the code.

Contrast Select Color

The app will display color contrast result with text, such as “Awesome, Pretty Good, Not Bad, and Nope, along with short description tells whether the color combination will properly work.

It also displays a score bar tells that if the color contrast meets the 3 WCAG Levels: A, AA and AAA. And, a contrast ratio is displayed at the bottom.

Reversed colors

How to Install Contrast in Ubuntu Linux:

As a GTK4 app, Contrast so far only available to install as Flatpak which runs in sandbox.

1. Firstly, press Ctrl+Alt+T on keyboard and open terminal. When it opens, run command to install the Flatpak daemon:

sudo apt install flatpak

For Ubuntu 18.04 and Ubuntu 16.04, the flatpak PPA is required to get the package.

2. Next, run command to install the WCAG color contrast app:

flatpak install https://dl.flathub.org/repo/appstream/org.gnome.design.Contrast.flatpakref

Note: If you’re first time installing a Gnome app as Flatpak, it will install the required GNOME 41 platform as shared runtime libraries, which take hundreds of megabytes disk space.

Once installed, search for and open the app from activities overview screen.

How to Remove Contrast Flatpak app:

To remove the software package, press Ctrl+Alt+T and run command in terminal:

flatpak uninstall --delete-data org.gnome.design.Contrast

And use flatpak uninstall --unused command may remove useless run-times if any.

The beautiful Debian based Linux distribution Deepin 20.3 was released. Features Kernel 5.15, new features and optimizations for its core apps.

The stable Linux kernel has been updated to v5.15 with better support for Intel 12th Gen processors and NTFS file systems. Though the iso image by default boots with 5.10 LTS kernel, user have to select the new kernel to install from ‘Advanced’ menu in Grub boot-loader.

The Deepin screen capture can now take scrolling screenshots via the ‘Scrollshot‘ option. After selecting an app window to capture, a ‘Scrollshot’ option is available in tool-bar. By clicking on it, you may scroll the page to take a continuous screenshot with real-time preview. Also OCR is supported in this mode to extract text from image.

Deepin Scrollshot

In the extended mode, you may now set how to display the Dock on multiple displays via its right-click context menu.

Other changes in Deepin 20.3 include:

  • Video search, preview, and management in the Album app.
  • Add support for 2K hard decoding of OLAND chips.
  • Add shortcut for Global Search, which also supports searching markdown files.
  • Add the print entrance in Document Viewer.
  • Improve the file manager, movie, music, as well as other core apps.

Get Deepin 20.3

Compare to other Linux, Deepin somehow requires too much disk space now: 64 GB at least and 128 GB recommended. And it does not provide a live system to try out before installing into disk.

To get it, go to the link button above. And see the release note at this page.

Free and open-source clone of Paint.Net 3.0, Pinta, released version 1.7.1 a few days ago with improvements and bug-fixes.

The release is the final version based on GTK2, as the GTK3 / .NET 6 version is nearly ready!

Pinta 1.7.1 is a small release with minor new features to improve user experience. For image with large resolution (or zoomed in), you may use mouse wheel to scroll up / down. Now by holding Shift + mouse wheel, the canvas can be scrolled horizontally.

Same to GIMP, user may now press X to exchange background and foreground palette colors quickly in Pinta since v1.7.1. And, zooming in and out can now be done without pressing the Ctrl key

The release also improved the pop-up dialog when you trying to open an unsupported file format. The file open dialog by default shows only supported images, including ani, png, bmp, jpg, gif, icns, ico, jpeg, ora, pnm, qtif, svg, tga, tif, tiff, xbm, xpm. If you chose show “All files” and selected an unsupported file, it will prompt that file not support and show you all supported file formats.

Error when opening unsupported file and display all supported formats

Other changes in Pinta 1.7.1 include:

  • Use arrow keys to move per pixel in Move Selected Pixels and Move Selection tools
  • Use Shift to constrain to a uniform scale when scaling using Move Selected Pixels tool
  • Text in ‘About’ is selectable to copy version for use to report bugs.
  • Improve handling of memory allocation failures for large images
  • And various bug-fixes.

How to Install Pinta 1.7.1 in Ubuntu Linux:

Option 1: Install Pinta via Snap:

The app is easy to install in Ubuntu using the Snap package, by simply searching for and installing from Ubuntu Software (Snap Store):

Pinta Snap app in Ubuntu Software.

Option 2: Install Pinta via Ubuntu PPA:

NOTE: the PPA package crashes randomly due to outdated Mono library in Ubuntu. It’s highly to upgrade mono library if you want to install Pinta in native deb package.

The app has an official Ubuntu ppa that contains the latest packages for Ubuntu 18.04, Ubuntu 20.04, Ubuntu 21.04, and Ubuntu 21.10 so far.

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

sudo add-apt-repository ppa:pinta-maintainers/pinta-stable

Secondly, run command to update system cache if you’re still running Ubuntu 18.04:

sudo apt update

Finally, install Pinta via command:

sudo apt install pinta

Or, upgrade the app if an old version present in your system using Software Updater:

In addition, Pinta is also available to install as Flatpak package. Check in Flathub if you’re interested in it.

How to Remove Pinta from Ubuntu:

To remove Pinta installed via PPA package, run command in terminal (Ctrl+Alt+T):

sudo apt remove --autoremove pinta

And remove the PPA either via ‘Software & Updates‘ utility under Other Software tab, or by running command:

sudo add-apt-repository --remove ppa:pinta-maintainers/pinta-stable

For Pinta snap package, remove it either via Ubuntu Software or by using command:

snap remove --purge pinta

More and more apps today publish Linux packages as Flatpak. Though the run-time libraries take hundreds of megabytes disk space, some apps are really good and useful.

If you have some apps installed as Flatpak in Ubuntu or other Linux like me, then Flatseal may be useful to protect your privacy by managing permissions in per app basis.

Flatseal is a stylish GNOME app that displays all the installed Flatpak apps in the left pane. By selecting an app, it displays the basic information as well as permissions with toggle buttons. The app has an adaptive UI that works great on small screen size, e.g., Linux Phone.

With Flatseal, you may configure following permissions for your Flatpak apps:

  • Network access.
  • Sound server access.
  • GPU acceleration to reduce CPU usage.
  • System file or user file access.
  • Send notifications.
  • System bus and session bus.
  • Print system, smart card, webcam, bluetooth access, and more.

Note: some options (e.g., inter-process communications and X11/Wayland windowing system) may be required for the app to work. Switching those options off may cause function issues, though you may reset them easily afterwards.

As some options are not easy to understand, you may press F1 on keyboard to bring up the ‘help‘ window, which contains the descriptions for each toggle option. And, if permissions are removed and somehow no longer possible to reset, run command below (press Ctrl+Alt+T in Ubuntu to open terminal) to clear the changes and restart Flatseal.

rm ~/.local/share/flatpak/overrides/com.github.tchx84.Flatseal

How to install Flatseal in Ubuntu Linux:

The app itself is available to install as Flatpak package. To try it out, you must have already installed some apps as Flatpak. If not, you need to install the daemon first. For Ubuntu/Debian based systems, simply open terminal and run command:

sudo apt install flatpak

Next, install the Flatseal by running command in terminal:

flatpak install https://dl.flathub.org/repo/appstream/com.github.tchx84.Flatseal.flatpakref

Or use the command below if you already added the Flathub repository:

flatpak install flathub com.github.tchx84.Flatseal

As you see in picture, the app itself is about 683 KB, while run-time libraries take more than 700 MB. The run-times (e.g., GNOME platform) are shared libraries though that can be used for other Flatpak apps.

Uninstall Flatseal:

To remove the app, simply run command in terminal:

flatpak uninstall --delete-data com.github.tchx84.Flatseal

Note: removing Flatseal won’t reset the permission changes you made for the flatpak apps. You have to manually clear the config files under “~/.local/share/flatpak/overrides” directory to restore them.