Making a Gnome Background Slide Show

“Background Slide Show”. That is what Gnome uses in code to refer to its time-based dynamic backgrounds feature.

Instead of having a static background, a Gnome Background Slide Show allows you to have a set of images that Gnome selects from based on the current time of the day. You can also configure the dynamic background to use transitions when changing from one picture to the next.

There are tools that you can install to build dynamic backgrounds. But I wanted to read some documentation and figure out how it works.

I recalled seeing something about writing an XML file to describe the slide show.

Making a Gnome Background Slide Show

After jumping through some hoops, I was able to find a C file under the gnome-desktop project that dealt with dynamic backgrounds.

A simple two-image dynamic background can be defined as follows:

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<background>
  <starttime>
    <year>2023</year>
    <month>9</month>
    <day>7</day>
    <hour>6</hour>
    <minute>0</minute>
    <second>0</second>
  </starttime>

  <static>
    <file>/home/hjr265/Pictures/Backgrounds/patterns-day.jpg</file>
    <duration>36000.0</duration>
  </static>

  <transition type="overlay">
    <duration>7200.0</duration>
    <from>/home/hjr265/Pictures/Backgrounds/patterns-day.jpg</from>
    <to>/home/hjr265/Pictures/Backgrounds/patterns-night.jpg</to>
  </transition>

  <static>
    <file>/home/hjr265/Pictures/Backgrounds/patterns-night.jpg</file>
    <duration>36000.0</duration>
  </static>

  <transition type="overlay">
    <duration>7200.0</duration>
    <from>/home/hjr265/Pictures/Backgrounds/patterns-night.jpg</from>
    <to>/home/hjr265/Pictures/Backgrounds/patterns-day.jpg</to>
  </transition>
</background>

This XML sets the background to day.jpg for 10 hours and then gradually transitions from day.jpg to night.jpg over 2 hours. The night.jpg stays for 10 hours and then gradually transitions back to day.jpg over 2 hours. After that, the slide show starts all over again.

You can, of course, add more images to the set.

Using a Gnome Background Slide Show

To use a Gnome Background Slide Show, you have two options:

Either, use the Gnome Tweaks and select the XML as your background.

Or, add an entry to the ~/.local/share/gnome-background-properties directory so that you can pick this dynamic background from Gnome Settings.

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<wallpapers>
  <wallpaper deleted="false">
    <name>Patterns</name>
    <filename>/home/hjr265/Pictures/Backgrounds/patterns-dynamic.xml</filename>
    <options>zoom</options>
  </wallpaper>
</wallpapers>

The filename element should contain the path to the XML defining the dynamic background.

Side Note

The open-source community is thriving. Undoubtedly, that is all thanks to the people contributing to this community.

Perhaps emphasis on writing more documentation could be the next logical step.

This post is 37th of my #100DaysToOffload challenge. Want to get involved? Find out more at 100daystooffload.com.