New Passdora Feature - Central instance for writing content to the display

We implemented a new feature for our PASSDORA Box. Passdora is a Raspberry Pi based system which hosts the Sequry password-manager.

• Repository

New Features (Reason)

What feature(s) did you add?

The Passdora-system has multiple scripts running in the background. These scripts need to write information to a small connected display.
When a foreground script, which needs the user's attention, outputs text to the display, the background scripts running in intervals, overwrite the foreground script's output which causes confusion.

A central instance is required which makes sure that only one script at a time is able to output text, without overwriting another scripts content. It should also take care of a uniform output formatting (e.g. centering the output text and placing the Passdora-logo in the first row). To indicate that a script is busy it should also provide functions that display a loading animation and/or a countdown. It should also be possible to clear the displays content completely or to show the default content.

Reasons

• prevent scripts from overwriting their output
• uniform output formatting
• loading animations and countdowns

How did you implement it/them?

• only one central Display instance should be usable -> Singleton: [4653c0e0]
• implement functions that allow an object to (un-)lock the display (only the object locking the display should be allowed to unlock it): [4653c0e0] [8ec98cbd]
• provide functions to output text to the display which formats the output in the same way: [4653c0e0]
• implement functions that asynchronously write a countdown or a loading animation to the display [3a4693f4] [5d53947f]
• implement a function to clear the display or display the default content [68a5ec62]

Preview

Thanks for reading
Jan, for PCSG Developers

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Posted on Utopian.io - Rewarding Open Source Contributors

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