Add reusable dashboard background templates

[GwiezdnySzeryf]

Describe the enhancement

Right now, dashboard background settings have to be configured separately for each dashboard. If I want to use the same background image and the same options across multiple dashboards, I have to repeat the setup every time.

Use cases

• A Templates section appears in the background settings
• Users can save the current background configuration as a template
• A template could include:
  • background image
  • opacity / transparency
  • attachment (scroll / fixed)
  • size
  • position
  • repeat
  • other related background options
• When creating or editing a dashboard, users could choose an existing template instead of setting everything manually

Visual examples

Add the ability to save a dashboard background configuration as a background template and select it later from the background settings.

Field that shows when there are no background templates:

And what shows when they are avaible:

(sorry for half Polish half English screenshot!)

Anything else?

This enchancment helps with:

• faster setup for multiple dashboards
• consistent visual styling across Home Assistant
• less manual work and fewer mistakes
• easier maintenance of a single visual theme

And btw, very important for me, that should be improved someday:

• Improve background image loading and caching so the same image is not reloaded every time a different panel or dashboard is opened - but that is a bit different thing :)

[oerix]

Agreed. By the way, there's a related PR here: home-assistant/frontend#51644, which addresses one part of your request. It essentially brings setting the background globally via the UI, instead of just yaml.

[GwiezdnySzeryf]

Oh, that's great news! I'll be looking forward to this change. Thanks!