A new value for background_image_layout to scale the background image…

… while preserving its aspect ratio.

Also have centered images work even for images larger than the window size
Fixes #6458

docs/changelog.rst

@@ -38,6 +38,8 @@ Detailed list of changes
 0.29.1 [future]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+- A new value for :opt:`background_image_layout` to scale the background image while preserving its aspect ratio. Also have centered images work even for images larger than the window size (:pull:`6458`)
+
 - macOS: Fix a regression that caused rendering to hang when transitioning to full screen with :opt:`macos_colorspace` set to ``default`` (:iss:`6435`)
 
 - macOS: Fix a regression causing *burn-in* of text when resizing semi-transparent OS windows (:iss:`6439`)

kitty/options/definition.py

@@ -1395,7 +1395,9 @@
     ctype='bglayout',
     long_text='''
 Whether to tile, scale or clamp the background image. The value can be one of
-:code:`tiled`, :code:`mirror-tiled`, :code:`scaled`, :code:`clamped` or :code:`centered`.
+:code:`tiled`, :code:`mirror-tiled`, :code:`scaled`, :code:`clamped`, :code:`centered`
+or :code:`cscaled`. The :code:`scaled` and :code:`cscaled` values scale the image to the
+window size, with :code:`cscaled` preserving the image aspect ratio.
 '''
     )