use the dedicated xycenter property
avoid setting the previous end-interpolation values before starting the new one, to avoid a jump if the player advances too quickly (also shortens the code)
add subpixel True, even though it doesn't seem very effective
prepare improvement in next renpy version
(cherry picked from commit 8b6627f588)
* Improved and posed "Give me a handy".
* Posed "Dance for me".
* Adjusted some of Hermione's nickname requirements to align with her attitude.
* Minor writing improvements.
* Fixed CGController incompatibility with Ren'py automatic image definition system causing issues with Cho handjob/blowjob CG scenes
* Converted introductory CGs into show statements
* Converted quidditch CGs into show statements
* Converted potions CGs into show statements
* Reviewed and removed redundant CG code
* Fixed miss-named Cho "crooked_smile" expression.
* Fixed Tonks' "Morph" effect being delayed in some instances.
* Fixed some calls showing multiple ">".
* Removed bld and blktone in some places where it's replaced by inner thought and narrator character.
* Minor writing fixes.
* Minor character positioning fixes.
