Add offset propriety for each animation on the Spriteframes resource, used on AnimatedSprite2D node

[sanlor]

Describe the project you are working on

A Godot port of a GameMaker game (RPG), with many different animations for each AnimatedSprite2D.

Describe the problem or limitation you are having in your project

This game uses a very large amount of animations for each character. Thing is, some animations uses a different center / origin point or different dimensions from others animations.

Here is an example of a character laying on the ground and one standing up. both cant have the same center point due to the different image dimensions.

Here is an extreme example of a character getting shot and falling:

The same issue happens with others spritesheet that can be found on the net:
https://www.spriters-resource.com/fullview/16912/
In this case, the character moving left and right have different center points from the character moving forward.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

For each animation on the SpriteFrame resource, having a "offset override" or something that applies an offset to the image ignoring the "offset" propriety on the AnimatedSprite2D node.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

Like the "FPS" propriety, have an Offset propriety to the Spriteframes resource.

If this enhancement will not be used often, can it be worked around with a few lines of script?

This issue has many workarounds, but many involves converting the spritesheet or mass changes on the game´s code.

Is there a reason why this should be core and not an add-on in the asset library?

There are many free resources and animations that expects that the offset / center can be changes per spritesheet / animation.
Resources made for Gamemaker could not be easily used without asset changes or special game code to take the different origin point into account.