Allow duplicating animation sprites

[nonunknown]

Implements #3942

PS:

• As I'm a new contributor, my code can be messed or not following rules, any review to the codebase is welcome!!!
• Cherrypick for 3.x

duplicate_anim.mp4

[groud]

It's not a big issue, but I wonder if it's the best to duplicate manually each property of the animation. If we add a property on SpriteFrames's animation, then this will break.
I think it would be better to modify the SpriteFrames.animations property directly instead, that should make it future-proof.

[nonunknown]

can you explain deeper please, I think I didnt got it! what I got was: create a for loop and execute each action like the animation was being created manually?

[groud]

I mean, that's fine and it works. But if we someday add a new property to an animation, then it will break because you will be missing an action to copy the new property in the new create animation. So instead, I think you could use the SpriteFrames.animations property instead.
It would be something like:

undo_redo->add_undo_property(frames, "animations", frames.animations);
// Find the animation to duplicate in the frames.animations array, put it in the duplicated_animation variable.
...
//
Array new_animations = frames.animations;
new_animations.push_back(duplicated_animation); 
undo_redo->add_do_property(frames, "animations", new_animations);

But if you think it's too complex your solution works too, I don't mind much, it might just be a bit less future-proof.

[groud]

Anyway, I will approve the PR anyway, I think it's good to merge as-is.

[KoBeWi]

SpriteFrames have a struct named Anim, so it's easy to duplicate everything at once. But this needs to be done in SpriteFrames, something like duplicate_animation(animation, new_animation) and the code

void duplicate_animation(from, to) {
animation[to] = animations[from];
}

(structs are passed by value, so this should be enough)

[nonunknown]

Related:

• AnimatedSprite{2D,3D} improvements #65609 - frame scale instead of duplicating frames (if they are consecutive)

this is not about duplicating frames, but rather, duplicate the entire animation, like creating a new one

[volokh0x]

Possible improvements:

• Wrong button icon:
  copy:
  duplicate:
• No shortcut for the new button
  The standard one is: Ctrl + D
  They work badly in this area, but that's for a separate PR, I guess
• No tooltip for the new button
  Could be provided with a button shortcut

[KoBeWi]

You should do something about this comment. Either use _animation_add() here if it's possible, or add a FIXME or something.

[KoBeWi]

Why was this closed? Are you going to open a new PR?

[nonunknown]

yes!