problem with flip of group in v6

[ShaMan123]

Discussed in #8740

^{Originally posted by thipm196 February 26, 2023}
The controls are working wrong when flipping an element inside a flipped group.
https://codesandbox.io/s/fabricjs-flip-inside-group-npz4xs

[ShaMan123]

#8745 is a first step to tackle this but for now it seems to me a won't fix

[asturur]

I will give it a stab to it too, with fresh eyes.
Even if i think is a low prio and a super edge case.

But first i ll follow the priority things to get 6.0 out of the door

[ShaMan123]

OK I found the cause and I managed to produce a fix that can't be accepted since it doesn't respect stroke.

Gist

positionHandler receives dim and finalMatrix. finalMatrix doesn't account for flipping of ancestors in the form of rotation, while dim account for complete flipping.
When calling positionHandler:

• dim is transformed by finalMatrix, meaning we apply flipping twice. Once when we calculated the transformed dimensions and again with the finalMatrix rotation value. That is why it was off by 180deg.
• offset is transformed by finalMatrix. The rotation value doesn't include own flipping values. That is why the offset was in the wrong direction