What is the best way to accelerate / decelerate stepper motors during a sharp change of direction in 3D printers?

Question

Algorithms

Greetings!
I am developing the kinematics of the printer, I need the speed of movement, there was a plug with how best to do acceleration / deceleration with a sharp change in direction, for example:

At the moment, in both cases, when the direction along the X or Y axis changes to the opposite, I just brake to zero, and then I accelerate, but, as you can see in the second case, you don’t have to slow down to zero, and I would say yes, you don’t need to slow down to zero. In general, the question is - what is the best way to slow down and accelerate in this case? Those. you need to find some optimal speed so that you can slow down on the red segment and then accelerate on the green one.
Of course, here the value of the angle between these lines suggests itself, but I can’t think of a formula for the dependence on the current speed, maximum acceleration.
PS acceleration and deceleration with constant acceleration.
PPS looked at the finished firmware, but in those that I found on github, they don’t bother with this moment, or I read the code extremely poorly, and I will be glad if one of the printer owners who has this implemented will tell the firmware.