Android Question B4xview SetRotationAnimated optimal rotation

[Angel Maza]

When there are more than 180 degrees of relative rotation, or going from 350 to 10, the displacement goes allways from angle1 to angle2, avoiding crossing 0.

Best regards.
Angel

 

[Erel]

You never want to cross 0 degrees?

 

[Angel Maza]

The problem is when I cross 0 degrees (from 350 to 10, or 10 to 350 by example), the rotation is done without crossing 0, doing a large rotation (very ugly!!).

Thanks.
Best regards.

 

[Erel]

I understand.

Sub RotateViewShortestArc (v As B4XView, Duration As Int, Target As Int)
   Dim Rotation As Int = v.Rotation
   Dim dx As Int = (Target - Rotation) Mod 360
   If dx > 180 Then
       dx = -(360 - dx)
   Else if dx < -180 Then
       dx = 360 + dx
   End If
   v.SetRotationAnimated(Duration, Rotation + dx)
End Sub

 

[Angel Maza]

Works perfect!!. Thanks a lot.

I attach the code with degrees in a float variable, so it's consistent with the SetRotationAnimated and also doesn't do small steps.

Sub RotateViewShortestArc (v As B4XView, Duration As Int, Target As Float)
    Dim Rotation As Float = v.Rotation
    Dim dx As Float = (Target - Rotation) Mod 360
    If dx > 180 Then
        dx = -(360 - dx)
    Else if dx < -180 Then
        dx = 360 + dx
    End If
    v.SetRotationAnimated(Duration, Rotation + dx)
End Sub

 

[Erel]

I attach the code with degrees in a float variable, so it's consistent with the SetRotationAnimated and also doesn't do small steps.

This is fine. The reason that I used ints is to make it compatible with B4i. Mod in B4i expects two ints (you can use Bit.FMod if you want to use floats).