TANGENTTRANSFORMFLAG

TANGENTTRANSFORMFLAG_NONE	None.
TANGENTTRANSFORMFLAG_LOCK_LENGTH	Fix the length of the tangents, only change the rotation.
TANGENTTRANSFORMFLAG_LOCK_ANGLE	Fix the angle of the tangents, only change the length.
TANGENTTRANSFORMFLAG_BREAK_SCALE	Only scale one handle (but rotate both).
TANGENTTRANSFORMFLAG_BREAK	Only modify one handle.