pyqtgraph.
CurveArrow
Provides an arrow that points to any specific sample on a PlotCurveItem. Provides properties that can be animated.
__init__
Position can be set either as an index referring to the sample number or the position 0.0 - 1.0 If rotate is True, then the item rotates to match the tangent of the curve.
CurvePoint
GridItem