Description of the desired feature

Presently, events offer -Mi|s|t to modulate a symbols intensity, size, and transparency via their individual amplitude-time curves. This allows us to briefly magnify a symbol, change the intensity of the color, and modify transparency as the time of that event reaches the time of a frame. The fourth attribute, color, is invariant other than via a CPT and is looked up via the symbols z-value. However, the z-value is fixed for the given event time (it is an attribute of the point). Hence, there is no way to change the color of a specific symbol through time (the intensity option keeps the hue constant and only changes saturation-value). An application where this may be desirable is when we plot a trajectory as a function of time and wish the leading head of the trajectory (or 'comet' in MATLAB speak) briefly to change its color from when it first arrives and then decay back to its background color when it joins the other points that make up the tail. The solution to this would be a new directive -Mc[amp]. The presence of this option would change a point's data value from z (static) to z + dz(t), where dz(t) is another time-function like those the user can define for size, intensity, and transparency. The dz(t) would go from 0 and reach a peak of amp at the time of the event. Without -Mc, amp = 0 and dz(t) = 0 for all times. Otherwise, the event's z-value will briefly increase and via the CPT lookup it will return different colors. A simulation is shown here:

I think this feature makes most sense for symbols such as dense circles simulating a line (probably generated via events -Ardpi), and that all these points share a z of zero (basically, they have no z-value). Then, -Ccpt would simply have a color ramp from z = 0 to z = amp and colors are thus changing because z(t) of each point is changing. As default, amp would be 1 and the CPT would be expected to return different colors on the z = 0/1 interval only.

@Esteban82 is probably best positioned to comment on this, but anything goes.