Velocity vs Time data while drawing with mouse pointer

Hi everyone. I will be very grateful for any opinion on my matter:

Briefly, I need to calculate velocity over time, while drawing a circle. For instance I start to draw the circle with constant velocity and subsequently slow down. I have to draw some kind of a graph attached.

It doesn't always have to be circle but the curve i draw should have continuity and non-linearity. I can write the code for polygons using the start and finish coordinates of the straight lines with tic-toc function. However for continuous curves, i unfortunately have no idea.

All help would be so appreciated.

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/97563-how-do-i-continuously-read-the-mouse-position-as-the-mouse-is-moving-without-a-click-event

This does not record the time of the events, but you can ask for the current time when the event is serviced; it will be a bit inaccurate though.

You might also wish to look at http://uk.mathworks.com/matlabcentral/answers/259577-how-to-record-mouse-coordinates-in-fixed-interval-like-0-01ms

Once you have the points and the time, you can calculate point-to-point distance using Euclidean distance calculations. That will not give you velocity as you need at least one further point in order to calculate relative direction. I notice, however, that in your question you are not plotting velocity, you are plotting instantaneous speed. (Remember: velocity is a vector, a direction and magnitude pair, not just magnitude.)

[Adelante]

Dear Walter Roberson,

Thank you for your rapid reply. The graph was an example to simplify the question, I actually need to record coordinates for very short time interval, therefore your second suggestion would work, I suppose.

Regards