CompuServe Thread

I hope this is helpful: If you are using the gameport.device to monitor the mouse, you will receive events in the form of an InputEvent structure. This contains x and y coordinates. I think these are relative to the last position i.e. delta, but no doubt someone will correct me if this is incorrect. Anyway, what you need are delta values so you can tell how far the mouse was moved and in what direction. If the values you have are absolute, delta values can be calculated from two coordinate pairs (x1,y1) = last position , (x2,y2) = this position as follows: deltax = x2 – x1 deltay = y2 – y1 With these values you can ascertain the 'slope' the mouse was moved along. This is the same as calculating the gradient: m = deltay / deltax ( = rise / run ). Movement along this line was left-to-right if deltax is positive and top-to-bottom if deltay is positive. Speed is expressed as distance/time (eg km/h), so you need values for distance and time. The distance the mouse has moved between two readings can be calculated using the deltax and deltay values as follows: ________________________ d = /(deltax)^2) + (deltay)^2 (distance = the square root of deltax squared + deltay squared) As for time, InputEvents have a TimeStamp field, so if time1 is the time of the last InputEvent, and time2 the time of this one, t = time2 – time1. If you are not getting your coordinates from InputEvents, perhaps you could read the coordinates at regular intervals (eg using the timer.device), the length of the intervals being the value you use for time. I hope that this is all clear and (more importantly) what you're after. James.