Calculating speed of mouse

[jondmml]

Hi, I have a question related to calculating the speed at which the mouse is moving right before it is released. I know that if I can find the distance the mouse moves in a certain period of time (by finding the position of the mouse at one point in time and then subtracting from the distance when it is released) I should be able to calculate it. However, I do not know how I can easily keep track of this period of time since I do not know when the user will be releasing his mouse. I will be using mousepressed, mousedragged and mouselistener methods for my canvas so I potentially have access to the mouse's location at any time. If anyone has any ideas as to how I could implement this, it would help me quite a bit.

Thanks again

[HeavenAgain]

code:

// Get current time     long start = System.currentTimeMillis();         // Do something ...         // Get elapsed time in milliseconds     long elapsedTimeMillis = System.currentTimeMillis()-start;         // Get elapsed time in seconds     float elapsedTimeSec = elapsedTimeMillis/1000F;

after you get time, nd you already have the distance, after that is just simple physics

[jondmml]

Yes, I had considered doing it similar to this, however, I am using a mousedragged listener and a mousreleased listener, and since mousdragged is constantly being called, when I determine the end time in mousreleased, it is always equal to the last time I recorded in mousedragged, so my time difference is zero.

[HeavenAgain]

oh, i see, in that case, ummmmm
did you put the starting time in the mousedragged listener, and ending time in the mousereleased listener? uhhhh

[jondmml]

Yes I did, here is a snippet of the code so that you can take a look


Code from mouseDragged listener

code:

if (movingObject) {                 // sets the centre of the currently moving circle to the location of the mouse                 circles.get(circles.size()-1).setXCentre(evt.getX());                                          circles.get(circles.size()-1).setYCentre(evt.getY());                 //   if (System.currentTimeMillis() - currentTime > 20) {                 // get current time                 currentTime = System.currentTimeMillis();                 // get current x and y coordinates of mouse                 xCurCentre = circles.get(circles.size()-1).getXCentre();                 yCurCentre = circles.get(circles.size()-1).getYCentre();                 //System.exit(0);                 // }         }

Code from mouseReleased listener

code:

if (movingObject) {             // find time difference             long time = (System.currentTimeMillis()- currentTime);             // stop moving circle             movingObject = false;              // set velocity of moving circle using previous velocity of mouse             circles.get(circles.size()-1).setXVelocity((circles.get(circles.size()-1).getXCentre()-xCurCentre)/time);             circles.get(circles.size()-1).setYVelocity((circles.get(circles.size()-1).getYCentre()-yCurCentre)/time);              // debugging code             System.out.println("x: "+(circles.get(circles.size()-1).getXCentre()-xCurCentre));             System.out.println("y: "+(circles.get(circles.size()-1).getYCentre()-yCurCentre));             System.out.println("time: "+time+ " curre:"+System.currentTimeMillis());             System.exit(1);         }

My debugging output usually looks something like:

Quote:

x: 0.0
y: 0.0
time: 16 curre:1197735772275

EDIT: the commented if condition was an idea of mine where I would only record the time and location after a certain time interval. However, this too did not work reliably.

[OneOffDriveByPoster]

Maybe you can have mouseDragged() keep the info for the last two times it was called. So when mouseDragged() is called, some "curPosAndTime" becomes "prevPosAndTime" and "curPosAndTime" gets set with new info. mouseReleased() will just read the info.