CODEWITHSUNDEEP
android
Salman Younas
Salman Younas

Reputation: 350

Android: Physical distance between 2 touch positions

In my app, the user will put 2 fingers on the screen. I want to calculate the distance between those 2 touch points in centimeters. Currently, I'm able to calculate the distance using x and y values provided in onTouchEvent. But that distance is not physical distance. Any suggestions?

Upvotes: 1

Views: 1380

Answers (1)

Dan Harms
Dan Harms

Reputation: 4840

Using your calculated pixel distances x and y you can use the following to return distance in inches:

public double getScreenDistance(double x1, double y1, double x2, double y2) {
    DisplayMetrics dm = new DisplayMetrics();
    getWindowManager().getDefaultDisplay().getMetrics(dm);
    double xDist = Math.pow(Math.abs(x1 - x2) / dm.xdpi, 2);
    double yDist = Math.pow(Math.abs(y1 - y2) / dm.ydpi, 2);
    return Math.sqrt(xDist + yDist);
}

Then to convert to centimeters just multiply by 2.54.

Upvotes: 1

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