# How to calculate the length of a touch/finger drawn line

Discussion in 'iOS Programming' started by Bayan, Jun 12, 2012.

1. ### Bayan macrumors newbie

Joined:
Apr 13, 2012
#1
I'm writing a code in which I ask the user to mark dots on a picture by touching the screen then I link each two to create a straight line..
What I want to do now is to calculate/measure the length of each line, is there a method to do that? or should I do it myself? if so, can someone give me a basic idea of how such method works?

2. ### robbieduncan Moderator emeritus

Joined:
Jul 24, 2002
Location:
London
3. , Jun 12, 2012
Last edited: Jun 12, 2012

### Ides macrumors member

Joined:
Mar 27, 2012
#3
Distance

It's the pythagorean theorem:

Code:
` float distance = sqrtf( powf(x1-x2, 2) + powf(y1-y2, 2) ); `
where (x1, y1) and (x2, y2) are the two points that are connected.

Edit: Thanks for the tip, chown33

4. ### chown33 macrumors 604

Joined:
Aug 9, 2009
Location:
on the Western Slopes, with E. A. Poe
#4
Bug.