Why the iPhone Timer app displays a fake time

#1

Post by _antix » Mon, Dec 28, 2020, 9:56 PM UTC

Why the iPhone Timer app displays a fake time
lukashermann.dev

Re: Why the iPhone Timer app displays a fake time

#2

Post by jewel » Mon, Dec 28, 2020, 10:17 PM UTC

From what I can see, the iPhone timer app is rounding to the nearest second. For positive numbers that can be accomplished with either Math.round(t) or Math.floor(t+0.5).

Re: Why the iPhone Timer app displays a fake time

#3

Post by tantalor » Mon, Dec 28, 2020, 10:22 PM UTC

Answer: it rounds to the nearest second.

Re: Why the iPhone Timer app displays a fake time

#4

Post by dan-robertson » Mon, Dec 28, 2020, 10:22 PM UTC

... or they just round the time to the nearest second instead of taking the floor

Re: Why the iPhone Timer app displays a fake time

#5

Post by nemetroid » Mon, Dec 28, 2020, 10:23 PM UTC

I think "rounds to closest" is a simpler way to put it than "adds 500 ms before truncating".

Re: Why the iPhone Timer app displays a fake time

#6

Post by sokoloff » Mon, Dec 28, 2020, 10:24 PM UTC

> Milliseconds are converted to seconds by dividing by 1000 and rounding down like so

It seems like the simpler explanation is that the iPhone actually rounds to the closest integer rather than rounding down. (Whether they do this invisibly by adding 0.5s and rounding down is an implementation detail.)

Re: Why the iPhone Timer app displays a fake time

#7

Post by mgkimsal » Mon, Dec 28, 2020, 10:29 PM UTC

iOS 9 and below, IIRC, the timer app stopwatch screen would really flake out after 1000 hours. By 'flake out' I mean it would slow down the updating a lot - screen got somewhat jerky and slow to respond.

From iOS 10 onwards, 1000+ hours doesn't seem to phase it at all - no slow downs.

source: 1490:43:24 ago I started my timer, but I can't remember why now.

Re: Why the iPhone Timer app displays a fake time

#8

Post by arthurofbabylon » Mon, Dec 28, 2020, 10:30 PM UTC

While building a tea timer I naturally stumbled into this exact solution.

Edit: sencha.app for those curious

Re: Why the iPhone Timer app displays a fake time

#9

Post by [deleted] » Mon, Dec 28, 2020, 10:31 PM UTC

[deleted]

Re: Why the iPhone Timer app displays a fake time

#10

Post by mey » Mon, Dec 28, 2020, 10:32 PM UTC

Round half up is the typical expectation for most people in rounding to the nearest whole value.

It isn't displaying a "fake" time, it's rounding.

https://en.wikipedia.org/wiki/Rounding#Round_half_up

Edit: Note, Round Half Up != Round half away from zero but that isn't important for this scenario :D