Re: NSStepper Action Problem

[David Chisnall]

The simplest fix may be to modify the stepper to use a double for the value.  
Given that steppers are commonly used with fixed increments that make sense in 
base 10, a better solution might be to modify it to store a base value and a 
number of applications of the increment, so that in your case it would be 
stored as 1000 + 0.1 * 100000… (i.e. base + step*steps), with the calculation 
performed on update.  If the user enters a new value without using the stepper 
buttons, then set this to the new base.

David

> On 21 Sep 2015, at 12:24, Riccardo Mottola <riccardo.mottola@libero.it> wrote:
> 
> Hi,
> 
> I noticed that when I define a NSStepper with a wide range (e.g. 1000) and a 
> float increment of 0.1, after a dozen of "increments" things go adrift with a 
> rounding error.. eg 5.10000001 instead of 5.1
> 
> I have tested on Mac 10.5 and PPC and get different errors (e.g. 5.099999998) 
> but the problem is the same, it is nto a GS bug, but probably a problem on 
> how the internals are handled.
> 
> What solution is possible? I have both a textfield and a stepper that should 
> interact.
> I was thinking of just getting the "action" of the Stepper and then keeping a 
> variable of mine with, eventually a different precision or that does other 
> rounding tricks.
> However, how can I know if increment or decrement have been clicked? Is there 
> a trick? can I reliably put an action on the two arrows but action was 
> desired by the user?
> 
> A really crude workaround would be to use just a very high number in the 
> stepper, integer values and not-wrapping and thus compating old and new value 
> to know if "+" or "-" were the choice, but looks pretty much a hack.
> 
> Thanks - Riccardo
> 
> 
> 
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