[sugar] Best way to display scale ?

[Edward Cherlin]

On Sun, Jun 29, 2008 at 10:17 PM, Arjun Sarwal <arjun at laptop.org> wrote:
> I was wondering if anyone could please suggest some good ways of
> writing 'scale' within Measure Activity.

I suggest finding some place with several different digital
oscilloscopes, and checking out their controls. Or you could get the
manuals online. Show Measure to some people who use these tools for a
living.

> When a user sees a signal, I want him to be able to measure/view the
> signal and compare it with other signals perhaps at different points
> of time. For this the process that I see should happen is that the
> user measures the divisions from the center line and multiplies it
> with the scale.
>
> There are a horizontal and vertical set of lines in the background
> that form a grid.
>
> Currently I am displaying the scale as
> Scale::
> X Axis: 1 division = x seconds
> Y Axis: 1 division = y volts
>
> The problem is that x and y are very small values. So it eventually
> comes out as something
> X Axis: 1 division =  0.125 seconds
> Would 10 divisions = 1.25 seconds be any better ?
>
> Alternatively, should I change the sampling rate and distance between
> the grid lines to conform to something that gives whole numbers on the
> right side.

This should be the user's choice, depending on the application.

> For example
> X Axis: 5 divisions = 1 second
>
> etc.
>
>
> Also, would a simple multiplication based text box be useful ? That
> allows one to multiply the number of divisions by the scale to get the
> final value that one is looking to measure ?

Yes. It is fairly common to offer a slider for gross settings, and a
text box both for display and for precise setting.

> Thanks,
> Arjun
>
>
>
> --
> Arjun Sarwal
> http://dev.laptop.org/~arjs
> http://youtube.com/watch?v=SwcSEcfR464
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>



-- 
Edward Cherlin
End Poverty at a Profit by teaching children business
http://www.EarthTreasury.org/
"The best way to predict the future is to invent it."--Alan Kay