ubuntu-phone team mailing list archive

[Calum K Pringle <calum.pringle@xxxxxxxxxxxxx>]

Hi everyone hope you’ve had a nice weekend!

Last week was a bit mad because of UDS, but we have honestly been thinking about Calculators a lot of the time too! Dalius raised a good point about the ‘equals’ feature, and as it came up on the blog too, we’ve cc’d the list in our reply.

Why have an equals button?

We don't calculate automatically as it would muddy the order of operations. 1 + 2 x 4 = 9. However, calculating automatically would result in 1 + 2 = 3 X 4 = 12. 

Secondly, when two things happen at the same time on screen - displaying typed entry AND answer - it can be confusing.

It is common to find yourself pressing the equals button for confirmation at the end of a calculation which also complements the physical metaphor we have used for the calculation history. We have also found it to be a common behaviour of simple calculators that pressing equals multiple times would repeat the previous operation.

Why do we need +/ - key

From last weeks discussion (copy below) we realised that it was not expected for subtract to be the entry point for making a negative number. For that reason, and to fit in the layout, we opted to add this button. 

If we follow our own direction, prioritising things like daily budgeting etc, minus might well be very useful! (Stay out of that overdraft!!!)

Cheers,

Calum

-------- Original Message --------
Subject:	[Ubuntu-touch-coreapps] [Calculator] Numpad layout design
Date:	Sat, 9 Mar 2013 14:57:42 +0200
From:	Dalius <dalius@xxxxxxxxxx>
To:	ubuntu-touch-coreapps@xxxxxxxxxxxxxxxxxxx


Hi,

Here is what design team proposes for simple calculator:
http://design.canonical.com/wp-content/uploads/numpad.png

Here is our current implementation:
http://i.imgur.com/F2DqWdL.png

Design team's proposal has two unnecessary buttons:

= - as I don't see any reason why calculations can't be automatic

± - it is simple calculator why we need negative numbers at all?

Any other opinions?

Regards,
Dalius




Calum Pringle
Interaction Designer

Canonical Design Team
m: 0773 9317055
e: calum.pringle@xxxxxxxxxxxxx