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List:       kde-usability
Subject:    Re: Few miscellaneous suggestions
From:       James Richard Tyrer <tyrerj () acm ! org>
Date:       2004-07-25 8:12:41
Message-ID: 41036B79.6080102 () acm ! org
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Brad Hards wrote:
> On Sun, 25 Jul 2004 05:53 am, James Richard Tyrer wrote:
> 
>> A simple metric would be to decompose it into three matrices one for each 
>> color, take the two dimensional FFT of each one.  You can obtain the 
>> digital equivalent to a volume under each FFT by a scalar addition of all 
>> of the entries in each FFT result matrix.  So that icons of different sizes
>>  can be compared, you actually want the average so you should normalize the
>>  sum by dividing it by the number of scalers summed (the area of the icon 
>> in square pixels).  Then take the square root of the sum of the squares of 
>> these three (normalized) scalar sums and you will have a very rough metric 
>> of the information contained in an icon. Note that for a first example, it 
>> should be obvious that a gray square would have a value of 0 indicating 
>> that it had no information.
> 
> You are still missing my point that the useability of a desktop is not only a
>  function of the information in each icon.

No, it is just that I am only talking about the viability of icons and widgets.
  Clearly, this is only a necessary condition, not a sufficient condition for
desktop usability.

> The screen doesn't have equal importance at all areas - you'd need to apply 
> some form of weighting function.

???
> 
> Even at the icon level, you're still incorrect in assuming that something 
> that has a wide range of frequencies in each colour is going to be more 
> useable than something that has less.

Since I didn't say that, I wouldn't be assuming it would I.

> That would mean that the more garish an icon, the more useable it is!

No, actually, it would be the other way around.  Black & White icons are 
actually more visible and would have higher scores.  Perhaps you don't 
understand the math well enough to visualize it.  But, what I am saying is that 
an icon with one predominant color and lacking contrast has less information 
than one with proper contrast, a balance of colors, and some black lines.  If 
you actually do the math, you will see that I am correct.

> I think that grey'd out icons actually convey information to the user, but by
>  the frequency measure, an icon set without grey'd out icons would be 
> considered more useable.

Nobody would argue that graying out icons is not a proper part of the desktop.
But, nobody would argue that grayed out icons were easy to see either.

> Further, why do you think that root-sum-squares of the per-colour scalar sums
>  is meaningful in general?

Because it is the proper formula to add orthogonal vectors.

> We know that men and women perceive colour differently.

No, we don't know that.  We know that there is a difference in the way that the
average man and the average woman perceive color.  This is the same as saying
that the average man is taller than the average woman.  But, this is just a
measure of central tendency.  There are many men that are shorter than many women.

> So I don't seen even a meaningful measure of how useful an icon is (even with
>  some opinion based weighting of a FFT of a YUV representation).
> 
I am ONLY talking about how visible various styles of icons, window decorations,
and widgets are.  I am making the obvious assumption that if they are hard to
see that they are less usable, and if they are easier to see that they more
usable.  I see no reason to think that the results would be significantly
different if you used YUV instead of RGB except that you would have to account
for the fact that the Y, U, & V are not orthogonal.

Remember that I said, a *rough* metric as an example.  Clearly weighing factors
would improve it.  Perhaps it would be valid to use the Y weighing factors when 
taking the geometric sum of R, G, & B since the eye is more sensitive to green. 
  But this would just help make my case that those damn blue icons are hard to see.
> 
> Real life test results of various theme options, using the same test tasks 
> (with the same apps, same displays, statistically significant test 
> population, etc) is objective. Anything less is opinion.

So, you deny the existence of information theory, and all knowledge of the
physiology of human vision, and state that anything based on scientific knowledge
is just opinion.  However, on the other hand, you would place your faith 100% in
subjective tests that were subject to numerous confounding factors.

--
JRT
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