Jens Scheidtmann wrote:
> > > So you want to have them as visually distinct as possible.
> > Hell no :-)! I'd like them to be different shades, to aid in visually
> > discerning matched strings. But I'd like to have different meanings
> > for different colours. Keeping the explanation as simple as "red
> > means removed, yellow means added, green is the same (might have been
> > moved around)" appeals to me.
> Yes, good point, but ...
> > Can you provide any good examples where it is vitally important to
> > have extremely contrasting colors?
> ... I often have to deal with very long lines in source code, where
> only some characters or words have been (ex)changed. In this case
> colors giving a black eye are really handy: You just scroll within
> TMerge from left to right and by these colors you are forced to look
> at the place where it has changed. Using different shades of green
> would make this more difficult. For me the information what's new and
> what's been left out is not so important, as this is IMOH an
> infrequent case for changes within lines (you drop some lines here and
> insert some more lines there, but that's account for differently).
> So the color differences should at least be easily spottable.
> And yes, maybe the colors have much to much contrast.
> Best would be (if you want to have them similar) to place a reference
> point in CIE L*a*b*, where euclidian distance is proportional to
> percepted color difference and place 5 - 11 colors (odd) around that
> reference point. Then enumerate these points so that the sequence has
> maximum color differences (for 5 points --- hope you don't use a
> proportional font):
> 4 . 3
> 2 5
> (You should do that in three dimensions taking luminance into account
Jens, thank you very much for the information.
Some experts are of the opinion that the euclidian distance between
colours in CIE L*a*b* is bogus when it comes to measuring perceptually
Here's an example:
Care to comment on exactly *how* bogus it is?
Also, do you know of any colour-picker program suitable for choosing
colors with high color-difference but a low cataracts factor that you
could recommend for the job at hand?
> BTW, if you have a look at
> http://en.wikipedia.org/wiki/Lab_color_space you'll see that green is
> not a good choice, because the eye does not differentiate bright green
> colors well. (See http://www.cs.rit.edu/~ncs/color/t_convert.html for
> conversion formulas to RGB)
Well, I like the "use shades of gray for fore-color" idea just as
well, seeing as it would keep the background color for unchanged lines
the same as is used in the diff windows (white).
How's that? Better or worse?
> But maybe the problem does not lie in the colors but in the algorithm:
> The algorithm has no notion of "relevant changes", it treats
> all substrings the same. Maybe something like a visualization of
> minimum edit distance (Levenshtein distance) would be more
> appropriate, but I haven't found good references on that yet (only the
> calculation of minimum edit distance).
Let's spare ourselves the trouble and not do that and just say we did :o).
Oh, and a last question, out of pure interest.
You seem to do some professional diff'ing - are you actually using
TMerge for it, or do you use some other solution?
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Received on Tue Mar 22 21:06:26 2005