[R] Bar Plot ggplot2 Filling bars with cross hatching

[hadley wickham]

>>        I disagree.  Grey levels suck; labels are a kludge.  It is an issue
>>        for ``many'' == 2, for which crosshatching works perfectly.
>>
>
> Could you show an example?
>
> There are several BW examples in example(barplot), and the gray ones look
> better on screen than the cross-hatched one.  (Not to say it makes a very
> good choice of cross-hatching, but I suspect the gray examples will look
> better than any 5 cross-hatch patterns.)  I haven't tried printing the
> examples, so I'm not sure the gray would reproduce well on paper; I wouldn't
> try to print those 5 gray levels on a typical printer.

My feeling is that the best cross-hatching is probably going to be
more aesthetically pleasing than the best solid greys (see e.g.
http://www.dannygregory.com/2005/09/cross_hatching.php).  However,
doing cross hatching well is far more difficult than doing grey well,
and for really nice cross-hatching I suspect you also need a high
quality printer.   It is also a challenging problem to come up with an
algorithm for generating perceptually uniform sets of cross-hatchings.
 I suspect there is some work on this area in vis/infovis, but I
haven't find it in a few minutes of casual searching.

Hadley

Hadley

-- 
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