[Rd] raster support in graphics devices

Martin Maechler maechler at stat.math.ethz.ch
Tue Dec 1 10:47:23 CET 2009

>>>>> "CM" == Charlotte Maia <maiagx at gmail.com>
>>>>>     on Tue, 1 Dec 2009 17:48:33 +1300 writes:

    CM> Hi,
    CM> I consider raster graphics highly problematic in statistics.
    CM> People get caught up in the idea of creating pretty pictures, rather
    CM> than effectively visualising information.

    CM> Plus a lot of people (who should know better) needlessly put raster
    CM> images inside reports and articles (even books), which either makes
    CM> the files large (and very difficult to view), or creates blurry
    CM> images, or both.

    CM> It's always good to have more functionality.

Yes indeed, and Paul has to be thanked loudly and heartfully and
very much for providing it in the realm of graphics !!!

    CM> However, I certainly hope that most of the R community stick to vector
    CM> graphics (with conservative colour use), unless it is absolutely
    CM> necessary to do otherwise

I agree with your reasoning *pro* using vector graphics
as much as possible, and warning against the overuse of raster
graphics in scientific work !

    CM> necessary to do otherwise (and the only example I can think of, is
    CM> modelling images themselves).

Did you look at the interesting page Paul sent the URL for,
http://developer.r-project.org/Raster/raster-RFC.html ?

Yes, modelling images is probably *the* most important
application area, but *fast* direct plotting of a large matrix,
mapping one matrix entry A_{i,j} to one pixel is also quite
attractive, and the Matrix package authors (me being one) are
quite interested to eventually see a version of 
  lattice::levelplot()  that builds on Paul's new
  grid::grid.raster() or grid::rasterGrob()  functions.

    CM> On a side issue, I have found that R plots tend to be getting slower
    CM> over the years.

    CM> I think cairo was a bad move, however that's just my opinion...

Dear me...  
using Cairo features for X11 graphics is just the new default,
so users notice the nice new possibilities !
If you want the very fast (but not so very nice looking)
previous default X11() graphics, please do read the help pages:
-->  ?X11  
-->  ?X11.options
and then either  X11.options(type = "Xlib")
or               X11(        type = "Xlib")

will give you the very fast (non-aliased, no alpha blending)
X11 graphics that used to be the only one in R originally.

Martin Maechler, ETH Zurich

    CM> regards
    CM> -- 
    CM> Charlotte Maia
    CM> http://sites.google.com/site/maiagx/home

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