[R] Remove "gray grid" from levelplot
Prof Brian Ripley
ripley at stats.ox.ac.uk
Mon Mar 6 13:10:17 CET 2006
On Mon, 6 Mar 2006, Martin Sandiford wrote:
> P.S. To me, the png() device does not appear to do sub-pixel
> rendering. The postscript() and pdf() devices do.
What could you possibly mean by that?
The postscript() and pdf() produce vector graphics and have no concept of
a pixel. There are filled polygons as part of the language they output.
(Of course the coordinates are output to finite resolution, in fact 0.01dp
= 1/7200", so you could think of that as the positioning quantum.)
The png device writes on a bitmap. It outputs a rectangular grid of
either pre-defined colour indices or RGB values. There is nothing in the
PNG standard to allow anything finer.
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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