[R] editing ".Internal" functions

[Prof Brian Ripley]

On Wed, 23 Aug 2006, B. Chasco wrote:

> There is a function called arrows() which is an .Internal function.  How 
> difficult is it to modify that function to return the xy coordinates for 
> the line "segments" that make up the arrowhead?

That depends on your 'core competencies'.  You have the source, which is 
in file src/main/plot.c (and GArrow in src/main/graphics.c).  I am not 
sure I understand your question, as arrows() is plural and draws multiple 
arrows with 0/1/2 heads each.  Also, the 'xy coordinates' are to be in 
which coordinate system, and you do realize that the sizes in user 
coordinates change if you resize the plot?

-- 
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)
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