[R] Rotation of parallel lines

[David Winsemius]

On Nov 19, 2013, at 5:53 AM, Tonio wrote:

> Thank you for your post. I believe that it is possible to make a function to rotate a graphical component that might be based on the rotation matrix.
> 
> 
> I'll take a look to the packages anyway...


It's certainly possible to "rotate"  abstract segment endpoints using a rotation matrix. What is not possible is to claenly erase the original image and replace it with the new image. You could also repeatedly draw new plots with a segment being rotated (around what center you do not say) in angular increments and then assemble a sequence of plots with the animation package. (A rotation matrix would transform segment end-points around the origin.)  As always, a complete description of the desired result is needed and I do not believe you have yet provided such.

-- 
David.
> 
> Den 15:38 mandag den 18. november 2013 skrev David Winsemius <dwinsemius at comcast.net>:
> 
> 
> On Nov 18, 2013, at 7:27 AM, Tonio wrote:
> 
>> 
>> 
>> Dear list,
>> 
>> Consider these two parallel segments in a plot.
>> 
>> plot(c(1, 6), c(2, 2), type="n", xlim=c(0, 7), ylim=c(-2, 6))
>> segments(1, 1, 6, 1)
>> segments(1, 3, 6, 3)
>> 
>> 
>> 
>> How can I rotate the two lines together by a defined angle?
> 
> Base graphics do not support object operations. You need to do the  
> calculation and redraw the plot.
> 
> Either lattice or ggplot2 which depend upon the "grid" system would  
> have the possibility to "rotate" a component.
> 
> -- 
> 
> David Winsemius, MD
> Alameda, CA, USA

David Winsemius
Alameda, CA, USA