[R] [FORGED] Re: draw stripes in a circle in R

Jeff Newmiller jdnewmil at dcn.davis.ca.us
Thu Jun 15 00:54:34 CEST 2017


Package 'scales' has the alpha function... associated with ggplot2. A bit out of place here if that is the origin. Yes, we are squarely in non-reproducible example territory, also known as the Twilight Zone.
-- 
Sent from my phone. Please excuse my brevity.

On June 14, 2017 1:53:21 PM PDT, Rolf Turner <r.turner at auckland.ac.nz> wrote:
>On 15/06/17 05:29, David Winsemius wrote:
>> 
>>> On Jun 14, 2017, at 10:18 AM, David Winsemius
><dwinsemius at comcast.net> wrote:
>>>
>>>
>>>> On Jun 14, 2017, at 9:46 AM, Jeff Newmiller
><jdnewmil at dcn.davis.ca.us> wrote:
>>>>
>>>> I don't see a question. If your question is whether R supports
>pattern fills, AFAIK it does not. If that is not your question, ask
>one.
>>>> -- 
>>>> Sent from my phone. Please excuse my brevity.
>>>>
>>>> On June 14, 2017 7:57:41 AM PDT, jean-philippe
><jeanphilippe.fontaine at gssi.infn.it> wrote:
>>>>> dear R users,
>>>>>
>>>>> I would like to fill a circle with yellow stripes instead of a
>uniform
>>>>> yellow color. To draw the circle I used the following command
>after
>>>>> having loaded the (very nice !) plotrix library :
>> 
>> I finally understood the question and it needs a hack to the
>draw.circle function in plotrix since the angle and density arguments
>don't get passed in:
>> 
>> First get code for draw.circle:
>> 
>> ------
>> 
>> draw.circle   # then copy to console and edit
>> 
>> draw.circle2  <- function (x, y, radius, nv = 100, border = NULL, col
>= NA, lty = 1,
>>                             density=NA, angle=45,  lwd = 1 )
>> {
>>      xylim <- par("usr")
>>      plotdim <- par("pin")
>>      ymult <- getYmult()
>>      angle.inc <- 2 * pi/nv
>>      angles <- seq(0, 2 * pi - angle.inc, by = angle.inc)
>>      if (length(col) < length(radius))
>>          col <- rep(col, length.out = length(radius))
>>      for (circle in 1:length(radius)) {
>>          xv <- cos(angles) * radius[circle] + x
>>          yv <- sin(angles) * radius[circle] * ymult + y
>>          polygon(xv, yv, border = border, col = col, lty = lty,
>density=density, angle=angle,
>>                  lwd = lwd)
>>      }
>>      invisible(list(x = xv, y = yv))
>> }
>> 
>> Now run your call to pdf with draw.circle2 instead of draw.circle.
>
>This is just idle curiosity, since I'm not really able to contribute 
>anything useful, but I can't resist asking:  When I try to run the OP's
>
>code I get an error:
>
>> Error in alpha("red", 0.4) : could not find function "alpha".
>
>Why does this (apparently) not happen to anyone else?  Why does the 
>universe pick on *me*?  What is the function "alpha()"?  Where is it to
>
>be found?
>
>Searching on "alpha" is of course completely unproductive; there are
>far 
>too many (totally irrelevant) instances.
>
>cheers,
>
>Rolf



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