draw stripes in a circle in R

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

Best;
David.
library(plotrix)
pdf("MWE.pdf",width=8, height=8)
plot(seq(-12.5,-8.7,length.out=100),seq(-11.3,-8.3,length.out=100),type="l",col="red",xlim=c(-12.5,-8.7),ylim=c(-11.5,-8.5))
par(new=T)
plot(seq(-12.5,-8.7,length.out=100),seq(-11.7,-8.7,length.out=100),type="l",col="red",xlim=c(-12.5,-8.7),ylim=c(-11.5,-8.5))
par(new=T)
polygon(c(seq(-12.5,-8.7,length.out=100), 
rev(seq(-12.5,-8.7,length.out=100))), c(seq(-11.3,-8.3,length.out=100),

rev(seq(-11.7,-8.7,length.out=100))),
      col = alpha("red",0.4), border = NA)
par(new=T)
draw.circle(-12.85,-10.9,0.85,nv=1000,border=NULL,col="yellow",lty=1,lwd=1)
dev.off()

Agree that the coding question remains unclear, so not using the offered example but responding to the natural language query. The `polygon` function has 'density' and 'angle' argument that with 'col' and 'lwd' can make slanted fill lines. This is a modification of hte first example on `?polygon`?

x <- c(1:9, 8:1)
y <- c(1, 2*(5:3), 2, -1, 17, 9, 8, 2:9)
op <- par(mfcol = c(3, 1))
for(xpd in c(FALSE, TRUE, NA)) {
   plot(1:10, main = paste("xpd =", xpd))
   box("figure", col = "pink", lwd = 3)
   polygon(x, y, xpd = xpd, col = "orange", density=3, angle=45,  lwd = 5, border = "red")
}

The polygon function is _not_ in pkg::plotrix.

It looks a bit ugly since they are not real data, but it is the
simplest 
MWE example that I found.

Thanks, best

Jean-Philippe

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David Winsemius
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draw stripes in a circle in R

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