...I did a slight tweak to your mandelbrot.R code, so
that x can be a list with components x and y. This allows you to keep zooming in using your mouse to click on the plot (one of the incredibly nifty features of such sets).
Using the "tweaked" version below, call the function as you suggested:
image(mandelbrot(), col = c(heat.colors(49), "black"))
Then use locator(2) to define your next view:
image(mandelbrot(locator(2)), col = c(heat.colors(49), "black"))
Of course, I would've been nice if I'd included the tweaked version. D'ho!
#######################################################################
# Function to calculate the Mandelbrot set. This function calls a #
# C routine in order to perform the calculations faster. #
# #
# Written by Mario dos Reis. September 2003 #
# Modified: added if(is.list(x)){...} at start to check if co-ords #
# are from locator() or similar - jason turner oct 2 2003 #
#######################################################################mandelbrot <- function(x = c(-3, 1), # x limits
y = c(-1.8, 1.8), # y limits
nx = 600, # x resolution
ny = 600, # y resolution
iter = 20) # maximun number of iterations
{
if(is.list(x)) {
y <- range(x$y)
x <- range(x$x)
}
xcoo <- seq(x[1], x[2], len = nx) # x coordinates
ycoo <- seq(y[1], y[2], len = ny) # y coordinates
set = numeric(nx*ny) # this will store the output of
# the C routine # This is the call to the C function itself
the.set = .C("mandelbrot",
xcoo = as.double(xcoo),
ycoo = as.double(ycoo),
nx = as.integer(nx),
ny = as.integer(ny),
set = as.integer(set),
iter = as.integer(iter))$set# Create a list with elements x, y and z,
# suitable for image(), persp(), etc. and return it.
return(list(x = xcoo, y = ycoo, z = matrix(the.set, ncol = ny, byrow = T)));
}
-- Indigo Industrial Controls Ltd. http://www.indigoindustrial.co.nz 64-21-343-545 [EMAIL PROTECTED]
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