Find the direction away from the closest point in a 3d projection
Jim Lemon's thigmophobe function in the
plotrix package
computes good directions for labels in a 2D plot. This function
does the same for a particular projection in a 3D plot by
projecting down to 2D and calling his function.
thigmophobe3d(x, y = NULL, z = NULL,
P = par3d("projMatrix"),
M = par3d("modelMatrix"),
windowRect = par3d("windowRect"))x, y, z |
point coordinates. Any reasonable way of defining
the coordinates is acceptable. See the function |
P, M, windowRect |
The projection and modelview matrices, and the size and position of the display in pixels. |
Since thigmophobe3d projects using fixed P and M,
it will not necessarily choose good directions if the user rotates
the display or makes any other change to the projection.
A vector of values from 1 to 4 to be used as the pos argument
in text3d.
The example below shows how to update the directions during an animation; I find that the moving labels are distracting, and prefer to live with fixed ones.
Duncan Murdoch
if (requireNamespace("plotrix", quietly = TRUE)) {
# Simulate some data
xyz <- matrix(rnorm(30), ncol = 3)
# Plot the data first, to establish the projection
plot3d(xyz)
# Now thigmophobe3d can choose directions
textid <- text3d(xyz, texts = 1:10, pos = thigmophobe3d(xyz))
# Update the label positions during an animation
if (interactive() && !rgl.useNULL()) {
spin <- spin3d(rpm = 5)
f <- function(time) {
par3d(skipRedraw = TRUE)
on.exit(par3d(skipRedraw = FALSE))
pop3d(id = textid)
# Need to rotate before thigmophobe3d is called
result <- spin(time)
par3d(userMatrix = result$userMatrix)
textid <<- text3d(xyz, texts = 1:10, pos = thigmophobe3d(xyz))
result
}
play3d(f, duration = 5)
} else
textid # just print the static display
}Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.