On 09/09/2011 11:10 AM, Marius Hofert wrote:
Dear all,
Below is some code where I try to get plotmath symbols in an rgl plot. Duncan
Murdoch kindly suggested to use a "sprite" for this. As you can see, on can get
it to work, but my knowledge about grid and rgl is too limited to perfectly
solve the problem.
1) As you can see (please rotate the plot a little bit so that (0,0,0) is "in
front"),
the quality of the .png seems poor. Can this be improved?
Generally plotting much larger and shrinking is the way to do this.
2) When I print the file to a .pdf, the label is just a black square... I assume
one then has to print to png again... hmmm... not perfect.
rgl.postscript has a lot of limitations. This one may be unavoidable.
3) Some parts of the z-axis are covered by the label. How can this be fixed?
The problem seems to be that sprites have a radius. Specifying a rectangle would
be better here, but I am not sure how this works (or even if it does).
I think I don't see this in Windows, which shows the black text for the
label on a transparent background. Do you see a solid background? Or
is it just the positioning? The tick marks go out at an angle, whereas
your sprite seems to be in line with the zy plane. I would increase the
x value to something like 1.4 to place it properly. (Just tried that,
and I think I see the problem you had: the new sprite is obscured by
the old one.
You may need to play with the depth_test or depth_mask material
properties. Not sure if those are visible on CRAN; if not, try the
R-forge version.)
The other thing I'd recommend is that before plotting the sprite, you
run par3d(ignoreExtent=TRUE) (and then set it back to the original value
afterwards). This will stop the label from affecting the bounding box
of the plot.
Duncan Murdoch
Cheers,
Marius
require(rgl)
require(grid)
s<- seq(0, 1, length.out=21)
M<- function(u) apply(u, 1, min)
u<- s
v<- s
z<- outer(u, v, function(u,v) M(cbind(u,v)))
## create z-axis label
png("zlabel.png", bg="transparent", width=70, height=70)
grid.newpage()
pushViewport(plotViewport(c(1,1,1,1)))
print(grid.text(expression(W(u[1],u[2])==c),rot=90))
popViewport()
dev.off()
## plot
persp3d(u, v, z, aspect="iso", front="line", lit=FALSE, axes=FALSE, xlab="",
ylab="", zlab="")
axes3d(edges=c('x--','y--','z+-'))
sprites3d(1,-0.4,0.65, radius=0.5, lit=FALSE, textype="alpha",
texture="zlabel.png")
rgl.postscript("W.pdf", fmt="pdf") # print to file
# par3d(c("userMatrix", "zoom", "FOV")):
#
# $userMatrix
# [,1] [,2] [,3] [,4]
# [1,] 0.7262191 -0.6867201 0.03195775 0
# [2,] 0.2750087 0.3328032 0.90200466 0
# [3,] -0.6300603 -0.6462642 0.43054202 0
# [4,] 0.0000000 0.0000000 0.00000000 1
#
# $zoom
# [1] 1
#
# $FOV
# [1] 30
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