[Rd] image() with all NAs fails (PR#8228)

[barry.rowlingson@gmail.com]

Full_Name: Barry Rowlingson
Version: 2.2.0
OS: Linux
Submission from: (NULL) (194.80.32.8)


The image function with a matrix of all NA values fails with:

> xyz=list(x=1:3,y=1:4,z=matrix(NA,3,4))
> image(xyz)
Error in image.default(xyz) : invalid z limits
In addition: Warning messages:
1: no finite arguments to min; returning Inf
2: no finite arguments to max; returning -Inf

Image can handle any number of NAs as long as there is at least one data value:

> xyz=list(x=1:3,y=1:4,z=matrix(c(1,rep(NA,11)),3,4))
> image(xyz)

 and shows NAs as transparent. However if it is all NAs then the z-limit
calculation breaks down as above.

  It seems reasonable to me that image() with all NAs should produce a
completely transparent/empty image (after displaying the axes if add!=TRUE) and
not fail with an error.

Barry