pixmap: no visible global function definition for 'new'
pixmap: no visible global function definition for 'as'
pixmapGrey: no visible global function definition for 'new'
pixmapIndexed: no visible global function definition for 'new'
pixmapIndexed: no visible global function definition for 'as'
pixmapIndexed: no visible global function definition for 'heat.colors'
pixmapIndexed: no visible global function definition for 'is'
pixmapRGB: no visible global function definition for 'new'
write.pnm: no visible global function definition for 'is'
write.pnm: no visible global function definition for 'as'
[,pixmap: no visible global function definition for 'is'
[,pixmap: no visible global function definition for 'slot<-'
[,pixmap: no visible global function definition for 'slot'
addChannels,pixmapRGB: no visible global function definition for 'new'
coerce,ANY-pixmapGrey: no visible global function definition for 'as'
coerce,ANY-pixmapIndexed: no visible global function definition for
  'as'
coerce,pixmapGrey-pixmapIndexed: no visible global function definition
  for 'new'
coerce,pixmapGrey-pixmapIndexed: no visible global function definition
  for 'as'
coerce,pixmapGrey-pixmapIndexed: no visible global function definition
  for 'grey'
coerce,pixmapGrey-pixmapRGB: no visible global function definition for
  'new'
coerce,pixmapGrey-pixmapRGB: no visible global function definition for
  'as'
coerce,pixmapIndexed-pixmapRGB: no visible global function definition
  for 'new'
coerce,pixmapIndexed-pixmapRGB: no visible global function definition
  for 'as'
coerce,pixmapIndexed-pixmapRGB: no visible global function definition
  for 'col2rgb'
coerce,pixmapRGB-pixmapIndexed: no visible global function definition
  for 'new'
coerce,pixmapRGB-pixmapIndexed: no visible global function definition
  for 'as'
coerce,pixmapRGB-pixmapIndexed: no visible global function definition
  for 'rgb'
getChannels,pixmapChannels: no visible global function definition for
  'slot'
plot,pixmap: no visible global function definition for 'as'
plot,pixmap: no visible global function definition for 'image'
show,pixmap: no visible global function definition for 'is'
show,pixmap: no visible global function definition for 'as'
Undefined global functions or variables:
  as col2rgb grey heat.colors image is new rgb slot slot<-
Consider adding
  importFrom("grDevices", "col2rgb", "grey", "heat.colors", "rgb")
  importFrom("graphics", "image")
  importFrom("methods", "as", "is", "new", "slot", "slot<-")
to your NAMESPACE file (and ensure that your DESCRIPTION Imports field
contains 'methods').