plotCDF1: no visible global function definition for ‘lines’
plotCDF1: no visible global function definition for ‘plot’
plotCDF2: no visible global function definition for ‘gray’
plotCDF2: no visible global function definition for ‘image’
plotCDF2: no visible global function definition for ‘box’
plotCDF2: no visible global function definition for ‘par’
plotCDF2: no visible global function definition for ‘rect’
plotCDF2: no visible global function definition for ‘text’
plotCM: no visible global function definition for ‘image’
plotCM: no visible global function definition for ‘axis’
plotCM: no visible global function definition for ‘box’
plotDens1: no visible global function definition for ‘plot’
plotDens1: no visible global function definition for ‘lines’
plotDens2: no visible global function definition for ‘gray’
plotDens2: no visible global function definition for ‘plot’
plotDens2: no visible global function definition for ‘rect’
plotDens2: no visible global function definition for ‘axis’
plotDens2: no visible global function definition for ‘text’
plotHM: no visible global function definition for ‘terrain.colors’
plotHM: no visible global function definition for ‘image’
plotHM: no visible global function definition for ‘box’
plotHM: no visible global function definition for ‘abline’
plotHM: no visible global function definition for ‘text’
plotHM: no visible global function definition for ‘par’
plotHM: no visible global function definition for ‘rect’
plotRects: no visible global function definition for ‘rainbow’
plotRects: no visible global function definition for ‘plot’
plotRects: no visible global function definition for ‘abline’
plotRects: no visible global function definition for ‘rect’
Undefined global functions or variables:
  abline axis box gray image lines par plot rainbow rect terrain.colors
  text
Consider adding
  importFrom("grDevices", "gray", "rainbow", "terrain.colors")
  importFrom("graphics", "abline", "axis", "box", "image", "lines",
             "par", "plot", "rect", "text")
to your NAMESPACE file.