'xyz_colormap()'

[trevorld]

• Get height (and colors) from pixels colors of an image
• https://github.com/cj-holmes/isocuboids has some awesome demos of this for isometric cuboids

[trevorld]

• Probably not going to support this as a separate function.

• Users will need to create appropriate matrices of heights manually:

  • Convert image to raster object which is gives a matrix of colors
  • Use apply(matrix, c(1,2), function(color) to_be_completed) to get matrix of heights
  • Pass both matrix of color and matrix of heights to xyz_heightmap()