RasterView is an Apple, CUPS, and PWG raster file viewing application. It basically allows you to look at the raster data produced by any of the standard CUPS RIP filters (cgpdftoraster, imagetoraster ...
For more background and an informational talk, see this page. This style file uses the values in https://github.com/BIDS/colormap/blob/master/colormaps.py to build ...