Color maps

Image files

It is possible to specify a color map using the --colormap-file option. The value of the option can be a path to an image file, a filename or a filestem. If it is not a path, these directories are used to find the file (in this order):

  • Linux: ${XDG_CONFIG_HOME}/f3d/colormaps, ~/.config/f3d/colormaps, /etc/f3d/colormaps, /usr/share/f3d/colormaps, [install_dir]/share/f3d/colormaps
  • Windows: %APPDATA%\f3d\colormaps, [install_dir]\share\f3d\configs\colormaps
  • macOS: ${XDG_CONFIG_HOME}/f3d/colormaps, ~/.config/f3d/colormaps, /usr/local/etc/f3d/colormaps, f3d.app/Contents/Resources/configs/colormaps The first existing file found is used. If it is a filestem, all supported image extensions are tried.

We provide some ready to use color maps files, listed in the table below:

Name Image
cividis
cubehelix
gist_earth
hot
inferno
magma
plasma
seismic
viridis

It is possible to create a custom color map by creating a simple RGB image in any supported formats, and any resolution (if the height is more than 1 row, only the first one is taken into account). The image must be copied in the user config directory:

  • Linux/macOS: ~/.config/f3d/colormaps
  • Windows: %APPDATA%\f3d\colormaps

Supported formats

Here’s the list of all supported image formats that can be used as color maps:

  • .png
  • .pnm, .pgm, .ppm
  • .tif, .tiff
  • .bmp
  • .slc
  • .hdr
  • .pic
  • .jpeg, .jpg
  • .MR
  • .CT
  • .mhd, .mha
  • .tga
  • .exr (if F3D_MODULE_EXR is enabled)

Custom values

If no colormap file is specified, it is also possible to set values manually using the --colormap option. A list of numbers between 0 and 1 must be specified. The size of the list is a multiple of 4 and each 4-components tuple correspond to the scalar value, followed by the RGB color. For example, the default value corresponds to the hot preset which can be defined manually with --colormap=0.0,0.0,0.0,0.0,0.4,0.9,0.0,0.0,0.8,0.9,0.9,0.0,1.0,1.0,1.0,1.0. It consists of 4 tuples:

Value RGB
0.0 ■ 0.0, 0.0, 0.0
0.4 ■ 0.9, 0.0, 0.0
0.8 ■ 0.9, 0.9, 0.0
1.0 ■ 1.0, 1.0, 1.0

Values in between are interpolated.