Generalised orientation overlay tool

[Lestropie]

So FODs are not the only type of intra-voxel orientation information that one may wish to display. Some possibiliities:

• FODs
• Tensors
• Output from SH2peaks / FSL (i.e. set of XYZ vectors per voxel)
• Fixel-based outputs using sparse data format
• Dixel-based data

The theory is to have a master 'orientation overlay' tool that has the file list, 3D preview window for the selected voxel, any options that are common for all types of orientation data, and an 'orientation data type' selector that toggles between the above. The appropriate additional tools then appear depending on the type of orientation overlay selected for the currently active file. Some examples:

General options: Toggle lighting & access lighting options, preview window snap to image axes / interpolation / show axes, scaling (preview window & overlay), toggle overlay

Options specific to different types of overlay:

• FODs: lmax (preview window & overlay), LOD, hide negative lobes
• Tensors: LOD, manual colour / colour by direction / colour by first eigenvector, scale by B0 / Mean ADC / none
• XYZ vectors: Line thickness, vectors defined in real / image space
• Fixel-based data: geometry (e.g. lines, thick lines, 3D cylinders/arrows, ...), colour by direction/amplitude/value, scale by amplitude/value/unity, lower/upper threshold by amplitude/value, colour mapping
• Dixel data: basis directions source (built-in / external file / DW table; can visualise the DW shell data directly without mapping to SH first), geometry (lines / mesh surface), colour mapping

[Lestropie]

I'm going to close this. The ODF tool now handles SH FODs, tensors, and dixel data, while the fixel tool handles XYZ vector data without too much trouble. These two tools can happily remain separate, even if there is a lot of common functionality. Enhancement requests (e.g. colouring SH/dixel FODs by amplitude, tensor glyph scaling by tensor properties, fixel geometries) can be opened separately if/when there is a want/need for them.