Presentation Ops
Manage presentation overlays on data fields. Provides logarithmic scaling, normalisation extraction, overlay attachment, and linear blending. Equivalent to Gwyddion's presentationops.c module.
Inputs
| Name |
Type |
Required |
Description |
| field |
DATA_FIELD |
Yes |
Primary data field |
| overlay |
DATA_FIELD |
No |
Field to attach or blend as an overlay (used by attach and blend modes) |
Outputs
| Name |
Type |
Description |
| result |
DATA_FIELD |
Processed data field |
Controls
| Name |
Type |
Default |
Description |
| operation |
dropdown |
logscale |
Operation mode: logscale, extract_presentation, attach, or blend |
| blend_factor |
FLOAT |
0.5 |
Linear blend ratio between field (0.0) and overlay (1.0); only shown in blend mode (0.0--1.0) |
Notes
- logscale: Shifts the data so the minimum becomes a small positive value, then applies log10. Useful for data with large dynamic range such as power spectral densities or FFT magnitudes.
- extract_presentation: Normalises the field to the [0, 1] range. Handy for generating a quick visual overview or feeding into colour-mapping nodes.
- attach: Replaces the field data with the overlay data. If the overlay has different dimensions it is resampled with cubic interpolation to match.
- blend: Linearly mixes
(1 - blend_factor) * field + blend_factor * overlay. The overlay is resampled if its dimensions differ from the field.
- Overlay resampling uses
scipy.ndimage.zoom with third-order (cubic) interpolation.
