annotate_colorbar — ANNOTATE paper op

• Data kinds: image2d × image2d → image2d

• Call: import fullseye as fs; fs.ledger.annotate_colorbar(img, field, rect, lut=None, vmin=None, vmax=None, alpha=0.6, mask=None, unit='', label_fmt='{:.3g}', orientation='vertical', font_size=12, scheme='okabe_ito', font_path=None, text_color=None, nan_transparent=False) (to call the implementation directly, import annotate; annotate.annotate_colorbar(img, field, rect, lut=None, vmin=None, vmax=None, alpha=0.6, mask=None, unit='', label_fmt='{:.3g}', orientation='vertical', font_size=12, scheme='okabe_ito', font_path=None, text_color=None, nan_transparent=False); from the registry, opsannotate.get("annotate_colorbar"))

Usage

Returns an image (image2d): a scalar field colour-mapped through a LUT and overlaid, with a colour bar.

t = (field - vmin)/(vmax - vmin) is clipped to [0,1] and turned into colour by lut[round(t*(n-1))] (out-of-range values get the end colour -- the same as the end of the colour bar, so it does not lie). Overlaying is α compositing with alpha; passing mask restricts it to those pixels.

Parameters

field : (H, W)

A scalar field the same size as the image. Non-finite values are allowed as transparent only when nan_transparent=True

(the default is ValueError).

lut : (n, 3) or None

If None, the 256 steps of palette.diverging_lut.

vmin, vmax : float or None

If None, the minimum / maximum of the field (over finite values). If they are equal, ValueError.

Raises

ValueError

Shape mismatch, non-finite values (without permission), vmin == vmax, alpha outside [0,1],

the bar rectangle outside the image, or the LUT shape.

Detailed usage guide

• figure_annotation family guide

Background guides (the physics and conventions behind this op)

• dataset_conventions — Training-dataset conventions — COCO / YOLO / VOC and pitfalls in visual inspection

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• paper_figure — py -3.11 examples/paper_figure.py

Ops the type connects to (they accept image2d as input)

text_box · arrow · leader_line · label_points · crosshair · legend_box · color_bar · scale_bar

Same category (paper)

annotate_leader_layout · annotate_leader · annotate_markers · annotate_legend · annotate_dimension_layout · annotate_dimension · annotate_angle_layout · annotate_angle

*Provenance: annotate.py — ANNOTATE operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.