tidy up old code

backend/nodes/helpers.py

@@ -122,84 +122,6 @@ def _measurement_value(table: list, selection: str) -> float:
     raise ValueError(f"Measurement '{row.get('quantity', selection)}' does not have a numeric value.")
 
 
-# ---------------------------------------------------------------------------
-# SI formatting helpers  (from display.py — used by Annotations)
-# ---------------------------------------------------------------------------
-
-_SI_PREFIXES = [
-    (1e24, "Y"), (1e21, "Z"), (1e18, "E"), (1e15, "P"), (1e12, "T"),
-    (1e9, "G"), (1e6, "M"), (1e3, "k"), (1.0, ""), (1e-3, "m"),
-    (1e-6, "u"), (1e-9, "n"), (1e-12, "p"), (1e-15, "f"),
-    (1e-18, "a"), (1e-21, "z"), (1e-24, "y"),
-]
-_PREFIXABLE_UNITS = {"m", "s", "A", "V", "W", "Hz", "F", "C", "J", "N", "Pa", "T", "H", "S", "g", "K", "Ohm", "ohm", "\u03a9"}
-
-
-def _format_numeric(value: float) -> str:
-    if not np.isfinite(value):
-        return str(value)
-    abs_value = abs(value)
-    if abs_value == 0:
-        return "0"
-    if abs_value >= 1e4 or abs_value < 1e-3:
-        return f"{value:.3e}"
-    return f"{value:.4g}"
-
-
-def _format_with_unit(value: float, unit: str) -> str:
-    unit = (unit or "").strip()
-    if not unit:
-        return _format_numeric(value)
-    if unit in _PREFIXABLE_UNITS and np.isfinite(value) and value != 0:
-        abs_value = abs(value)
-        for scale, prefix in _SI_PREFIXES:
-            scaled = abs_value / scale
-            if 1 <= scaled < 1000:
-                signed = value / scale
-                return f"{_format_numeric(signed)} {prefix}{unit}"
-    return f"{_format_numeric(value)} {unit}"
-
-
-def _nice_length(target: float) -> float:
-    if not np.isfinite(target) or target <= 0:
-        return 0.0
-    exponent = np.floor(np.log10(target))
-    base = 10.0 ** exponent
-    for step in (5.0, 2.0, 1.0):
-        candidate = step * base
-        if candidate <= target:
-            return candidate
-    return base
-
-
-def _display_value_range(field) -> tuple[float, float, float]:
-    data = np.asarray(field.data, dtype=np.float64)
-    dmin = float(data.min())
-    dmax = float(data.max())
-    if not np.isfinite(dmin) or not np.isfinite(dmax) or dmax <= dmin:
-        return dmin, dmin, dmin
-
-    offset = float(field.display_offset)
-    scale = float(field.display_scale)
-    if not np.isfinite(offset):
-        offset = 0.0
-    if not np.isfinite(scale) or scale <= 0.0:
-        scale = 1.0
-
-    low_norm = float(np.clip(offset, 0.0, 1.0))
-    high_norm = float(np.clip(offset + scale, 0.0, 1.0))
-    if high_norm < low_norm:
-        low_norm, high_norm = high_norm, low_norm
-    mid_norm = 0.5 * (low_norm + high_norm)
-
-    span = dmax - dmin
-    return (
-        dmin + low_norm * span,
-        dmin + mid_norm * span,
-        dmin + high_norm * span,
-    )
-
-
 def _render_annotation_text(text: str, size_px: int, color: tuple[int, int, int]):
     from PIL import Image, ImageDraw, ImageFont