Улучшить две шкалы, навигацию и формулы графиков

python/set_devices/plot_formula.py

@@ -4,6 +4,7 @@
 
 """Local polynomial representation of the curves actually drawn on a plot."""
 from dataclasses import dataclass
+from functools import lru_cache
 import math
 
 
@@ -38,7 +39,7 @@ class FormulaPiece:
                 + f'{number(left)} ≤ x ≤ {number(self.right - origin)} {unit}').rstrip()
 
 
-def linear_piece(timestamps, values, x):
+def linear_piece(timestamps, values, x, window=None):
     """A source polyline has a linear equation, not an inferred analytic model."""
     previous = None
     for stamp, value in zip(timestamps, values):
@@ -48,11 +49,39 @@ def linear_piece(timestamps, values, x):
         if previous is not None:
             t0, y0 = previous
             if t0 <= x <= stamp and stamp > t0:
+                if window is not None:
+                    left, right = max(t0, window[0]), min(stamp, window[1])
+                    if not left <= x <= right or left >= right:
+                        return None
+                    slope = (value - y0) / (stamp - t0)
+                    return FormulaPiece(left, right, (y0 + slope * (left - t0), slope * (right - left)))
                 return FormulaPiece(t0, stamp, (y0, value - y0))
         previous = stamp, value
     return None
 
 
+@lru_cache(maxsize=32)
+def window_curve(curve, left, right):
+    """Reconstruct a formula using only source samples in the focused window."""
+    from dataclasses import replace
+    from .plot_processing import process
+    request = curve.request
+    points = tuple((x, y) for x, y in request.series.points if left <= x <= right)
+    if points == request.series.points:
+        return curve
+    if len({x for x, _ in points}) < 2:
+        return None
+    try:
+        return process(replace(request, series=replace(request.series, points=points), x_range=(left, right)))
+    except ValueError:
+        return None
+
+
+def window_piece(curve, x, left, right):
+    local = window_curve(curve, left, right)
+    return local.piece_at(x) if local is not None and left <= x <= right else None
+
+
 def polynomial_coefficients(nodes, values):
     """Convert evaluations of an existing polynomial to power coefficients."""
     divided = list(values)