fixes graphics

backend/app/fitness/body_composition.py

@@ -6,10 +6,6 @@ def _is_female(sex: str) -> bool:
     return sex.lower() in ("f", "female", "ж", "женский", "woman")
 
 
-def _cm_to_inches(cm: float) -> float:
-    return cm / 2.54
-
-
 def _clamp_bf(value: float) -> float:
     return round(max(3.0, min(50.0, value)), 1)
 
@@ -25,30 +21,25 @@ def navy_body_fat_pct(
     if height_cm <= 0 or neck_cm <= 0 or waist_cm <= 0:
         return None
 
-    height_in = _cm_to_inches(height_cm)
-    neck_in = _cm_to_inches(neck_cm)
-    waist_in = _cm_to_inches(waist_cm)
-
     if _is_female(sex):
         if hip_cm is None or hip_cm <= 0:
             return None
-        hip_in = _cm_to_inches(hip_cm)
-        sum_in = waist_in + hip_in - neck_in
-        if sum_in <= 0:
+        measurement_sum_cm = waist_cm + hip_cm - neck_cm
+        if measurement_sum_cm <= 0:
             return None
         denom = (
             1.29579
-            - 0.35004 * math.log10(sum_in)
-            + 0.22100 * math.log10(height_in)
+            - 0.35004 * math.log10(measurement_sum_cm)
+            + 0.22100 * math.log10(height_cm)
         )
     else:
-        diff_in = waist_in - neck_in
-        if diff_in <= 0:
+        measurement_diff_cm = waist_cm - neck_cm
+        if measurement_diff_cm <= 0:
             return None
         denom = (
             1.0324
-            - 0.19077 * math.log10(diff_in)
-            + 0.15456 * math.log10(height_in)
+            - 0.19077 * math.log10(measurement_diff_cm)
+            + 0.15456 * math.log10(height_cm)
         )
 
     if denom <= 0: