Font-aware unit sizing; half-height unit toggle; bump to 0.86

Paths-mode unit rendering now always goes through _markup_unit_svg,
which fits the font's actual ink bounds (width AND height) to the
unit box — correct for all fonts, not just ГОСТ тип А.

Added half-height unit toggle: restricts the unit label to the upper
half of the panel box (y1 = midpoint at 103.8 mm), keeping it clear
of the numeric labels when they visually crowd the unit area.

web/app.py

@@ -9,7 +9,7 @@ from fontTools.pens.svgPathPen import SVGPathPen
 
 app = Flask(__name__)
 
-VERSION = "0.85"
+VERSION = "0.86"
 
 _LOGO_PATH = pathlib.Path(__file__).parent / 'static' / 'logo.png'
 _LOGO_B64 = base64.b64encode(_LOGO_PATH.read_bytes()).decode()
@@ -74,6 +74,7 @@ _FRAC_SIDE  = 0.12
 
 _UNIT_BOX_X0, _UNIT_BOX_X1 = 39.6, 57.4
 _UNIT_BOX_Y0, _UNIT_BOX_Y1 = 92.8, 114.8
+_UNIT_BOX_HALF_Y1 = (_UNIT_BOX_Y0 + _UNIT_BOX_Y1) / 2  # 103.8 — upper half of panel
 
 
 def _glyph_svg(ch: str, x: float, y: float, fs: float, fill: str, fd: _FontData):
@@ -244,9 +245,10 @@ def _has_markup(s: str) -> bool:
     return any(c in s for c in '^_') or ('{' in s and '}' in s)
 
 
-def _markup_unit_svg(unit: str, fd: _FontData, fill='#1a1a1a') -> str:
+def _markup_unit_svg(unit: str, fd: _FontData, fill='#1a1a1a', box_y1=None) -> str:
     nodes = _parse_markup(unit)
-    x0, x1, y0, y1 = _UNIT_BOX_X0, _UNIT_BOX_X1, _UNIT_BOX_Y0, _UNIT_BOX_Y1
+    x0, x1 = _UNIT_BOX_X0, _UNIT_BOX_X1
+    y0, y1 = _UNIT_BOX_Y0, (box_y1 if box_y1 is not None else _UNIT_BOX_Y1)
     xc, yc = (x0 + x1) / 2, (y0 + y1) / 2
 
     w1 = _measure(nodes, 1.0, fd)
@@ -316,8 +318,9 @@ def _fmt(v: float) -> str:
 
 def generate_svg(unit, min_val, max_val, range_label, big_ticks, small_ticks, label_count,
                  use_paths=True, scale_type='linear', custom_labels=None, label_size=9,
-                 font_key=None):
+                 font_key=None, half_height_unit=False):
     fd = _FONTS.get(font_key) or _FONTS.get(_DEFAULT_FONT) or next(iter(_FONTS.values()))
+    unit_box_y1 = _UNIT_BOX_HALF_Y1 if half_height_unit else None
 
     if scale_type == 'log':
         if min_val <= 0 or max_val <= 0:
@@ -424,13 +427,12 @@ def generate_svg(unit, min_val, max_val, range_label, big_ticks, small_ticks, la
         ' M 58.443978,107.54692 H 183.64409 v 6.19963 H 58.443978 Z" />'
     )
 
-    if _has_markup(unit):
-        unit_svg = '    ' + _markup_unit_svg(unit, fd)
-    elif use_paths:
-        unit_svg = '    ' + _text_to_paths(
-            unit, 41.455711, 109.03796, _unit_font_size(unit, fd), fd,
-            wrap_transform=f'scale({_UNIT_SCALE_X},1.0364155)'
-        )
+    # Paths mode and any unit needing special handling (markup, half-height):
+    # use _markup_unit_svg which fits actual ink bounds to the box, giving
+    # correct sizing for all fonts. Text mode for plain normal-height units
+    # keeps live <text> nodes; half-height always uses paths for correct centering.
+    if use_paths or _has_markup(unit) or half_height_unit:
+        unit_svg = '    ' + _markup_unit_svg(unit, fd, box_y1=unit_box_y1)
     else:
         fs = _unit_font_size(unit, fd)
         unit_svg = (
@@ -503,7 +505,8 @@ def generate():
     label_count = max(2, int(request.form.get('label_count', 6)))
     use_paths   = request.form.get('output_mode', 'paths') == 'paths'
     scale_type  = request.form.get('scale_type', 'linear')
-    font_key    = request.form.get('font', _DEFAULT_FONT)
+    font_key         = request.form.get('font', _DEFAULT_FONT)
+    half_height_unit = request.form.get('half_height_unit') == '1'
     if request.form.get('max_is_inf') == '1':
         max_val = math.inf
 
@@ -513,7 +516,7 @@ def generate():
     try:
         svg = generate_svg(unit, min_val, max_val, range_label, big_ticks, small_ticks,
                            label_count, use_paths, scale_type, custom_labels, label_size,
-                           font_key)
+                           font_key, half_height_unit)
     except ValueError as err:
         return Response(str(err), status=400, mimetype='text/plain')
     return Response(svg, mimetype='image/svg+xml')

web/templates/index.html

@@ -302,6 +302,14 @@
             <label>Unit</label>
             <input name="unit" type="text" value="%" required>
             <span style="font-family:var(--f-mono);font-size:0.65rem;color:var(--muted)">Markup: cm^2 · H_2O · {1/2} fraction · nests, e.g. {m/s^2}</span>
+            <div style="display:flex;align-items:center;gap:0.5rem;margin-top:0.2rem">
+              <div class="mode-toggle" role="group" aria-label="Unit height">
+                <button type="button" class="mode-btn active" data-unit-height="normal">Full height</button>
+                <button type="button" class="mode-btn" data-unit-height="half"
+                  title="Restrict unit label to the upper half of the panel — use when numeric labels visually crowd the unit">Half height</button>
+              </div>
+              <input type="hidden" name="half_height_unit" id="half-height-unit" value="0">
+            </div>
           </div>
           <div class="field">
             <label>Range label</label>
@@ -511,6 +519,15 @@
 
     document.getElementById('font-select').addEventListener('change', doGenerate);
 
+    document.querySelectorAll('[data-unit-height]').forEach(btn => {
+      btn.addEventListener('click', () => {
+        document.querySelectorAll('[data-unit-height]').forEach(b => b.classList.remove('active'));
+        btn.classList.add('active');
+        document.getElementById('half-height-unit').value = btn.dataset.unitHeight === 'half' ? '1' : '0';
+        doGenerate();
+      });
+    });
+
     doGenerate();
   </script>
 </body>