Font Manger: improve baseline

ThomasFarstrike · ThomasFarstrike · commit 3f9740c7d74d · 2026-05-27T14:43:09.000+02:00
diff --git a/internal_filesystem/builtin/apps/com.micropythonos.about/assets/about.py b/internal_filesystem/builtin/apps/com.micropythonos.about/assets/about.py
@@ -4,7 +4,7 @@
 
 import lvgl as lv
 
-from mpos import Activity, DisplayMetrics, BuildInfo, DeviceInfo
+from mpos import Activity, DisplayMetrics, BuildInfo, DeviceInfo, FontManager
 import mpos
 
 class About(Activity):
@@ -15,6 +15,8 @@ class About(Activity):
     def onCreate(self):
         self._uptime_label = None
         self._timer = None
+        self._header_font = FontManager.getFont(size=14, family="Montserrat", emoji=False)
+        self._body_font = FontManager.getFont(size=12, family="Montserrat", emoji=False)
         screen = lv.obj()
         screen.set_style_border_width(0, lv.PART.MAIN)
         screen.set_flex_flow(lv.FLEX_FLOW.COLUMN)
@@ -233,11 +235,11 @@ def _add_label(self, parent, text, is_header=False, margin_top=DisplayMetrics.pc
         if is_header:
             primary_color = lv.theme_get_color_primary(None)
             label.set_style_text_color(primary_color, lv.PART.MAIN)
-            label.set_style_text_font(lv.font_montserrat_14, lv.PART.MAIN)
+            label.set_style_text_font(self._header_font, lv.PART.MAIN)
             label.set_style_margin_top(margin_top, lv.PART.MAIN)
             label.set_style_margin_bottom(DisplayMetrics.pct_of_height(2), lv.PART.MAIN)
         else:
-            label.set_style_text_font(lv.font_montserrat_12, lv.PART.MAIN)
+            label.set_style_text_font(self._body_font, lv.PART.MAIN)
             label.set_style_margin_bottom(2, lv.PART.MAIN)
         return label
 
diff --git a/internal_filesystem/lib/mpos/ui/font_manager.py b/internal_filesystem/lib/mpos/ui/font_manager.py
@@ -157,6 +157,9 @@ def _get_composed_font(cls, base_font, size=None):
         try:
             # Do not mutate builtin font fallback: builtins may live in readonly memory.
             emoji_font.fallback = base_font
+            emoji_font.base_line = cls._font_base_line(base_font)
+            emoji_font.underline_position = cls._font_underline_position(base_font)
+            emoji_font.underline_thickness = cls._font_underline_thickness(base_font)
         except Exception as err:
             cls._debug("compose fallback set failed: " + repr(err))
             return base_font
@@ -308,13 +311,14 @@ def _safe_getcwd(cls):
 
     @classmethod
     def _imgfont_path_cb(cls, font, unicode_cp, unicode_next, offset_y, user_data):
+        baseline = cls._font_base_line(font)
         if unicode_cp == CP_VARIATION_SELECTOR_TEXT or unicode_cp == CP_VARIATION_SELECTOR_EMOJI:
-            offset_y.__dereference__(0)
+            offset_y.__dereference__(-baseline)
             return cls._get_empty_imgfont_src(cls._font_pixel_height(font))
 
         src = cls._get_emoji_src(unicode_cp, cls._font_pixel_height(font))
         if src is not None:
-            offset_y.__dereference__(0)
+            offset_y.__dereference__(-baseline)
             return cls._get_scaled_imgfont_src(src, cls._font_pixel_height(font))
 
         cls._log_unknown_emoji_codepoint(unicode_cp)
@@ -380,6 +384,27 @@ def _font_pixel_height(cls, font):
         except Exception:
             return 1
 
+    @classmethod
+    def _font_base_line(cls, font):
+        try:
+            return int(font.base_line)
+        except Exception:
+            return 0
+
+    @classmethod
+    def _font_underline_position(cls, font):
+        try:
+            return int(font.underline_position)
+        except Exception:
+            return 0
+
+    @classmethod
+    def _font_underline_thickness(cls, font):
+        try:
+            return int(font.underline_thickness)
+        except Exception:
+            return 0
+
     @classmethod
     def _get_scaled_imgfont_src(cls, src, target_height):
         key = (src, target_height)
