fix(pages): make a line taller by the borders its characters' shapes draw above and below

CHANGELOG.md

@@ -18,6 +18,8 @@
   끝은 줄에 자리를 차지하지 않는다. 전에는 필드 끝을 다음 줄로 보내 빈 줄을 하나 더 셌다.
 - 쪽 수 추정이 글 문단 첫 줄 아래로 놓인 나누지 않는 위아래 표가 쪽에 들어가지 않을 때, 한/글처럼 문단 줄은 들어가는 쪽에
   두고 표만 다음 쪽 맨 위로 보낸다. 전에는 문단 줄까지 다음 쪽 표 아래로 보내 쪽 수가 하나 늘었다.
+- 쪽 수 추정이 글자 모양의 위·아래 테두리를 줄 높이에 넣는다. 한/글은 테두리가 있는 글자(문단 끝 빈 run 포함)가 선 줄을 그 두께만큼
+  위아래로 키우고 줄 간격도 그 높이로 잰다. 그런 문단의 줄 캐시는 쓰지 않는다.
 
 ## [6.11.0] - 2026-11-02
 

src/hwpx/layout/line_cache.py

@@ -468,6 +468,8 @@ def _lines(measure: Any, paragraph: Any, width: int, *, first: bool,
     size, refs, sizes = _pages._text_size(measure, runs)
     if headed and not sizes and _pages._text_size(measure, runs, paragraph)[0] > size:
         return None  # an empty paragraph under a taller number label (its line as tall as that): left for Hancom
+    if any(measure.char_box(run.get("charPrIDRef")) > measure.char_height(run.get("charPrIDRef")) for run in runs):
+        return None  # a character border above or below: Hancom writes its lines' heights and baselines otherwise
     end = _pages._end_size(measure, runs, sizes)
     if sizes and end > sizes[-1] and _pages._run_text(runs).endswith("\n"):
         return None  # a larger empty end after a line break: Hancom writes the line before it as tall as the end

src/hwpx/layout/pages.py

@@ -625,6 +625,8 @@ def __init__(self, root: Any) -> None:
         self._numbered: dict[str, bool] = {}
         self._label_sizes: dict[str, int] = {}
         self._pictured: dict[str, bool] = {}
+        self._boxes: dict[str, int] = {}
+        self._edges: dict[str, int] | None = None
         #: how far apart the default tab stops of the section at hand are (see :func:`_tab_stop`)
         self.tab_stop = _DEFAULT_TAB_STOP
 
@@ -638,6 +640,24 @@ def char_height(self, char_pr_id: Any) -> int:
         style = self._root.char_property(char_pr_id)
         return int(style.attributes.get("height", 1000)) if style is not None else 1000
 
+    def char_box(self, char_pr_id: Any) -> int:
+        """How tall a character of *char_pr_id* makes its line: its height, and the width of a border its shape
+        draws above and below it (Hancom: the line that much taller, spaced from that height)."""
+
+        if self._edges is None:  # each border fill's width above and below, read once from the header
+            self._edges = {}
+            for fill in self._header.iter(f"{HH}borderFill"):
+                self._edges[fill.get("id")] = sum(
+                    round(float(rule.get("width", "0 mm").split()[0]) * 7200 / 25.4)
+                    for rule in (fill.find(f"{HH}topBorder"), fill.find(f"{HH}bottomBorder"))
+                    if rule is not None and rule.get("type", "NONE") != "NONE")
+        key = str(char_pr_id)
+        if key not in self._boxes:
+            style = self._root.char_property(char_pr_id)
+            fill = style.attributes.get("borderFillIDRef") if style is not None else None
+            self._boxes[key] = self.char_height(char_pr_id) + self._edges.get(fill, 0)
+        return self._boxes[key]
+
     def font_line(self, size: int, style: Any) -> int:
         """How tall a line of characters *size* tall in *style* is in a paragraph taking its line height from
         the font (see :func:`~hwpx.form_fit.measure.font_line_height`); *size* for a face the glyph table does
@@ -2745,7 +2765,7 @@ def _end_size(measure: _Measure, runs: list[Any], sizes: list[int]) -> int:
 
     if not runs or not sizes or any(len(child) or child.tag != f"{HP}t" or child.text for child in runs[-1]):
         return 0
-    size = measure.char_height(runs[-1].get("charPrIDRef"))
+    size = measure.char_box(runs[-1].get("charPrIDRef"))
     if _run_text(runs).endswith("\n"):  # after a line break the empty last line is the run alone: as tall as
         return size if size != sizes[-1] else 0  # itself, smaller or larger (see _line_metrics)
     return size if size > min(sizes) else 0
@@ -2783,15 +2803,20 @@ def _held_sizes(measure: _Measure, runs: list[Any], sizes: list[int]) -> dict[in
     """Where in the text a run holding a control shown on a line (see :func:`_shown_control`; not a note) or an
     object not set as a character stands after the first character -> that run's size, when it is larger than the
     smallest character: Hancom sets it as a character of no width, the line it falls on as tall as its run's
-    characters (those before the text, see :func:`_head_size`)."""
+    characters (those before the text, see :func:`_head_size`). Each character whose shape draws a border above
+    or below it is held too, its line as tall as the character and the border (see :meth:`_Measure.char_box`)."""
 
     if not sizes:
         return {}
     place, held = 0, {}
     for run in runs:
+        box = measure.char_box(run.get("charPrIDRef"))
+        boxed = box > measure.char_height(run.get("charPrIDRef"))  # a border above or below its characters
         for child in run:
             name = _local(child)
             if name == "t":
+                for offset in range(len(_t_text(child))) if boxed else ():
+                    held[place + offset + 1] = max(held.get(place + offset + 1, 0), box)
                 place += len(_t_text(child))
             elif place and (_shown_control(child) and not any(_local(kind) in ("footNote", "endNote") for kind in child)
                             or name in _OBJECTS and (child.find(f"{HP}pos") is None

tests/test_layout_page_estimate.py

@@ -246,6 +246,10 @@
     # empty one at 10 or 20 pt: after the break the empty last line is that run alone, as tall as itself smaller
     # or larger, the line before it spaced from its own characters
     "pages_empty_end_run_after_a_line_break": 12,
+    # Twenty-six times on a page of its own: ten characters at 10 or 14 pt, an empty run ending them, all of them
+    # or two amid them in a character shape with a border 0.1 or 0.4 mm on every side, above and below or left
+    # and right: a border above or below makes the line that much taller on each side, spaced from that height
+    "pages_character_border_line_height": 26,
     # A run of 14 pt before a line of 10 pt text (함초롬바탕, spaced 160%): one holding nothing but controls
     # makes the line as tall as itself (1400, spaced 840), an empty one takes no room:
     "pages_section_controls_run_taller_than_the_text": 1,  # the section's and the columns' definitions