fix: 얇은 여백 띠 · 쪽 경계의 표 선 + feat: 여백 mm 통일 · 도구 모음 선택

CHANGELOG.md

@@ -12,14 +12,54 @@ The margins were two constants nothing could reach: a host could pick the paper
 write on, and an RTF from Word or HWP had its own margins dropped, so a document opened here paginated
 differently from what its author saw.
 
-- `RichEditor.PageMargin` (a `Thickness`, DIPs, four sides) and `PageSetup.Margin`, defaulting to
-  `PageSetup.DefaultMargin` — 48 left and right, 40 top and bottom, the previous constants.
+- `RichEditor.PageMargin` and `PageSetup.Margin`, four sides in **millimetres** (`PageMargins`), defaulting
+  to `PageSetup.DefaultMargin` — 15 mm on every side. Millimetres because that is the unit a page is discussed in: paper sizes
+  are defined in mm, Word and HWP show margins in mm, and RTF carries them as physical length. A dedicated
+  type rather than Avalonia's `Thickness`, which means device pixels everywhere else in a UI framework.
 - They belong to the document: saved in JSON/`.flow` (omitted at the default, so a document that never
   touched them keeps its bytes) and applied on load, like the paper size.
 - RTF writes them (`\margl`/`\margr`/`\margt`/`\margb`, and the section-level pair HWP reads) and now
   **reads** them, so a file from another word processor keeps its own margins.
 - A margin that would leave no page to write on — negative, NaN, or two sides adding up past the paper — is
   refused: the property keeps its last usable value, and a file falls back to the default.
+- A margin band too thin for the header, footer or page number leaves it undrawn, rather than centring the
+  line half off the paper and half over the body text. The margins stay exactly what was asked for.
+- The toolbar's page controls gained a **margin picker** beside paper and orientation, so the person using
+  an app built on `RichEditorView` can change them too: five steps in millimetres (5 / 10 / 15 / 20 / 30)
+  in a box built like the line-spacing control — the margin icon, the current step, a chevron for the list. Margins that match no preset (a host's, or a document's) select nothing rather
+  than showing one that is not the page's. New icon slot `RichEditorIcon.PageMargin`.
+
+### Changed — a table, picture or divider sits one line gap below the text above it (2026-09-21)
+
+Reported from the demo: a table sat flush against the paragraph above, with none of the air the line
+spacing gives between two lines of text. Both ends were at zero — paragraphs carry no bottom margin
+(HWP-style) and these blocks carried no top one.
+
+- `Block.AutoTopMargin` (NaN) is the new default `MarginTop` for `TableBlock`, `ImageBlock` and
+  `DividerBlock`: the editor resolves it to one line gap of body text, so it follows the document's font
+  size and line spacing. A stated margin, **0 included**, is used as given.
+- JSON writes nothing for it and reads a missing top margin back as auto, so a file that never expressed
+  an opinion — every file written before the field existed — gains the gap.
+
+### Fixed — a picture's own outline was painting over its edge (2026-09-23)
+
+Reported from the demo: at a high zoom, a picture looked cut by a pixel or two. Nothing clipped it — a
+picture carries a faint outline marking it as an object, and a pen is centred on the rect it strokes, so
+half of that line lay on the picture and replaced its outermost half-pen on every side. The bold border of
+a selected picture, and the one around a picture inside a table cell or a selected inline icon, did the
+same with twice the weight. All of them now sit half a pen outside the picture, touching none of its
+pixels. (A table's borders go the other way — see below — because there the line is the table's own ink.)
+That moved the top line of a picture opening a page just above the page's content clip, which cut it off;
+the outline, selection border and handles are now drawn after the page's content, bounded by the paper.
+
+### Fixed — a table's outline was cut where a page break crossed it (2026-09-20)
+
+Reported from the demo. A 1px pen is centred on the rect it strokes, so a cell on the table's edge put half
+its line outside the table's own box; a page break lands on that box, and the page's clip cut the line in
+two — part of its weight at the bottom of one page, the rest at the top of the next (measured: 67% of a
+whole line). The edges that are the table's boundary are now drawn half a pen inwards, which keeps a
+table's ink inside the box pagination knows about — and lands those lines on whole pixels, so they come out
+crisper as well. Interior borders, shared by two cells, are unchanged.
 
 ### Added — the keyboard shortcut table is public (2026-09-20)
 

README.ko.md

@@ -123,7 +123,7 @@ Editor.FontFamilyChoices = new[] { "Segoe UI", "Arial", "맑은 고딕" }; // 
 
 - 인라인 및 블록 **이미지** — 삽입, 크기 조절(모서리 또는 가로·세로 한 변 손잡이), 교체, 저장, 대체 텍스트
 - 워드 스타일 **페이지 뷰**: `PageSize`(기본 Continuous, 또는 A4/A3/A5/B4/B5/Letter/Legal/Tabloid),
-  `PageOrientation`, `PageMargin`(네 변), `ShowPageBoundaries`, 줄 단위 페이지 나누기, 머리글/바닥글/쪽번호
+  `PageOrientation`, `PageMargin`(네 변, mm), `ShowPageBoundaries`, 줄 단위 페이지 나누기, 머리글/바닥글/쪽번호
 - 페이지 설정은 **문서 단위로 저장**되고(`FlowDocument.PageSetup`) 불러올 때 다시 적용됩니다 —
   워드프로세서와 같습니다
 - **인쇄 및 PDF**: 페이지별 렌더링(`RenderPrintPage`, 300 DPI)과 글자를 선택·검색할 수 있는 PDF

README.md

@@ -116,7 +116,7 @@ for a full editor host.
 
 - Inline and block **images** — insert, resize (corner or single-edge handles), replace, save, alt text
 - Word-style **page view**: `PageSize` (Continuous by default, or A4/A3/A5/B4/B5/Letter/Legal/Tabloid),
-  `PageOrientation`, `PageMargin` (four sides), `ShowPageBoundaries`, line-boundary page breaks,
+  `PageOrientation`, `PageMargin` (four sides, in mm), `ShowPageBoundaries`, line-boundary page breaks,
   headers/footers/page numbers
 - Page setup is **persisted per document** (`FlowDocument.PageSetup`) and re-applied on load, like a word
   processor

docs/DOCUMENT_FORMAT.md

@@ -64,15 +64,16 @@ FlowDocument
     "Header": null,              // 머리글 텍스트(없으면 생략)
     "Footer": null,              // 바닥글 텍스트(없으면 생략)
     "ShowPageNumbers": false,
-    "MarginLeft": 96,            // 페이지 여백 px(DIP), 변마다 하나. 기본값이면 생략
-    "MarginTop": 80,             // 기본 좌우 48 · 상하 40
-    "MarginRight": 96,
-    "MarginBottom": 80
+    "MarginLeft": 25,            // 페이지 여백 **mm**, 변마다 하나. 기본값이면 생략
+    "MarginTop": 20,             // 기본 좌우 12.7mm(=0.5인치) · 상하 10.6mm
+    "MarginRight": 25,
+    "MarginBottom": 20
   }
 }
 ```
 
-- **여백(`Margin*`)**: 용지 가장자리와 본문 사이의 띠(머리글·바닥글·쪽번호가 그려지는 곳). 변마다 하나이며 **기본값(좌우 48 · 상하 40)이면 생략**되므로 여백을 건드리지 않은 문서의 바이트는 그대로다. 일부 변만 있으면 나머지는 기본값. **본문을 놓을 자리가 남지 않는 값**(음수·NaN·무한대, 또는 마주 보는 두 변의 합이 용지보다 큼)은 한 변만 고치지 않고 **네 변 모두 기본값으로 되돌린다** — 파일이 뜻한 바가 아니므로 절반만 적용하지 않는다.
+- **여백(`Margin*`)**: 용지 가장자리와 본문 사이의 띠(머리글·바닥글·쪽번호가 그려지는 곳). 단위는 **밀리미터**다 — 용지 크기가 mm로 정의되고 Word·아래한글도 mm로 보여 주며, RTF는 물리 길이(twips)로 싣는다(렌더는 96dpi DIP로 환산: 1mm = 96/25.4 ≈ 3.7795px). 변마다 하나이며 **기본값(좌우 12.7 · 상하 10.6mm)이면 생략**되므로 여백을 건드리지 않은 문서의 바이트는 그대로다. 일부 변만 있으면 나머지는 기본값. **본문을 놓을 자리가 남지 않는 값**(음수·NaN·무한대, 또는 마주 보는 두 변의 합이 용지보다 큼)은 한 변만 고치지 않고 **네 변 모두 기본값으로 되돌린다** — 파일이 뜻한 바가 아니므로 절반만 적용하지 않는다.
+  - RTF는 정수 twips라 mm가 정확히 왕복되지 않는다(25mm → 1417 → 24.994). 오차는 최대 1 twip(≈0.018mm).
 - **`PageSetup`(선택)**: 워드프로세서식 페이지 설정. 로드 시 에디터의 용지/방향/머리글·바닥글/쪽번호 속성에 적용되고, 이후 페이지 속성을 바꾸면 문서로 다시 캡처된다. **기본 상태(용지 `Continuous`, 머리글/바닥글/쪽번호 없음)면 통째로 생략**되므로 평범한 문서의 바이트는 이전과 동일하다. 열거값은 이름으로 직렬화되어 미래의 알 수 없는 값은 기본값으로 안전하게 강등된다. 이 필드를 모르는 (구) 판독기는 무시한다 — 추가 필드라 버전 증가 없음.
 
 #### 버전 이력

samples/AvaloniaRichEditor.Demo/Views/MainWindow.axaml

@@ -15,7 +15,17 @@
          behaviour (right-click Copy on a table, the table-border click) can only be checked in a viewer. -->
     <DockPanel>
         <Border DockPanel.Dock="Top" Padding="8,2" BorderThickness="0,0,0,1" BorderBrush="#DDDDDD">
-            <CheckBox x:Name="ReadOnlyToggle" Content="읽기 전용 (IsReadOnly)"/>
+            <StackPanel Orientation="Horizontal" Spacing="16">
+                <CheckBox x:Name="ReadOnlyToggle" Content="읽기 전용 (IsReadOnly)"/>
+                <!-- The view's toolbar has paper and orientation but no margins; without this the margin
+                     bands (header/footer/page numbers, print) could not be checked in the demo at all. -->
+                <StackPanel Orientation="Horizontal" Spacing="6" VerticalAlignment="Center">
+                    <TextBlock Text="여백 (PageMargin)" VerticalAlignment="Center"/>
+                    <!-- SelectedIndex is set in code, AFTER ItemsSource: setting it here runs first and the
+                         box comes up blank. -->
+                    <ComboBox x:Name="MarginPicker" MinWidth="220"/>
+                </StackPanel>
+            </StackPanel>
         </Border>
         <controls:RichEditorView x:Name="EditorView"/>
     </DockPanel>

samples/AvaloniaRichEditor.Demo/Views/MainWindow.axaml.cs

@@ -32,8 +32,29 @@ public MainWindow()
             Editor.IsReadOnly = ReadOnlyToggle.IsChecked == true;
             Editor.ShowFormattingMenu = !Editor.IsReadOnly;
         };
+
+        // Page margins (1.3.0). The view's toolbar has paper and orientation but no margins, and the
+        // margin band is where the header, the footer and the page number are drawn — the asymmetric
+        // preset is the one that tells "four sides" apart from "two", on screen and in print.
+        MarginPicker.ItemsSource = MarginPresets.ConvertAll(p => p.Label);
+        MarginPicker.SelectedIndex = 0;
+        MarginPicker.SelectionChanged += (_, _) =>
+        {
+            int i = MarginPicker.SelectedIndex;
+            if (i >= 0 && i < MarginPresets.Count) Editor.PageMargin = MarginPresets[i].Margin;
+        };
     }
 
+    // Millimetres, like the toolbar's own picker — these exist to reach shapes the toolbar's five steps
+    // do not: a band too thin for the header, and an asymmetric one (which tells "four sides" from "two").
+    private static readonly System.Collections.Generic.List<(string Label, AvaloniaRichEditor.Documents.PageMargins Margin)> MarginPresets =
+    [
+        ("기본 12.7 / 10.6mm", AvaloniaRichEditor.Documents.PageSetup.DefaultMargin),
+        ("아주 좁게 4 / 3mm", new AvaloniaRichEditor.Documents.PageMargins(4, 3, 4, 3)),
+        ("아주 넓게 40 / 30mm", new AvaloniaRichEditor.Documents.PageMargins(40, 30, 40, 30)),
+        ("비대칭 좌42 상6 우8 하31mm", new AvaloniaRichEditor.Documents.PageMargins(42, 6, 8, 31)),
+    ];
+
     protected override void OnOpened(EventArgs e)
     {
         base.OnOpened(e);

src/AvaloniaRichEditor/Controls/RichEditor.HitTesting.cs

@@ -57,7 +57,7 @@ public partial class RichEditor
         double yOffset = 0, maxWidth = ContentLayoutWidth;
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             double top = yOffset;
             double h = BlockExtent(block, maxWidth, top, out var ft, out var tl);
             yOffset += h + block.MarginBottom;
@@ -260,6 +260,24 @@ private static TableLayout AssembleTableLayout(TableBlock tb, double[] colX, dou
         return new TableLayout(colX, rowY, colX[cols] - startX, rowY[rows] - top, anchors);
     }
 
+    // The gap above a block, which every walker advances by before the block's own box starts.
+    //
+    // Normally the block's MarginTop. A table whose margin is unset (NaN — TableBlock.AutoMarginTop) gets
+    // ONE LINE GAP instead: the white space a line break leaves between two lines of body text. Without it
+    // a table butts straight against the paragraph above, because paragraphs carry no bottom margin
+    // (HWP-style, round 24) and a table carried no top one, so the two met at zero (reported from the
+    // demo, 2026-09-21). An explicit margin, including 0, is used as given.
+    //
+    // Sized from the DOCUMENT's default typography rather than from the block above: every walker below
+    // iterates blocks without tracking a predecessor, and several `continue` past culled ones, so a
+    // "previous block" would go stale in exactly the walkers that skip — the drift class G1/G2 cleaned up.
+    // The cost is that a table under a big heading gets a body-text gap, not a heading-sized one.
+    internal double TopGapOf(Block block)
+        => double.IsNaN(block.MarginTop) ? AutoBlockTopGap : block.MarginTop;
+
+    // One line gap of body text: the line box (font size x spacing) minus the text it holds.
+    internal double AutoBlockTopGap => Math.Max(0, PtToPx(DefaultFontSize) * (DefaultLineSpacing - 1));
+
     // G1 — single source of a block's vertical extent (height, EXCLUDING MarginTop/MarginBottom) at the
     // given top, plus the layout objects the walkers reuse (a paragraph's TextLayout / a table's
     // TableLayout; null otherwise). Every read-only document walk — measure, hit-tests, block-at-y —
@@ -308,7 +326,7 @@ private double BlockExtent(Block block, double maxWidth, double top,
         double yOffset = 0, listIndent = 10, maxWidth = ContentLayoutWidth;
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             double top = yOffset;
             double h = BlockExtent(block, maxWidth, top, out _, out var tl);
             yOffset += h + block.MarginBottom;
@@ -332,7 +350,7 @@ private double BlockExtent(Block block, double maxWidth, double top,
         double yOffset = 0, maxWidth = ContentLayoutWidth;
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             double top = yOffset;
             double h = BlockExtent(block, maxWidth, top, out _, out var tl);
             if (block == target && tl is { } t) return (top, t);
@@ -381,7 +399,7 @@ private bool IsOnTableLeftOrTopBorder(TableBlock tb, Point p)
         const double m = 4;
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             double top = yOffset;
             double h = BlockExtent(block, maxWidth, top, out _, out var tl);
             yOffset += h + block.MarginBottom;
@@ -662,7 +680,7 @@ private TextPointer GetPositionFromPoint(Point p)
 
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             double top = yOffset;
             double h = BlockExtent(block, maxWidth, top, out var ft, out var tl);
             yOffset += h + block.MarginBottom;

src/AvaloniaRichEditor/Controls/RichEditor.Input.cs

@@ -1803,7 +1803,7 @@ private bool TryEnterTableRow(TableBlock tb, bool firstRow)
         bool found = false;
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             if (found) return yOffset;
             double h = BlockExtent(block, maxWidth, yOffset, out _, out _);
             found = ReferenceEquals(block, p);
@@ -1818,7 +1818,7 @@ private bool TryEnterTableRow(TableBlock tb, bool firstRow)
         double yOffset = 0, maxWidth = ContentLayoutWidth;
         foreach (var block in Document.Blocks)
         {
-            yOffset += block.MarginTop;
+            yOffset += TopGapOf(block);
             double top = yOffset;
             double h = BlockExtent(block, maxWidth, top, out _, out _);
             // Only image/table blocks are "entered" by Up/Down arrow navigation.