Map ViewBorder in the Python host model; record DXF kind blocker

Bounds, scale and rotation are writable with viewport and scale reference
rules. staged_python_view_border_lifecycle_over_real_ipc passes every gate
in DWG; a DXF DRAWINGVIEW reopens as an opaque entity, pinned by a canary.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

crates/ocs_plugin_api/build.rs

@@ -795,6 +795,7 @@ fn generate_entity_coverage(out_dir: &Path, registry: &TypeRegistry) {
                     | ("Wipeout", _)
                     | ("Underlay", _)
                     | ("Viewport", _)
+                    | ("ViewBorder", _)
                     | (
                         "MLine",
                         "flags"

crates/ocs_plugin_api/entity_coverage_policy.json

@@ -452,6 +452,16 @@
       "render_mode",
       "circle_sides",
       "ucs_icon_visible"
+    ],
+    "ViewBorder": [
+      "layer",
+      "min",
+      "max",
+      "center",
+      "scale",
+      "rotation_angle",
+      "active_viewport",
+      "scale_handle"
     ]
   },
   "readable": {
@@ -553,6 +563,9 @@
       "brightness",
       "contrast",
       "ambient_color"
+    ],
+    "ViewBorder": [
+      "version"
     ]
   },
   "aliases": {

crates/ocs_plugin_api/src/entity_coverage.rs

@@ -949,6 +949,32 @@ fn validate_viewport(
     Ok(())
 }
 
+/// ViewBorder: the frame of a drawing view, tied to a viewport and a scale.
+#[cfg(feature = "host")]
+fn validate_view_border(
+    old: Option<&crate::host::acadrust::entities::ViewBorder>,
+    new: &crate::host::acadrust::entities::ViewBorder,
+) -> Result<(), String> {
+    if old == Some(new) {
+        return Ok(());
+    }
+    for (name, pair) in [("min", new.min), ("max", new.max), ("center", new.center)] {
+        if !pair[0].is_finite() || !pair[1].is_finite() {
+            return Err(format!("ViewBorder.{name} must be finite"));
+        }
+    }
+    if new.min[0] >= new.max[0] || new.min[1] >= new.max[1] {
+        return Err("ViewBorder.min must be below max on both axes".into());
+    }
+    if !new.scale.is_finite() || new.scale <= 0.0 {
+        return Err("ViewBorder.scale must be finite and greater than zero".into());
+    }
+    if !new.rotation_angle.is_finite() {
+        return Err("ViewBorder.rotation_angle must be finite".into());
+    }
+    Ok(())
+}
+
 /// Validate newly created geometry for the kinds whose mapped fields have
 /// host checks. Called by the Python add path before an entity enters the document.
 #[cfg(feature = "host")]
@@ -1053,6 +1079,7 @@ pub fn validate_new_canvas_entity(entity: &crate::host::EntityType) -> Result<()
         EntityType::Wipeout(value) => validate_wipeout(None, value)?,
         EntityType::Underlay(value) => validate_underlay(None, value)?,
         EntityType::Viewport(value) => validate_viewport(None, value)?,
+        EntityType::ViewBorder(value) => validate_view_border(None, value)?,
         EntityType::AttributeDefinition(value) => {
             finite_vector(
                 "AttributeDefinition.insertion_point",
@@ -1418,6 +1445,7 @@ pub fn validate_entity_mutation(
         (EntityType::Wipeout(old), EntityType::Wipeout(new)) => validate_wipeout(Some(old), new)?,
         (EntityType::Underlay(old), EntityType::Underlay(new)) => validate_underlay(Some(old), new)?,
         (EntityType::Viewport(old), EntityType::Viewport(new)) => validate_viewport(Some(old), new)?,
+        (EntityType::ViewBorder(old), EntityType::ViewBorder(new)) => validate_view_border(Some(old), new)?,
         (EntityType::MLine(old), EntityType::MLine(new)) => validate_mline(Some(old), new)?,
         (EntityType::Leader(old), EntityType::Leader(new)) => validate_leader(Some(old), new)?,
         (EntityType::AttributeDefinition(old), EntityType::AttributeDefinition(new)) => {
@@ -1681,6 +1709,17 @@ pub fn validate_canvas_entity_references(
             return Err(format!("Shape text style {:?} has no SHX file", style.name));
         }
     }
+    if let EntityType::ViewBorder(value) = entity {
+        if !matches!(document.get_entity(value.active_viewport), Some(EntityType::Viewport(_))) {
+            return Err(format!("ViewBorder viewport {:?} does not exist", value.active_viewport));
+        }
+        if !matches!(
+            document.objects.get(&value.scale_handle),
+            Some(crate::host::acadrust::objects::ObjectType::Scale(_))
+        ) {
+            return Err(format!("ViewBorder scale {:?} does not exist", value.scale_handle));
+        }
+    }
     if let EntityType::Viewport(value) = entity {
         let owner = value.common.owner_handle;
         let in_paper_space = !owner.is_null()
@@ -2144,6 +2183,7 @@ mod tests {
                         | "Wipeout"
                         | "Underlay"
                         | "Viewport"
+                        | "ViewBorder"
                 )
             {
                 assert!(
@@ -2459,6 +2499,13 @@ mod tests {
                 "Viewport.render_mode".to_owned(),
                 "Viewport.circle_sides".to_owned(),
                 "Viewport.ucs_icon_visible".to_owned(),
+                "ViewBorder.min".to_owned(),
+                "ViewBorder.max".to_owned(),
+                "ViewBorder.center".to_owned(),
+                "ViewBorder.scale".to_owned(),
+                "ViewBorder.rotation_angle".to_owned(),
+                "ViewBorder.active_viewport".to_owned(),
+                "ViewBorder.scale_handle".to_owned(),
             ])
         );
     }

docs/plugin-host-model-completion-plan.md

@@ -7,13 +7,13 @@ Build a general Python document model over the OCS host API for all **43 canvas
 As of 20 September 2026, the working branch is `plugin/host-model-api` at
 `a8dd3640` plus the Leader increment, published as draft PR
 [#1391](https://github.com/HakanSeven12/OpenCADStudio/pull/1391). Host API is
-v7. The Python feature has explicit writes for **35 of 43** canvas kinds: 34
-are creatable and `Insert` remains update-only. This is **not** 35 completed
+v7. The Python feature has explicit writes for **36 of 43** canvas kinds: 35
+are creatable and `Insert` remains update-only. This is **not** 36 completed
 kinds: Tolerance, Shape, AttributeEntity, Hatch, MLine, Dimension, MultiLeader, Table, PolygonMesh, PolyfaceMesh, Mesh and Wipeout pass every completion gate.
 AttributeDefinition passes its host and real IPC lifecycle but remains short of
 `Complete` because the previously pinned CAD codec dropped optional ATTDEF
 fields during DXF reads; revalidate that blocker against the current
-`acadrust` revision `7ea4247`. Leader is mapped and integration-tested but blocked at W by three acadrust persistence gaps (see the ledger). Leader, Helix and Underlay are mapped and integration-tested but blocked at W by acadrust persistence gaps, and RasterImage and Viewport are held short of `Complete` by unverifiable or missing oracles (see the ledger). RasterImage is mapped and integration-tested, held short of `Complete` by unverifiable image-dictionary linkage. The other 8 canvas kinds have only `layer`
+`acadrust` revision `7ea4247`. Leader is mapped and integration-tested but blocked at W by three acadrust persistence gaps (see the ledger). Leader, Helix, Underlay and ViewBorder are mapped and integration-tested but blocked at W by acadrust persistence gaps, and RasterImage and Viewport are held short of `Complete` by unverifiable or missing oracles (see the ledger). RasterImage is mapped and integration-tested, held short of `Complete` by unverifiable image-dictionary linkage. The other 7 canvas kinds have only `layer`
 writes through the document model. All 43 have raw typed snapshots. There are
 three internal records and two opaque fallbacks outside the 43 canvas kinds.
 
@@ -123,7 +123,7 @@ The last five may require new engine capabilities rather than only Python conver
 
 ## Handoff start point
 
-Continue with **ViewBorder** (queue item 14). Leader is done except for its W
+Continue with **SectionSymbol** (queue item 15). Leader is done except for its W
 gate; when the engine writes DXF group 340, reads group 213 and the DWG
 R2010+ text-size question is decided, flip the canary assertions in
 `staged_python_leader_lifecycle_over_real_ipc` and mark it `Complete`.
@@ -168,3 +168,4 @@ exact queue above and update statuses with evidence after each increment.
 - Completed `Wipeout` (queue item 11) with rectangular and polygonal clip masks through the shared lifecycle driver; scripted creation matches OCS's native command. The queue now continues with `Underlay`.
 - Mapped `Underlay` against a fixture PDF `UnderlayDefinition`. All gates pass except DXF W: the reader does not convert the degree-valued rotation back to radians, and repeated DXF round trips compound the error (pinned by a canary). The queue now continues with `Viewport`.
 - Mapped `Viewport` with a paper-space owner rule and frozen-layer reference validation. Every gate except a paper-space canvas oracle passes through the shared driver; the kind stays integration-tested. The queue now continues with `ViewBorder`.
+- Mapped `ViewBorder` with viewport and scale reference rules. All gates pass in DWG; DXF loading does not restore the typed entity (pinned by a canary). The queue now continues with `SectionSymbol`.

docs/plugin-host-model-coverage-ledger.md

@@ -1,6 +1,6 @@
 # OCS canvas kind coverage ledger
 
-Use with [the completion plan](plugin-host-model-completion-plan.md). This ledger is current as of 20 September 2026: **35 of 43 canvas kinds have explicit geometry writes** (34 creatable, plus update-only `Insert`), **12 kinds are complete**, and 8 remain layer-only. `Mapped` means at least one non-layer field is exposed for Python writes; it does **not** mean the kind passes the completion gate. `Update-only` means Python creation is unavailable. `Layer-only` means raw inspection and canvas layer edits exist, but geometry is not mapped. Record actual evidence or a blocking issue before changing any status to `Complete`.
+Use with [the completion plan](plugin-host-model-completion-plan.md). This ledger is current as of 20 September 2026: **36 of 43 canvas kinds have explicit geometry writes** (35 creatable, plus update-only `Insert`), **12 kinds are complete**, and 7 remain layer-only. `Mapped` means at least one non-layer field is exposed for Python writes; it does **not** mean the kind passes the completion gate. `Update-only` means Python creation is unavailable. `Layer-only` means raw inspection and canvas layer edits exist, but geometry is not mapped. Record actual evidence or a blocking issue before changing any status to `Complete`.
 
 Completion gate codes: **C** = create through Python document model; **R** = read; **E** = edit defining geometry and another property; **D** = delete; **U** = undo/redo and atomic failure; **I** = real IPC plus GUI/canvas pick or observable behavior; **W** = DWG and DXF save/reopen; **V** = invalid-input checks and untouched-field/reference preservation; **P** = build and load the in-tree bundled plugin with a manifest matching the host toolchain and acadrust source. A kind is `Complete` only when **C/R/E/D/U/I/W/V/P** all pass and its property catalog matches implementation. `Blocked` requires a specific dependency or failing fixture.
 
@@ -41,7 +41,7 @@ Completion gate codes: **C** = create through Python document model; **R** = rea
 | Wipeout | **Complete** | Writable: `insertion_point`, `u_vector`, `v_vector` (the region's world extent), `size`, `flags`, `clipping_enabled`, `brightness`, `contrast`, `fade`, `clip_mode`, `clip_type` and `clip_boundary_vertices` (normalized image coordinates, -0.5..0.5). Read-only: `class_version`, `definition_handle`, `definition_reactor_handle`. Scripted creation matches OCS's native WIPEOUT command, which also leaves the definition link unset. Host validation requires finite non-parallel `u`/`v` vectors, a positive `size`, brightness/contrast/fade within 0..=100, known flags, finite clip vertices, exactly 2 vertices for a rectangular clip and at least 3 for a polygonal one. `staged_python_wipeout_lifecycle_over_real_ipc` (shared `run_mesh_lifecycle`) passes C/R/E/D/U/I/W/V/P: rectangular creation, a switch to a three-vertex polygonal inside-clip with a move in one transaction, canvas wires, eight rejection cases plus an atomic rollback, DWG and DXF reopen with re-edit, and three-step undo/redo. |
 | Underlay | **Integration-tested / blocked at W by acadrust (DXF rotation units)** | Writable: `underlay_type` and `definition_handle` (both fixed by the definition: creation names an existing `UnderlayDefinition`, and a mismatched type or missing definition is rejected), `insertion_point`, `x_scale`, `y_scale`, `z_scale`, `rotation`, `normal`, `flags`, `contrast`, `fade`, `clip_boundary_vertices`, `clip_inverted`. The file path and page live on the definition object, which scripts cannot create or list yet; they reference one the drawing already owns. Host validation requires finite nonzero scales, a finite rotation, a nonzero normal, contrast/fade within 0..=100, known flags, finite clip vertices (none, or at least 2) and an existing definition of the same type. `staged_python_underlay_lifecycle_over_real_ipc` (shared `run_mesh_lifecycle` with a fixture PDF definition) passes C/R/E/D/U/I/V/P and DWG W: creation, a placement/scale/rotation/contrast/fade/clip transaction, canvas wires, eight rejection cases plus an atomic rollback, DWG reopen and re-edit, and three-step undo/redo. **W blocker (engine, pinned by canary assertions):** DXF stores the rotation in degrees but the reader returns it unconverted, so 0.5 rad reopens as 28.6 and each further DXF save-reopen compounds it (1641.4 after a second), silently corrupting the rotation. Not `Complete` until the reader converts degrees back to radians. Not covered: creating definitions from a file path, DWF/DGN fixtures. |
 | Viewport | **Integration-tested** | Writable: `center`, `width`, `height`, `status`, `view_center`, `view_direction`, `view_target`, `lens_length`, `front_clip_z`, `back_clip_z`, `view_height`, `twist_angle`, `custom_scale`, `frozen_layers` (layer handles), `render_mode`, `circle_sides`, `ucs_icon_visible`. Read-only: `id`, snap/grid settings, UCS fields, `clip_boundary_handle`, `style_sheet`, shade-plot, background, visual-style and sun handles, lighting, `ambient_color`, `elevation`. Reference rules: the owner must be a paper-space layout block (a model-space viewport is rejected) and every frozen-layer handle must be an existing layer. Host validation requires finite centers, positive width, height, view height, lens length and scale, a nonzero view direction, finite clip planes and twist, and at least 3 circle sides. `staged_python_viewport_lifecycle_over_real_ipc` (shared `run_mesh_lifecycle`, paper-space owner supplied by the driver) passes C/R/E/D/U/V/W/P: creation in the paper-space block, a move/resize/view-height/twist/frozen-layer transaction, seven rejection cases plus an atomic rollback, DWG and DXF reopen with re-edit, and three-step undo/redo. **Why not `Complete`:** the I gate lacks a canvas oracle because a paper-space viewport only draws on its layout tab, which the driver does not activate; viewport `id` uniqueness within a layout, clip boundary entities and view-to-scale synchronization are not handled by the host. |
-| ViewBorder | Layer-only | Requires linked view records. |
+| ViewBorder | **Integration-tested / blocked at W by acadrust (DXF kind)** | Writable: `min`, `max`, `center` (2-D pairs), `scale`, `rotation_angle`, `active_viewport` and `scale_handle` (both required at creation). `version` is read-only. Reference rules: `active_viewport` must be an existing Viewport entity and `scale_handle` an existing `Scale` object. Host validation requires finite bounds with `min` below `max` on both axes, a positive scale and a finite rotation. `staged_python_view_border_lifecycle_over_real_ipc` (shared `run_mesh_lifecycle`, driver-made viewport and scale fixtures) passes C/R/E/D/U/I/V/P and DWG W: creation, a resize/recenter/scale/rotation transaction, canvas wires, seven rejection cases plus an atomic rollback, DWG reopen and re-edit, and three-step undo/redo. **W blocker (engine, pinned by a canary):** a DXF `DRAWINGVIEW` reopens as a different, opaque entity kind rather than as a ViewBorder, so only DWG restores the typed record. Not `Complete` until DXF loading restores the typed entity. Not covered: the linked view representation and drawing-view definition records. |
 | SectionSymbol | Layer-only | Requires section-view style and point records. |
 | Light | Layer-only | Requires position/target and photometric-state fixture. |
 | Region | Layer-only | Requires valid ACIS region payload. |

docs/plugin-host-model.md

@@ -35,7 +35,7 @@ attached attribute and sequence records. Those fields report `transaction_geomet
 catalog. All 43 canvas kinds also support nonempty `layer` changes through
 the same undoable transaction; internal and opaque variants remain read-only
 through the document model. The adapter accepts only `layer` patches for
-canvas kinds outside its 35 geometry converters. Other writable properties
+canvas kinds outside its 36 geometry converters. Other writable properties
 still report `type_conversion_only`; broader CAD range and cross-property
 checks remain outstanding.
 The host's `entity_snapshot` helper serializes any typed entity as a detached
@@ -91,7 +91,7 @@ Input tokens are bound to the drawing tab that requested the pick. Polling a
 token from another tab returns no result and does not consume it.
 
 Python `doc.entities[handle]` returns a descriptor for every entity. For kinds
-outside the 35-kind generated schema it contains only handle, kind, and layer;
+outside the 36-kind generated schema it contains only handle, kind, and layer;
 `layer` is editable on canvas kinds. `doc.coverage()` enumerates the
 catalog; `doc.coverage("Line")` and `line.coverage` return one entry. For
 covered kinds, the coverage object lists actual readable and editable

plugins/opencad-python/README.md

@@ -94,7 +94,7 @@ The host-owned catalog classifies all 48 entity variants and tracks every
 traced field, including fields marked `unmapped`. Query it with
 `doc.coverage()` or `doc.coverage("Line")`; each row includes source field,
 type, access, and current validation status. Geometry edits remain limited to
-the 35 mapped kinds.
+the 36 mapped kinds.
 For any entity, `entity.snapshot` returns a detached dictionary of its raw
 CAD fields, including `snapshot["common"]` and kind-specific nested values.
 It can inspect an unmapped kind; editing the dictionary does

plugins/opencad-python/entity_manifest.json

@@ -34,7 +34,8 @@
     "RasterImage",
     "Wipeout",
     "Underlay",
-    "Viewport"
+    "Viewport",
+    "ViewBorder"
   ],
   "manual_kinds": ["Dimension"],
   "base_fields": ["handle", "layer", "owner_handle"],
@@ -403,6 +404,15 @@
         "width": { "required": true },
         "height": { "required": true }
       }
+    },
+    "ViewBorder": {
+      "fields": {
+        "version": { "read_only": true },
+        "min": { "required": true },
+        "max": { "required": true },
+        "active_viewport": { "required": true },
+        "scale_handle": { "required": true }
+      }
     }
   }
 }

plugins/opencad-python/src/ocs_module.rs

@@ -4756,7 +4756,7 @@ mod tests {
                 );
             }
         }
-        assert_eq!(emitted.len(), 35);
+        assert_eq!(emitted.len(), 36);
     }
 
     #[cfg(feature = "experimental-host-model")]

src/app/plugin_host.rs

@@ -3197,6 +3197,20 @@ mod tests {
         let mut create_script = case.create.replace("TMPDIR", &tmp);
         let paper = host.document().block_records.iter().find(|r| r.is_paper_space()).map(|r| r.handle.value());
         let layer0 = host.document().layers.iter().find(|l| l.name == "0").map(|l| l.handle.value());
+        if create_script.contains("VIEWPORTHANDLE") || create_script.contains("SCALEHANDLE") {
+            // A view border ties to an existing viewport and scale.
+            let owner = host.document().block_records.iter().find(|r| r.is_paper_space()).map(|r| r.handle).unwrap();
+            let mut viewport = acadrust::entities::Viewport::new();
+            viewport.common.owner_handle = owner;
+            let viewport_handle = host.add_entity(EntityType::Viewport(viewport));
+            let scale_handle = host.document_mut().allocate_handle();
+            let mut scale = acadrust::objects::Scale::new("1:1", 1.0, 1.0);
+            scale.handle = scale_handle;
+            host.document_mut().objects.insert(scale_handle, acadrust::objects::ObjectType::Scale(scale));
+            create_script = create_script
+                .replace("VIEWPORTHANDLE", &viewport_handle.value().to_string())
+                .replace("SCALEHANDLE", &scale_handle.value().to_string());
+        }
         create_script = create_script
             .replace("PAPERSPACE", &paper.unwrap_or_default().to_string())
             .replace("LAYER0", &layer0.unwrap_or_default().to_string());
@@ -3637,6 +3651,46 @@ mod tests {
         });
     }
 
+    #[test]
+    fn staged_python_view_border_lifecycle_over_real_ipc() {
+        run_mesh_lifecycle(&MeshCase {
+            create: concat!(
+                "doc.create_entity('ViewBorder', min=[0.0, 0.0], max=[40.0, 30.0], center=[20.0, 15.0], scale=1.0,\n",
+                "    active_viewport=VIEWPORTHANDLE, scale_handle=SCALEHANDLE)\n"),
+            edit: concat!(
+                "vb = doc.entities[HANDLE]\n",
+                "with doc.transaction('Edit view border'):\n",
+                "    vb.max = [60.0, 45.0]\n",
+                "    vb.center = [30.0, 22.5]\n",
+                "    vb.scale = 2.0\n",
+                "    vb.rotation_angle = 0.3\n",
+                "doc.selection = [vb]\n"),
+            rejects: &[
+                ("'max':[-1.0, 5.0]", "below max"),
+                ("'scale':0.0", "greater than zero"),
+                ("'rotation_angle':float('nan')", "finite"),
+                ("'center':[float('inf'), 0.0]", "finite"),
+                ("'active_viewport':999999", "does not exist"),
+                ("'scale_handle':999999", "does not exist"),
+                ("'version':3", "read-only"),
+            ],
+            is_kind: |entity| matches!(entity, EntityType::ViewBorder(_)),
+            digest: |entity| match entity {
+                EntityType::ViewBorder(v) => format!("max{:.1},{:.1} c{:.1},{:.1} s{:.1} r{:.1}", v.max[0], v.max[1],
+                    v.center[0], v.center[1], v.scale, v.rotation_angle),
+                _ => "wrong kind".into(),
+            },
+            reedit: |entity| if let EntityType::ViewBorder(v) = entity { v.scale = 3.0; },
+            expect_created: "max40.0,30.0 c20.0,15.0 s1.0 r0.0",
+            expect_edited: "max60.0,45.0 c30.0,22.5 s2.0 r0.3",
+            expect_reedited: "max60.0,45.0 c30.0,22.5 s3.0 r0.3",
+            // BLOCKER: a DXF DRAWINGVIEW reopens as a different (opaque) entity
+            // kind, not as a ViewBorder; only DWG restores the typed record.
+            expect_edited_dxf: "wrong kind",
+            expect_reedited_dxf: "wrong kind",
+        });
+    }
+
     #[test]
     fn staged_python_point_pick_and_cancel_over_real_ipc() {
         let Some(plugin_path) = std::env::var_os("OCS_TEST_PYTHON_PLUGIN") else {