feat: add geometry picker for server mode

doc/changelog.d/199.added.md

@@ -0,0 +1 @@
+Add geometry picker for server mode

src/ansys/visor/viewer/app/trame/scene_trigger_app.py

@@ -12,6 +12,10 @@
 from ansys.visor.viewer.core.visor_enums import RenderingMode, VisorVtkVariableType
 from ansys.visor.viewer.core.visor_logging import VisorDefaultLogger
 from ansys.visor.viewer.models.common.visor_camera_state import VisorCameraState
+from ansys.visor.viewer.models.runtime.picking.geometry_pick import GeometryPick
+from ansys.visor.viewer.models.runtime.requests.geometry_pick_payloads import (
+    SetGeometryHighlightPayload,
+)
 from ansys.visor.viewer.models.runtime.requests.sync_camera_payload import SyncCameraPayload
 from ansys.visor.viewer.models.runtime.requests.variable_range_payload import SetVariableRangePayload
 from ansys.visor.viewer.models.runtime.requests.widget_state_payloads import (
@@ -88,6 +92,8 @@ def set_panel_top_right_legend_collapsed(self, collapsed: bool) -> None: ...
 
     def set_panel_top_right_tab_index(self, tab_index: int) -> None: ...
 
+    def set_geometry_highlight(self, pick: GeometryPick) -> None: ...
+
 
 # ----------------------------------------------------------------------
 # Trigger payload models
@@ -564,6 +570,19 @@ def set_panel_top_right_tab_index(self, payload) -> None:
             return
         api.set_panel_top_right_tab_index(payload.tab_index)
 
+    @trigger("set_geometry_highlight")
+    @parse_payload(SetGeometryHighlightPayload)
+    def set_geometry_highlight(self, payload) -> None:
+        """Frontend -> Backend: highlight the picked feature, or clear the highlight on a not-found pick.
+
+        Transient: the scene stores nothing.  The renderer pushes the
+        highlight to the client itself, without rebuilding the frontend.
+        """
+        api = self._mutation_api("set_geometry_highlight", payload)
+        if api is None:
+            return
+        api.set_geometry_highlight(payload.pick)
+
     def set_only_cookie(self, key: str, value: str):
         """
         Sets a cookie on the server. NOTE: there is a limitation

src/ansys/visor/viewer/app/trame/server_app.py

@@ -1,9 +1,9 @@
 """
 ServerApp
 =========
-Trame app for server-side rendering: the shared scene triggers, part picking,
-the client theme report, and the trame-rca area the rendered frames stream
-through.
+Trame app for server-side rendering: the shared scene triggers, part and
+geometry picking, the client theme report, and the trame-rca area the rendered
+frames stream through.
 """
 
 from __future__ import annotations
@@ -23,6 +23,8 @@
 )
 from ansys.visor.viewer.app.trame.server_loop_bridge import ServerLoopBridge
 from ansys.visor.viewer.core.visor_enums import RenderingMode
+from ansys.visor.viewer.models.runtime.picking.geometry_pick import GeometryPick
+from ansys.visor.viewer.models.runtime.requests.geometry_pick_payloads import PickGeometryAtPayload
 from ansys.visor.viewer.renderer.server_window import VisorRcaWindow
 
 RCA_AREA_NAME: str = "view"
@@ -44,7 +46,7 @@ class SetDarkThemePayload(BaseModel):
 
 @TrameApp()
 class ServerApp(SceneTriggerApp):
-    """Serves the scene triggers, part picking and the streamed view for server-side rendering."""
+    """Serves the scene triggers, part and geometry picking and the streamed view for server-side rendering."""
 
     def __init__(
         self,
@@ -54,12 +56,14 @@ def __init__(
         trame_logger: Logger | None,
         scene_mutation_api: SceneMutationApi,
         pick_part_at: Callable[[int, int], int | None],
+        pick_geometry_at: Callable[[int, int, str], GeometryPick],
         set_dark_mode: Callable[[bool], None],
         rca_window: VisorRcaWindow,
         bridge: ServerLoopBridge,
     ) -> None:
         """Create the area before start; the view handler is built when the server is ready."""
         self._pick_part_at = pick_part_at
+        self._pick_geometry_at = pick_geometry_at
         self._set_dark_mode = set_dark_mode
         self._rca_window = rca_window
         self._bridge = bridge
@@ -96,6 +100,7 @@ def _bind_stream(self) -> None:
             interactive_quality=60,
             still_quality=90,
         )
+        self._rca_window.bind_pixel_scale(lambda: view_handler.scale_factor)
         self._bridge.bind(view_handler)
 
     @trigger("pick_part_at")
@@ -104,6 +109,12 @@ def pick_part_at(self, payload) -> int | None:
         """Frontend -> Backend: the node under a render-window pixel, or None; selects nothing."""
         return self._pick_part_at(payload.x, payload.y)
 
+    @trigger("pick_geometry_at")
+    @parse_payload(PickGeometryAtPayload)
+    def pick_geometry_at(self, payload) -> dict:
+        """Frontend -> Backend: the geometry feature under a render-window pixel, dumped by alias; highlights nothing."""
+        return self._pick_geometry_at(payload.x, payload.y, payload.mode).model_dump(by_alias=True)
+
     @trigger("set_dark_theme")
     @parse_payload(SetDarkThemePayload)
     def set_dark_theme(self, payload) -> None:

src/ansys/visor/viewer/app/visor_vtk_server.py

@@ -50,6 +50,7 @@ def _initialize_rendering(self, standalone: bool, trame_log_dir: str | None) ->
             trame_logger=get_trame_logger(trame_log_dir),
             scene_mutation_api=self._scene,
             pick_part_at=self._scene.pick_part_at,
+            pick_geometry_at=self._scene.pick_geometry_at,
             set_dark_mode=self._scene.set_dark_mode,
             rca_window=self._scene.rca_window,
             bridge=bridge,

src/ansys/visor/viewer/models/runtime/picking/geometry_pick.py

@@ -0,0 +1,79 @@
+"""
+Geometry pick results
+=====================
+The four results a geometry pick can report.  Each dumps by alias to the
+wire shape the client's result panel reads.
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, List, Literal, Union
+
+from pydantic import BaseModel, ConfigDict, Field
+
+if TYPE_CHECKING:
+    from ansys.visor.viewer.vtk.widgets.geometry_highlight import GeometryHighlight
+
+GeometryPickMode = Literal["vertex", "edge", "face"]
+
+
+class NoGeometryPick(BaseModel):
+    """No part cell under the pick."""
+
+    model_config = ConfigDict(populate_by_name=True)
+
+    found: Literal[False] = False
+
+    def highlight_with(self, highlight: "GeometryHighlight") -> None:
+        """Hide the highlight."""
+        highlight.hide()
+
+
+class VertexPick(BaseModel):
+    """The picked cell's vertex nearest the pick position."""
+
+    model_config = ConfigDict(populate_by_name=True)
+
+    found: Literal[True] = True
+    mode: Literal["vertex"] = "vertex"
+    position: List[float]
+
+    def highlight_with(self, highlight: "GeometryHighlight") -> None:
+        """Draw a dot at the vertex."""
+        highlight.show_vertex(self.position)
+
+
+class EdgePick(BaseModel):
+    """The picked cell's edge nearest the pick position, with its length."""
+
+    model_config = ConfigDict(populate_by_name=True)
+
+    found: Literal[True] = True
+    mode: Literal["edge"] = "edge"
+    point_a: List[float] = Field(alias="pointA")
+    point_b: List[float] = Field(alias="pointB")
+    # Not "length" on the wire: trame's trigger decorators read an object with a
+    # numeric length as a file list and send it as an array.
+    length: float = Field(alias="edgeLength")
+
+    def highlight_with(self, highlight: "GeometryHighlight") -> None:
+        """Draw a line along the edge."""
+        highlight.show_edge(self.point_a, self.point_b)
+
+
+class FacePick(BaseModel):
+    """The picked cell as a whole, with its area."""
+
+    model_config = ConfigDict(populate_by_name=True)
+
+    found: Literal[True] = True
+    mode: Literal["face"] = "face"
+    area: float
+    points: List[List[float]]
+
+    def highlight_with(self, highlight: "GeometryHighlight") -> None:
+        """Draw the cell as a filled outline."""
+        highlight.show_face(self.points)
+
+
+GeometryPick = Union[VertexPick, EdgePick, FacePick, NoGeometryPick]

src/ansys/visor/viewer/models/runtime/requests/geometry_pick_payloads.py

@@ -0,0 +1,19 @@
+"""Models for the geometry-pick trigger payloads."""
+
+from pydantic import BaseModel
+
+from ansys.visor.viewer.models.runtime.picking.geometry_pick import GeometryPick, GeometryPickMode
+
+
+class PickGeometryAtPayload(BaseModel):
+    """pick_geometry_at payload: a render-window pixel, origin bottom-left, and the mode."""
+
+    x: int
+    y: int
+    mode: GeometryPickMode
+
+
+class SetGeometryHighlightPayload(BaseModel):
+    """set_geometry_highlight payload: the pick whose feature to highlight; a not-found pick clears it."""
+
+    pick: GeometryPick

src/ansys/visor/viewer/renderer/base.py

@@ -26,6 +26,7 @@
 
     from ansys.visor.viewer.core.visor_enums import VisorVtkVariableType
     from ansys.visor.viewer.models.common.visor_camera_state import VisorCameraState
+    from ansys.visor.viewer.models.runtime.picking.geometry_pick import GeometryPick
     from ansys.visor.viewer.models.runtime.vtk.renderer_annotation import RendererAnnotation
     from ansys.visor.viewer.vtk.scene_graph import VisorSceneGraphPartNode
 
@@ -316,6 +317,18 @@ def update_bounds(self, bounds: list[float]) -> None:
     def update_actor_count(self, count: int) -> None:
         """Propagate the current part-node count to widgets."""
 
+    # ------------------------------------------------------------------------
+    # Geometry highlight
+    # ------------------------------------------------------------------------
+
+    @abstractmethod
+    def show_geometry_highlight(self, pick: "GeometryPick") -> None:
+        """Draw pick on the scene's one highlight, or hide it when not found.
+
+        On return, the client has been sent what it needs to show the
+        highlight, without rebuilding its frontend.
+        """
+
 
     # ------------------------------------------------------------------------
     # Render