"""VTK/PyVista scene inspection (optional, graceful degradation if VTK unavailable)."""
from __future__ import annotations
import base64
from typing import Any
from qt_mcp.probe._qt_compat import QtWidgets
from qt_mcp.probe.ref_registry import RefRegistry
QWidget = QtWidgets.QWidget
def _try_import_vtk() -> bool:
try:
import vtkmodules # noqa: F401
return True
except ImportError:
return False
def _invoke(obj: Any, method_name: str) -> Any:
method = getattr(obj, method_name, None)
if method is None or not callable(method):
return None
return method()
class VtkInspector:
"""Inspects PyVista/VTK render windows embedded in Qt."""
def __init__(self, registry: RefRegistry) -> None:
self._registry = registry
def vtk_scene_info(self, ref: str) -> dict:
"""Get VTK scene state from a widget that wraps a VTK render window."""
widget = self._resolve(ref)
render_window = self._get_render_window(widget)
renderer_collection = _invoke(render_window, "GetRenderers")
renderer = _invoke(renderer_collection, "GetFirstRenderer")
if renderer is None:
return {"error": "No renderer found"}
# Camera
camera = _invoke(renderer, "GetActiveCamera")
camera_info: dict[str, Any] = {}
if camera:
camera_info = {
"position": list(_invoke(camera, "GetPosition") or []),
"focal_point": list(_invoke(camera, "GetFocalPoint") or []),
"view_up": list(_invoke(camera, "GetViewUp") or []),
"clipping_range": list(_invoke(camera, "GetClippingRange") or []),
}
# Actors
actors: list[dict[str, Any]] = []
actor_collection = _invoke(renderer, "GetActors")
_invoke(actor_collection, "InitTraversal")
actor_count = int(_invoke(actor_collection, "GetNumberOfItems") or 0)
for _ in range(actor_count):
actor = _invoke(actor_collection, "GetNextActor")
if actor is None:
break
info: dict[str, Any] = {
"class": type(actor).__name__,
"visibility": bool(_invoke(actor, "GetVisibility")),
"bounds": list(_invoke(actor, "GetBounds") or []),
}
mapper = _invoke(actor, "GetMapper")
dataset = _invoke(mapper, "GetInput")
if mapper and dataset:
info["points"] = _invoke(dataset, "GetNumberOfPoints")
info["cells"] = _invoke(dataset, "GetNumberOfCells")
info["scalar_range"] = list(_invoke(mapper, "GetScalarRange") or [])
actors.append(info)
# Background
bg = list(_invoke(renderer, "GetBackground") or [])
size = _invoke(render_window, "GetSize") or (0, 0)
return {
"camera": camera_info,
"actors": actors,
"background": bg,
"size": list(size),
}
def vtk_screenshot(self, ref: str) -> dict:
"""Capture VTK render window to base64 PNG."""
widget = self._resolve(ref)
# First, try QWidget.grab() which often works
pixmap = widget.grab()
if not pixmap.isNull():
from qt_mcp.probe._qt_compat import QtCore as _QtC
QBuffer = _QtC.QBuffer
QIODevice = _QtC.QIODevice
buf = QBuffer()
buf.open(QIODevice.OpenModeFlag.WriteOnly)
pixmap.save(buf, "PNG")
png_bytes = bytes(buf.data())
buf.close()
b64 = base64.b64encode(png_bytes).decode("ascii")
return {"image": b64, "width": pixmap.width(), "height": pixmap.height()}
# Fallback: use vtkWindowToImageFilter
render_window = self._get_render_window(widget)
render_window.Render()
from vtkmodules.vtkIOImage import vtkPNGWriter
from vtkmodules.vtkRenderingCore import vtkWindowToImageFilter
w2i = vtkWindowToImageFilter()
w2i.SetInput(render_window)
w2i.Update()
writer = vtkPNGWriter()
writer.SetInputConnection(w2i.GetOutputPort())
writer.WriteToMemoryOn()
writer.Write()
png_bytes = bytes(writer.GetResult())
b64 = base64.b64encode(png_bytes).decode("ascii")
size = render_window.GetSize()
return {"image": b64, "width": size[0], "height": size[1]}
def _resolve(self, ref: str) -> QWidget:
obj = self._registry.resolve(ref)
if obj is None:
raise ValueError(f"Ref not found: {ref}")
if not isinstance(obj, QWidget):
raise ValueError(f"Ref {ref} is not a QWidget")
return obj
def _get_render_window(self, widget: QWidget) -> Any:
"""Extract vtkRenderWindow from a PyVista or VTK Qt widget."""
# pyvistaqt.QtInteractor
if hasattr(widget, "GetRenderWindow"):
return widget.GetRenderWindow()
# Try finding child with render window
for child in widget.children():
if hasattr(child, "GetRenderWindow"):
return child.GetRenderWindow()
raise ValueError(f"No VTK render window found in {type(widget).__name__}")
