Bond graph ports and drawing added

BEdit/AGENTS.md

@@ -59,7 +59,12 @@ Keep the root of `src/bedit` minimal. New UI modules should go into the relevant
 - Port orientation is presented as one unified list in the UI, while the model
   indexes inputs and outputs separately for connection semantics.
 - Port types are registered in `core/port_types.py`. Only compatible types may be
-  connected. `signal` is currently the only type.
+  connected. Signal ports connect by type; power ports additionally require the
+  same domain. Editable power domains and causalities live in
+  `core/power_domains.py`.
+- Power ports may use `indifferent` orientation and can act as either connection
+  endpoint. For two indifferent ports, click order determines source/arrow
+  direction; otherwise output/input semantics determine direction.
 - Port connector type and signal value type are separate. Signal ports and
   parameters carry editable value type, quantity, unit, row/column dimensions,
   and description metadata. Editable quantity/unit suggestions live in
@@ -78,7 +83,8 @@ Keep the root of `src/bedit` minimal. New UI modules should go into the relevant
   intersection of the owning hitbox and its center-to-adjacent-route-point ray.
 - Connection appearance is configured per port type in
   `gui/graphics/connection_styles.py`, including color, width, pen style, and
-  source/target arrowheads. Do not scatter those constants through painters.
+  source/target arrowheads. Arrow styles are `open`, `half`, or `filled`. Do not
+  scatter those constants through painters.
 - Graph annotations are `box`, `line`, or `text` objects in `Graph.annotations`.
   They use integer layers below or above graph layer 0. Annotation lines reuse
   connection polyline and absolute `properties.waypoints` semantics. Graph

BEdit/src/bedit/core/model.py

@@ -6,6 +6,7 @@ from typing import Any
 from uuid import uuid4
 
 from bedit.core.port_types import PortTypeRegistry
+from bedit.core.power_domains import POWER_CAUSALITIES, POWER_DOMAINS
 
 
 def _dimensions(data: Any, subject: str) -> tuple[int, int]:
@@ -36,6 +37,9 @@ class Port:
     rows: int = 1
     columns: int = 1
     description: str = ""
+    orientation: str = "input"
+    domain: str = "power"
+    causality: str = "indifferent"
 
     def to_dict(self) -> dict[str, Any]:
         return {
@@ -50,10 +54,13 @@ class Port:
             "unit": self.unit,
             "dimensions": {"rows": self.rows, "columns": self.columns},
             "description": self.description,
+            "orientation": self.orientation,
+            "domain": self.domain,
+            "causality": self.causality,
         }
 
     @classmethod
-    def from_dict(cls, data: dict[str, Any]) -> "Port":
+    def from_dict(cls, data: dict[str, Any], default_orientation: str = "input") -> "Port":
         position = data.get("position", {})
         rows, columns = _dimensions(data.get("dimensions", {}), "Port")
         return cls(
@@ -70,6 +77,9 @@ class Port:
             rows=rows,
             columns=columns,
             description=str(data.get("description", "")),
+            orientation=str(data.get("orientation", default_orientation)),
+            domain=str(data.get("domain", "power")),
+            causality=str(data.get("causality", "indifferent")),
         )
 
 
@@ -417,8 +427,8 @@ class Component:
             x=float(position.get("x", 0.0)),
             y=float(position.get("y", 0.0)),
             rotation=float(data.get("rotation", 0.0)),
-            inputs=[Port.from_dict(item) for item in interface.get("inputs", [])],
+            inputs=[Port.from_dict(item, "input") for item in interface.get("inputs", [])],
-            outputs=[Port.from_dict(item) for item in interface.get("outputs", [])],
+            outputs=[Port.from_dict(item, "output") for item in interface.get("outputs", [])],
             parameters=[Parameter.from_dict(item) for item in parameters],
             icon=Icon.from_dict(data.get("icon")),
             properties=dict(data.get("properties", {})),
@@ -528,6 +538,15 @@ class GraphDocument:
             raise ValueError(f"Component {owner.name} contains duplicate port IDs")
         for port in (*owner.inputs, *owner.outputs):
             PortTypeRegistry.get(port.type)
+            if port.orientation not in {"input", "output", "indifferent"}:
+                raise ValueError(f"Port {port.name!r} has an invalid orientation")
+            if port.orientation == "indifferent" and port.type != "power":
+                raise ValueError("Only power ports may have indifferent orientation")
+            if port.type == "power":
+                if port.domain not in {domain.id for domain in POWER_DOMAINS}:
+                    raise ValueError(f"Power port {port.name!r} has an unknown domain")
+                if port.causality not in POWER_CAUSALITIES:
+                    raise ValueError(f"Power port {port.name!r} has invalid causality")
             if not port.value_type.strip():
                 raise ValueError(f"Port {port.name!r} has no value type")
             if port.rows < 1 or port.columns < 1:
@@ -549,9 +568,17 @@ class GraphDocument:
                 source_port = next(p for p in owner.inputs if p.id == connection.source.interface)
             else:
                 source = owner.graph.blocks.get(connection.source.block or "")
-                if source is None or connection.source.port not in {p.id for p in source.outputs}:
+                source_ports = (
+                    []
+                    if source is None
+                    else [
+                        *source.outputs,
+                        *(p for p in source.inputs if p.orientation == "indifferent"),
+                    ]
+                )
+                if source is None or connection.source.port not in {p.id for p in source_ports}:
                     raise ValueError(f"Connection {connection.id} uses an unknown block output")
-                source_port = next(p for p in source.outputs if p.id == connection.source.port)
+                source_port = next(p for p in source_ports if p.id == connection.source.port)
             if connection.target.junction is not None:
                 junction = owner.graph.junctions.get(connection.target.junction)
                 if junction is None:
@@ -565,15 +592,27 @@ class GraphDocument:
                     allows_multiple_connections=False,
                 )
             elif connection.target.interface is not None:
-                if connection.target.interface not in output_ids:
+                indifferent_ids = {
+                    port.id for port in owner.inputs if port.orientation == "indifferent"
+                }
+                if connection.target.interface not in output_ids | indifferent_ids:
                     raise ValueError(f"Connection {connection.id} uses an unknown interface output")
-                target_port = next(p for p in owner.outputs if p.id == connection.target.interface)
+                target_port = next(
+                    p
+                    for p in (*owner.outputs, *owner.inputs)
+                    if p.id == connection.target.interface
+                )
             else:
                 target = owner.graph.blocks.get(connection.target.block or "")
                 if target is None or connection.target.port not in {p.id for p in target.inputs}:
                     raise ValueError(f"Connection {connection.id} uses an unknown block input")
                 target_port = next(p for p in target.inputs if p.id == connection.target.port)
-            if not PortTypeRegistry.compatible(source_port.type, target_port.type):
+            if not PortTypeRegistry.compatible(
+                source_port.type,
+                target_port.type,
+                source_port.domain,
+                target_port.domain,
+            ):
                 raise ValueError(f"Connection {connection.id} joins incompatible port types")
             source_key = (
                 "source-junction"
@@ -670,27 +709,11 @@ def clone_component(source: Component) -> Component:
             x=current.x,
             y=current.y,
             inputs=[
-                Port(
+                Port.from_dict(port.to_dict(), "input")
-                    port.id,
-                    port.name,
-                    port.x,
-                    port.y,
-                    deepcopy(port.properties),
-                    port.type,
-                    port.allows_multiple_connections,
-                )
                 for port in current.inputs
             ],
             outputs=[
-                Port(
+                Port.from_dict(port.to_dict(), "output")
-                    port.id,
-                    port.name,
-                    port.x,
-                    port.y,
-                    deepcopy(port.properties),
-                    port.type,
-                    port.allows_multiple_connections,
-                )
                 for port in current.outputs
             ],
             parameters=deepcopy(current.parameters),

BEdit/src/bedit/core/port_types.py

@@ -14,6 +14,7 @@ class PortType:
 class PortTypeRegistry:
     _types = {
         "signal": PortType("signal", "Signal", "A scalar signal connection"),
+        "power": PortType("power", "Power", "A two-variable power connection"),
     }
 
     @classmethod
@@ -28,5 +29,13 @@ class PortTypeRegistry:
             raise ValueError(f"Unknown port type: {type_id}") from error
 
     @classmethod
-    def compatible(cls, first: str, second: str) -> bool:
+    def compatible(
-        return cls.get(first).accepts(cls.get(second))
+        cls,
+        first: str,
+        second: str,
+        first_domain: str = "",
+        second_domain: str = "",
+    ) -> bool:
+        if not cls.get(first).accepts(cls.get(second)):
+            return False
+        return first != "power" or first_domain == second_domain

BEdit/src/bedit/core/power_domains.py

@@ -0,0 +1,31 @@
+"""Editable power-port domain definitions used by the port editor."""
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class PowerDomain:
+    id: str
+    display_name: str
+    effort: str
+    flow: str
+
+
+POWER_DOMAINS: tuple[PowerDomain, ...] = (
+    PowerDomain("power", "Power", "p.e", "p.f"),
+)
+
+
+def power_domain(domain_id: str) -> PowerDomain:
+    return next((domain for domain in POWER_DOMAINS if domain.id == domain_id), POWER_DOMAINS[0])
+
+
+POWER_CAUSALITIES = (
+    "fixed flow out",
+    "fixed effort out",
+    "preferred flow out",
+    "preferred effort out",
+    "likes flow out",
+    "likes effort out",
+    "indifferent",
+)

BEdit/src/bedit/gui/controllers/document.py

@@ -285,7 +285,12 @@ class DocumentController(QObject):
         target_port = self._port_for_endpoint(target, "target")
         if source_port is None or target_port is None:
             raise ValueError("A connection endpoint no longer exists")
-        if not PortTypeRegistry.compatible(source_port.type, target_port.type):
+        if not PortTypeRegistry.compatible(
+            source_port.type,
+            target_port.type,
+            source_port.domain,
+            target_port.domain,
+        ):
             raise ValueError(f"Cannot connect {source_port.type!r} to {target_port.type!r}")
         if not self.endpoint_accepts_connection(source, "source"):
             raise ValueError(
@@ -573,11 +578,24 @@ class DocumentController(QObject):
             )
         if endpoint.interface is not None:
             ports = owner.inputs if role == "source" else owner.outputs
+            ports = [
+                *ports,
+                *(
+                    port
+                    for port in owner.inputs
+                    if port.orientation == "indifferent" and port not in ports
+                ),
+            ]
         else:
             component = owner.graph.blocks.get(endpoint.block or "")
             if component is None:
                 return None
             ports = component.outputs if role == "source" else component.inputs
+            if role == "source":
+                ports = [
+                    *ports,
+                    *(port for port in component.inputs if port.orientation == "indifferent"),
+                ]
         return next(
             (port for port in ports if port.id == (endpoint.interface or endpoint.port)), None
         )
@@ -664,6 +682,9 @@ class DocumentController(QObject):
             raise ValueError("Only text-defined components can be edited here")
         input_ids = [port.id for port in inputs]
         output_ids = [port.id for port in outputs]
+        source_ids = output_ids + [
+            port.id for port in inputs if port.orientation == "indifferent"
+        ]
         if len(set(input_ids)) != len(input_ids) or len(set(output_ids)) != len(output_ids):
             raise ValueError("Input and output IDs must be unique")
         if any(not port.name.strip() for port in (*inputs, *outputs)):
@@ -686,7 +707,7 @@ class DocumentController(QObject):
                         )
                     if (
                         connection.source.block == component.id
-                        and connection.source.port not in output_ids
+                        and connection.source.port not in source_ids
                     ):
                         raise ValueError(
                             f"Output {connection.source.port!r} is still connected in the containing graph"
@@ -842,6 +863,9 @@ class DocumentController(QObject):
             return
         input_ids = {port.id for port in inputs}
         output_ids = {port.id for port in outputs}
+        source_ids = output_ids | {
+            port.id for port in inputs if port.orientation == "indifferent"
+        }
         parent = self.document.find_parent(component_id)
         if parent is not None:
             for connection in parent.graph.connections.values():
@@ -852,7 +876,7 @@ class DocumentController(QObject):
                     raise ValueError("An input cannot be removed or reoriented while connected")
                 if (
                     connection.source.block == component_id
-                    and connection.source.port not in output_ids
+                    and connection.source.port not in source_ids
                 ):
                     raise ValueError("An output cannot be removed or reoriented while connected")
         for connection in component.graph.connections.values():

BEdit/src/bedit/gui/dialogs/port_options.py

@@ -6,6 +6,7 @@ from PySide6.QtWidgets import QDialog, QDialogButtonBox, QListWidgetItem, QMessa
 
 from bedit.core.model import Component, Port
 from bedit.core.physical_types import QUANTITIES, UNITS
+from bedit.core.power_domains import POWER_CAUSALITIES, POWER_DOMAINS, power_domain
 from bedit.core.port_types import PortTypeRegistry
 from bedit.gui.generated.ui_port_options_dialog import Ui_PortOptionsDialog
 
@@ -13,6 +14,13 @@ from bedit.gui.generated.ui_port_options_dialog import Ui_PortOptionsDialog
 PORT_ROLE = Qt.ItemDataRole.UserRole
 
 
+def _oriented_copy(port: Port, fallback: str) -> Port:
+    copied = deepcopy(port)
+    if copied.orientation != "indifferent":
+        copied.orientation = fallback
+    return copied
+
+
 class PortOptionsDialog(QDialog):
     """Unified editor for a component's typed, oriented ports."""
 
@@ -25,8 +33,8 @@ class PortOptionsDialog(QDialog):
         self.setWindowTitle(f"Port Options — {component.name}")
         self.read_only = read_only
         self.ports: list[tuple[Port, str]] = [
-            *((deepcopy(port), "input") for port in component.inputs),
+            *((_oriented_copy(port, "input"), port.orientation or "input") for port in component.inputs),
-            *((deepcopy(port), "output") for port in component.outputs),
+            *((_oriented_copy(port, "output"), "output") for port in component.outputs),
         ]
         self._loading = False
         self.ui.typeCombo.clear()
@@ -36,6 +44,10 @@ class PortOptionsDialog(QDialog):
         self.ui.unitCombo.addItems(UNITS)
         self.ui.orientationCombo.setItemData(0, "input")
         self.ui.orientationCombo.setItemData(1, "output")
+        self.ui.orientationCombo.setItemData(2, "indifferent")
+        for domain in POWER_DOMAINS:
+            self.ui.domainCombo.addItem(domain.display_name, domain.id)
+        self.ui.causalityCombo.addItems(POWER_CAUSALITIES)
         self.ui.portList.currentRowChanged.connect(self._load_current)
         self.ui.addPortButton.clicked.connect(self.add_port)
         self.ui.removePortButton.clicked.connect(self.remove_port)
@@ -49,6 +61,9 @@ class PortOptionsDialog(QDialog):
         self.ui.rowsSpin.valueChanged.connect(self._store_current)
         self.ui.columnsSpin.valueChanged.connect(self._store_current)
         self.ui.descriptionEdit.textChanged.connect(self._store_current)
+        self.ui.domainCombo.currentIndexChanged.connect(self._power_domain_changed)
+        self.ui.causalityCombo.currentTextChanged.connect(self._store_current)
+        self.ui.powerDescriptionEdit.textChanged.connect(self._store_current)
         self.ui.portSplitter.setSizes([250, 370])
         if read_only:
             self.ui.addPortButton.setEnabled(False)
@@ -64,7 +79,11 @@ class PortOptionsDialog(QDialog):
 
     @property
     def inputs(self) -> list[Port]:
-        return [port for port, orientation in self.ports if orientation == "input"]
+        return [
+            port
+            for port, orientation in self.ports
+            if orientation in {"input", "indifferent"}
+        ]
 
     @property
     def outputs(self) -> list[Port]:
@@ -96,6 +115,9 @@ class PortOptionsDialog(QDialog):
             self.ui.rowsSpin.setValue(port.rows)
             self.ui.columnsSpin.setValue(port.columns)
             self.ui.descriptionEdit.setPlainText(port.description)
+            self.ui.domainCombo.setCurrentIndex(self.ui.domainCombo.findData(port.domain))
+            self.ui.causalityCombo.setCurrentText(port.causality)
+            self.ui.powerDescriptionEdit.setPlainText(port.description)
             self._show_type_options(port.type)
         else:
             self.ui.nameEdit.clear()
@@ -113,15 +135,27 @@ class PortOptionsDialog(QDialog):
         self.ui.typeOptionsStack.setEnabled(enabled and not self.read_only)
 
     def _port_type_changed(self) -> None:
-        self._show_type_options(self.ui.typeCombo.currentData())
+        port_type = self.ui.typeCombo.currentData()
+        indifferent_item = self.ui.orientationCombo.model().item(2)
+        indifferent_item.setEnabled(port_type == "power")
+        if port_type != "power" and self.ui.orientationCombo.currentData() == "indifferent":
+            self.ui.orientationCombo.setCurrentIndex(0)
+        self._show_type_options(port_type)
         self._store_current()
 
     def _show_type_options(self, port_type: str) -> None:
-        self.ui.typeOptionsStack.setCurrentWidget(
+        self.ui.orientationCombo.model().item(2).setEnabled(port_type == "power")
-            self.ui.signalOptionsPage
+        page = {
-            if port_type == "signal"
+            "signal": self.ui.signalOptionsPage,
-            else self.ui.unsupportedTypePage
+            "power": self.ui.powerOptionsPage,
-        )
+        }.get(port_type, self.ui.unsupportedTypePage)
+        self.ui.typeOptionsStack.setCurrentWidget(page)
+
+    def _power_domain_changed(self) -> None:
+        domain = power_domain(self.ui.domainCombo.currentData())
+        self.ui.effortValueLabel.setText(domain.effort)
+        self.ui.flowValueLabel.setText(domain.flow)
+        self._store_current()
 
     def _store_current(self) -> None:
         row = self.ui.portList.currentRow()
@@ -136,8 +170,16 @@ class PortOptionsDialog(QDialog):
         port.unit = self.ui.unitCombo.currentText().strip()
         port.rows = self.ui.rowsSpin.value()
         port.columns = self.ui.columnsSpin.value()
-        port.description = self.ui.descriptionEdit.toPlainText()
+        port.domain = self.ui.domainCombo.currentData() or "power"
-        self.ports[row] = (port, self.ui.orientationCombo.currentData())
+        port.causality = self.ui.causalityCombo.currentText()
+        port.description = (
+            self.ui.powerDescriptionEdit.toPlainText()
+            if port.type == "power"
+            else self.ui.descriptionEdit.toPlainText()
+        )
+        orientation = self.ui.orientationCombo.currentData()
+        port.orientation = orientation
+        self.ports[row] = (port, orientation)
         self.ui.portList.item(row).setText(
             f"{port.name}   [{self.ports[row][1]}, {port.type}]"
         )
@@ -146,8 +188,8 @@ class PortOptionsDialog(QDialog):
     def set_ports(self, inputs: list[Port], outputs: list[Port]) -> None:
         self._loading = True
         self.ports = [
-            *((deepcopy(port), "input") for port in inputs),
+            *((_oriented_copy(port, "input"), port.orientation or "input") for port in inputs),
-            *((deepcopy(port), "output") for port in outputs),
+            *((_oriented_copy(port, "output"), "output") for port in outputs),
         ]
         self._loading = False
         self._rebuild_list(0 if self.ports else -1)

BEdit/src/bedit/gui/generated/ui_port_options_dialog.py

@@ -92,6 +92,7 @@ class Ui_PortOptionsDialog(object):
         self.orientationCombo = QComboBox(self.portDetailsPanel)
         self.orientationCombo.addItem("")
         self.orientationCombo.addItem("")
+        self.orientationCombo.addItem("")
         self.orientationCombo.setObjectName(u"orientationCombo")
 
         self.portDetailsForm.setWidget(2, QFormLayout.ItemRole.FieldRole, self.orientationCombo)
@@ -185,6 +186,61 @@ class Ui_PortOptionsDialog(object):
         self.signalOptionsForm.setWidget(4, QFormLayout.ItemRole.FieldRole, self.descriptionEdit)
 
         self.typeOptionsStack.addWidget(self.signalOptionsPage)
+        self.powerOptionsPage = QWidget()
+        self.powerOptionsPage.setObjectName(u"powerOptionsPage")
+        self.powerOptionsForm = QFormLayout(self.powerOptionsPage)
+        self.powerOptionsForm.setObjectName(u"powerOptionsForm")
+        self.domainLabel = QLabel(self.powerOptionsPage)
+        self.domainLabel.setObjectName(u"domainLabel")
+
+        self.powerOptionsForm.setWidget(0, QFormLayout.ItemRole.LabelRole, self.domainLabel)
+
+        self.domainCombo = QComboBox(self.powerOptionsPage)
+        self.domainCombo.setObjectName(u"domainCombo")
+
+        self.powerOptionsForm.setWidget(0, QFormLayout.ItemRole.FieldRole, self.domainCombo)
+
+        self.effortLabel = QLabel(self.powerOptionsPage)
+        self.effortLabel.setObjectName(u"effortLabel")
+
+        self.powerOptionsForm.setWidget(1, QFormLayout.ItemRole.LabelRole, self.effortLabel)
+
+        self.effortValueLabel = QLabel(self.powerOptionsPage)
+        self.effortValueLabel.setObjectName(u"effortValueLabel")
+
+        self.powerOptionsForm.setWidget(1, QFormLayout.ItemRole.FieldRole, self.effortValueLabel)
+
+        self.flowLabel = QLabel(self.powerOptionsPage)
+        self.flowLabel.setObjectName(u"flowLabel")
+
+        self.powerOptionsForm.setWidget(2, QFormLayout.ItemRole.LabelRole, self.flowLabel)
+
+        self.flowValueLabel = QLabel(self.powerOptionsPage)
+        self.flowValueLabel.setObjectName(u"flowValueLabel")
+
+        self.powerOptionsForm.setWidget(2, QFormLayout.ItemRole.FieldRole, self.flowValueLabel)
+
+        self.causalityLabel = QLabel(self.powerOptionsPage)
+        self.causalityLabel.setObjectName(u"causalityLabel")
+
+        self.powerOptionsForm.setWidget(3, QFormLayout.ItemRole.LabelRole, self.causalityLabel)
+
+        self.causalityCombo = QComboBox(self.powerOptionsPage)
+        self.causalityCombo.setObjectName(u"causalityCombo")
+
+        self.powerOptionsForm.setWidget(3, QFormLayout.ItemRole.FieldRole, self.causalityCombo)
+
+        self.powerDescriptionLabel = QLabel(self.powerOptionsPage)
+        self.powerDescriptionLabel.setObjectName(u"powerDescriptionLabel")
+
+        self.powerOptionsForm.setWidget(4, QFormLayout.ItemRole.LabelRole, self.powerDescriptionLabel)
+
+        self.powerDescriptionEdit = QPlainTextEdit(self.powerOptionsPage)
+        self.powerDescriptionEdit.setObjectName(u"powerDescriptionEdit")
+
+        self.powerOptionsForm.setWidget(4, QFormLayout.ItemRole.FieldRole, self.powerDescriptionEdit)
+
+        self.typeOptionsStack.addWidget(self.powerOptionsPage)
         self.unsupportedTypePage = QWidget()
         self.unsupportedTypePage.setObjectName(u"unsupportedTypePage")
         self.unsupportedTypeLayout = QVBoxLayout(self.unsupportedTypePage)
@@ -228,6 +284,7 @@ class Ui_PortOptionsDialog(object):
         self.orientationLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Orientation:", None))
         self.orientationCombo.setItemText(0, QCoreApplication.translate("PortOptionsDialog", u"Input", None))
         self.orientationCombo.setItemText(1, QCoreApplication.translate("PortOptionsDialog", u"Output", None))
+        self.orientationCombo.setItemText(2, QCoreApplication.translate("PortOptionsDialog", u"Indifferent", None))
 
         self.multipleConnectionsCheckBox.setText(QCoreApplication.translate("PortOptionsDialog", u"Allow multiple connections", None))
         self.positionHintLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"New ports start at (0, 0) in the icon editor.", None))
@@ -241,6 +298,13 @@ class Ui_PortOptionsDialog(object):
         self.unitLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Unit:", None))
         self.rowsColumnsLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Matrix size:", None))
         self.descriptionLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Description:", None))
+        self.domainLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Domain:", None))
+        self.effortLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Effort:", None))
+        self.effortValueLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"p.e", None))
+        self.flowLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Flow:", None))
+        self.flowValueLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"p.f", None))
+        self.causalityLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Causality:", None))
+        self.powerDescriptionLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"Description:", None))
         self.unsupportedTypeLabel.setText(QCoreApplication.translate("PortOptionsDialog", u"This port type does not have an options editor yet.", None))
     # retranslateUi
 

BEdit/src/bedit/gui/graphics/connection_styles.py

@@ -1,8 +1,12 @@
 from dataclasses import dataclass
+from typing import Literal
 
 from PySide6.QtCore import Qt
 
 
+ArrowStyle = Literal["open", "half", "filled"]
+
+
 @dataclass(frozen=True)
 class ConnectionStyle:
     color: str = "#285f9e"
@@ -13,11 +17,17 @@ class ConnectionStyle:
     arrow_at_source: bool = False
     arrow_at_target: bool = True
     arrow_size: float = 10.0
+    arrow_style: ArrowStyle = "filled"
+
+    def __post_init__(self) -> None:
+        if self.arrow_style not in {"open", "half", "filled"}:
+            raise ValueError(f"Unknown connection arrow style: {self.arrow_style}")
 
 
 # This is the intentional code-level styling point for every port/connection type.
 CONNECTION_STYLES: dict[str, ConnectionStyle] = {
     "signal": ConnectionStyle(),
+    "power": ConnectionStyle(width=3.0, arrow_style="half", color="#000000"),
 }
 
 

BEdit/src/bedit/gui/graphics/icon_editor.py

@@ -1,6 +1,6 @@
 from copy import deepcopy
 
-from PySide6.QtCore import QPointF, QRectF, QSizeF, Qt
+from PySide6.QtCore import QPointF, QRectF, QSizeF, Qt, QTimer
 from PySide6.QtGui import QColor, QPainter, QPainterPath, QPen, QPolygonF
 from PySide6.QtWidgets import (
     QColorDialog,
@@ -487,7 +487,13 @@ class IconEditorDialog(QDialog):
             self.scene.addItem(ShapeItem(element))
         self._add_ports(self.inputs, "input", 0.0)
         self._add_ports(self.outputs, "output", self.icon.width)
-        self.view.center_icon()
+        self._initial_fit_pending = True
+
+    def showEvent(self, event) -> None:  # noqa: N802 (Qt API name)
+        super().showEvent(event)
+        if self._initial_fit_pending:
+            self._initial_fit_pending = False
+            QTimer.singleShot(0, self.view.center_icon)
 
     def _add_ports(self, ports: list[Port], direction: str, default_x: float) -> None:
         spacing = self.icon.height / (len(ports) + 1)

BEdit/src/bedit/gui/graphics/workspace.py

@@ -485,23 +485,39 @@ class ConnectionGraphicsItem(QGraphicsPathItem):
             handle.setVisible(self.isSelected())
 
     @staticmethod
-    def _arrow(end: QPointF, direction: QPointF, size: float) -> QPolygonF:
+    def _arrow_points(
+        end: QPointF, direction: QPointF, size: float
+    ) -> tuple[QPointF, QPointF, QPointF]:
         length = max(0.001, (direction.x() ** 2 + direction.y() ** 2) ** 0.5)
         unit = QPointF(direction.x() / length, direction.y() / length)
         normal = QPointF(-unit.y(), unit.x())
         base = end - unit * size
-        return QPolygonF([end, base + normal * size * 0.45, base - normal * size * 0.45])
+        return end, base + normal * size * 0.45, base - normal * size * 0.45
+
+    def _draw_arrow(
+        self, painter: QPainter, end: QPointF, direction: QPointF
+    ) -> None:
+        tip, left, right = self._arrow_points(
+            end, direction, self.style.arrow_size
+        )
+        color = self.pen().color()
+        if self.style.arrow_style == "filled":
+            painter.setPen(Qt.PenStyle.NoPen)
+            painter.setBrush(color)
+            painter.drawPolygon(QPolygonF([tip, left, right]))
+            return
+        painter.setPen(QPen(color, self.pen().widthF(), Qt.PenStyle.SolidLine))
+        painter.setBrush(Qt.BrushStyle.NoBrush)
+        painter.drawLine(tip, left)
+        if self.style.arrow_style == "open":
+            painter.drawLine(tip, right)
 
     def paint(self, painter: QPainter, option, widget=None) -> None:
         super().paint(painter, option, widget)
-        painter.setPen(Qt.PenStyle.NoPen)
-        painter.setBrush(self.pen().color())
         if self.style.arrow_at_target and not self.target_is_junction:
-            painter.drawPolygon(self._arrow(self.end, self.end_direction, self.style.arrow_size))
+            self._draw_arrow(painter, self.end, self.end_direction)
         if self.style.arrow_at_source and not self.source_is_junction:
-            painter.drawPolygon(
+            self._draw_arrow(painter, self.start, -self.start_direction)
-                self._arrow(self.start, -self.start_direction, self.style.arrow_size)
-            )
 
 
 class WaypointHandle(QGraphicsEllipseItem):
@@ -1207,9 +1223,22 @@ class GraphScene(QGraphicsScene):
         def add_pairs(
             source_item: ComponentGraphicsItem, target_item: ComponentGraphicsItem
         ) -> None:
-            for output in source_item.component.outputs:
+            source_ports = [
+                *source_item.component.outputs,
+                *(
+                    port
+                    for port in source_item.component.inputs
+                    if port.orientation == "indifferent"
+                ),
+            ]
+            for output in source_ports:
                 for input_port in target_item.component.inputs:
-                    if not PortTypeRegistry.compatible(output.type, input_port.type):
+                    if not PortTypeRegistry.compatible(
+                        output.type,
+                        input_port.type,
+                        output.domain,
+                        input_port.domain,
+                    ):
                         continue
                     source = Endpoint(block=source_item.component_id, port=output.id)
                     target = Endpoint(block=target_item.component_id, port=input_port.id)
@@ -1240,7 +1269,9 @@ class GraphScene(QGraphicsScene):
         if terminal.direction == "input":
             for port in component.component.inputs:
                 target = Endpoint(block=component.component_id, port=port.id)
-                if not PortTypeRegistry.compatible(terminal.port.type, port.type):
+                if not PortTypeRegistry.compatible(
+                    terminal.port.type, port.type, terminal.port.domain, port.domain
+                ):
                     continue
                 if not self.controller.endpoint_accepts_connection(interface, "source"):
                     continue
@@ -1254,9 +1285,19 @@ class GraphScene(QGraphicsScene):
                     )
                 )
         else:
-            for port in component.component.outputs:
+            ports = [
+                *component.component.outputs,
+                *(
+                    port
+                    for port in component.component.inputs
+                    if port.orientation == "indifferent"
+                ),
+            ]
+            for port in ports:
                 source = Endpoint(block=component.component_id, port=port.id)
-                if not PortTypeRegistry.compatible(port.type, terminal.port.type):
+                if not PortTypeRegistry.compatible(
+                    port.type, terminal.port.type, port.domain, terminal.port.domain
+                ):
                     continue
                 if not self.controller.endpoint_accepts_connection(source, "source"):
                     continue

BEdit/ui/port_options_dialog.ui

@@ -94,6 +94,11 @@
            <string>Output</string>
           </property>
          </item>
+         <item>
+          <property name="text">
+           <string>Indifferent</string>
+          </property>
+         </item>
         </widget>
        </item>
        <item row="3" column="0" colspan="2">
@@ -222,6 +227,20 @@
            </item>
           </layout>
          </widget>
+         <widget class="QWidget" name="powerOptionsPage">
+          <layout class="QFormLayout" name="powerOptionsForm">
+           <item row="0" column="0"><widget class="QLabel" name="domainLabel"><property name="text"><string>Domain:</string></property></widget></item>
+           <item row="0" column="1"><widget class="QComboBox" name="domainCombo"/></item>
+           <item row="1" column="0"><widget class="QLabel" name="effortLabel"><property name="text"><string>Effort:</string></property></widget></item>
+           <item row="1" column="1"><widget class="QLabel" name="effortValueLabel"><property name="text"><string>p.e</string></property></widget></item>
+           <item row="2" column="0"><widget class="QLabel" name="flowLabel"><property name="text"><string>Flow:</string></property></widget></item>
+           <item row="2" column="1"><widget class="QLabel" name="flowValueLabel"><property name="text"><string>p.f</string></property></widget></item>
+           <item row="3" column="0"><widget class="QLabel" name="causalityLabel"><property name="text"><string>Causality:</string></property></widget></item>
+           <item row="3" column="1"><widget class="QComboBox" name="causalityCombo"/></item>
+           <item row="4" column="0"><widget class="QLabel" name="powerDescriptionLabel"><property name="text"><string>Description:</string></property></widget></item>
+           <item row="4" column="1"><widget class="QPlainTextEdit" name="powerDescriptionEdit"/></item>
+          </layout>
+         </widget>
          <widget class="QWidget" name="unsupportedTypePage">
           <layout class="QVBoxLayout" name="unsupportedTypeLayout">
            <item>

BEdit/untitled.bedit.json

@@ -6,7 +6,7 @@
   },
   "roots": [
     {
-      "id": "4014ba90-5538-4050-a9be-552318197ce1",
+      "id": "4aefc7e3-ac23-4b31-9087-bbad16156be0",
       "name": "New Graph Block 1",
       "position": {
         "x": 0.0,
@@ -61,19 +61,47 @@
         "graph": {
           "blocks": [
             {
-              "id": "86ba2bf6-0da5-40a4-98e9-fb0d9c12c576",
+              "id": "c6169e52-e993-4293-8fc8-5b97e8ad59be",
-              "name": "Constant0",
+              "name": "C",
               "position": {
-                "x": -224.0,
+                "x": -96.0,
-                "y": -160.0
+                "y": -288.0
               },
               "rotation": 0.0,
               "interface": {
-                "inputs": [],
+                "inputs": [
+                  {
+                    "id": "port-2e1d884f",
+                    "name": "p",
+                    "position": {
+                      "x": 0.0,
+                      "y": 0.0
+                    },
+                    "properties": {
+                      "iconPosition": {
+                        "x": 64.0,
+                        "y": 64.0
+                      }
+                    },
+                    "type": "power",
+                    "multipleConnections": false,
+                    "valueType": "real",
+                    "quantity": "",
+                    "unit": "",
+                    "dimensions": {
+                      "rows": 1,
+                      "columns": 1
+                    },
+                    "description": "",
+                    "orientation": "input",
+                    "domain": "power",
+                    "causality": "preferred effort out"
+                  }
+                ],
                 "outputs": [
                   {
-                    "id": "port-ddc97277",
+                    "id": "port-ca7716d5",
-                    "name": "y",
+                    "name": "state",
                     "position": {
                       "x": 0.0,
                       "y": 0.0
@@ -87,22 +115,25 @@
                     "type": "signal",
                     "multipleConnections": false,
                     "valueType": "real",
-                    "quantity": "Length",
+                    "quantity": "",
-                    "unit": "m",
+                    "unit": "",
                     "dimensions": {
                       "rows": 1,
                       "columns": 1
                     },
-                    "description": ""
+                    "description": "",
+                    "orientation": "output",
+                    "domain": "power",
+                    "causality": "indifferent"
                   }
                 ]
               },
               "parameters": [
                 {
-                  "id": "parameter-022177fc",
+                  "id": "parameter-d056bc27",
-                  "name": "v",
+                  "name": "c",
                   "type": "real",
-                  "value": "2",
+                  "value": "1",
                   "quantity": "",
                   "unit": "",
                   "dimensions": {
@@ -123,54 +154,23 @@
                 },
                 "elements": [
                   {
-                    "cornerRadius": 5.0,
+                    "type": "text",
-                    "fill": "#f4f4f4",
+                    "x": 40.0,
-                    "height": 64.0,
+                    "y": 40.0,
+                    "width": 48.0,
+                    "height": 48.0,
+                    "text": "C",
+                    "color": "#303030",
+                    "fontSize": 32.0,
                     "lineStyle": "solid",
                     "lineWidth": 1.5,
                     "stroke": "#303030",
-                    "type": "rectangle",
+                    "fill": "#ffffff"
-                    "width": 64.0,
-                    "x": 32.0,
-                    "y": 32.0
-                  },
-                  {
-                    "fill": "none",
-                    "height": 48.0,
-                    "lineStyle": "solid",
-                    "lineWidth": 1.5,
-                    "stroke": "#00007f",
-                    "type": "line",
-                    "width": 0.0,
-                    "x": 40.0,
-                    "y": 40.0
-                  },
-                  {
-                    "fill": "none",
-                    "height": 0.0,
-                    "lineStyle": "solid",
-                    "lineWidth": 1.5,
-                    "stroke": "#00007f",
-                    "type": "line",
-                    "width": 48.0,
-                    "x": 40.0,
-                    "y": 88.0
-                  },
-                  {
-                    "fill": "none",
-                    "height": 0.0,
-                    "lineStyle": "solid",
-                    "lineWidth": 1.0,
-                    "stroke": "#ffaa00",
-                    "type": "line",
-                    "width": 48.0,
-                    "x": 40.0,
-                    "y": 64.0
                   }
                 ]
               },
               "properties": {
-                "showName": true
+                "showName": false
               },
               "library": {
                 "showSubtree": true
@@ -178,15 +178,15 @@
               "implementation": {
                 "kind": "text",
                 "source": {
-                  "equations": "y = v;",
+                  "equations": "der(state) = p.f;\np.e = state/c;",
                   "declarations": "",
                   "initialEquations": ""
                 }
               }
             },
             {
-              "id": "7805cb2f-c938-44b2-a1f8-e1b4af13f7bf",
+              "id": "bfa506d8-ee41-4bab-ae19-a97fd67bfcf6",
-              "name": "Gain0",
+              "name": "1",
               "position": {
                 "x": -96.0,
                 "y": -160.0
@@ -195,8 +195,8 @@
               "interface": {
                 "inputs": [
                   {
-                    "id": "port-df34ce84",
+                    "id": "port-3e53bf80",
-                    "name": "u",
+                    "name": "p",
                     "position": {
                       "x": 0.0,
                       "y": 0.0
@@ -207,8 +207,8 @@
                         "y": 64.0
                       }
                     },
-                    "type": "signal",
+                    "type": "power",
-                    "multipleConnections": false,
+                    "multipleConnections": true,
                     "valueType": "real",
                     "quantity": "",
                     "unit": "",
@@ -216,24 +216,80 @@
                       "rows": 1,
                       "columns": 1
                     },
-                    "description": ""
+                    "description": "",
+                    "orientation": "indifferent",
+                    "domain": "power",
+                    "causality": "indifferent"
                   }
                 ],
-                "outputs": [
+                "outputs": []
+              },
+              "parameters": [],
+              "icon": {
+                "shape": "rectangle",
+                "fill": "#f4f4f4",
+                "border": "#303030",
+                "text": "Text",
+                "size": {
+                  "width": 128.0,
+                  "height": 128.0
+                },
+                "elements": [
                   {
-                    "id": "port-fe9e6486",
+                    "type": "text",
-                    "name": "y",
+                    "x": 40.0,
+                    "y": 40.0,
+                    "width": 48.0,
+                    "height": 48.0,
+                    "text": "1",
+                    "color": "#303030",
+                    "fontSize": 32.0,
+                    "lineStyle": "solid",
+                    "lineWidth": 1.5,
+                    "stroke": "#303030",
+                    "fill": "#ffffff"
+                  }
+                ]
+              },
+              "properties": {
+                "showName": false
+              },
+              "library": {
+                "showSubtree": true
+              },
+              "implementation": {
+                "kind": "text",
+                "source": {
+                  "equations": "flow = p[1].f;\nsum(p[i].e for i in 1:$p_N$) = 0;\nfor i in 2:$p_N$ loop\n    p[i].f = p[i-1].f;\nend for;",
+                  "declarations": "Real flow;",
+                  "initialEquations": ""
+                }
+              }
+            },
+            {
+              "id": "ea95e8ee-7f2d-4e14-a65d-d56bec5b4eb2",
+              "name": "R",
+              "position": {
+                "x": 32.0,
+                "y": -160.0
+              },
+              "rotation": 0.0,
+              "interface": {
+                "inputs": [
+                  {
+                    "id": "port-2e1d884f",
+                    "name": "p",
                     "position": {
                       "x": 0.0,
                       "y": 0.0
                     },
                     "properties": {
                       "iconPosition": {
-                        "x": 88.0,
+                        "x": 64.0,
-                        "y": 40.0
+                        "y": 64.0
                       }
                     },
-                    "type": "signal",
+                    "type": "power",
                     "multipleConnections": false,
                     "valueType": "real",
                     "quantity": "",
@@ -242,18 +298,22 @@
                       "rows": 1,
                       "columns": 1
                     },
-                    "description": ""
+                    "description": "",
+                    "orientation": "input",
+                    "domain": "power",
+                    "causality": "indifferent"
                   }
-                ]
+                ],
+                "outputs": []
               },
               "parameters": [
                 {
-                  "id": "parameter-61a43a86",
+                  "id": "parameter-d056bc27",
-                  "name": "k",
+                  "name": "r",
                   "type": "real",
-                  "value": "2.5",
+                  "value": "1",
-                  "quantity": "Current",
+                  "quantity": "",
-                  "unit": "A",
+                  "unit": "",
                   "dimensions": {
                     "rows": 1,
                     "columns": 1
@@ -272,35 +332,23 @@
                 },
                 "elements": [
                   {
-                    "cornerRadius": 5.0,
+                    "type": "text",
-                    "fill": "#f4f4f4",
+                    "x": 40.0,
-                    "height": 64.0,
+                    "y": 40.0,
+                    "width": 48.0,
+                    "height": 48.0,
+                    "text": "R",
+                    "color": "#303030",
+                    "fontSize": 32.0,
                     "lineStyle": "solid",
                     "lineWidth": 1.5,
                     "stroke": "#303030",
-                    "type": "rectangle",
+                    "fill": "#ffffff"
-                    "width": 64.0,
-                    "x": 32.0,
-                    "y": 32.0
-                  },
-                  {
-                    "color": "#00007f",
-                    "fill": "#ffffff",
-                    "fontSize": 24.0,
-                    "height": 48.0,
-                    "lineStyle": "solid",
-                    "lineWidth": 1.5,
-                    "stroke": "#00007f",
-                    "text": "K",
-                    "type": "text",
-                    "width": 48.0,
-                    "x": 40.0,
-                    "y": 40.0
                   }
                 ]
               },
               "properties": {
-                "showName": true
+                "showName": false
               },
               "library": {
                 "showSubtree": true
@@ -308,23 +356,149 @@
               "implementation": {
                 "kind": "text",
                 "source": {
-                  "equations": "y = k*u;",
+                  "equations": "p.e = r*p.f;",
                   "declarations": "",
                   "initialEquations": ""
                 }
               }
+            },
+            {
+              "id": "063a6341-cb18-4bfe-a1e4-00957a88a874",
+              "name": "Se",
+              "position": {
+                "x": -224.0,
+                "y": -160.0
+              },
+              "rotation": 0.0,
+              "interface": {
+                "inputs": [],
+                "outputs": [
+                  {
+                    "id": "port-2e1d884f",
+                    "name": "p",
+                    "position": {
+                      "x": 0.0,
+                      "y": 0.0
+                    },
+                    "properties": {
+                      "iconPosition": {
+                        "x": 64.0,
+                        "y": 64.0
+                      }
+                    },
+                    "type": "power",
+                    "multipleConnections": false,
+                    "valueType": "real",
+                    "quantity": "",
+                    "unit": "",
+                    "dimensions": {
+                      "rows": 1,
+                      "columns": 1
+                    },
+                    "description": "",
+                    "orientation": "output",
+                    "domain": "power",
+                    "causality": "fixed effort out"
+                  }
+                ]
+              },
+              "parameters": [
+                {
+                  "id": "parameter-d056bc27",
+                  "name": "effort",
+                  "type": "real",
+                  "value": "1",
+                  "quantity": "",
+                  "unit": "",
+                  "dimensions": {
+                    "rows": 1,
+                    "columns": 1
+                  },
+                  "description": ""
+                }
+              ],
+              "icon": {
+                "shape": "rectangle",
+                "fill": "#f4f4f4",
+                "border": "#303030",
+                "text": "Text",
+                "size": {
+                  "width": 128.0,
+                  "height": 128.0
+                },
+                "elements": [
+                  {
+                    "type": "text",
+                    "x": 32.0,
+                    "y": 32.0,
+                    "width": 64.0,
+                    "height": 64.0,
+                    "text": "Se",
+                    "color": "#303030",
+                    "fontSize": 32.0,
+                    "lineStyle": "solid",
+                    "lineWidth": 1.5,
+                    "stroke": "#303030",
+                    "fill": "#ffffff"
+                  }
+                ]
+              },
+              "properties": {
+                "showName": false
+              },
+              "library": {
+                "showSubtree": true
+              },
+              "implementation": {
+                "kind": "text",
+                "source": {
+                  "equations": "p.e = effort;\nflow = p.f;",
+                  "declarations": "Real flow;",
+                  "initialEquations": ""
+                }
+              }
             }
           ],
           "connections": [
             {
-              "id": "5582d4ad-7c7a-40fe-87d2-9b78410336b3",
+              "id": "4b09ba21-baa0-4db7-9431-4c919478bce4",
               "source": {
-                "block": "86ba2bf6-0da5-40a4-98e9-fb0d9c12c576",
+                "block": "063a6341-cb18-4bfe-a1e4-00957a88a874",
-                "port": "port-ddc97277"
+                "port": "port-2e1d884f"
               },
               "target": {
-                "block": "7805cb2f-c938-44b2-a1f8-e1b4af13f7bf",
+                "block": "bfa506d8-ee41-4bab-ae19-a97fd67bfcf6",
-                "port": "port-df34ce84"
+                "port": "port-3e53bf80"
+              },
+              "name": "",
+              "properties": {
+                "waypoints": []
+              }
+            },
+            {
+              "id": "a73a99a1-54e2-461d-a9a7-2d6d11d500f4",
+              "source": {
+                "block": "bfa506d8-ee41-4bab-ae19-a97fd67bfcf6",
+                "port": "port-3e53bf80"
+              },
+              "target": {
+                "block": "ea95e8ee-7f2d-4e14-a65d-d56bec5b4eb2",
+                "port": "port-2e1d884f"
+              },
+              "name": "",
+              "properties": {
+                "waypoints": []
+              }
+            },
+            {
+              "id": "dd5fb1e2-b125-4b5f-a792-dac89dd89ad3",
+              "source": {
+                "block": "bfa506d8-ee41-4bab-ae19-a97fd67bfcf6",
+                "port": "port-3e53bf80"
+              },
+              "target": {
+                "block": "c6169e52-e993-4293-8fc8-5b97e8ad59be",
+                "port": "port-2e1d884f"
               },
               "name": "",
               "properties": {