Start of graph view

src/bedit_gui/controllers/document_tree_controller.py

@@ -96,7 +96,7 @@ class DocumentTreeController(QObject):
 
     def _on_document_changed(self, model: CoreDocument) -> None:
         """Rebuild the tree whenever New/Open replaces the core document."""
-        self._show_equation_component(None)
+        self._show_component(None)
         self.model.set_document(model)
         self._components = {}
         self._collect_components(model.root)
@@ -111,15 +111,21 @@ class DocumentTreeController(QObject):
     def _selection_changed(self, *_args: object) -> None:
         indexes = self.window.ui.documentTree.selectionModel().selectedRows(0)
         component = self.model.value(indexes[0]) if len(indexes) == 1 else None
-        self._show_equation_component(component if isinstance(component, Component) else None)
+        self._show_component(component if isinstance(component, Component) else None)
 
-    def _show_equation_component(self, component: Component | None) -> None:
+    def _show_component(self, component: Component | None) -> None:
         if component is not None and isinstance(component.implementation, EquationImplementation):
             self.window.equation_editor.set_component(component)
             self.window.equation_editor.show()
         else:
             self.window.equation_editor.set_component(None)
             self.window.equation_editor.hide()
+        if component is not None and isinstance(component.implementation, GraphImplementation):
+            self.window.graph_editor.set_component(component)
+            self.window.graph_editor.show()
+        else:
+            self.window.graph_editor.set_component(None)
+            self.window.graph_editor.hide()
 
     def _on_equation_text_changed(self, component: Component, section: str) -> None:
         if self.window.equation_editor.component() is component:

src/bedit_gui/ui/forms/graph_editor_widget.ui

@@ -0,0 +1,98 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>graphEditorWidget</class>
+ <widget class="QWidget" name="graphEditorWidget">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>1079</width>
+    <height>730</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Graph Editor</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="spacing">
+    <number>0</number>
+   </property>
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
+    <number>0</number>
+   </property>
+   <item>
+    <widget class="QToolBar" name="graphToolBar">
+     <property name="windowTitle">
+      <string>Graph tools</string>
+     </property>
+     <property name="movable">
+      <bool>false</bool>
+     </property>
+     <property name="floatable">
+      <bool>false</bool>
+     </property>
+     <addaction name="actionSelect"/>
+     <addaction name="actionAddComponent"/>
+     <addaction name="actionAddConnection"/>
+     <addaction name="actionDelete"/>
+    </widget>
+   </item>
+   <item>
+    <widget class="QGraphicsView" name="graphicsView">
+     <property name="frameShape">
+      <enum>QFrame::Shape::NoFrame</enum>
+     </property>
+     <property name="dragMode">
+      <enum>QGraphicsView::DragMode::RubberBandDrag</enum>
+     </property>
+     <property name="renderHints">
+      <set>QPainter::RenderHint::Antialiasing</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+  <action name="actionSelect">
+   <property name="text">
+    <string>Select</string>
+   </property>
+   <property name="toolTip">
+    <string>Select graph items</string>
+   </property>
+  </action>
+  <action name="actionAddComponent">
+   <property name="text">
+    <string>Add Component</string>
+   </property>
+   <property name="toolTip">
+    <string>Add a component</string>
+   </property>
+  </action>
+  <action name="actionAddConnection">
+   <property name="text">
+    <string>Add Connection</string>
+   </property>
+   <property name="toolTip">
+    <string>Add a connection</string>
+   </property>
+  </action>
+  <action name="actionDelete">
+   <property name="text">
+    <string>Delete</string>
+   </property>
+   <property name="toolTip">
+    <string>Delete selected graph items</string>
+   </property>
+  </action>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

src/bedit_gui/views/graph_editor_widget.py

@@ -0,0 +1,83 @@
+from __future__ import annotations
+
+from PySide6.QtCore import QEvent, QObject, QRectF, Qt
+from PySide6.QtGui import QColor, QPainter, QPen, QWheelEvent
+from PySide6.QtWidgets import QGraphicsScene, QGraphicsView, QWidget
+
+from bedit_core.models import Component, GraphImplementation
+from bedit_gui.ui.generated.ui_graph_editor_widget import Ui_graphEditorWidget
+
+GRID_SPACING = 32
+SCENE_SIZE = 10000
+MIN_ZOOM = 0.2
+MAX_ZOOM = 4.0
+ZOOM_STEP = 1.15
+
+
+class GraphGraphicsScene(QGraphicsScene):
+    """Graph canvas with a lightweight dotted-line grid."""
+
+    def drawBackground(self, painter: QPainter, rect: QRectF) -> None:
+        painter.fillRect(rect, QColor("white"))
+        pen = QPen(QColor(205, 205, 205), 0, Qt.PenStyle.DotLine)
+        painter.setPen(pen)
+
+        left = int(rect.left()) - int(rect.left()) % GRID_SPACING
+        top = int(rect.top()) - int(rect.top()) % GRID_SPACING
+        x = left
+        while x <= rect.right():
+            painter.drawLine(x, rect.top(), x, rect.bottom())
+            x += GRID_SPACING
+        y = top
+        while y <= rect.bottom():
+            painter.drawLine(rect.left(), y, rect.right(), y)
+            y += GRID_SPACING
+
+
+class GraphEditorWidget(QWidget):
+    def __init__(self, parent: QWidget | None = None) -> None:
+        super().__init__(parent)
+
+        self.ui = Ui_graphEditorWidget()
+        self.ui.setupUi(self)
+        self._component: Component | None = None
+        self.scene = GraphGraphicsScene(self)
+        self.scene.setSceneRect(-SCENE_SIZE / 2, -SCENE_SIZE / 2, SCENE_SIZE, SCENE_SIZE)
+        self.ui.graphicsView.setScene(self.scene)
+        self.ui.graphicsView.setTransformationAnchor(QGraphicsView.ViewportAnchor.AnchorUnderMouse)
+        self.ui.graphicsView.viewport().installEventFilter(self)
+        self.ui.graphicsView.centerOn(0, 0)
+
+    def set_component(self, component: Component | None) -> None:
+        if component is not None and not isinstance(component.implementation, GraphImplementation):
+            raise TypeError("GraphEditorWidget only supports components with a graph implementation")
+        self._component = component
+
+    def component(self) -> Component | None:
+        return self._component
+
+    def eventFilter(self, watched: QObject, event: QEvent) -> bool:
+        if watched is self.ui.graphicsView.viewport() and event.type() == QEvent.Type.Wheel:
+            assert isinstance(event, QWheelEvent)
+            if event.modifiers() & Qt.KeyboardModifier.ControlModifier:
+                self._zoom(event)
+                return True
+            if event.modifiers() & Qt.KeyboardModifier.ShiftModifier:
+                self._scroll_horizontally(event)
+                return True
+        return super().eventFilter(watched, event)
+
+    def _zoom(self, event: QWheelEvent) -> None:
+        delta = event.angleDelta().y() or event.pixelDelta().y()
+        if not delta:
+            return
+        current_zoom = self.ui.graphicsView.transform().m11()
+        requested_zoom = current_zoom * ZOOM_STEP ** (delta / 120)
+        target_zoom = min(MAX_ZOOM, max(MIN_ZOOM, requested_zoom))
+        self.ui.graphicsView.scale(target_zoom / current_zoom, target_zoom / current_zoom)
+
+    def _scroll_horizontally(self, event: QWheelEvent) -> None:
+        scrollbar = self.ui.graphicsView.horizontalScrollBar()
+        pixel_delta = event.pixelDelta().y()
+        distance = pixel_delta if pixel_delta else event.angleDelta().y() / 120 * scrollbar.singleStep() * 3
+        scrollbar.setValue(scrollbar.value() - round(distance))

src/bedit_gui/views/main_window.py

@@ -3,6 +3,7 @@ from PySide6.QtWidgets import QMainWindow, QTabWidget, QVBoxLayout
 
 from bedit_gui.ui.generated.ui_main_window import Ui_MainWindow
 from bedit_gui.views.equation_editor_widget import EquationEditorWidget
+from bedit_gui.views.graph_editor_widget import GraphEditorWidget
 
 
 class MainWindow(QMainWindow):
@@ -17,6 +18,9 @@ class MainWindow(QMainWindow):
         self.equation_editor = EquationEditorWidget(self.ui.centralwidget)
         self.equation_editor.hide()
         central_layout.addWidget(self.equation_editor)
+        self.graph_editor = GraphEditorWidget(self.ui.centralwidget)
+        self.graph_editor.hide()
+        central_layout.addWidget(self.graph_editor)
 
         self.setTabPosition(Qt.AllDockWidgetAreas, QTabWidget.North)
         self.setCorner(Qt.Corner.BottomLeftCorner, Qt.DockWidgetArea.LeftDockWidgetArea)