NodeGraphView

Remarks

Two graph types, and the view is the only thing that knows both. NodeGraphModel is the document — identities, port names, saved and diffed — and Vixen.Ui.Controls.Advanced.NodeGraph is what a canvas draws, which is boxes with sockets on and no idea what a node type is. Keeping them apart is what lets the model be tested against numbers and the canvas be tested against a fixture with three nodes called "a", "b" and "c"; this class is the projection between them and it is one direction only. The model is the truth and the canvas is a picture of it.

⚠ Every structural change reprojects the whole graph. A cheaper incremental update is possible and was not written, for two reasons: the canvas culls to the viewport already, so the expensive part is bounded by the screen rather than by the graph; and a projection that is rebuilt cannot drift from the model, which an incremental one does the first time somebody adds an edit path and forgets a case. A drag is the one thing that does not reproject — it writes positions in place — because that is the path that runs every frame.

⚠ The canvas edits its own copy optimistically, and that is on purpose. Dragging a wire connects it in the picture before this class has recorded anything, which is what makes the gesture feel live. What follows is either a command — and the reprojection agrees with it — or a reprojection alone, which puts the picture back. A canvas that had to ask permission before drawing would be a canvas with a frame of latency in every gesture.

No stack means read-only. Every edit here goes through Stack, so a view without one shows a graph and refuses to change it — which is exactly what a preview of a sub-graph, or of an asset that is not open for editing, should do.

Fields and properties (17)

• protected override string TagName

  The element name this type answers to when a caller does not choose one.

• protected override bool AcceptsFocus

  Whether the focus can rest on this kind of control at all.

• public NodeCanvas Canvas

  The canvas everything is drawn on.

• public NodeMinimap Minimap

  The overview in the corner, which is the canvas's own.

• public NodePreviewLayer Previews

  The swatches under the nodes that asked for one.

• public NodeSearchPopup Search

  The create-a-node popup.

• public float NodeWidth

  How wide a node is drawn, in graph units.

• public int Decimals

  How many decimal places a number on a node shows.

• public NodeGraphModel Graph

  The graph being shown.

• public NodeTypeRegistry Registry

  The node types the graph may contain.

• public ISubGraphSource? SubGraphSource

  Where sub-graphs are found, when this graph has any.

• public INodePreviewSource? PreviewSource

  Where a preview swatch's colour comes from.

• public NodeGraphClipboard Clipboard

  Where copy and paste put things.

• public CommandStack? Stack

  Where edits are recorded, or null for a view that cannot be edited.

• public EditorDocument? EditedDocument

  The document to mark dirty, if the graph belongs to one.

• public bool IsReadOnly

  Whether edits are refused because there is nowhere to record them.

• public IReadOnlyCollection<NodeId> Selection

  What is selected, by identity.

Events (4)

• public Action<NodeGraphView>? SelectionChanged

  Raised after the selection changes.

• public Action<NodeGraphView, ConnectionRefusal>? ConnectionRefused

  Raised when a wire was dropped somewhere it could not go.

• public Action<NodeGraphView, string, NodeGraphModel>? SubGraphOpened

  Raised when a node standing for a sub-graph is opened.

• public Action<NodeGraphView>? GraphChanged

  Raised after the model this view is showing changed, however it changed.

Methods (20)

• protected override void OnCreated()

  Builds whatever this element is made of, once, as it joins a document.

• protected override void OnRemoved()
• protected override void OnDraw(DrawContext context)
• public NodeTypeDefinition? Definition(string type)

  The node type at a path, including the two a sub-graph's boundary nodes use.

• public GraphNode? NodeOf(GraphNode node)

  The model node an element on the canvas is showing.

• public void Project()

  Rebuilds the picture from the model.

• public GraphNode? Create(string type, Vector2 position)

  Adds a node.

• public bool DeleteSelection()

  Deletes what is selected, and the wires that touched it.

• public bool GroupSelection(string title = "Group")

  Draws a box round what is selected.

• public bool UngroupSelection()

  Removes every group that holds a selected node, leaving the nodes where they are.

• public GraphComment? AddComment(string text, Vector2 position)

  Adds a sticky note.

• public bool CopySelection()

  Copies what is selected.

• public bool CutSelection()

  Copies what is selected and deletes it.

• public bool Paste(Vector2? at = null)

  Pastes whatever was copied, offset so it does not land on the original.

• public bool AutoLayout()

  Lays the whole graph out left to right.

• public NodeLayoutOptions LayoutOptions()

  What the layout should assume about node sizes, read off the canvas's theme.

• public NodeGraphModel? ExtractSelection(string name, string path, SubGraphLibrary library)

  Lifts what is selected out into a sub-graph.

• public void Frame(bool selectionOnly = false)

  Pans and zooms until everything fits, or until the selection does.

• public void Select(IEnumerable<NodeId> nodes)

  Selects some nodes and nothing else.

• public void OpenSearch(float x, float y)

  Opens the create-a-node popup, with nothing wired to it.

Used by (9)

• CompositorViewVixen.Editor.AssetEditors
• NodeInspectorVixen.Editor.NodeGraph
• NodePreviewLayerVixen.Editor.NodeGraph
• PortValueTestsVixen.Editor.NodeGraph.Tests
• ShaderGraphViewVixen.Editor.AssetEditors
• ShaderGraphViewTestsVixen.Editor.AssetEditors.Tests
• VfxGraphViewVixen.Editor.AssetEditors
• ViewFixtureVixen.Editor.NodeGraph.Tests
• ViewTestsVixen.Editor.NodeGraph.Tests