Editor Gestures

Editor gestures

Nodify uses EditorGestures to map mouse and keyboard input to built-in editor operations. The default mappings live in EditorGestures.Mappings. A NodifyEditor can also receive its own mappings through InputGestures.

Use per-editor mappings when one editor needs different interaction rules than the rest of the application. Use EditorGestures.Mappings only when you want to change the application-wide defaults.

Per-editor mappings

Create an EditorGestures instance in your view model and bind it to NodifyEditor.InputGestures.

using Nodify.Interactivity;
using System.Windows.Input;

public class EditorViewModel
{
    public EditorGestures Gestures { get; } = new EditorGestures();

    public EditorViewModel()
    {
        Gestures.Editor.Pan.Value = new AnyGesture(
            new Nodify.Interactivity.MouseGesture(MouseAction.MiddleClick),
            new Nodify.Interactivity.MouseGesture(MouseAction.LeftClick, Key.Space));

        Gestures.Editor.ZoomModifierKey = ModifierKeys.Control;
        Gestures.Editor.PanWithMouseWheel = true;
    }
}

<nodify:NodifyEditor ItemsSource="{Binding Nodes}"
                     InputGestures="{Binding Gestures}" />

If InputGestures is not set, the editor uses EditorGestures.Mappings.

Changing global defaults

Change EditorGestures.Mappings when every editor should use the same mappings.

using Nodify.Interactivity;
using System.Windows.Input;

EditorGestures.Mappings.Editor.ZoomModifierKey = ModifierKeys.Control;
EditorGestures.Mappings.Editor.PanWithMouseWheel = true;
EditorGestures.Mappings.Connection.Disconnect.Unbind();

Global defaults can be changed whenever the application needs to switch its default editor interactions. Existing editors that use EditorGestures.Mappings pick up those changes through the shared mapping instance.

Replacing a gesture

Most gesture properties are InputGestureRef values. Replace the Value property instead of replacing the reference.

Gestures.Editor.Cutting.Value =
    new Nodify.Interactivity.MouseGesture(MouseAction.LeftClick, ModifierKeys.Alt);

Use AnyGesture when more than one input should trigger the same action.

Gestures.Editor.Pan.Value = new AnyGesture(
    new Nodify.Interactivity.MouseGesture(MouseAction.RightClick),
    new Nodify.Interactivity.MouseGesture(MouseAction.MiddleClick));

Use AllGestures when every gesture in the list must match the same input event before the action is triggered.

Use Unbind() to disable an action.

Gestures.Editor.Cutting.Unbind();
Gestures.Connector.Connect.Unbind();
Gestures.Connection.Split.Unbind();

Selection gestures

Selection is made of several related gestures:

• Replace
• Append
• Remove
• Invert
• Cancel
• Select

Use SelectionGestures when you want to move the full selection group from one mouse button to another.

Gestures.Editor.Selection.Apply(
    new EditorGestures.SelectionGestures(MouseAction.RightClick));

If item containers should use the same selection behavior, apply the same mapping to ItemContainer.Selection and update ItemContainer.Drag.

Gestures.Editor.Selection.Apply(
    new EditorGestures.SelectionGestures(MouseAction.RightClick));

Gestures.ItemContainer.Selection.Apply(Gestures.Editor.Selection);
Gestures.ItemContainer.Drag.Value = new AnyGesture(
    Gestures.ItemContainer.Selection.Replace.Value,
    Gestures.ItemContainer.Selection.Remove.Value,
    Gestures.ItemContainer.Selection.Append.Value,
    Gestures.ItemContainer.Selection.Invert.Value);

This keeps selecting and dragging in sync.

Read-only mode

For a read-only editor, unbind gestures that can modify graph state and leave navigation gestures enabled.

public static void MakeReadOnly(EditorGestures gestures)
{
    gestures.Editor.Selection.Unbind();
    gestures.Editor.SelectAll.Unbind();
    gestures.Editor.Cutting.Unbind();
    gestures.Editor.PushItems.Unbind();

    gestures.Editor.Keyboard.ToggleSelected.Unbind();
    gestures.Editor.Keyboard.DragSelection.Unbind();
    gestures.Editor.Keyboard.DeselectAll.Unbind();

    gestures.ItemContainer.Selection.Unbind();
    gestures.ItemContainer.Drag.Unbind();

    gestures.Connection.Disconnect.Unbind();
    gestures.Connection.Split.Unbind();
    gestures.Connection.Selection.Unbind();

    gestures.Connector.Connect.Unbind();
    gestures.Connector.Disconnect.Unbind();
}

The exact list depends on what your editor is allowed to do. For example, a viewer may keep panning, zooming, keyboard navigation, and minimap navigation enabled.

Copying and restoring mappings

Use Apply() to copy one gesture set into another. This is useful for editor modes such as "locked", "drawing", or "connection editing".

private readonly EditorGestures _activeGestures = new EditorGestures();
private readonly EditorGestures _backupGestures = new EditorGestures();

public EditorGestures ActiveGestures => _activeGestures;

public void LockEditing()
{
    _backupGestures.Apply(_activeGestures);
    MakeReadOnly(_activeGestures);
}

public void UnlockEditing()
{
    _activeGestures.Apply(_backupGestures);
}

Bind ActiveGestures to InputGestures.

Common gesture targets

The most common groups are:

• Editor: panning, zooming, selecting, cutting, pushing, keyboard navigation, fit to screen, reset viewport.
• ItemContainer: selecting and dragging node containers.
• Connector: starting pending connections and disconnecting connectors.
• Connection: selecting, splitting, and disconnecting connections.
• GroupingNode: grouped movement behavior and content selection.
• Minimap: panning, dragging the viewport, zooming, reset viewport.

For the full API, see EditorGestures.