More graph utils

Cavern/Filters/Utilities/FilterGraphNodeUtils.cs

@@ -5,9 +5,27 @@ namespace Cavern.Filters.Utilities {
     /// Special functions for handling <see cref="FilterGraphNode"/>s.
     /// </summary>
     public static class FilterGraphNodeUtils {
+        /// <summary>
+        /// Check if the graph has cycles.
+        /// </summary>
+        /// <param name="rootNodes">All nodes which have no parents</param>
+        public static bool HasCycles(IEnumerable<FilterGraphNode> rootNodes) {
+            HashSet<FilterGraphNode> visited = new HashSet<FilterGraphNode>(),
+                inProgress = new HashSet<FilterGraphNode>();
+            foreach (FilterGraphNode node in rootNodes) {
+                if (!visited.Contains(node)) {
+                    if (HasCycles(node, visited, inProgress)) {
+                        return true;
+                    }
+                }
+            }
+            return false;
+        }
+
         /// <summary>
         /// Get all nodes in a filter graph knowing the root nodes.
         /// </summary>
+        /// <param name="rootNodes">All nodes which have no parents</param>
         public static HashSet<FilterGraphNode> MapGraph(IEnumerable<FilterGraphNode> rootNodes) {
             HashSet<FilterGraphNode> visited = new HashSet<FilterGraphNode>();
             Queue<FilterGraphNode> queue = new Queue<FilterGraphNode>(rootNodes);
@@ -25,5 +43,27 @@ public static HashSet<FilterGraphNode> MapGraph(IEnumerable<FilterGraphNode> roo
 
             return visited;
         }
+
+        /// <summary>
+        /// Starting from a single node, checks if the graph has cycles.
+        /// </summary>
+        static bool HasCycles(FilterGraphNode currentNode, HashSet<FilterGraphNode> visited, HashSet<FilterGraphNode> inProgress) {
+            if (inProgress.Contains(currentNode)) {
+                return true;
+            }
+            if (visited.Contains(currentNode)) {
+                return false;
+            }
+
+            inProgress.Add(currentNode);
+            foreach (FilterGraphNode child in currentNode.Children) {
+                if (HasCycles(child, visited, inProgress)) {
+                    return true;
+                }
+            }
+            inProgress.Remove(currentNode);
+            visited.Add(currentNode);
+            return false;
+        }
     }
 }

CavernSamples/FilterStudio/Graphs/ManipulatableGraph.cs

@@ -23,11 +23,21 @@ public class ManipulatableGraph : ScrollViewer {
         /// </summary>
         public event Action<object> OnRightClick;
 
+        /// <summary>
+        /// When the user connects a parent (first parameter) and child (second parameter) nodes, this function is called.
+        /// </summary>
+        public event Action<StyledNode, StyledNode> OnConnect;
+
         /// <summary>
         /// The currently selected node is determined by border line thickness.
         /// </summary>
         public StyledNode SelectedNode => (StyledNode)viewer.Graph?.Nodes.FirstOrDefault(x => x.Attr.LineWidth > 1);
 
+        /// <summary>
+        /// The user started dragging from this node.
+        /// </summary>
+        StyledNode dragStart;
+
         /// <summary>
         /// Handle to MSAGL.
         /// </summary>
@@ -95,6 +105,9 @@ protected override void OnPreviewMouseUp(MouseButtonEventArgs e) {
             IViewerObject element = viewer.ObjectUnderMouseCursor;
             object param = null;
             if (element is IViewerNode vnode) {
+                if (dragStart != null && vnode.Node != dragStart) {
+                    OnConnect?.Invoke(dragStart, (StyledNode)vnode.Node);
+                }
                 param = vnode.Node;
             } else if (element is IViewerEdge edge) {
                 param = edge.Edge;
@@ -121,5 +134,11 @@ protected override void OnPreviewMouseMove(MouseEventArgs e) {
                 e.Handled = true;
             }
         }
+
+        /// <summary>
+        /// Starts to track dragging a new edge from a node.
+        /// </summary>
+        protected override void OnPreviewMouseDown(MouseButtonEventArgs e) =>
+            dragStart = (StyledNode)(viewer.ObjectUnderMouseCursor as IViewerNode)?.Node;
     }
 }

CavernSamples/FilterStudio/MainWindow.Graph.cs

@@ -3,6 +3,8 @@
 using System.Collections.Generic;
 using System.Windows;
 
+using Cavern.Filters;
+using Cavern.Filters.Utilities;
 using VoidX.WPF;
 
 using FilterStudio.Graphs;
@@ -52,6 +54,33 @@ void SetDirection(LayerDirection direction) {
         /// </summary>
         void Recenter(object _, RoutedEventArgs e) => ReloadGraph();
 
+        /// <summary>
+        /// Delete the currently selected node.
+        /// </summary>
+        void DeleteNode(object sender, RoutedEventArgs e) {
+            StyledNode node = graph.GetSelectedNode(sender);
+            if (node == null || node.Filter == null) {
+                Error((string)language["NFNod"]);
+            } else if (node.Filter.Filter is InputChannel) {
+                Error((string)language["NFInp"]);
+            } else if (node.Filter.Filter is OutputChannel) {
+                Error((string)language["NFOut"]);
+            } else {
+                node.Filter.DetachFromGraph();
+                ReloadGraph();
+            }
+        }
+
+        /// <summary>
+        /// Delete the selected edge.
+        /// </summary>
+        void DeleteEdge(Edge edge) {
+            FilterGraphNode parent = ((StyledNode)edge.SourceNode).Filter,
+                child = ((StyledNode)edge.TargetNode).Filter;
+            parent.DetachChild(child, false);
+            ReloadGraph();
+        }
+
         /// <summary>
         /// When selecting a node, open it for modification.
         /// </summary>
@@ -71,19 +100,47 @@ void GraphLeftClick(object _) {
         /// Display the context menu when the graph is right clicked.
         /// </summary>
         void GraphRightClick(object element) {
+            if (element is not Node && element is not Edge) {
+                return;
+            }
+
             List<(string, Action<object, RoutedEventArgs>)> menuItems = [
                     ((string)language["FLabe"], (_, e) => AddLabel(element, e)),
                     ((string)language["FGain"], (_, e) => AddGain(element, e)),
                     ((string)language["FDela"], (_, e) => AddDelay(element, e)),
                     ((string)language["FBiqu"], (_, e) => AddBiquad(element, e)),
+                    (null, null) // Separator for deletion
                 ];
             if (element is Node) {
-                menuItems.Add((null, null));
                 menuItems.Add(((string)language["CoDel"], (_, e) => DeleteNode(element, e)));
+            } else {
+                menuItems.Add(((string)language["CoDel"], (_, e) => DeleteEdge((Edge)element)));
             }
             QuickContextMenu.Show(menuItems);
         }
 
+        /// <summary>
+        /// Handle creating a user-selected connection.
+        /// </summary>
+        void GraphConnect(StyledNode parent, StyledNode child) {
+            if (child.Filter.Filter is InputChannel) {
+                Error((string)language["NCInp"]);
+                return;
+            }
+            if (parent.Filter.Filter is OutputChannel) {
+                Error((string)language["NCOut"]);
+                return;
+            }
+
+            parent.Filter.AddChild(child.Filter);
+            if (FilterGraphNodeUtils.HasCycles(rootNodes)) {
+                Error((string)language["NLoop"]);
+                parent.Filter.DetachChild(child.Filter, false);
+            } else {
+                ReloadGraph();
+            }
+        }
+
         /// <summary>
         /// Updates the graph based on the <see cref="rootNodes"/>.
         /// </summary>

CavernSamples/FilterStudio/MainWindow.xaml

@@ -54,8 +54,9 @@
             <fs:PipelineEditor VerticalAlignment="Top" Height="100" x:Name="pipeline"/>
             <Separator Margin="0,99,0,0" VerticalAlignment="Top"/>
             <fs:ManipulatableGraph Margin="0,100,0,0" x:Name="graph"/>
-            <TextBlock Name="help1" Margin="10,0,0,30" HorizontalAlignment="Left" VerticalAlignment="Bottom" Text="{StaticResource Help1}"/>
-            <TextBlock Name="help2" Margin="10,0,0,10" HorizontalAlignment="Left" VerticalAlignment="Bottom" Text="{StaticResource Help2}"/>
+            <TextBlock Name="help1" Margin="10,0,0,50" HorizontalAlignment="Left" VerticalAlignment="Bottom" Text="{StaticResource Help1}"/>
+            <TextBlock Name="help2" Margin="10,0,0,30" HorizontalAlignment="Left" VerticalAlignment="Bottom" Text="{StaticResource Help2}"/>
+            <TextBlock Name="help3" Margin="10,0,0,10" HorizontalAlignment="Left" VerticalAlignment="Bottom" Text="{StaticResource Help3}"/>
         </Grid>
     </DockPanel>
 </Window>

CavernSamples/FilterStudio/MainWindow.xaml.cs

@@ -49,6 +49,7 @@ public MainWindow() {
             pipeline.language = language;
             graph.OnLeftClick += GraphLeftClick;
             graph.OnRightClick += GraphRightClick;
+            graph.OnConnect += GraphConnect;
 
             showInstructions.IsChecked = Settings.Default.showInstructions;
             SetInstructions(null, null);
@@ -120,30 +121,14 @@ void SelectChannels(object _, RoutedEventArgs e) {
             }
         }
 
-        /// <summary>
-        /// Delete the currently selected node.
-        /// </summary>
-        void DeleteNode(object sender, RoutedEventArgs e) {
-            StyledNode node = graph.GetSelectedNode(sender);
-            if (node == null || node.Filter == null) {
-                Error((string)language["NFNod"]);
-            } else if (node.Filter.Filter is InputChannel) {
-                Error((string)language["NFInp"]);
-            } else if (node.Filter.Filter is OutputChannel) {
-                Error((string)language["NFOut"]);
-            } else {
-                node.Filter.DetachFromGraph();
-                ReloadGraph();
-            }
-        }
-
         /// <summary>
         /// Handle when the instructions are enabled or disabled.
         /// </summary>
         void SetInstructions(object _, RoutedEventArgs e) {
             Visibility instructions = showInstructions.IsChecked ? Visibility.Visible : Visibility.Hidden;
             help1.Visibility = instructions;
             help2.Visibility = instructions;
+            help3.Visibility = instructions;
         }
 
         /// <summary>

CavernSamples/FilterStudio/Resources/MainWindowStrings.hu-HU.xaml

@@ -29,6 +29,7 @@
 
     <system:String x:Key="Help1">Jobb klikkelj egy szűrőre, hogy új szűrőútvonalat indíts belőle.</system:String>
     <system:String x:Key="Help2">Jobb klikkelj egy nyílra, hogy új szűrőt adj hozzá két szűrő közé.</system:String>
+    <system:String x:Key="Help3">Húzz egy szűrőt lenyomott egérgombbal a másikba, hogy összekösd őket.</system:String>
 
     <system:String x:Key="OpFil">Equalizer APO konfigurációk|*.txt</system:String>
     <system:String x:Key="Error">Hiba</system:String>
@@ -40,6 +41,9 @@ A csatornakonfiguráció csak új konfigurációs fájl létrehozásakor lesz al
     <system:String x:Key="NFLas">Kimenetek után nem adható hozzá szűrő.</system:String>
     <system:String x:Key="NFInp">Egy csatorna bemenete nem törölhető.</system:String>
     <system:String x:Key="NFOut">Egy csatorna kimenete nem törölhető.</system:String>
+    <system:String x:Key="NCInp">Szűrök nem köthetők bemenetbe.</system:String>
+    <system:String x:Key="NCOut">Kimenetek nem köthetők szűrőkbe.</system:String>
+    <system:String x:Key="NLoop">Ez az összeköttetés érvénytelen, mert kört okozna a gráfban.</system:String>
 
     <system:String x:Key="NSNew">Új</system:String>
     <system:String x:Key="NInpu">Bemenet</system:String>

CavernSamples/FilterStudio/Resources/MainWindowStrings.xaml

@@ -29,6 +29,7 @@
 
     <system:String x:Key="Help1">Right click a filter to start a new path from it with a new filter.</system:String>
     <system:String x:Key="Help2">Right click an arrow to add a filter between two filters.</system:String>
+    <system:String x:Key="Help3">Drag and drop from one filter to another to connect them.</system:String>
 
     <system:String x:Key="OpFil">Equalizer APO configurations|*.txt</system:String>
     <system:String x:Key="Error">Error</system:String>
@@ -40,6 +41,9 @@ The channel configuration will only be applied when you create a new configurati
     <system:String x:Key="NFLas">Filters can't be added after an output.</system:String>
     <system:String x:Key="NFInp">The input of a channel can't be deleted.</system:String>
     <system:String x:Key="NFOut">The output of a channel can't be deleted.</system:String>
+    <system:String x:Key="NCInp">Filters cannot be connected to inputs.</system:String>
+    <system:String x:Key="NCOut">Outputs cannot be connected to filters.</system:String>
+    <system:String x:Key="NLoop">This connection is invalid, because it would cause a cycle in the graph.</system:String>
 
     <system:String x:Key="NSNew">New</system:String>
     <system:String x:Key="NInpu">Input</system:String>