Refactor Editor Tab controls system to allows customizing the tab header controls

Source/Editor/GUI/Tabs/Tab.cs

@@ -77,5 +77,14 @@ namespace FlaxEditor.GUI.Tabs
         {
             Deselected?.Invoke(this);
         }
+
+        /// <summary>
+        /// Factory method for tabs header control (UI for the tabs strip to represent this tab).
+        /// </summary>
+        /// <returns>The tab header control.</returns>
+        public virtual Tabs.TabHeader CreateHeader()
+        {
+            return new Tabs.TabHeader((Tabs)Parent, this);
+        }
     }
 }

Source/Editor/GUI/Tabs/Tabs.cs

@@ -24,11 +24,6 @@ namespace FlaxEditor.GUI.Tabs
             /// </summary>
             protected Tabs Tabs;
 
-            /// <summary>
-            /// The index of the tab.
-            /// </summary>
-            protected int Index;
-
             /// <summary>
             /// The tab.
             /// </summary>
@@ -38,21 +33,22 @@ namespace FlaxEditor.GUI.Tabs
             /// Initializes a new instance of the <see cref="TabHeader"/> class.
             /// </summary>
             /// <param name="tabs">The tabs.</param>
-            /// <param name="index">The tab index.</param>
             /// <param name="tab">The tab.</param>
-            public TabHeader(Tabs tabs, int index, Tab tab)
+            public TabHeader(Tabs tabs, Tab tab)
             : base(Float2.Zero, tabs._tabsSize)
             {
                 Tabs = tabs;
-                Index = index;
                 Tab = tab;
             }
 
             /// <inheritdoc />
             public override bool OnMouseUp(Float2 location, MouseButton button)
             {
-                Tabs.SelectedTabIndex = Index;
+                if (EnabledInHierarchy && Tab.Enabled)
-                Tabs.Focus();
+                {
+                    Tabs.SelectedTab = Tab;
+                    Tabs.Focus();
+                }
                 return true;
             }
 
@@ -61,19 +57,20 @@ namespace FlaxEditor.GUI.Tabs
             {
                 base.Draw();
 
-                // Cache data
                 var style = Style.Current;
+                var enabled = EnabledInHierarchy && Tab.EnabledInHierarchy;
                 var tabRect = new Rectangle(Float2.Zero, Size);
-                bool isTabSelected = Tabs._selectedIndex == Index;
-                bool isMouseOverTab = IsMouseOver;
                 var textOffset = Tabs._orientation == Orientation.Horizontal ? 0 : 8;
 
                 // Draw bar
-                if (isTabSelected)
+                if (Tabs.SelectedTab == Tab)
                 {
+                    var color = style.BackgroundSelected;
+                    if (!enabled)
+                        color *= 0.6f;
                     if (Tabs._orientation == Orientation.Horizontal)
                     {
-                        Render2D.FillRectangle(tabRect, style.BackgroundSelected);
+                        Render2D.FillRectangle(tabRect, color);
                     }
                     else
                     {
@@ -84,10 +81,10 @@ namespace FlaxEditor.GUI.Tabs
                         fillRect.Size.X -= lefEdgeWidth;
                         fillRect.Location.X += lefEdgeWidth;
                         Render2D.FillRectangle(fillRect, style.Background);
-                        Render2D.FillRectangle(leftEdgeRect, style.BackgroundSelected);
+                        Render2D.FillRectangle(leftEdgeRect, color);
                     }
                 }
-                else if (isMouseOverTab)
+                else if (IsMouseOver && enabled)
                 {
                     Render2D.FillRectangle(tabRect, style.BackgroundHighlighted);
                 }
@@ -131,20 +128,15 @@ namespace FlaxEditor.GUI.Tabs
             {
                 base.PerformLayoutBeforeChildren();
 
-                // Cache data
-                var tabsSize = Tabs._tabsSize;
-                var clientSize = GetClientArea();
-                tabsSize = Float2.Min(tabsSize, clientSize.Size);
-                var tabRect = new Rectangle(Float2.Zero, tabsSize);
-                var tabStripOffset = Tabs._orientation == Orientation.Horizontal ? new Float2(tabsSize.X, 0) : new Float2(0, tabsSize.Y);
-
                 // Arrange tab header controls
+                var pos = Float2.Zero;
+                var sizeMask = Tabs._orientation == Orientation.Horizontal ? Float2.UnitX : Float2.UnitY;
                 for (int i = 0; i < Children.Count; i++)
                 {
                     if (Children[i] is TabHeader tabHeader)
                     {
-                        tabHeader.Bounds = tabRect;
+                        tabHeader.Location = pos;
-                        tabRect.Offset(tabStripOffset);
+                        pos += tabHeader.Size * sizeMask;
                     }
                 }
             }
@@ -160,6 +152,11 @@ namespace FlaxEditor.GUI.Tabs
         /// </summary>
         protected Float2 _tabsSize;
 
+        /// <summary>
+        /// Automatic tab size based on the fill axis.
+        /// </summary>
+        protected bool _autoTabsSizeAuto;
+
         /// <summary>
         /// The orientation.
         /// </summary>
@@ -174,15 +171,31 @@ namespace FlaxEditor.GUI.Tabs
             set
             {
                 _tabsSize = value;
-                for (int i = 0; i < TabsPanel.ChildrenCount; i++)
+                if (!_autoTabsSizeAuto)
                 {
-                    if (TabsPanel.Children[i] is TabHeader tabHeader)
+                    for (int i = 0; i < TabsPanel.ChildrenCount; i++)
-                        tabHeader.Size = value;
+                    {
+                        if (TabsPanel.Children[i] is TabHeader tabHeader)
+                            tabHeader.Size = value;
+                    }
                 }
                 PerformLayout();
             }
         }
 
+        /// <summary>
+        /// Enables automatic tabs size to fill the space.
+        /// </summary>
+        public bool AutoTabsSize
+        {
+            get => _autoTabsSizeAuto;
+            set
+            {
+                _autoTabsSizeAuto = value;
+                PerformLayout();
+            }
+        }
+
         /// <summary>
         /// Gets or sets the orientation.
         /// </summary>
@@ -339,14 +352,10 @@ namespace FlaxEditor.GUI.Tabs
 
             // Update tabs headers
             TabsPanel.DisposeChildren();
-            int index = 0;
             for (int i = 0; i < Children.Count; i++)
             {
                 if (Children[i] is Tab tab)
-                {
+                    TabsPanel.AddChild(tab.CreateHeader());
-                    var tabHeader = new TabHeader(this, index++, tab);
-                    TabsPanel.AddChild(tabHeader);
-                }
             }
 
             TabsPanel.IsLayoutLocked = wasLocked;
@@ -371,23 +380,46 @@ namespace FlaxEditor.GUI.Tabs
         /// <inheritdoc />
         protected override void PerformLayoutBeforeChildren()
         {
+            var tabsSize = _tabsSize;
+            if (_autoTabsSizeAuto)
+            {
+                // Horizontal is default for Toolbox so tabs go to the right
+                int tabsCount = 0;
+                for (int i = 0; i < TabsPanel.ChildrenCount; i++)
+                {
+                    if (TabsPanel.Children[i] is TabHeader)
+                        tabsCount++;
+                }
+                if (tabsCount == 0)
+                    tabsCount = 1;
+                if (_orientation == Orientation.Horizontal)
+                    tabsSize.X = Width / tabsCount;
+                else
+                    tabsSize.Y = Height / tabsCount;
+                for (int i = 0; i < TabsPanel.ChildrenCount; i++)
+                {
+                    if (TabsPanel.Children[i] is TabHeader tabHeader)
+                        tabHeader.Size = tabsSize;
+                }
+            }
+
             // Fit the tabs panel
-            TabsPanel.Size = _orientation == Orientation.Horizontal ? new Float2(Width, _tabsSize.Y) : new Float2(_tabsSize.X, Height);
+            TabsPanel.Size = _orientation == Orientation.Horizontal
+                             ? new Float2(Width, tabsSize.Y)
+                             : new Float2(tabsSize.X, Height);
 
             // Hide all pages except selected one
-            var clientArea = _orientation == Orientation.Horizontal
-                             ? new Rectangle(0, _tabsSize.Y, Width, Height - _tabsSize.Y)
-                             : new Rectangle(_tabsSize.X, 0, Width - _tabsSize.X, Height);
             for (int i = 0; i < Children.Count; i++)
             {
                 if (Children[i] is Tab tab)
                 {
-                    // Check if is selected or not
                     if (i - 1 == _selectedIndex)
                     {
                         // Show and fit size
                         tab.Visible = true;
-                        tab.Bounds = clientArea;
+                        tab.Bounds = _orientation == Orientation.Horizontal
+                                     ? new Rectangle(0, tabsSize.Y, Width, Height - tabsSize.Y)
+                                     : new Rectangle(tabsSize.X, 0, Width - tabsSize.X, Height);
                     }
                     else
                     {