Improve extensibility

WinFormsUI/Docking/DockPanel.SplitterDragHandler.cs

@@ -157,7 +157,7 @@ private SplitterDragHandler GetSplitterDragHandler()
             return m_splitterDragHandler;
         }
 
-        internal void BeginDrag(ISplitterDragSource dragSource, Rectangle rectSplitter)
+        public void BeginDrag(ISplitterDragSource dragSource, Rectangle rectSplitter)
         {
             GetSplitterDragHandler().BeginDrag(dragSource, rectSplitter);
         }

WinFormsUI/Docking/DockPanel.cs

@@ -799,20 +799,27 @@ public void SetPaneIndex(DockPane pane, int index)
                 Panes.AddAt(pane, index);
         }
 
+        int suspendCount = 0;
         public void SuspendLayout(bool allWindows)
         {
-            FocusManager.SuspendFocusTracking();
-            SuspendLayout();
-            if (allWindows)
-                SuspendMdiClientLayout();
+            if (suspendCount++ == 0)
+            {
+                FocusManager.SuspendFocusTracking();
+                SuspendLayout();
+                if (allWindows)
+                    SuspendMdiClientLayout();
+            }
         }
 
         public void ResumeLayout(bool performLayout, bool allWindows)
         {
-            FocusManager.ResumeFocusTracking();
-            ResumeLayout(performLayout);
-            if (allWindows)
-                ResumeMdiClientLayout(performLayout);
+            if (--suspendCount == 0)
+            {
+                FocusManager.ResumeFocusTracking();
+                ResumeLayout(performLayout);
+                if (allWindows)
+                    ResumeMdiClientLayout(performLayout);
+            }
         }
 
         internal Form ParentForm

WinFormsUI/Docking/DockWindow.cs

@@ -15,7 +15,7 @@ public partial class DockWindow : Panel, INestedPanesContainer, ISplitterDragSou
         private SplitterBase m_splitter;
         private NestedPaneCollection m_nestedPanes;
 
-        internal DockWindow(DockPanel dockPanel, DockState dockState)
+        protected internal DockWindow(DockPanel dockPanel, DockState dockState)
         {
             m_nestedPanes = new NestedPaneCollection(this);
             m_dockPanel = dockPanel;

WinFormsUI/Docking/Helpers/DockHelper.cs

@@ -4,7 +4,7 @@
 
 namespace WeifenLuo.WinFormsUI.Docking
 {
-    internal static class DockHelper
+    public static class DockHelper
     {
         public static bool IsDockStateAutoHide(DockState dockState)
         {

WinFormsUI/Docking/Helpers/DrawHelper.cs

@@ -6,7 +6,7 @@
 
 namespace WeifenLuo.WinFormsUI.Docking
 {
-    internal static class DrawHelper
+    public static class DrawHelper
     {
         public static Point RtlTransform(Control control, Point point)
         {

WinFormsUI/Docking/InertButtonBase.cs

@@ -7,7 +7,7 @@
 
 namespace WeifenLuo.WinFormsUI.Docking
 {
-    internal abstract class InertButtonBase : Control
+    public abstract class InertButtonBase : Control
     {
         protected InertButtonBase()
         {
@@ -34,11 +34,45 @@ private set
             }
         }
 
+        private bool m_isMouseDown = false;
+        protected bool IsMouseDown
+        {
+            get { return m_isMouseDown; }
+            private set
+            {
+                if (m_isMouseDown == value)
+                    return;
+
+                m_isMouseDown = value;
+                Invalidate();
+            }
+        }
+
         protected override Size DefaultSize
         {
             get { return Resources.DockPane_Close.Size; }
         }
 
+        protected virtual Color HoverBackColor
+        {
+            get { return Color.Transparent; }
+        }
+
+        protected virtual Color HoverBorderColor
+        {
+            get { return ForeColor; }
+        }
+
+        protected virtual Color HoverForeColor
+        {
+            get { return ForeColor; }
+        }
+
+        protected virtual Color PressedBackColor
+        {
+            get { return Color.Transparent; }
+        }
+
         protected override void OnMouseMove(MouseEventArgs e)
         {
             base.OnMouseMove(e);
@@ -61,27 +95,44 @@ protected override void OnMouseLeave(EventArgs e)
                 IsMouseOver = false;
         }
 
+        protected override void OnMouseDown(MouseEventArgs e)
+        {
+            base.OnMouseLeave(e);
+            if (!IsMouseDown)
+                IsMouseDown = true;
+        }
+
+        protected override void OnMouseUp(MouseEventArgs e)
+        {
+            base.OnMouseLeave(e);
+            if (IsMouseDown)
+                IsMouseDown = false;
+        }
+
         protected override void OnPaint(PaintEventArgs e)
         {
             if (IsMouseOver && Enabled)
             {
-                using (Pen pen = new Pen(ForeColor))
+                using (Pen pen = new Pen(this.HoverBorderColor)) 
+                using (Brush brush = new SolidBrush(IsMouseDown ? PressedBackColor : HoverBackColor))
                 {
-                    e.Graphics.DrawRectangle(pen, Rectangle.Inflate(ClientRectangle, -1, -1));
+                    Rectangle rect = ClientRectangle;
+                    rect.Width--;
+                    rect.Height--;
+                    e.Graphics.FillRectangle(brush, rect);
+                    e.Graphics.DrawRectangle(pen, rect);
                 }
             }
 
             using (ImageAttributes imageAttributes = new ImageAttributes())
             {
-                ColorMap[] colorMap = new ColorMap[2];
-                colorMap[0] = new ColorMap();
-                colorMap[0].OldColor = Color.FromArgb(0, 0, 0);
-                colorMap[0].NewColor = ForeColor;
-                colorMap[1] = new ColorMap();
-                colorMap[1].OldColor = Image.GetPixel(0, 0);
-                colorMap[1].NewColor = Color.Transparent;
-
-                imageAttributes.SetRemapTable(colorMap);
+                Color color = IsMouseOver ? HoverForeColor : ForeColor;
+                ColorMatrix matrix = new ColorMatrix();
+                matrix.Matrix40 = color.R / 255f;
+                matrix.Matrix41 = color.G / 255f;
+                matrix.Matrix42 = color.B / 255f;
+
+                imageAttributes.SetColorMatrix(matrix);
 
                 e.Graphics.DrawImage(
                    Image,

WinFormsUI/Docking/Interfaces.cs

@@ -20,12 +20,12 @@ public interface INestedPanesContainer
         bool IsFloat	{	get;	}
     }
 
-    internal interface IDragSource
+    public interface IDragSource
     {
         Control DragControl { get; }
     }
 
-    internal interface IDockDragSource : IDragSource
+    public interface IDockDragSource : IDragSource
     {
         Rectangle BeginDrag(Point ptMouse);
         void EndDrag();
@@ -36,7 +36,7 @@ internal interface IDockDragSource : IDragSource
         void DockTo(DockPanel panel, DockStyle dockStyle);
     }
 
-    internal interface ISplitterDragSource : IDragSource
+    public interface ISplitterDragSource : IDragSource
     {
         void BeginDrag(Rectangle rectSplitter);
         void EndDrag();

WinFormsUI/Docking/NestedPaneCollection.cs

@@ -69,7 +69,7 @@ private void CheckFloatWindowDispose()
         /// Switches a pane with its first child in the pane hierarchy. (The actual hiding happens elsewhere.)
         /// </summary>
         /// <param name="pane">Pane to switch</param>
-        internal void SwitchPaneWithFirstChild(DockPane pane)
+        public void SwitchPaneWithFirstChild(DockPane pane)
         {
             if (!Contains(pane))
                 return;