Reverted text width calculation. Updated EnsureVisible.

Text width calculation changes were causing the tab text to be cut off
early. Updated EnsureVisible to better handle the total tab size being
smaller/larger than the tab area.

DarkUI/Docking/DarkDockGroup.cs

@@ -159,6 +159,8 @@ namespace DarkUI.Docking
             }
 
             BuildTabs();
+
+            EnsureVisible();
         }
 
         private void BuildTabs()
@@ -182,15 +184,10 @@ namespace DarkUI.Docking
                     width = tab.CalculateWidth(g, Font);
                 }
 
-                // Add addition 5px width to tool window tabs
-                if (DockArea != DarkDockArea.Document)
-                {
-                    width += 5;
-                }
-
                 // Add additional width for document tab items
                 if (DockArea == DarkDockArea.Document)
                 {
+                    width += 5;
                     width += closeButtonSize;
 
                     if (tab.DockContent.Icon != null)
@@ -271,6 +268,12 @@ namespace DarkUI.Docking
                 }
             }
 
+            // Update the tab area with the new total tab width
+            totalSize = 0;
+            foreach (var tab in _tabs.Values)
+                totalSize += tab.ClientRectangle.Width;
+            _tabArea.TotalTabSize = totalSize;
+
             ResumeLayout();
 
             Invalidate();
@@ -281,16 +284,10 @@ namespace DarkUI.Docking
             if (DockArea != DarkDockArea.Document)
                 return;
 
-            if (DockPanel.ActiveContent == null)
-                return;
-
             var width = ClientRectangle.Width - Padding.Horizontal - _tabArea.DropdownRectangle.Width;
             var offsetArea = new Rectangle(Padding.Left, 0, width, 0);
 
-            if (!_tabs.ContainsKey(DockPanel.ActiveContent))
+            var tab = _tabs[VisibleContent];
-                return;
-
-            var tab = _tabs[DockPanel.ActiveContent];
 
             if (tab.ClientRectangle.IsEmpty)
                 return;
@@ -300,6 +297,19 @@ namespace DarkUI.Docking
             else if (RectangleToTabArea(tab.ClientRectangle).Right > offsetArea.Right)
                 _tabArea.Offset = tab.ClientRectangle.Right - width;
 
+            if (_tabArea.TotalTabSize < offsetArea.Width)
+                _tabArea.Offset = 0;
+
+            if (_tabArea.TotalTabSize > offsetArea.Width)
+            {
+                var lastTab = _tabs.Values.Last();
+                if (lastTab != null)
+                {
+                    if (RectangleToTabArea(lastTab.ClientRectangle).Right < offsetArea.Right)
+                        _tabArea.Offset = lastTab.ClientRectangle.Right - width;
+                }
+            }
+
             Invalidate();
         }
 
@@ -566,16 +576,17 @@ namespace DarkUI.Docking
 
             var tabTextFormat = new StringFormat
             {
-                Alignment = StringAlignment.Center,
+                Alignment = StringAlignment.Near,
                 LineAlignment = StringAlignment.Center,
-                FormatFlags = StringFormatFlags.NoWrap
+                FormatFlags = StringFormatFlags.NoWrap,
+                Trimming = StringTrimming.EllipsisCharacter
             };
 
             // Draw text
             var textColor = isVisibleTab ? Colors.LightText : Colors.DisabledText;
             using (var b = new SolidBrush(textColor))
             {
-                var textRect = new Rectangle(tabRect.Left + 2 + xOffset, tabRect.Top, tabRect.Width - tab.CloseButtonRectangle.Width - 7 - 5 - xOffset, tabRect.Height);
+                var textRect = new Rectangle(tabRect.Left + 5 + xOffset, tabRect.Top, tabRect.Width - tab.CloseButtonRectangle.Width - 7 - 5 - xOffset, tabRect.Height);
                 g.DrawString(tab.DockContent.DockText, Font, b, textRect, tabTextFormat);
             }
 
@@ -621,7 +632,7 @@ namespace DarkUI.Docking
 
             var tabTextFormat = new StringFormat
             {
-                Alignment = StringAlignment.Center,
+                Alignment = StringAlignment.Near,
                 LineAlignment = StringAlignment.Center,
                 FormatFlags = StringFormatFlags.NoWrap,
                 Trimming = StringTrimming.EllipsisCharacter
@@ -630,7 +641,7 @@ namespace DarkUI.Docking
             var textColor = isVisibleTab ? Colors.BlueHighlight : Colors.DisabledText;
             using (var b = new SolidBrush(textColor))
             {
-                var textRect = new Rectangle(tabRect.Left, tabRect.Top, tabRect.Width - 2, tabRect.Height);
+                var textRect = new Rectangle(tabRect.Left + 5, tabRect.Top, tabRect.Width - 5, tabRect.Height);
                 g.DrawString(tab.DockContent.DockText, Font, b, textRect, tabTextFormat);
             }
         }

DarkUI/Docking/Items/DarkDockTab.cs

@@ -33,7 +33,7 @@ namespace DarkUI.Docking
 
         public int CalculateWidth(Graphics g, Font font)
         {
-            var width = (int)g.MeasureString(DockContent.DockText, font, 0, StringFormat.GenericTypographic).Width;
+            var width = (int)g.MeasureString(DockContent.DockText, font).Width;
             width += 10;
 
             return width;

DarkUI/Docking/Items/DarkDockTabArea.cs

@@ -27,6 +27,8 @@ namespace DarkUI.Docking
 
         public int Offset { get; set; }
 
+        public int TotalTabSize { get; set; }
+
         public bool Visible { get; set; }
 
         public DarkContextMenu TabMenu { get { return _tabMenu; } }