Fixes #3982. Add Draw trace category and instrument View.Drawing.cs

Examples/UICatalog/UICatalogRunnable.cs

@@ -398,6 +398,48 @@ View [] CreateLoggingMenuItems ()
                 Enabled = false, CommandView = navTraceCheckBox, HelpText = "Toggle Focus & TabBehavior tracing", Key = Key.K.WithCtrl
             });
 
+            CheckBox configTraceCheckBox = new ()
+            {
+                Text = "Con_figuration",
+                Value = Trace.EnabledCategories.HasFlag (TraceCategory.Configuration) ? CheckState.Checked : CheckState.UnChecked,
+                CanFocus = false
+            };
+
+            configTraceCheckBox.ValueChanging += (_, e) =>
+                                                 {
+                                                     if (e.NewValue == CheckState.Checked)
+                                                     {
+                                                         Trace.EnabledCategories |= TraceCategory.Configuration;
+                                                     }
+                                                     else
+                                                     {
+                                                         Trace.EnabledCategories &= ~TraceCategory.Configuration;
+                                                     }
+                                                 };
+
+            menuItems.Add (new MenuItem { CommandView = configTraceCheckBox, HelpText = "Toggle Configuration management tracing" });
+
+            CheckBox drawTraceCheckBox = new ()
+            {
+                Text = "_Draw",
+                Value = Trace.EnabledCategories.HasFlag (TraceCategory.Draw) ? CheckState.Checked : CheckState.UnChecked,
+                CanFocus = false
+            };
+
+            drawTraceCheckBox.ValueChanging += (_, e) =>
+                                               {
+                                                   if (e.NewValue == CheckState.Checked)
+                                                   {
+                                                       Trace.EnabledCategories |= TraceCategory.Draw;
+                                                   }
+                                                   else
+                                                   {
+                                                       Trace.EnabledCategories &= ~TraceCategory.Draw;
+                                                   }
+                                               };
+
+            menuItems.Add (new MenuItem { CommandView = drawTraceCheckBox, HelpText = "Toggle Draw operation tracing" });
+
             // add a separator
             menuItems.Add (new Line ());
 

Terminal.Gui/App/ApplicationImpl.Screen.cs

@@ -1,5 +1,7 @@
 namespace Terminal.Gui.App;
 
+using Trace = Terminal.Gui.Tracing.Trace;
+
 internal partial class ApplicationImpl
 {
     /// <inheritdoc/>
@@ -48,6 +50,8 @@ private void RaiseScreenChangedEvent (Rectangle screen)
     /// <inheritdoc/>
     public void LayoutAndDraw (bool forceRedraw = false)
     {
+        Trace.Draw ("ApplicationImpl", "Start", $"forceRedraw={forceRedraw}");
+
         if (ClearScreenNextIteration)
         {
             forceRedraw = true;
@@ -94,5 +98,7 @@ public void LayoutAndDraw (bool forceRedraw = false)
             // Cause the driver to flush any pending updates to the terminal
             Driver?.Refresh ();
         }
+
+        Trace.Draw ("ApplicationImpl", "End", $"neededLayout={neededLayout}, needsDraw={needsDraw}");
     }
 }

Terminal.Gui/App/Tracing/Trace.cs

@@ -286,6 +286,28 @@
 
     #endregion
 
+    #region Draw Tracing
+
+    /// <summary>
+    ///     Traces a draw operation.
+    /// </summary>
+    /// <param name="id">An identifying string for the trace (e.g., <see cref="View.ToIdentifyingString"/>).</param>
+    /// <param name="phase">The phase of the draw operation (e.g., "Start", "End", "Adornments", "SubViews", "Text", "Content").</param>
+    /// <param name="message">Optional additional context.</param>
+    /// <param name="method">Automatically captured caller method name.</param>
+    [Conditional ("DEBUG")]
+    public static void Draw (string? id, string phase, string? message = null, [CallerMemberName] string method = "")
+    {
+        if (!EnabledCategories.HasFlag (TraceCategory.Draw))
+        {
+            return;
+        }
+
+        Backend.Log (new TraceEntry (TraceCategory.Draw, id ?? string.Empty, phase, method, message, DateTime.UtcNow, null));
+    }
+
+    #endregion
+
     #region Keyboard Tracing
 
     /// <summary>

Terminal.Gui/App/Tracing/TraceCategory.cs

@@ -29,6 +29,9 @@ public enum TraceCategory
     /// <summary>Configuration management traces (property discovery, source loading, property assignment).</summary>
     Configuration = 32,
 
+    /// <summary>Draw operation traces (layout-and-draw, view draw phases, adornments, subviews).</summary>
+    Draw = 64,
+
     /// <summary>All trace categories enabled.</summary>
-    All = Lifecycle | Command | Mouse | Keyboard | Navigation | Configuration
+    All = Lifecycle | Command | Mouse | Keyboard | Navigation | Configuration | Draw
 }

Terminal.Gui/ViewBase/View.Drawing.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel;
+using Terminal.Gui.Tracing;
 
 namespace Terminal.Gui.ViewBase;
 
@@ -27,6 +28,7 @@ internal static void Draw (IEnumerable<View> views, bool force)
                 view.SetNeedsDraw ();
             }
 
+            Trace.Draw (view.ToIdentifyingString (), "Draw", $"force={force}");
             view.Draw (context);
         }
 
@@ -83,6 +85,8 @@ public void Draw (DrawContext? context = null)
             return;
         }
 
+        Trace.Draw (this.ToIdentifyingString (), "Start", $"NeedsDraw={NeedsDraw}, SubViewNeedsDraw={SubViewNeedsDraw}");
+
         Region? originalClip = GetClip ();
 
         // TODO: This can be further optimized by checking NeedsDraw below and only
@@ -93,6 +97,7 @@ public void Draw (DrawContext? context = null)
             // Draw the Border and Padding Adornments.
             // Note: Margin with a Shadow is special-cased and drawn in a separate pass to support
             // transparent shadows.
+            Trace.Draw (this.ToIdentifyingString (), "Adornments");
             DoDrawAdornments (originalClip);
             SetClip (originalClip);
 
@@ -114,16 +119,19 @@ public void Draw (DrawContext? context = null)
             // Draw the SubViews first (order matters: SubViews, Text, Content)
             if (SubViewNeedsDraw)
             {
+                Trace.Draw (this.ToIdentifyingString (), "SubViews");
                 DoDrawSubViews (context);
             }
 
             // ------------------------------------
             // Draw the text
+            Trace.Draw (this.ToIdentifyingString (), "Text");
             SetAttributeForRole (Enabled ? VisualRole.Normal : VisualRole.Disabled);
             DoDrawText (context);
 
             // ------------------------------------
             // Draw the content
+            Trace.Draw (this.ToIdentifyingString (), "Content");
             DoDrawContent (context);
 
             // ------------------------------------
@@ -132,6 +140,7 @@ public void Draw (DrawContext? context = null)
             // because they may draw outside the viewport.
             SetClip (originalClip);
             originalClip = AddFrameToClip ();
+            Trace.Draw (this.ToIdentifyingString (), "LineCanvas");
             DoRenderLineCanvas (context);
 
             // ------------------------------------
@@ -179,6 +188,8 @@ public void Draw (DrawContext? context = null)
         // But the context contains the region that was drawn by this view
         DoDrawComplete (context);
 
+        Trace.Draw (this.ToIdentifyingString (), "End");
+
         // When DoDrawComplete returns, Driver.Clip has been updated to exclude this view's area.
         // The next view drawn (earlier in Z-order, typically a peer view or the SuperView) will see
         // a clip with "holes" where this view (and any SubViews drawn before it) are located.

Tests/UnitTestsParallelizable/Tracing/TraceTests.cs

@@ -476,6 +476,43 @@ public void LoggingBackend_FormatsConfigurationCorrectly ()
 
     #endregion
 
+    #region Draw Category Tests
+
+    // Copilot
+    [Fact]
+    public void TraceCategory_Draw_HasExpectedValue ()
+    {
+        Assert.Equal (64, (int)TraceCategory.Draw);
+    }
+
+    // Copilot
+    [Fact]
+    public void TraceCategory_All_IncludesDraw ()
+    {
+        Assert.True (TraceCategory.All.HasFlag (TraceCategory.Draw));
+    }
+
+    // Copilot
+    [Fact]
+    public void Draw_Category_CanBeEnabled ()
+    {
+        Trace.EnabledCategories = TraceCategory.None;
+
+        try
+        {
+            Trace.EnabledCategories = TraceCategory.Draw;
+
+            Assert.True (Trace.EnabledCategories.HasFlag (TraceCategory.Draw));
+        }
+        finally
+        {
+            Trace.EnabledCategories = TraceCategory.None;
+            Trace.Backend = new NullBackend ();
+        }
+    }
+
+    #endregion
+
     #region Scenario Tests (merged from IssueScenarioTraceTests)
 
     /// <summary>