Theme the editor with ktsu.ThemeProvider, and stop clipping tree labels

CLAUDE.md

@@ -82,6 +82,7 @@ Schema elements maintain parent references via `AssociateWith()` methods. After
 - `Schema/Models/SchemaClass.cs` - Class definitions containing `SchemaMember` collections
 - `SchemaEditor/SchemaEditor.cs` - Main editor application using `ktsu.ImGui.App`
 - `SchemaEditor/EditorHost.cs` - Builds the `ImGuiAppConfig`; `CreateConfig` is what the tests drive too
+- `SchemaEditor/EditorTheme.cs` - The ktsu.ThemeProvider theme, and the one definition of how a validation issue is coloured
 - `SchemaEditor/Program.cs` - The entry point, and the only file excluded from coverage measurement
 - `SchemaEditor.Test/EditorHarness.cs` - Runs a real editor headlessly, frames advanced by the test
 - `SchemaEditor.Test/WidgetHarness.cs` - A headless frame containing only the widget under test

Directory.Packages.props

@@ -11,6 +11,7 @@
     <PackageVersion Include="ktsu.ForceDirectedLayout" Version="3.16.6" />
     <PackageVersion Include="ktsu.FuzzySearch" Version="1.2.39" />
     <PackageVersion Include="ktsu.ImGui.Styler" Version="3.16.6" />
+    <PackageVersion Include="ktsu.ThemeProvider" Version="3.0.14" />
     <PackageVersion Include="ktsu.IntervalAction" Version="1.3.41" />
     <PackageVersion Include="ktsu.Keybinding.Core" Version="1.0.41" />
     <PackageVersion Include="ktsu.UndoRedo.Core" Version="1.0.19" />

SchemaEditor.Test/EditorHarness.cs

@@ -55,13 +55,25 @@ private EditorHarness(SchemaEditor editor, ImGuiAppHarness app)
 	/// Starts an editor with empty settings and advances the frames it needs to be drawing.
 	/// </summary>
 	/// <returns>The running harness. Dispose it to release the ImGui context.</returns>
-	internal static EditorHarness Start()
+	internal static EditorHarness Start() => Start(new HarnessOptions());
+
+	/// <summary>
+	/// Starts an editor at a chosen display size.
+	/// </summary>
+	/// <remarks>
+	/// Size matters to more than layout: the editor derives its field and column widths from the
+	/// display width, so a narrow window is what puts a long label past the width its column
+	/// gives it.
+	/// </remarks>
+	/// <param name="options">Determinism settings, including the display size.</param>
+	/// <returns>The running harness. Dispose it to release the ImGui context.</returns>
+	internal static EditorHarness Start(HarnessOptions options)
 	{
 		// Must precede the constructor: it is the constructor that loads the settings.
 		ktsu.AppDataStorage.AppData.ConfigureForTesting(() => new MockFileSystem());
 
 		SchemaEditor editor = new();
-		ImGuiAppHarness app = ImGuiAppHarness.Start(EditorHost.CreateConfig(editor), new HarnessOptions());
+		ImGuiAppHarness app = ImGuiAppHarness.Start(EditorHost.CreateConfig(editor), options);
 
 		// The first frame builds the font atlas and lays the panels out; nothing is measurable
 		// before it has run.

SchemaEditor.Test/SchemaEditor.Test.csproj

@@ -14,6 +14,8 @@
     <!-- The headless harness: it drives ImGuiApp frames through a software rasterizer, so the
          editor's draw code runs with no window, no display and no GPU. -->
     <PackageReference Include="ktsu.ImGui.App.Testing" />
+    <PackageReference Include="ktsu.ImGui.Styler" />
+    <PackageReference Include="ktsu.ThemeProvider" />
     <!-- A mock file system for AppDataStorage, so a test never reads or writes the settings of
          whoever is running it. -->
     <PackageReference Include="TestableIO.System.IO.Abstractions.TestingHelpers" />

SchemaEditor.Test/ThemeBrowserTests.cs

@@ -0,0 +1,70 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.SchemaEditor.Test;
+
+/// <summary>
+/// Picking a theme from the browser the Theme menu opens.
+/// </summary>
+/// <remarks>
+/// The themes named here are ones near the top of the browser's grid. The grid scrolls, and a card
+/// below the fold is recorded by the probe at a position that is clipped away, so clicking it hits
+/// the modal behind rather than the card.
+/// </remarks>
+[TestClass]
+public sealed class ThemeBrowserTests
+{
+	private EditorHarness harness = null!;
+
+	[TestInitialize]
+	public void StartEditor()
+	{
+		harness = EditorHarness.Start();
+		harness.Editor.Options.ThemeName = string.Empty;
+		harness.Editor.OnStart();
+	}
+
+	[TestCleanup]
+	public void StopEditor() => harness.Dispose();
+
+	[TestMethod]
+	public void ChoosingAThemeAppliesIt()
+	{
+		EditorTheme.OpenBrowser();
+
+		harness.Click("theme-card/Dracula");
+
+		Assert.AreEqual("Dracula", EditorTheme.CurrentName);
+	}
+
+	/// <summary>
+	/// The choice has to reach the settings, or it is gone at the next launch - which is the whole
+	/// point of storing it.
+	/// </summary>
+	[TestMethod]
+	public void ChoosingAThemeRemembersIt()
+	{
+		EditorTheme.OpenBrowser();
+
+		harness.Click("theme-card/Gruvbox Dark");
+
+		Assert.AreEqual("Gruvbox Dark", harness.Editor.Options.ThemeName);
+	}
+
+	/// <summary>
+	/// A theme chosen now is the theme applied on the next start, which is the round trip the
+	/// setting exists for.
+	/// </summary>
+	[TestMethod]
+	public void ARememberedThemeComesBackOnTheNextStart()
+	{
+		EditorTheme.OpenBrowser();
+		harness.Click("theme-card/Dracula");
+
+		EditorTheme.Apply("Nord");
+		Assert.AreEqual("Nord", EditorTheme.CurrentName);
+
+		harness.Editor.OnStart();
+
+		Assert.AreEqual("Dracula", EditorTheme.CurrentName);
+	}
+}

SchemaEditor.Test/ThemeTests.cs

@@ -0,0 +1,80 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.SchemaEditor.Test;
+
+/// <summary>
+/// Which ktsu.ThemeProvider theme the editor runs under, and where that choice comes from.
+/// </summary>
+/// <remarks>
+/// The editor used to have no theme at all. It wrapped every frame in
+/// <c>Theme.FromColor(Palette.Semantic.Primary)</c> - a scoped colour meant for one widget -
+/// which tinted the entire interface with the primary colour and left an ordinary button looking
+/// the same as one marked with an error.
+/// </remarks>
+[TestClass]
+public sealed class ThemeTests
+{
+	private EditorHarness harness = null!;
+
+	[TestInitialize]
+	public void StartEditor() => harness = EditorHarness.Start();
+
+	[TestCleanup]
+	public void StopEditor() => harness.Dispose();
+
+	/// <summary>
+	/// Settings that name no theme still get one, rather than falling back to unstyled ImGui.
+	/// </summary>
+	[TestMethod]
+	public void SettingsWithNoThemeGetTheDefault()
+	{
+		EditorTheme.Apply(string.Empty);
+
+		Assert.AreEqual("VSCode Dark", EditorTheme.CurrentName);
+	}
+
+	[TestMethod]
+	public void ANamedThemeIsApplied()
+	{
+		EditorTheme.Apply("Nord");
+
+		Assert.AreEqual("Nord", EditorTheme.CurrentName);
+	}
+
+	/// <summary>
+	/// A theme that has left the registry - renamed upstream, or dropped - must not leave the
+	/// editor unstyled, because the name is read from settings written by an older build.
+	/// </summary>
+	[TestMethod]
+	public void AThemeThatIsNoLongerRegisteredFallsBack()
+	{
+		EditorTheme.Apply("A Theme That Does Not Exist");
+
+		Assert.AreEqual("VSCode Dark", EditorTheme.CurrentName);
+	}
+
+	[TestMethod]
+	public void TheSavedThemeIsAppliedWhenTheEditorStarts()
+	{
+		harness.Editor.Options.ThemeName = "Gruvbox Dark";
+
+		harness.Editor.OnStart();
+
+		Assert.AreEqual("Gruvbox Dark", EditorTheme.CurrentName);
+	}
+
+	/// <summary>
+	/// Starting with whatever the previous test left applied must still end with a theme, which is
+	/// the property that stops the blanket-tint approach coming back as "no theme at all".
+	/// </summary>
+	[TestMethod]
+	public void TheEditorAlwaysRunsUnderSomeTheme()
+	{
+		harness.Editor.Options.ThemeName = string.Empty;
+
+		harness.Editor.OnStart();
+		harness.App.Step(3);
+
+		Assert.IsFalse(string.IsNullOrEmpty(EditorTheme.CurrentName), "The editor drew a frame with no theme applied.");
+	}
+}

SchemaEditor.Test/TreeRowWidthTests.cs

@@ -0,0 +1,80 @@
+// Copyright (c) 2023-2026 ktsu-dev contributors
+
+namespace ktsu.SchemaEditor.Test;
+
+using ktsu.ImGui.App.Testing;
+using ktsu.Schema.Models;
+using ktsu.Schema.Models.Names;
+using ktsu.Semantics.Strings;
+
+/// <summary>
+/// How wide a tree row is drawn.
+/// </summary>
+/// <remarks>
+/// The rows shared one fixed width, and ImGui clips a button's label to its frame, so the longest
+/// label in the tree - "Code Generators (0)" - was drawn without its count. The width is a minimum
+/// now: short labels still line up as a column, and a long one grows to fit.
+/// </remarks>
+[TestClass]
+public sealed class TreeRowWidthTests
+{
+	private EditorHarness harness = null!;
+
+	[TestCleanup]
+	public void StopEditor() => harness?.Dispose();
+
+	private int WidthOf(string item)
+	{
+		harness.StepUntil(() => harness.App.Probe.Matches(item).Count > 0, $"'{item}' appearing");
+		Rectangle rect = harness.App.Probe.Rect(item) ?? throw new AssertFailedException($"'{item}' was not recorded.");
+		return rect.Width;
+	}
+
+	/// <summary>
+	/// The four tree headings are drawn from the same code with labels of very different lengths,
+	/// which is where the clipping showed up.
+	/// </summary>
+	[TestMethod]
+	public void ALongerHeadingIsDrawnWiderThanSpareColumnWidthAllows()
+	{
+		// Narrow, because the column is 15% of the display width: at a wide display every heading
+		// fits and there is nothing to prove. This is the shape of window the clipping was
+		// reported from.
+		harness = EditorHarness.Start(new HarnessOptions { Width = 700, Height = 600 });
+		harness.Editor.CurrentSchema = new Schema();
+
+		Assert.IsTrue(
+			WidthOf("RootCode Generators") > WidthOf("RootEnums"),
+			"'Code Generators (0)' is the longest heading in the tree; drawn at the same width as 'Enums (0)' it loses its count.");
+	}
+
+	[TestMethod]
+	public void ALongerClassNameIsDrawnWider()
+	{
+		harness = EditorHarness.Start();
+		Schema schema = new();
+		schema.AddClass("A".As<ClassName>());
+		schema.AddClass("AClassNameLongEnoughToNeedMoreRoomThanTheColumnGives".As<ClassName>());
+		harness.Editor.CurrentSchema = schema;
+
+		Assert.IsTrue(
+			WidthOf("BtnAClassNameLongEnoughToNeedMoreRoomThanTheColumnGives") > WidthOf("BtnA"),
+			"A class name longer than the column was clipped instead of widening its row.");
+	}
+
+	/// <summary>
+	/// The width is a minimum, not a per-row measurement: rows whose labels both fit still line up,
+	/// or the tree would be a ragged edge.
+	/// </summary>
+	[TestMethod]
+	public void ShortLabelsShareOneColumnWidth()
+	{
+		harness = EditorHarness.Start();
+		Schema schema = new();
+		schema.AddClass("A".As<ClassName>());
+		schema.AddClass("Bee".As<ClassName>());
+		harness.Editor.CurrentSchema = schema;
+
+		Assert.AreEqual(WidthOf("BtnA"), WidthOf("BtnBee"));
+	}
+}