Map every ImGuiCol slot in ImGuiPaletteMapper

ThemeProvider.ImGui/ImGuiPaletteMapper.cs

@@ -42,6 +42,9 @@ public IReadOnlyDictionary<ImGuiCol, Vector4> MapTheme(ISemanticTheme theme)
 			{ ImGuiCol.FrameBgActive, new(SemanticMeaning.Neutral, Priority.Medium)},
 			{ ImGuiCol.TextDisabled, new(SemanticMeaning.Neutral, Priority.High)},
 			{ ImGuiCol.Text, new(SemanticMeaning.Neutral, Priority.VeryHigh)},
+			// The caret is drawn over input frames like text is, so it takes the text color.
+			{ ImGuiCol.InputTextCursor, new(SemanticMeaning.Neutral, Priority.VeryHigh)},
+			{ ImGuiCol.TextLink, new(SemanticMeaning.Primary, Priority.High)},
 
 			{ ImGuiCol.ScrollbarBg, new(SemanticMeaning.Neutral, Priority.Low)},
 			{ ImGuiCol.ScrollbarGrab, new(SemanticMeaning.Neutral, Priority.Medium)},
@@ -66,17 +69,31 @@ public IReadOnlyDictionary<ImGuiCol, Vector4> MapTheme(ISemanticTheme theme)
 			{ ImGuiCol.ResizeGripActive, new(SemanticMeaning.Neutral, Priority.VeryHigh)},
 
 			{ ImGuiCol.NavWindowingHighlight, new(SemanticMeaning.Primary, Priority.VeryHigh)},
+			{ ImGuiCol.NavCursor, new(SemanticMeaning.Primary, Priority.High)},
+			{ ImGuiCol.DragDropTarget, new(SemanticMeaning.Primary, Priority.High)},
+			{ ImGuiCol.DockingPreview, new(SemanticMeaning.Primary, Priority.High)},
+			{ ImGuiCol.DockingEmptyBg, new(SemanticMeaning.Neutral, Priority.VeryLow)},
+
+			// The dimming overlays cover the whole viewport; their alpha is set below.
+			{ ImGuiCol.NavWindowingDimBg, new(SemanticMeaning.Neutral, Priority.Medium)},
+			{ ImGuiCol.ModalWindowDimBg, new(SemanticMeaning.Neutral, Priority.Medium)},
 
 			{ ImGuiCol.SliderGrab, new(SemanticMeaning.Primary, Priority.MediumLow)},
 			{ ImGuiCol.SliderGrabActive, new(SemanticMeaning.Primary, Priority.High)},
 
 			{ ImGuiCol.Separator, new(SemanticMeaning.Neutral, Priority.MediumHigh)},
 			{ ImGuiCol.SeparatorHovered, new(SemanticMeaning.Neutral, Priority.High)},
 			{ ImGuiCol.SeparatorActive, new(SemanticMeaning.Neutral, Priority.VeryHigh)},
+			{ ImGuiCol.TreeLines, new(SemanticMeaning.Neutral, Priority.MediumHigh)},
 
 			{ ImGuiCol.Tab, new(SemanticMeaning.Neutral, Priority.Low)},
 			{ ImGuiCol.TabSelected, new(SemanticMeaning.Primary, Priority.VeryLow)},
 			{ ImGuiCol.TabHovered, new(SemanticMeaning.Primary, Priority.Low)},
+			{ ImGuiCol.TabSelectedOverline, new(SemanticMeaning.Primary, Priority.High)},
+			// Tabs in an unfocused window drop to neutral so the focused window's tabs stand out.
+			{ ImGuiCol.TabDimmed, new(SemanticMeaning.Neutral, Priority.VeryLow)},
+			{ ImGuiCol.TabDimmedSelected, new(SemanticMeaning.Neutral, Priority.Low)},
+			{ ImGuiCol.TabDimmedSelectedOverline, new(SemanticMeaning.Primary, Priority.High)},
 
 			// Alternate elements spread across the full 50-90% range for better contrast
 			{ ImGuiCol.PlotLines, new(SemanticMeaning.Alternate, Priority.Medium)},
@@ -101,6 +118,13 @@ public IReadOnlyDictionary<ImGuiCol, Vector4> MapTheme(ISemanticTheme theme)
 			{ ImGuiCol.BorderShadow, new(SemanticMeaning.Neutral, Priority.Low) },
 		};
 
+		// Overlays drawn over other content, with the opacity ImGui's stock styles give them.
+		Dictionary<ImGuiCol, float> alphaOverrides = new()
+		{
+			{ ImGuiCol.NavWindowingDimBg, 0.20f },
+			{ ImGuiCol.ModalWindowDimBg, 0.35f },
+		};
+
 		// Convert the semantic colors to ImGui Vector4 format
 		Dictionary<ImGuiCol, Vector4> result = [];
 		foreach (KeyValuePair<ImGuiCol, SemanticColorRequest> kv in colorMapping)
@@ -109,7 +133,13 @@ public IReadOnlyDictionary<ImGuiCol, Vector4> MapTheme(ISemanticTheme theme)
 			SemanticColorRequest request = kv.Value;
 			if (completePalette.TryGetValue(request, out Color color))
 			{
-				result[imguiCol] = color.ToSrgbVector4();
+				Vector4 value = color.ToSrgbVector4();
+				if (alphaOverrides.TryGetValue(imguiCol, out float alpha))
+				{
+					value.W = alpha;
+				}
+
+				result[imguiCol] = value;
 			}
 		}
 

ThemeProvider.Test/ImGuiPaletteMapperTests.cs

@@ -75,6 +75,66 @@ public void MapTheme_ProducesSamePaletteSizeForEveryTheme()
 		}
 	}
 
+	/// <summary>
+	/// Every <see cref="ImGuiCol"/> slot must be assigned. An unassigned slot keeps whatever style was
+	/// active before the theme was applied, usually <c>StyleColorsDark()</c>, so a light theme would be
+	/// left with a white text cursor and navy dimmed tabs. Comparing themes against each other cannot
+	/// catch a slot that every theme is missing.
+	/// </summary>
+	[TestMethod]
+	public void MapTheme_AssignsEveryImGuiColor()
+	{
+		ImGuiPaletteMapper mapper = new();
+
+		foreach (ThemeRegistry.ThemeInfo info in ThemeRegistry.AllThemes)
+		{
+			IReadOnlyDictionary<ImGuiCol, Vector4> palette = mapper.MapTheme(info.CreateInstance());
+
+			for (int i = 0; i < (int)ImGuiCol.Count; i++)
+			{
+				ImGuiCol key = (ImGuiCol)i;
+				Assert.IsTrue(palette.ContainsKey(key), $"{info.Name}: missing ImGui color {key}");
+			}
+		}
+	}
+
+	/// <summary>
+	/// The text cursor is drawn over input frames, so it takes the text color rather than a fixed one.
+	/// </summary>
+	[TestMethod]
+	public void MapTheme_InputTextCursorMatchesText()
+	{
+		ImGuiPaletteMapper mapper = new();
+
+		foreach (ThemeRegistry.ThemeInfo info in ThemeRegistry.AllThemes)
+		{
+			IReadOnlyDictionary<ImGuiCol, Vector4> palette = mapper.MapTheme(info.CreateInstance());
+			Assert.IsTrue(palette.TryGetValue(ImGuiCol.InputTextCursor, out Vector4 cursor), $"{info.Name}: InputTextCursor unmapped");
+			Assert.AreEqual(palette[ImGuiCol.Text], cursor, info.Name);
+		}
+	}
+
+	/// <summary>
+	/// The dimming overlays cover the whole viewport, so they must be translucent or they would hide
+	/// everything behind a modal or the window switcher.
+	/// </summary>
+	[TestMethod]
+	public void MapTheme_DimBackgroundsAreTranslucent()
+	{
+		ImGuiPaletteMapper mapper = new();
+
+		foreach (ThemeRegistry.ThemeInfo info in ThemeRegistry.AllThemes)
+		{
+			IReadOnlyDictionary<ImGuiCol, Vector4> palette = mapper.MapTheme(info.CreateInstance());
+
+			foreach (ImGuiCol key in new[] { ImGuiCol.ModalWindowDimBg, ImGuiCol.NavWindowingDimBg })
+			{
+				Assert.IsTrue(palette.TryGetValue(key, out Vector4 dim), $"{info.Name}: {key} unmapped");
+				Assert.IsTrue(dim.W is > 0f and < 1f, $"{info.Name}: {key} alpha is {dim.W}");
+			}
+		}
+	}
+
 	/// <summary>
 	/// ImGui expects color components in [0, 1]; anything outside that renders as a clipped or
 	/// wrapped color.