ktsu.ThemeProvider

A semantic color theming library for .NET applications with 44+ themes, intelligent color mapping, and framework integration.

Introduction

ktsu.ThemeProvider is a comprehensive theming system that uses semantic color specifications rather than arbitrary color names. Instead of hardcoding colors like "blue" or "red", you define colors by their purpose (Primary, Error, Warning) and priority level, and the library generates consistent, accessible color palettes. It includes 44 carefully crafted themes from popular color schemes and provides built-in Dear ImGui integration with an extensible architecture for other UI frameworks.

Features

• Semantic Color System: Define colors by purpose (Primary, Error, Warning, Neutral) and priority level rather than specific hues, enabling consistent theming across any UI framework
• 44 Built-in Themes: Includes Catppuccin, Tokyo Night, Gruvbox, Everforest, Nightfox, Kanagawa, PaperColor, Nord, Dracula, VSCode, One Dark, Monokai, and Nightfly theme families
• Centralized Theme Registry: Discover, filter, and instantiate themes by name, family, or light/dark classification with rich metadata
• Dear ImGui Integration: Companion package ktsu.ThemeProvider.ImGui provides complete ImGui color palette mapping via ImGuiPaletteMapper
• Perceptual Color Science: Uses Oklab perceptual color space for uniform color interpolation, extrapolation, and lightness-based priority mapping
• WCAG Accessibility: Built-in contrast ratio calculations, accessibility level checking (AA/AAA), and automatic color adjustment to meet WCAG standards
• Extensible Framework Mappers: Implement IPaletteMapper<TColorKey, TColorValue> to integrate with any UI framework
• Priority-Based Color Hierarchy: Seven priority levels (VeryLow to VeryHigh) automatically mapped to appropriate lightness values, with theme-aware ordering for dark and light themes
• Multi-Target Support: Targets .NET 5.0 through 10.0, plus .NET Standard 2.0 and 2.1

Installation

Package Manager Console

Install-Package ktsu.ThemeProvider

.NET CLI

dotnet add package ktsu.ThemeProvider

Package Reference

<PackageReference Include="ktsu.ThemeProvider" Version="x.y.z" />

For Dear ImGui integration, also install:

dotnet add package ktsu.ThemeProvider.ImGui

Usage Examples

Basic Example

using ktsu.ThemeProvider;
using static ktsu.ThemeProvider.ThemeRegistry;

// Create a theme directly
var theme = new Themes.Catppuccin.Mocha();

// Or find and create via the registry
ThemeInfo? themeInfo = FindTheme("Catppuccin Mocha");
ISemanticTheme? registryTheme = themeInfo?.CreateInstance();

// Map semantic color requests to actual colors
var requests = new[]
{
    new SemanticColorRequest(SemanticMeaning.Primary, Priority.Medium),
    new SemanticColorRequest(SemanticMeaning.Error, Priority.High),
    new SemanticColorRequest(SemanticMeaning.Neutral, Priority.VeryLow),
};
IReadOnlyDictionary<SemanticColorRequest, Color> colors =
    SemanticColorMapper.MapColors(requests, theme);

Theme Discovery with the Registry

using ktsu.ThemeProvider;
using static ktsu.ThemeProvider.ThemeRegistry;

// Browse all themes
IReadOnlyList<ThemeInfo> allThemes = AllThemes;
IReadOnlyList<ThemeInfo> darkThemes = DarkThemes;
IReadOnlyList<ThemeInfo> lightThemes = LightThemes;

// Browse by family
IReadOnlyList<string> families = Families;
IReadOnlyList<ThemeInfo> catppuccinThemes = GetThemesInFamily("Catppuccin");

// Find a specific theme by name (case-insensitive)
ThemeInfo? themeInfo = FindTheme("Tokyo Night Storm");
ISemanticTheme? theme = themeInfo?.CreateInstance();

// Create all theme instances at once
IReadOnlyList<ISemanticTheme> allInstances = CreateAllThemeInstances();
IReadOnlyList<ISemanticTheme> gruvboxInstances = CreateThemeInstancesInFamily("Gruvbox");

Complete Palette Generation

using ktsu.ThemeProvider;
using ktsu.Semantics.Color;

var theme = new Themes.Nord.Nord();

// Generate the complete palette (all meaning + priority combinations)
IReadOnlyDictionary<SemanticColorRequest, Color> completePalette =
    SemanticColorMapper.MakeCompletePalette(theme);

// Access any color from the palette
var primaryMedium = completePalette[new SemanticColorRequest(SemanticMeaning.Primary, Priority.Medium)];
string hex = primaryMedium.ToHex();

Dear ImGui Integration

using ktsu.ThemeProvider;
using ktsu.ThemeProvider.ImGui;
using Hexa.NET.ImGui;

// Create theme and mapper
var theme = new Themes.Catppuccin.Mocha();
var mapper = new ImGuiPaletteMapper();

// Get complete ImGui color palette
IReadOnlyDictionary<ImGuiCol, Vector4> imguiColors = mapper.MapTheme(theme);

// Apply to ImGui style
var style = ImGui.GetStyle();
foreach ((ImGuiCol colorKey, Vector4 colorValue) in imguiColors)
{
    style.Colors[(int)colorKey] = colorValue;
}

Accessibility Checking

using ktsu.ThemeProvider;
using ktsu.Semantics.Color;

Color foreground = Color.FromHex("#FFFFFF");
Color background = Color.FromHex("#1E1E2E");

// Calculate contrast ratio (1.0 .. 21.0)
double contrastRatio = foreground.ContrastRatio(background);

// Check WCAG compliance
AccessibilityLevel level = foreground.AccessibilityLevelAgainst(background, largeText: false);

// Adjust a color to meet accessibility requirements
Color adjusted = foreground.AdjustForContrast(background, AccessibilityLevel.AA);

// Create perceptually uniform gradients
IReadOnlyList<Color> gradient = foreground.Gradient(background, steps: 10);

Advanced Usage

Creating Custom Framework Mappers

Implement IPaletteMapper<TColorKey, TColorValue> to integrate with any UI framework:

using ktsu.ThemeProvider;

public class MyFrameworkMapper : IPaletteMapper<MyColorEnum, MyColorType>
{
    public string FrameworkName => "My UI Framework";

    public IReadOnlyDictionary<MyColorEnum, MyColorType> MapTheme(ISemanticTheme theme)
    {
        var requests = new Dictionary<MyColorEnum, SemanticColorRequest>
        {
            { MyColorEnum.Button, new(SemanticMeaning.Primary, Priority.Medium) },
            { MyColorEnum.Background, new(SemanticMeaning.Neutral, Priority.VeryLow) },
            { MyColorEnum.ErrorText, new(SemanticMeaning.Error, Priority.High) },
        };

        var palette = SemanticColorMapper.MapColors(requests.Values, theme);

        var result = new Dictionary<MyColorEnum, MyColorType>();
        foreach (var kvp in requests)
        {
            if (palette.TryGetValue(kvp.Value, out var color))
            {
                result[kvp.Key] = ConvertToMyColor(color.RgbValue);
            }
        }
        return result;
    }
}

Creating Custom Themes

Implement ISemanticTheme with colors from your palette:

using ktsu.ThemeProvider;
using ktsu.Semantics.Color;
using System.Collections.ObjectModel;

public class MyCustomTheme : ISemanticTheme
{
    private static readonly Color Background = Color.FromHex("#1A1B26");
    private static readonly Color Foreground = Color.FromHex("#C0CAF5");
    private static readonly Color Blue = Color.FromHex("#7AA2F7");
    private static readonly Color Green = Color.FromHex("#9ECE6A");
    private static readonly Color Red = Color.FromHex("#F7768E");

    public bool IsDarkTheme => true;

    public Dictionary<SemanticMeaning, Collection<Color>> SemanticMapping { get; } = new()
    {
        { SemanticMeaning.Neutral, new() { Background, Foreground } },
        { SemanticMeaning.Primary, new() { Blue } },
        { SemanticMeaning.Success, new() { Green } },
        { SemanticMeaning.Error, new() { Red } },
    };
}

API Reference

SemanticMeaning (enum)

Defines semantic color purposes.

Value	Description
Neutral	Backgrounds, borders, inactive elements
Primary	Main brand/accent colors
Alternate	Secondary accent, binary choice emphasis
Success	Successful operations, confirmations
CallToAction	Important buttons and highlights demanding attention
Information	Informational content, help text
Caution	Cautionary content needing attention
Warning	Warning states, potentially problematic
Error	Error states, incorrect conditions
Failure	Failed operations (distinct from error)
Debug	Debug/development information

Priority (enum)

Controls color intensity and lightness within a semantic meaning.

Value	Description
VeryLow	Lowest intensity (backgrounds in dark themes, lightest in light themes)
Low	Low intensity
MediumLow	Below-medium intensity
Medium	Default intensity level
MediumHigh	Above-medium intensity
High	High intensity
VeryHigh	Highest intensity (foreground text in dark themes, darkest in light themes)

SemanticColorRequest

A readonly record struct combining a SemanticMeaning and Priority to specify a color.

Property	Type	Description
Meaning	SemanticMeaning	The semantic purpose of the color
Priority	Priority	The intensity/lightness level

SemanticColorMapper

Static class that maps semantic color requests to actual colors.

Methods

Name	Return Type	Description
MapColors(requests, theme)	IReadOnlyDictionary<SemanticColorRequest, Color>	Maps a collection of requests to colors using the theme
MakeCompletePalette(theme)	IReadOnlyDictionary<SemanticColorRequest, Color>	Generates all possible meaning+priority combinations for a theme

ThemeRegistry

Static class providing centralized theme discovery and management.

Properties

Name	Type	Description
AllThemes	IReadOnlyList<ThemeInfo>	All 44 registered themes with metadata
DarkThemes	IReadOnlyList<ThemeInfo>	All dark themes
LightThemes	IReadOnlyList<ThemeInfo>	All light themes
Families	IReadOnlyList<string>	All theme family names
ThemesByFamily	IReadOnlyDictionary<string, IReadOnlyList<ThemeInfo>>	Themes grouped by family

Methods

Name	Return Type	Description
FindTheme(name)	ThemeInfo?	Finds a theme by name (case-insensitive)
GetThemesInFamily(family)	IReadOnlyList<ThemeInfo>	Gets all themes in a family
CreateAllThemeInstances()	IReadOnlyList<ISemanticTheme>	Creates instances of all themes
CreateThemeInstancesInFamily(family)	IReadOnlyList<ISemanticTheme>	Creates instances of themes in a family

Color types (ktsu.Semantics.Color)

Colors are represented by the Color type from the ktsu.Semantics.Color package (linear RGB + alpha, gamma-correct). It is the currency type for themes (ISemanticTheme.SemanticMapping) and SemanticColorMapper.

Common members:

Member	Description
Color.FromHex(hex)	Creates a color from an sRGB hex string (proper sRGB→linear decode)
ToHex() / ToBytes()	Converts back to an sRGB hex string / 8-bit channels
ToSrgbVector4()	sRGB-encoded Vector4 for UI frameworks (e.g. ImGui)
ToOklab() / ToOklch()	Perceptual (Oklab / polar LCh) representations
ContrastRatio(other)	WCAG contrast ratio (1:1 .. 21:1)
AccessibilityLevelAgainst(bg, largeText)	WCAG AA/AAA compliance (returns AccessibilityLevel)
AdjustForContrast(bg, level, largeText)	Adjusts lightness to meet a WCAG level
DistanceTo(other)	Perceptual (Oklab) distance
MixOklab(other, t) / Gradient(to, steps)	Perceptual blend / uniform gradient

Migration note (v2.0): ThemeProvider's in-house RgbColor, SRgbColor, OklabColor, PerceptualColor, and ColorMath types were removed in favour of ktsu.Semantics.Color. This also fixed a long-standing sRGB-as-linear gamma bug — base theme colors render identically, but the semantic mapper's derived colors and accessibility numbers are now computed correctly.

IPaletteMapper<TColorKey, TColorValue>

Interface for mapping semantic themes to framework-specific color palettes.

Properties

Name	Type	Description
FrameworkName	string	The name of the target UI framework

Methods

Name	Return Type	Description
MapTheme(theme)	IReadOnlyDictionary<TColorKey, TColorValue>	Maps a theme to a framework-specific palette

Available Themes

Family	Variants	Description
Catppuccin	Latte, Frappe, Macchiato, Mocha	Warm pastel themes with excellent readability
Tokyo Night	Night, Storm, Day	Clean themes inspired by Tokyo's neon nights
Gruvbox	Dark, Dark Hard, Dark Soft, Light, Light Hard, Light Soft	Retro groove colors with warm backgrounds
Everforest	Dark, Dark Hard, Dark Soft, Light, Light Hard, Light Soft	Green forest colors for comfortable viewing
Nightfox	Nightfox, Dayfox, Duskfox, Nordfox, Terafox, Carbonfox, Dawnfox	Fox-inspired vibrant themes
Kanagawa	Wave, Dragon, Lotus	Japanese-inspired themes
PaperColor	Light, Dark	Material Design inspired themes
VSCode	Dark, Light	Microsoft VSCode default themes
Nord	-	Arctic-inspired theme with cool blue tones
Dracula	-	Gothic theme with purple and pink accents
One Dark	-	Atom's iconic One Dark theme
Monokai	-	Classic Monokai with vibrant colors
Nightfly	-	Dark blue theme inspired by night flying

Contributing

Contributions are welcome! Feel free to open issues or submit pull requests.

License

This project is licensed under the MIT License. See the LICENSE.md file for details.