Material3.Avalonia

Appearance

Color System (HCT / Material Color Utilities) ​

The palette engine is a C# port of Google's material-color-utilities (Apache-2.0), namespace Material3.Avalonia.Colors. You can use it directly — independent of the XAML theme — to generate schemes, tonal palettes, or do HCT color math.

Colors are represented as uint ARGB (0xFFRRGGBB). Convert to Avalonia with Color.FromUInt32(argb).

Build a full scheme ​

csharp
using Material3.Avalonia.Colors;

MaterialColorScheme scheme = SchemeBuilder.Build(
    seedArgb:      0xFF6750A4,
    variant:       SchemeVariant.TonalSpot,
    isDark:        false,
    contrastLevel: 0.0);

uint primary   = scheme.Primary;            // 0xFF6750A4-derived P40
uint container = scheme.PrimaryContainer;
var  avalonia  = Color.FromUInt32(scheme.Surface);

MaterialColorScheme is a record with all 45 role properties — the exact set the theme injects as Md3* resources.

HCT color space ​

HCT (Hue / Chroma / Tone) is the perceptual color space M3 is built on:

csharp
var hct = Hct.FromInt(0xFF6750A4);
double hue    = hct.Hue;     // 0–360
double chroma = hct.Chroma;  // 0–~150
double tone   = hct.Tone;    // 0–100 (L*)

hct.Tone = 80;               // mutate; re-solves to nearest displayable color
uint argb = hct.ToInt();

var custom = Hct.From(hue: 25, chroma: 84, tone: 40);  // ≈ M3 error-40

Tonal palettes ​

A TonalPalette fixes hue+chroma and exposes any tone:

csharp
var palette = TonalPalette.FromInt(0xFF6750A4);
uint t40 = palette.Tone(40);   // key tone used for light primary
uint t80 = palette.Tone(80);   // dark primary
uint t90 = palette.Tone(90);   // light container

CorePalettes.Of(sourceHct, variant) gives you the six palettes (primary, secondary, tertiary, neutral, neutral-variant, error) a variant is made of.

Utility helpers ​

  • DislikeAnalyzer.FixIfDisliked(hct) — moves universally-disliked (bile-like) colors to a pleasant tone
  • TemperatureCache(hct).Analogous(...) / .Complement — warm/cool color relations
  • ColorUtils, Cam16, ViewingConditions, HctSolver — low-level CAM16 math, same API shape as the Google library

Known deviations from upstream MCU

  • Tone mapping uses the fixed 2021 M3 baseline (no ContrastCurve/ToneDeltaPair solver)
  • ContrastLevel applies a linear interpolation approximation
  • Fidelity/Content skip the container tone fine-tuning step

These are documented implementation choices; visual output matches the reference for standard contrast.