更新

WPFDark/Controls/Effects/HsvWheelBackgroundEffect.fx

@@ -0,0 +1,36 @@
+float Value : register(C0);
+float AspectRatioCorrectionX : register(C1);
+float AspectRatioCorrectionY : register(C2);
+float3 BorderColor : register(C3);
+float IsEnabled : register(C6);
+float3 DisableColor : register(C7);
+
+float4 main(float2 uv : TEXCOORD) : COLOR
+{
+    float2 d = float2(
+            (uv.x - 0.5) * AspectRatioCorrectionX,
+            (uv.y - 0.5) * AspectRatioCorrectionY);
+    float i = dot(d, d);
+
+    if (i >= 0.5*0.5)
+        return float4(0,0,0,0);
+
+	if (IsEnabled != 0.0f)
+	{
+		float h = (atan2(-d.y, -d.x) + 3.14159265359) / (2.0*3.14159265359);
+		float s10 = sqrt(i) * 2;
+
+        // https://qiita.com/keim_at_si/items/c2d1afd6443f3040e900
+        float3 color = ((clamp(abs(frac(h + float3(0, 2, 1) / 3) * 6 - 3) - 1, 0, 1) - 1) * s10 + 1) * Value;
+
+		float r = min(1, (0.5 - sqrt(i)) * 100 * 2);
+		color = lerp(BorderColor, color, r);
+
+		return float4(color, 1);
+	}
+	else
+	{
+		return float4(DisableColor, 1);
+	}
+}
+