Normalize hue angles instead of clamping (#60)

ajalt · Apr 17, 2024 · 0b478a8 · 0b478a8
1 parent 1ba9b1b
commit 0b478a8
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Showing 12 changed files with 101 additions and 19 deletions.
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/Color.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/Color.kt
@@ -95,7 +95,10 @@ interface Color {
             val info = space.components[i]
             if (values[i] !in info.min..info.max) {
                 clamped = true
-                values[i] = values[i].coerceIn(info.min, info.max)
+                values[i] = when {
+                    info.isPolar -> values[i] % 360
+                    else -> values[i].coerceIn(info.min, info.max)
+                }
             }
         }
         return if (clamped) space.create(values) else this

diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/internal/ColorSpaceUtils.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/internal/ColorSpaceUtils.kt
@@ -72,7 +72,7 @@ internal fun polarComponentInfo(
                 name = it.toString(),
                 isPolar = it == 'H',
                 min = if (it == 'H') 0f else l,
-                max = if (it == 'H') 1f else r
+                max = if (it == 'H') 360f else r
             )
         }
         add(alphaInfo)
@@ -88,9 +88,9 @@ internal inline fun <T : Color> T.clamp3(
 ): T {
     val (c1, c2, c3) = space.components
     return when {
-        v1 >= c1.min && v1 <= c1.max
-                && v2 >= c2.min && v2 <= c2.max
-                && v3 >= c3.min && v3 <= c3.max
+        v1 in c1.min..c1.max
+                && v2 in c2.min..c2.max
+                && v3 in c3.min..c3.max
                 && alpha in 0f..1f -> this
 
         else -> copy(
@@ -101,3 +101,49 @@ internal inline fun <T : Color> T.clamp3(
         )
     }
 }
+
+internal inline fun <T : Color> T.clampLeadingHue(
+    v1: Float,
+    v2: Float,
+    v3: Float,
+    alpha: Float,
+    copy: (v1: Float, v2: Float, v3: Float, alpha: Float) -> T,
+): T {
+    val (c1, c2, c3) = space.components
+    return when {
+        v1 in c1.min..c1.max
+                && v2 in c2.min..c2.max
+                && v3 in c3.min..c3.max
+                && alpha in 0f..1f -> this
+
+        else -> copy(
+            v1 % 360,
+            v2.coerceIn(c2.min, c2.max),
+            v3.coerceIn(c3.min, c3.max),
+            alpha.coerceIn(0f, 1f)
+        )
+    }
+}
+
+internal inline fun <T : Color> T.clampTrailingHue(
+    v1: Float,
+    v2: Float,
+    v3: Float,
+    alpha: Float,
+    copy: (v1: Float, v2: Float, v3: Float, alpha: Float) -> T,
+): T {
+    val (c1, c2, c3) = space.components
+    return when {
+        v1 in c1.min..c1.max
+                && v2 in c2.min..c2.max
+                && v3 in c3.min..c3.max
+                && alpha in 0f..1f -> this
+
+        else -> copy(
+            v1.coerceIn(c1.min, c1.max),
+            v2.coerceIn(c2.min, c2.max),
+            v3 % 360,
+            alpha.coerceIn(0f, 1f)
+        )
+    }
+}
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HPLuv.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HPLuv.kt
@@ -4,7 +4,7 @@ import com.github.ajalt.colormath.Color
 import com.github.ajalt.colormath.ColorComponentInfo
 import com.github.ajalt.colormath.ColorSpace
 import com.github.ajalt.colormath.HueColor
-import com.github.ajalt.colormath.internal.clamp3
+import com.github.ajalt.colormath.internal.clampLeadingHue
 import com.github.ajalt.colormath.internal.doCreate
 import com.github.ajalt.colormath.internal.polarComponentInfo
 
@@ -52,5 +52,5 @@ data class HPLuv(
     override fun toXYZ(): XYZ = toLCHuv().toXYZ()
     override fun toHPLuv(): HPLuv = this
     override fun toArray(): FloatArray = floatArrayOf(h, p, l, alpha)
-    override fun clamp(): HPLuv = clamp3(h, p, l, alpha, ::copy)
+    override fun clamp(): HPLuv = clampLeadingHue(h, p, l, alpha, ::copy)
 }
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HSL.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HSL.kt
@@ -1,7 +1,7 @@
 package com.github.ajalt.colormath.model
 
 import com.github.ajalt.colormath.*
-import com.github.ajalt.colormath.internal.clamp3
+import com.github.ajalt.colormath.internal.clampLeadingHue
 import com.github.ajalt.colormath.internal.doCreate
 import com.github.ajalt.colormath.internal.normalizeDeg
 import com.github.ajalt.colormath.internal.polarComponentInfo
@@ -66,5 +66,5 @@ data class HSL(override val h: Float, val s: Float, val l: Float, override val a
 
     override fun toHSL() = this
     override fun toArray(): FloatArray = floatArrayOf(h, s, l, alpha)
-    override fun clamp(): HSL = clamp3(h, s, l, alpha, ::copy)
+    override fun clamp(): HSL = clampLeadingHue(h, s, l, alpha, ::copy)
 }
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HSLuv.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HSLuv.kt
@@ -52,7 +52,7 @@ data class HSLuv(
     override fun toXYZ(): XYZ = toLCHuv().toXYZ()
     override fun toHSLuv(): HSLuv = this
     override fun toArray(): FloatArray = floatArrayOf(h, s, l, alpha)
-    override fun clamp(): HSLuv = clamp3(h, s, l, alpha, ::copy)
+    override fun clamp(): HSLuv = clampLeadingHue(h, s, l, alpha, ::copy)
 }
 
 

diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HSV.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HSV.kt
@@ -4,7 +4,7 @@ import com.github.ajalt.colormath.Color
 import com.github.ajalt.colormath.ColorComponentInfo
 import com.github.ajalt.colormath.ColorSpace
 import com.github.ajalt.colormath.HueColor
-import com.github.ajalt.colormath.internal.clamp3
+import com.github.ajalt.colormath.internal.clampLeadingHue
 import com.github.ajalt.colormath.internal.doCreate
 import com.github.ajalt.colormath.internal.normalizeDeg
 import com.github.ajalt.colormath.internal.polarComponentInfo
@@ -59,5 +59,5 @@ data class HSV(override val h: Float, val s: Float, val v: Float, override val a
 
     override fun toHSV() = this
     override fun toArray(): FloatArray = floatArrayOf(h, s, v, alpha)
-    override fun clamp(): HSV = clamp3(h, s, v, alpha, ::copy)
+    override fun clamp(): HSV = clampLeadingHue(h, s, v, alpha, ::copy)
 }
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HWB.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/HWB.kt
@@ -4,10 +4,9 @@ import com.github.ajalt.colormath.Color
 import com.github.ajalt.colormath.ColorComponentInfo
 import com.github.ajalt.colormath.ColorSpace
 import com.github.ajalt.colormath.HueColor
-import com.github.ajalt.colormath.internal.clamp3
+import com.github.ajalt.colormath.internal.clampLeadingHue
 import com.github.ajalt.colormath.internal.doCreate
 import com.github.ajalt.colormath.internal.polarComponentInfo
-import kotlin.math.roundToInt
 
 /**
  * A color model represented with Hue, Whiteness, and Blackness.
@@ -79,5 +78,5 @@ data class HWB(override val h: Float, val w: Float, val b: Float, override val a
 
     override fun toHWB(): HWB = this
     override fun toArray(): FloatArray = floatArrayOf(h, w, b, alpha)
-    override fun clamp(): HWB = clamp3(h, w, b, alpha, ::copy)
+    override fun clamp(): HWB = clampLeadingHue(h, w, b, alpha, ::copy)
 }
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/LCHab.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/LCHab.kt
@@ -78,5 +78,5 @@ data class LCHab internal constructor(
 
     override fun toLCHab(): LCHab = this
     override fun toArray(): FloatArray = floatArrayOf(l, c, h, alpha)
-    override fun clamp(): LCHab = clamp3(l, c, h, alpha, ::copy)
+    override fun clamp(): LCHab = clampTrailingHue(l, c, h, alpha, ::copy)
 }
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/LCHuv.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/LCHuv.kt
@@ -88,5 +88,5 @@ data class LCHuv internal constructor(
 
     override fun toLCHuv(): LCHuv = this
     override fun toArray(): FloatArray = floatArrayOf(l, c, h, alpha)
-    override fun clamp(): LCHuv = clamp3(l, c, h, alpha, ::copy)
+    override fun clamp(): LCHuv = clampTrailingHue(l, c, h, alpha, ::copy)
 }
diff --git a/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/Oklch.kt b/colormath/src/commonMain/kotlin/com/github/ajalt/colormath/model/Oklch.kt
@@ -4,7 +4,7 @@ import com.github.ajalt.colormath.Color
 import com.github.ajalt.colormath.ColorComponentInfo
 import com.github.ajalt.colormath.ColorSpace
 import com.github.ajalt.colormath.HueColor
-import com.github.ajalt.colormath.internal.clamp3
+import com.github.ajalt.colormath.internal.*
 import com.github.ajalt.colormath.internal.componentInfoList
 import com.github.ajalt.colormath.internal.doCreate
 import com.github.ajalt.colormath.internal.fromPolarModel
@@ -45,5 +45,5 @@ data class Oklch(
     override fun toOklab(): Oklab = fromPolarModel(c, h) { a, b -> Oklab(l, a, b, alpha) }
     override fun toOklch(): Oklch = this
     override fun toArray(): FloatArray = floatArrayOf(l, c, h, alpha)
-    override fun clamp(): Oklch = clamp3(l, c, h, alpha, ::copy)
+    override fun clamp(): Oklch = clampTrailingHue(l, c, h, alpha, ::copy)
 }
diff --git a/test/src/commonTest/kotlin/com/github/ajalt/colormath/model/HSLTest.kt b/test/src/commonTest/kotlin/com/github/ajalt/colormath/model/HSLTest.kt
@@ -1,7 +1,11 @@
 package com.github.ajalt.colormath.model
 
 import com.github.ajalt.colormath.roundtripTest
+import com.github.ajalt.colormath.shouldEqualColor
 import com.github.ajalt.colormath.testColorConversions
+import io.kotest.data.blocking.forAll
+import io.kotest.data.row
+import io.kotest.matchers.types.shouldBeSameInstanceAs
 import kotlin.js.JsName
 import kotlin.test.Test
 
@@ -26,4 +30,18 @@ class HSLTest {
         HSL(144.00, 0.50, 0.60) to HSV(144.0, 0.5, 0.8),
         HSL(0.00, 0.00, 1.00) to HSV(0.0, 0.0, 1.0),
     )
+
+    @Test
+    fun clamp() {
+        forAll(
+            row(HSL(0.0, 0.0, 0.0), HSL(0.0, 0.0, 0.0)),
+            row(HSL(359, 1.0, 1.0), HSL(359, 1.0, 1.0)),
+            row(HSL(361, 1.0, 1.0), HSL(1, 1.0, 1.0)),
+            row(HSL(180, 2, 2), HSL(180, 1.0, 1.0)),
+        ) { hsl, ex ->
+            hsl.clamp().shouldEqualColor(ex)
+        }
+        val hsl = HSL(359, .9, .9, .9)
+        hsl.clamp().shouldBeSameInstanceAs(hsl)
+    }
 }
diff --git a/test/src/commonTest/kotlin/com/github/ajalt/colormath/model/OklchTest.kt b/test/src/commonTest/kotlin/com/github/ajalt/colormath/model/OklchTest.kt
@@ -1,7 +1,11 @@
 package com.github.ajalt.colormath.model
 
 import com.github.ajalt.colormath.roundtripTest
+import com.github.ajalt.colormath.shouldEqualColor
 import com.github.ajalt.colormath.testColorConversions
+import io.kotest.data.blocking.forAll
+import io.kotest.data.row
+import io.kotest.matchers.types.shouldBeSameInstanceAs
 import kotlin.js.JsName
 import kotlin.test.Test
 
@@ -18,4 +22,16 @@ class OklchTest {
         Oklab(0.25, 0.5, 0.75) to Oklch(0.25, 0.90138782, 56.30993247),
         Oklab(1.0, 1.0, 1.0) to Oklch(1.0, 1.41421356, 45.0),
     )
+
+    @Test
+    fun clamp() {
+        forAll(
+            row(Oklch(0.0, 0.0, 0.0), Oklch(0.0, 0.0, 0.0)),
+            row(Oklch(-1, -1, 361, 3), Oklch(0.0, 0.0, 1)),
+        ) { color, ex ->
+            color.clamp().shouldEqualColor(ex)
+        }
+        val oklch = Oklch(.9, .2, 359, .9)
+        oklch.clamp().shouldBeSameInstanceAs(oklch)
+    }
 }