From d2d3a6995ee2a3b1d6406b2ab84abdab135eff52 Mon Sep 17 00:00:00 2001
From: Jan Seeger <seeger@sipgate.de>
Date: Wed, 20 Dec 2023 16:15:32 +0100
Subject: [PATCH] Add color blending func

---
 .../sipgate/dachlatten/compose/color/blend.kt  | 18 ++++++++++++++++++
 .../dachlatten/compose/color/ColorTest.kt      | 16 ++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 dachlatten-compose/src/main/kotlin/de/sipgate/dachlatten/compose/color/blend.kt
 create mode 100644 dachlatten-compose/src/test/kotlin/de/sipgate/dachlatten/compose/color/ColorTest.kt

diff --git a/dachlatten-compose/src/main/kotlin/de/sipgate/dachlatten/compose/color/blend.kt b/dachlatten-compose/src/main/kotlin/de/sipgate/dachlatten/compose/color/blend.kt
new file mode 100644
index 0000000..ef6ff86
--- /dev/null
+++ b/dachlatten-compose/src/main/kotlin/de/sipgate/dachlatten/compose/color/blend.kt
@@ -0,0 +1,18 @@
+package de.sipgate.dachlatten.compose.color
+
+import androidx.compose.ui.graphics.Color
+
+fun blend(
+    color1: Color,
+    color2: Color,
+    ratio: Float,
+): Color {
+    val inverseRatio = 1f - ratio
+
+    val red = color1.red * ratio + color2.red * inverseRatio
+    val green = color1.green * ratio + color2.green * inverseRatio
+    val blue = color1.blue * ratio + color2.blue * inverseRatio
+    val alpha = color1.alpha * ratio + color2.alpha * inverseRatio
+
+    return Color(red, green, blue, alpha)
+}
diff --git a/dachlatten-compose/src/test/kotlin/de/sipgate/dachlatten/compose/color/ColorTest.kt b/dachlatten-compose/src/test/kotlin/de/sipgate/dachlatten/compose/color/ColorTest.kt
new file mode 100644
index 0000000..9c9ac50
--- /dev/null
+++ b/dachlatten-compose/src/test/kotlin/de/sipgate/dachlatten/compose/color/ColorTest.kt
@@ -0,0 +1,16 @@
+package de.sipgate.dachlatten.compose.color
+
+import androidx.compose.ui.graphics.Color
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+class ColorTest {
+    @Test
+    fun equalPartsOfRedAndBlueResultInPurple() {
+        val red = Color.Red
+        val blue = Color.Blue
+
+        val result = blend(red, blue, 0.5f)
+        assertEquals(Color(128, 0, 128), result)
+    }
+}