Automatically set issue label title color based on background color

app/src/main/java/com/commit451/gitlab/extension/Label.kt

@@ -3,6 +3,7 @@ package com.commit451.gitlab.extension
 import android.graphics.Color
 import android.support.annotation.ColorInt
 import com.commit451.gitlab.model.api.Label
+import com.commit451.gitlab.util.ColorUtil
 @ColorInt
 fun Label.getColor(): Int {
@@ -11,5 +12,9 @@ fun Label.getColor(): Int {
     } catch (e: Exception) {
         return Color.TRANSPARENT
     }
+}
+@ColorInt
+fun Label.getTitleColor(): Int {
+    return ColorUtil.getTitleColor(getColor())
 }
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app/src/main/java/com/commit451/gitlab/util/ColorUtil.kt

 package com.commit451.gitlab.util
+import android.graphics.Color
 import android.support.annotation.ColorInt
 /**
@@ -10,4 +11,18 @@ object ColorUtil {
     fun convertColorIntToString(@ColorInt color: Int): String {
         return String.format("#%06X", 0xFFFFFF and color)
     }
+
+    fun getTitleColor(@ColorInt color: Int): Int {
+        val darkness = 1.0 - (0.299 * Color.red(color).toDouble() +
+                0.587 * Color.green(color).toDouble() +
+                0.114 * Color.blue(color).toDouble()) / 255.0
+
+        if (darkness < 0.35) {
+            val hsv = FloatArray(3)
+            Color.colorToHSV(color, hsv)
+            hsv[2] *= 0.25f
+            return Color.HSVToColor(hsv)
+        }
+        return Color.WHITE;
+    }
 }

app/src/main/java/com/commit451/gitlab/viewHolder/AddLabelViewHolder.kt

 package com.commit451.gitlab.viewHolder
+import android.graphics.Color
 import android.support.v7.widget.RecyclerView
 import android.view.LayoutInflater
 import android.view.View
@@ -9,6 +10,7 @@ import butterknife.BindView
 import butterknife.ButterKnife
 import com.commit451.gitlab.R
 import com.commit451.gitlab.extension.getColor
+import com.commit451.gitlab.extension.getTitleColor
 import com.commit451.gitlab.model.api.Label
 /**
@@ -33,6 +35,7 @@ class AddLabelViewHolder(view: View) : RecyclerView.ViewHolder(view) {
     fun bind(label: Label) {
         textTitle.text = label.name
+        textTitle.setTextColor(label.getTitleColor())
         textTitle.setBackgroundColor(label.getColor())
     }
 }
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app/src/main/java/com/commit451/gitlab/viewHolder/LabelViewHolder.kt

@@ -9,6 +9,7 @@ import butterknife.BindView
 import butterknife.ButterKnife
 import com.commit451.gitlab.R
 import com.commit451.gitlab.extension.getColor
+import com.commit451.gitlab.extension.getTitleColor
 import com.commit451.gitlab.model.api.Label
 /**
@@ -34,6 +35,7 @@ class LabelViewHolder(view: View) : RecyclerView.ViewHolder(view) {
     fun bind(label: Label) {
         textTitle.text = label.name
+        textTitle.setTextColor(label.getTitleColor())
         viewColor.setBackgroundColor(label.getColor())
     }
 }
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