diff --git a/app/src/main/java/de/kuschku/quasseldroid/util/ui/ShadowView.java b/app/src/main/java/de/kuschku/quasseldroid/util/ui/ShadowView.java
deleted file mode 100644
index 2e30afb8ee978526854449b6ae427ce606f80beb..0000000000000000000000000000000000000000
--- a/app/src/main/java/de/kuschku/quasseldroid/util/ui/ShadowView.java
+++ /dev/null
@@ -1,188 +0,0 @@
-/*
- * Copyright 2014 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package de.kuschku.quasseldroid.util.ui;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-import android.content.res.TypedArray;
-import android.graphics.Color;
-import android.graphics.LinearGradient;
-import android.graphics.Shader;
-import android.graphics.drawable.Drawable;
-import android.graphics.drawable.PaintDrawable;
-import android.graphics.drawable.ShapeDrawable;
-import android.graphics.drawable.shapes.RectShape;
-import android.os.Build;
-import android.support.annotation.Nullable;
-import android.support.annotation.RequiresApi;
-import android.util.AttributeSet;
-import android.util.LruCache;
-import android.view.Gravity;
-import android.view.View;
-
-import de.kuschku.quasseldroid.R;
-
-/**
- * Shadow view based on the {@code ScrimUtil.java} class from the Muzei App. Take a look at
- * <a href="https://plus.google.com/+RomanNurik/posts/2QvHVFWrHZf">this post</a> from Roman
- * Nurik for more details. Find the source code
- * <a href="https://github.com/romannurik/muzei/blob/master/main/src/main/java/com/google/android/apps/muzei/util/ScrimUtil.java">here</a>.
- */
-public class ShadowView extends View {
-
- private static final LruCache<Integer, Drawable> cubicGradientScrimCache = new LruCache<>(10);
-
- public ShadowView(Context context) {
- super(context);
- initialize(context, null, 0, 0);
- }
-
- public ShadowView(Context context, @Nullable AttributeSet attrs) {
- super(context, attrs);
- initialize(context, attrs, 0, 0);
- }
-
- public ShadowView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
- super(context, attrs, defStyleAttr);
- initialize(context, attrs, defStyleAttr, 0);
- }
-
- @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
- public ShadowView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
- super(context, attrs, defStyleAttr, defStyleRes);
- initialize(context, attrs, defStyleAttr, defStyleRes);
- }
-
- /**
- * Initializes the view.
- *
- * @param context The Context the view is running in, through which it can
- * access the current theme, resources, etc.
- * @param attrs The attributes of the XML tag that is inflating the view.
- * @param defStyleAttr An attribute in the current theme that contains a
- * reference to a style resource that supplies default values for
- * the view. Can be 0 to not look for defaults.
- * @param defStyleRes A resource identifier of a style resource that
- * supplies default values for the view, used only if
- * defStyleAttr is 0 or can not be found in the theme. Can be 0
- * to not look for defaults.
- * @see View(Context, AttributeSet, int)
- */
- private void initialize(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
- int gravity = Gravity.TOP;
-
- // Get the attributes.
- TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ShadowView, defStyleAttr, defStyleRes);
- try {
- if (a != null) {
- gravity = a.getInt(R.styleable.ShadowView_android_gravity, gravity);
- }
-
- } finally {
- if (a != null) a.recycle();
- }
-
- // Set the gradient as background.
- setBackground(makeCubicGradientScrimDrawable(0x44000000, 8, gravity));
- }
-
- /**
- * Creates an approximated cubic gradient using a multi-stop linear gradient.
- */
- @SuppressLint("RtlHardcoded")
- private Drawable makeCubicGradientScrimDrawable(int baseColor, int numStops, int gravity) {
-
- // Generate a cache key by hashing together the inputs, based on the method described in the Effective Java book
- int cacheKeyHash = baseColor;
- cacheKeyHash = 31 * cacheKeyHash + numStops;
- cacheKeyHash = 31 * cacheKeyHash + gravity;
-
- Drawable cachedGradient = cubicGradientScrimCache.get(cacheKeyHash);
- if (cachedGradient != null) {
- return cachedGradient;
- }
-
- numStops = Math.max(numStops, 2);
-
- PaintDrawable paintDrawable = new PaintDrawable();
- paintDrawable.setShape(new RectShape());
-
- final int[] stopColors = new int[numStops];
-
- int red = Color.red(baseColor);
- int green = Color.green(baseColor);
- int blue = Color.blue(baseColor);
- int alpha = Color.alpha(baseColor);
-
- for (int i = 0; i < numStops; i++) {
- float x = i * 1f / (numStops - 1);
- float opacity = constrain(0, 1, (float) Math.pow(x, 3));
- stopColors[i] = Color.argb((int) (alpha * opacity), red, green, blue);
- }
-
- final float x0, x1, y0, y1;
- switch (gravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
- case Gravity.LEFT:
- x0 = 1;
- x1 = 0;
- break;
- case Gravity.RIGHT:
- x0 = 0;
- x1 = 1;
- break;
- default:
- x0 = 0;
- x1 = 0;
- break;
- }
- switch (gravity & Gravity.VERTICAL_GRAVITY_MASK) {
- case Gravity.TOP:
- y0 = 1;
- y1 = 0;
- break;
- case Gravity.BOTTOM:
- y0 = 0;
- y1 = 1;
- break;
- default:
- y0 = 0;
- y1 = 0;
- break;
- }
-
- paintDrawable.setShaderFactory(new ShapeDrawable.ShaderFactory() {
- @Override
- public Shader resize(int width, int height) {
- return new LinearGradient(
- width * x0,
- height * y0,
- width * x1,
- height * y1,
- stopColors, null,
- Shader.TileMode.CLAMP);
- }
- });
-
- cubicGradientScrimCache.put(cacheKeyHash, paintDrawable);
- return paintDrawable;
- }
-
- private float constrain(float min, float max, float v) {
- return Math.max(min, Math.min(max, v));
- }
-
-}
diff --git a/app/src/main/java/de/kuschku/quasseldroid/util/ui/ShadowView.kt b/app/src/main/java/de/kuschku/quasseldroid/util/ui/ShadowView.kt
new file mode 100644
index 0000000000000000000000000000000000000000..613b438c3153d41559e9c8eabac71e9618f0fd88
--- /dev/null
+++ b/app/src/main/java/de/kuschku/quasseldroid/util/ui/ShadowView.kt
@@ -0,0 +1,182 @@
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package de.kuschku.quasseldroid.util.ui
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.graphics.Color
+import android.graphics.LinearGradient
+import android.graphics.Shader
+import android.graphics.drawable.Drawable
+import android.graphics.drawable.PaintDrawable
+import android.graphics.drawable.ShapeDrawable
+import android.graphics.drawable.shapes.RectShape
+import android.os.Build
+import android.support.annotation.RequiresApi
+import android.util.AttributeSet
+import android.util.LruCache
+import android.view.Gravity
+import android.view.View
+import de.kuschku.quasseldroid.R
+
+/**
+ * Shadow view based on the `ScrimUtil.java` class from the Muzei App. Take a look at
+ * [this post](https://plus.google.com/+RomanNurik/posts/2QvHVFWrHZf) from Roman
+ * Nurik for more details. Find the source code
+ * [here](https://github.com/romannurik/muzei/blob/master/main/src/main/java/com/google/android/apps/muzei/util/ScrimUtil.java).
+ */
+class ShadowView : View {
+ constructor(context: Context) : super(context) {
+ initialize(context, null, 0, 0)
+ }
+
+ constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {
+ initialize(context, attrs, 0, 0)
+ }
+
+ constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
+ super(context, attrs, defStyleAttr) {
+ initialize(context, attrs, defStyleAttr, 0)
+ }
+
+ @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
+ constructor(context: Context, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int) :
+ super(context, attrs, defStyleAttr, defStyleRes) {
+ initialize(context, attrs, defStyleAttr, defStyleRes)
+ }
+
+ /**
+ * Initializes the view.
+ *
+ * @param context The Context the view is running in, through which it can
+ * access the current theme, resources, etc.
+ * @param attrs The attributes of the XML tag that is inflating the view.
+ * @param defStyleAttr An attribute in the current theme that contains a
+ * reference to a style resource that supplies default values for
+ * the view. Can be 0 to not look for defaults.
+ * @param defStyleRes A resource identifier of a style resource that
+ * supplies default values for the view, used only if
+ * defStyleAttr is 0 or can not be found in the theme. Can be 0
+ * to not look for defaults.
+ * @see View
+ */
+ private fun initialize(context: Context, attrs: AttributeSet?, defStyleAttr: Int,
+ defStyleRes: Int) {
+ var gravity = Gravity.TOP
+
+ // Get the attributes.
+ val a = context.obtainStyledAttributes(attrs, R.styleable.ShadowView, defStyleAttr, defStyleRes)
+ try {
+ if (a != null) {
+ gravity = a.getInt(R.styleable.ShadowView_android_gravity, gravity)
+ }
+
+ } finally {
+ a?.recycle()
+ }
+
+ // Set the gradient as background.
+ background = makeCubicGradientScrimDrawable(0x44000000, 8, gravity)
+ }
+
+ /**
+ * Creates an approximated cubic gradient using a multi-stop linear gradient.
+ */
+ @SuppressLint("RtlHardcoded")
+ private fun makeCubicGradientScrimDrawable(baseColor: Int, numStops: Int,
+ gravity: Int): Drawable {
+ // Generate a cache key by hashing together the inputs, based on the method described in the Effective Java book
+ val cacheKeyHash = ((baseColor) * 31 + numStops) * 31 + gravity
+ val cachedGradient = cubicGradientScrimCache.get(cacheKeyHash)
+ if (cachedGradient != null) {
+ return cachedGradient
+ }
+
+ val paintDrawable = PaintDrawable()
+ paintDrawable.shape = RectShape()
+
+ val red = Color.red(baseColor)
+ val green = Color.green(baseColor)
+ val blue = Color.blue(baseColor)
+ val alpha = Color.alpha(baseColor)
+
+ val stopColors = IntArray(numStops) {
+ val x = it * 1f / (numStops - 1)
+ val opacity = constrain(0f, 1f, Math.pow(x.toDouble(), 3.0).toFloat())
+ Color.argb((alpha * opacity).toInt(), red, green, blue)
+ }
+
+ val x0: Float
+ val x1: Float
+ val y0: Float
+ val y1: Float
+ when (gravity and Gravity.HORIZONTAL_GRAVITY_MASK) {
+ Gravity.LEFT -> {
+ x0 = 1f
+ x1 = 0f
+ }
+ Gravity.RIGHT -> {
+ x0 = 0f
+ x1 = 1f
+ }
+ else -> {
+ x0 = 0f
+ x1 = 0f
+ }
+ }
+ when (gravity and Gravity.VERTICAL_GRAVITY_MASK) {
+ Gravity.TOP -> {
+ y0 = 1f
+ y1 = 0f
+ }
+ Gravity.BOTTOM -> {
+ y0 = 0f
+ y1 = 1f
+ }
+ else -> {
+ y0 = 0f
+ y1 = 0f
+ }
+ }
+
+ paintDrawable.shaderFactory = ShadowShaderFactory(x0, y0, x1, y1, stopColors)
+ cubicGradientScrimCache.put(cacheKeyHash, paintDrawable)
+ return paintDrawable
+ }
+
+ private fun constrain(min: Float, max: Float, v: Float): Float {
+ return Math.max(min, Math.min(max, v))
+ }
+
+ class ShadowShaderFactory(
+ private val x0: Float, private val y0: Float,
+ private val x1: Float, private val y1: Float,
+ private val stopColors: IntArray
+ ) : ShapeDrawable.ShaderFactory() {
+ override fun resize(width: Int, height: Int) = LinearGradient(
+ width * x0,
+ height * y0,
+ width * x1,
+ height * y1,
+ stopColors, null,
+ Shader.TileMode.CLAMP)
+ }
+
+ companion object {
+ private val cubicGradientScrimCache = LruCache<Int, Drawable>(10)
+ }
+}