Add an option to use custom brightness

app/src/main/res/layout/reader_brightness.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:orientation="vertical"
+    android:layout_width="wrap_content"
+    android:layout_height="match_parent"
+    android:background="#333333"
+    android:paddingRight="10dp"
+    android:paddingLeft="5dp"
+    android:paddingTop="5dp"
+    android:paddingBottom="5dp">
+
+    <CheckBox
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        style="@style/grey_text"
+        android:text="@string/pref_custom_brightness"
+        android:id="@+id/custom_brightness" />
+
+    <SeekBar
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:id="@+id/brightness_seekbar" />
+</LinearLayout>

app/src/main/res/layout/reader_menu.xml

@@ -72,14 +72,16 @@
                 android:layout_width="0dp"
                 android:layout_height="match_parent"
                 android:layout_weight="1"
-                android:id="@+id/lock_orientation"
-                android:src="@drawable/ic_screen_rotation"
+                android:id="@+id/reader_brightness"
+                android:src="@drawable/ic_brightness_high"
                 android:layout_gravity="center_vertical"
                 android:background="?android:selectableItemBackground" />
             <ImageButton
                 android:layout_width="0dp"
                 android:layout_height="match_parent"
                 android:layout_weight="1"
+                android:id="@+id/lock_orientation"
+                android:src="@drawable/ic_screen_rotation"
                 android:layout_gravity="center_vertical"
                 android:background="?android:selectableItemBackground" />
             <ImageButton

app/src/main/res/values/keys.xml

@@ -10,6 +10,8 @@
     <string name="pref_enable_transitions_key">pref_enable_transitions_key</string>
     <string name="pref_show_page_number_key">pref_show_page_number_key</string>
     <string name="pref_keep_screen_on_key">pref_keep_screen_on_key</string>
+    <string name="pref_custom_brightness_key">pref_custom_brightness_key</string>
+    <string name="pref_custom_brightness_value_key">pref_custom_brightness_value_key</string>
 
     <string name="pref_download_directory_key">pref_download_directory_key</string>
     <string name="pref_download_threads_key">pref_download_threads_key</string>

app/src/main/res/values/strings.xml

@@ -28,15 +28,16 @@
 
       <!-- Reader section -->
     <string name="pref_hide_status_bar">Hide status bar</string>
+    <string name="pref_lock_orientation">Lock orientation</string>
+    <string name="pref_enable_transitions">Enable transitions</string>
+    <string name="pref_show_page_number">Show page number</string>
+    <string name="pref_custom_brightness">Use custom brightness</string>
     <string name="pref_viewer_type">Default viewer</string>
     <string name="default_viewer">Default</string>
     <string name="left_to_right_viewer">Left to right</string>
     <string name="right_to_left_viewer">Right to left</string>
     <string name="vertical_viewer">Vertical</string>
     <string name="webtoon_viewer">Webtoon (experimental)</string>
-    <string name="pref_lock_orientation">Lock orientation</string>
-    <string name="pref_enable_transitions">Enable transitions</string>
-    <string name="pref_show_page_number">Show page number</string>
 
       <!-- Downloads section -->
     <string name="pref_download_directory">Downloads directory</string>

app/src/main/res/values/styles.xml

@@ -103,6 +103,10 @@
         <item name="android:windowEnterAnimation">@anim/enter_from_right</item>
         <item name="android:windowExitAnimation">@anim/exit_to_right</item>
     </style>
+    <style name="reader_brightness_popup_animation">
+        <item name="android:windowEnterAnimation">@anim/enter_from_left</item>
+        <item name="android:windowExitAnimation">@anim/exit_to_left</item>
+    </style>
     <style name="grey_text">
         <item name="android:textColor">#e0e0e0</item>
     </style>

app/src/main/res/xml/pref_reader.xml

@@ -17,6 +17,10 @@
         android:key="@string/pref_show_page_number_key"
         android:defaultValue="true" />
 
+    <CheckBoxPreference android:title="@string/pref_custom_brightness"
+        android:key="@string/pref_custom_brightness_key"
+        android:defaultValue="false" />
+
     <ListPreference android:title="@string/pref_viewer_type"
         android:key="@string/pref_default_viewer_key"
         android:entries="@array/viewers"