Implement zoom start position. Closes #92. Rapid decoder properly throws an error when it fails to decode.

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

@@ -78,6 +78,16 @@
                 android:src="@drawable/ic_screen_rotation"
                 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/reader_zoom_selector"
+                android:src="@drawable/ic_crop_original_white_24dp"
+                android:layout_gravity="center_vertical"
+                android:background="?android:selectableItemBackground"/>
+
             <ImageButton
                 android:layout_width="0dp"
                 android:layout_height="match_parent"
@@ -95,6 +105,7 @@
                 android:src="@drawable/ic_view_carousel"
                 android:layout_gravity="center_vertical"
                 android:background="?android:selectableItemBackground" />
+
             <ImageButton
                 android:layout_width="0dp"
                 android:layout_height="match_parent"

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

@@ -66,6 +66,20 @@
         <item>6</item>
     </string-array>
 
+    <string-array name="zoom_start">
+        <item>@string/zoom_start_automatic</item>
+        <item>@string/zoom_start_left</item>
+        <item>@string/zoom_start_right</item>
+        <item>@string/zoom_start_center</item>
+    </string-array>
+
+    <string-array name="zoom_start_values">
+        <item>1</item>
+        <item>2</item>
+        <item>3</item>
+        <item>4</item>
+    </string-array>
+
     <string-array name="library_update_interval">
         <item>@string/update_never</item>
         <item>@string/update_1hour</item>

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

@@ -17,6 +17,7 @@
 
     <string name="pref_default_viewer_key">pref_default_viewer_key</string>
     <string name="pref_image_scale_type_key">pref_image_scale_type_key</string>
+    <string name="pref_zoom_start_key">pref_zoom_start_key</string>
     <string name="pref_hide_status_bar_key">pref_hide_status_bar_key</string>
     <string name="pref_lock_orientation_key">pref_lock_orientation_key</string>
     <string name="pref_enable_transitions_key">pref_enable_transitions_key</string>

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

@@ -93,7 +93,7 @@
     <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="webtoon_viewer">Webtoon</string>
     <string name="pref_image_decoder">Image decoder</string>
     <string name="rapid_decoder">Rapid</string>
     <string name="skia_decoder">Skia</string>
@@ -104,7 +104,11 @@
     <string name="scale_type_fit_height">Fit height</string>
     <string name="scale_type_original_size">Original size</string>
     <string name="scale_type_smart_fit">Smart fit</string>
-
+    <string name="pref_zoom_start">Zoom start position</string>
+    <string name="zoom_start_automatic">Automatic</string>
+    <string name="zoom_start_left">Left</string>
+    <string name="zoom_start_right">Right</string>
+    <string name="zoom_start_center">Center</string>
 
       <!-- Downloads section -->
     <string name="pref_download_directory">Downloads directory</string>

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

@@ -37,6 +37,14 @@
         android:defaultValue="1"
         android:summary="%s"/>
 
+    <eu.kanade.tachiyomi.widget.preference.IntListPreference
+        android:title="@string/pref_zoom_start"
+        android:key="@string/pref_zoom_start_key"
+        android:entries="@array/zoom_start"
+        android:entryValues="@array/zoom_start_values"
+        android:defaultValue="1"
+        android:summary="%s"/>
+
     <eu.kanade.tachiyomi.widget.preference.IntListPreference
         android:title="@string/pref_reader_theme"
         android:key="@string/pref_reader_theme_key"