(docs): Add Information about how to use Dark Mode SplashScreens (#286)

Author: EinfachHans

README.md

@@ -38,6 +38,7 @@ This plugin displays and hides a splash screen while your web application is lau
       - [Image Layout](#image-layout)
       - [`density`](#density)
       - [Image Sizing Table](#image-sizing-table)
+      - [Dark Mode](#dark-mode)
       - [Example Android Configuration](#example-android-configuration)
     - [iOS-specific Information](#ios-specific-information)
       - [Launch Storyboard Images](#launch-storyboard-images)
@@ -47,6 +48,7 @@ This plugin displays and hides a splash screen while your web application is lau
         - [Size classes](#size-classes)
         - [Single-image launch screen](#single-image-launch-screen)
         - [Multi-image launch screen](#multi-image-launch-screen)
+        - [Dark Mode](#dark-mode-1)
         - [Quirks and Known Issues](#quirks-and-known-issues)
     - [Windows-specific Information](#windows-specific-information)
   - [Preferences](#preferences)
@@ -177,6 +179,13 @@ If not all DPI images are considered, some devices might not show a SplashScreen
 | xxhdpi  | 960x1600  | 1600x960  |
 | xxxhdpi | 1280x1920 | 1920x1280 |
 
+#### Dark Mode (API 28+)
+
+You can optionally provide an extra SplashScreen image to be used in dark/night mode when enabled on supported devices.
+To do this, add the `-night` keyword in between the **layout** and **size** keywords of the image's `density` attribute value. E.g.: `land-night-hdpi`
+
+For more examples, please see [the Example Configuration](#example-android-configuration) section.
+
 #### Example Android Configuration
 
 ```xml
@@ -194,6 +203,21 @@ If not all DPI images are considered, some devices might not show a SplashScreen
     <splash src="res/screen/android/splash-port-xhdpi.png" density="port-xhdpi" />
     <splash src="res/screen/android/splash-port-xxhdpi.png" density="port-xxhdpi" />
     <splash src="res/screen/android/splash-port-xxxhdpi.png" density="port-xxxhdpi" />
+  
+    <!-- Dark Mode -->
+    <splash src="res/screen/android/splash-land-hdpi.png" density="land-night-hdpi" />
+    <splash src="res/screen/android/splash-land-ldpi.png" density="land-night-ldpi" />
+    <splash src="res/screen/android/splash-land-mdpi.png" density="land-night-mdpi" />
+    <splash src="res/screen/android/splash-land-xhdpi.png" density="land-night-xhdpi" />
+    <splash src="res/screen/android/splash-land-xxhdpi.png" density="land-night-xxhdpi" />
+    <splash src="res/screen/android/splash-land-xxxhdpi.png" density="land-night-xxxhdpi" />
+
+    <splash src="res/screen/android/splash-port-hdpi.png" density="port-night-hdpi" />
+    <splash src="res/screen/android/splash-port-ldpi.png" density="port-night-ldpi" />
+    <splash src="res/screen/android/splash-port-mdpi.png" density="port-night-mdpi" />
+    <splash src="res/screen/android/splash-port-xhdpi.png" density="port-night-xhdpi" />
+    <splash src="res/screen/android/splash-port-xxhdpi.png" density="port-night-xxhdpi" />
+    <splash src="res/screen/android/splash-port-xxxhdpi.png" density="port-night-xxxhdpi" />
 </platform>
 ```
 
@@ -343,6 +367,23 @@ The above looks like the following in `config.xml`:
     <splash src="res/screen/ios/Default@2x~ipad~comany.png" />
 ```
 
+##### Dark Mode
+
+Since [[email protected]](https://github.com/apache/cordova-ios), it is now possible to optionally specify different SplashScreen images to use when the app is running in dark mode. The luminosity of SplashScreen images can be defined in `config.xml` using the `~dark` and `~light` suffixes.
+
+```xml
+<!-- Default image to be used for all modes -->
+<splash src="res/screen/ios/Default@2x~universal~anyany.png" />
+
+<!-- Image to use specifically for dark mode devices -->
+<splash src="res/screen/ios/Default@2x~universal~anyany~dark.png" />
+
+<!-- Image to use specifically for light mode devices -->
+<splash src="res/screen/ios/Default@2x~universal~anyany~light.png" />
+```
+
+**Note:** This works since iOS 13. iOS 12 and below will use the default SplashScreen without a luminosity suffix specified.
+
 ##### Quirks and Known Issues
 
 1. **App on target may not reflect changes to images**