disabled by default variant of XEP-0392

build.gradle

@@ -64,6 +64,7 @@ dependencies {
     implementation 'com.googlecode.ez-vcard:ez-vcard:0.10.3'
     implementation 'in.championswimmer:SimpleFingerGestures_Android_Library:1.2'
     implementation 'rocks.xmpp:xmpp-addr:0.8.0'
+    implementation 'org.hsluv:hsluv:0.2'
 }
 
 ext {

src/main/java/de/pixart/messenger/Config.java

@@ -77,6 +77,8 @@ public final class Config {
     public static final int CONNECT_DISCO_TIMEOUT = 30;
     public static final int MINI_GRACE_PERIOD = 750;
 
+    public static final boolean XEP_0392 = false; //enables a variant of XEP-0392 that is based on HSLUV
+
     public static final int FILE_SIZE = 1048576; // 1 MiB
 
     public static final int AVATAR_SIZE = 480;

src/main/java/de/pixart/messenger/utils/UIHelper.java

@@ -222,6 +222,9 @@ public class UIHelper {
     }
 
     public static int getColorForName(String name, boolean safe) {
+        if (Config.XEP_0392) {
+            return XEP0392Helper.rgbFromNick(name);
+        }
         if (name == null || name.isEmpty()) {
             return 0xFF202020;
         }

src/main/java/de/pixart/messenger/utils/XEP0392Helper.java

@@ -0,0 +1,30 @@
+package de.pixart.messenger.utils;
+
+import android.graphics.Color;
+
+import org.hsluv.HUSLColorConverter;
+
+import java.security.MessageDigest;
+
+public class XEP0392Helper {
+
+    private static double angle(String nickname) {
+        try {
+            MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
+            byte[] digest = sha1.digest(nickname.getBytes("UTF-8"));
+            int angle = ((int) (digest[0]) & 0xff) + ((int) (digest[1]) & 0xff) * 256;
+            return angle / 65536.;
+        } catch (Exception e) {
+            return 0.0;
+        }
+    }
+
+    public static int rgbFromNick(String name) {
+        double[] hsluv = new double[3];
+        hsluv[0] = angle(name) * 360;
+        hsluv[1] = 100;
+        hsluv[2] = 50;
+        double[] rgb = HUSLColorConverter.hsluvToRgb(hsluv);
+        return Color.rgb((int) Math.round(rgb[0] * 255), (int) Math.round(rgb[1] * 255), (int) Math.round(rgb[2] * 255));
+    }
+}