disabled by default variant of XEP-0392

build.gradle

@@ -51,6 +51,7 @@ dependencies {
     implementation 'net.ypresto.androidtranscoder:android-transcoder:0.2.0'
     implementation 'rocks.xmpp:xmpp-addr:0.8.0'
     implementation 'org.osmdroid:osmdroid-android:6.0.1'
+    implementation 'org.hsluv:hsluv:0.2'
 }
 
 ext {

src/main/java/eu/siacs/conversations/Config.java

@@ -68,6 +68,8 @@ public final class Config {
 	public static final int CONNECT_DISCO_TIMEOUT = 20;
 	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 AVATAR_SIZE = 192;
 	public static final Bitmap.CompressFormat AVATAR_FORMAT = Bitmap.CompressFormat.JPEG;
 	public static final int AVATAR_CHAR_LIMIT = 9400;

src/main/java/eu/siacs/conversations/utils/UIHelper.java

@@ -230,6 +230,9 @@ 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/eu/siacs/conversations/utils/XEP0392Helper.java

@@ -0,0 +1,31 @@
+package eu.siacs.conversations.utils;
+
+import android.graphics.Color;
+import android.util.Log;
+
+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));
+    }
+}