Align relative to text direction

app/src/main/java/eu/faircode/email/Helper.java

@@ -876,6 +876,31 @@ public class Helper {
     }
     // https://issuetracker.google.com/issues/37054851
 
+    static boolean isRtl(String text) {
+        if (TextUtils.isEmpty(text))
+            return false;
+
+        int rtl = 0;
+        int ltr = 0;
+        for (int i = 0; i < text.length(); i++)
+            switch (Character.getDirectionality(text.charAt(i))) {
+                case java.lang.Character.DIRECTIONALITY_RIGHT_TO_LEFT:
+                case java.lang.Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC:
+                case java.lang.Character.DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING:
+                case java.lang.Character.DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE:
+                    rtl++;
+                    break;
+
+                case java.lang.Character.DIRECTIONALITY_LEFT_TO_RIGHT:
+                case java.lang.Character.DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING:
+                case java.lang.Character.DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE:
+                    ltr++;
+                    break;
+            }
+
+        return (rtl > ltr);
+    }
+
     static DateFormat getTimeInstance(Context context) {
         return Helper.getTimeInstance(context, SimpleDateFormat.MEDIUM);
     }

app/src/main/java/eu/faircode/email/HtmlHelper.java

@@ -55,7 +55,6 @@ import android.text.style.URLSpan;
 import android.text.style.UnderlineSpan;
 import android.util.Base64;
 import android.util.Patterns;
-import android.view.View;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -1951,7 +1950,6 @@ public class HtmlHelper {
         final int dp3 = Helper.dp2pixels(context, 3);
         final int dp6 = Helper.dp2pixels(context, 6);
         final int dp24 = Helper.dp2pixels(context, 24);
-        final boolean ltr = (TextUtils.getLayoutDirectionFromLocale(Locale.getDefault()) == View.LAYOUT_DIRECTION_LTR);
 
         int message_zoom = prefs.getInt("message_zoom", 100);
         float textSize = Helper.getTextSize(context, 0) * message_zoom / 100f;
@@ -2185,17 +2183,18 @@ public class HtmlHelper {
                                 case "text-align":
                                     // https://developer.mozilla.org/en-US/docs/Web/CSS/text-align
                                     Layout.Alignment alignment = null;
+                                    boolean rtl = Helper.isRtl(ssb.subSequence(start, ssb.length()).toString());
                                     switch (value) {
                                         case "left":
                                         case "start":
-                                            alignment = (ltr ? Layout.Alignment.ALIGN_NORMAL : Layout.Alignment.ALIGN_OPPOSITE);
+                                            alignment = (rtl ? Layout.Alignment.ALIGN_OPPOSITE : Layout.Alignment.ALIGN_NORMAL);
                                             break;
                                         case "center":
                                             alignment = Layout.Alignment.ALIGN_CENTER;
                                             break;
                                         case "right":
                                         case "end":
-                                            alignment = (ltr ? Layout.Alignment.ALIGN_OPPOSITE : Layout.Alignment.ALIGN_NORMAL);
+                                            alignment = (rtl ? Layout.Alignment.ALIGN_NORMAL : Layout.Alignment.ALIGN_OPPOSITE);
                                             break;
                                     }
                                     if (alignment != null)