Transform mathematical characters

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

@@ -2396,6 +2396,7 @@ public class AdapterMessage extends RecyclerView.Adapter<AdapterMessage.ViewHold
                             ssb.setSpan(new ForegroundColorSpan(textColorLink), start, ssb.length(), 0);
                         }
                     } else {
+                        personal = Helper.transformMathematical(personal);
                         if (full) {
                             ssb.append(personal).append(" <");
                             if (!TextUtils.isEmpty(email)) {

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

@@ -2166,6 +2166,44 @@ public class Helper {
         return value;
     }
 
+    static String transformMathematical(String value) {
+        // https://www.w3.org/TR/xml-entity-names/1D4.html
+        // https://www.utf8-chartable.de/unicode-utf8-table.pl?start=119808
+
+        StringBuilder sb = new StringBuilder();
+
+        int k = 0;
+        while (k < value.length()) {
+            int cp = value.codePointAt(k);
+
+            if (cp >= 0x1D400 && cp <= 0x1D419) // MATHEMATICAL BOLD CAPITAL A-Z
+                sb.append((char) (cp - 0x1D400 + 65));
+            else if (cp >= 0x1D41A && cp <= 0x1D433) // MATHEMATICAL BOLD SMALL A-Z
+                sb.append((char) (cp - 0x1D41A + 97));
+            else if (cp >= 0x1D434 && cp <= 0x1D44D) // MATHEMATICAL ITALIC CAPITAL A-Z
+                sb.append((char) (cp - 0x1D434 + 65));
+            else if (cp >= 0x1D44E && cp <= 0x1D467) // MATHEMATICAL ITALIC SMALL A-Z
+                sb.append((char) (cp - 0x1D44E + 97));
+            else if (cp >= 0x1D468 && cp <= 0x1D481) // MATHEMATICAL BOLD ITALIC CAPITAL A-Z
+                sb.append((char) (cp - 0x1D468 + 65));
+            else if (cp >= 0x1D482 && cp <= 0x1D49B) // MATHEMATICAL BOLD ITALIC SMALL A-Z
+                sb.append((char) (cp - 0x1D482 + 97));
+            else if (cp >= 0x1D49C && cp <= 0x1D4B5) // MATHEMATICAL SCRIPT CAPITAL A-Z
+                sb.append((char) (cp - 0x1D49C + 65));
+            else if (cp >= 0x1D4B6 && cp <= 0x1D4CF) // MATHEMATICAL SCRIPT SMALL A-Z
+                sb.append((char) (cp - 0x1D4B6 + 97));
+            else if (cp >= 0x1D4D0 && cp <= 0x1D4E9) // MATHEMATICAL BOLD SCRIPT CAPITAL A-Z
+                sb.append((char) (cp - 0x1D4D0 + 65));
+            else if (cp >= 0x1D4EA && cp <= 0x1D4FF) // MATHEMATICAL BOLD SCRIPT SMALL A-Z
+                sb.append((char) (cp - 0x1D4EA + 97));
+            else
+                sb.appendCodePoint(cp);
+
+            k += Character.charCount(cp);
+        }
+        return sb.toString();
+    }
+
     // Files
 
     static {

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

@@ -2796,7 +2796,8 @@ public class MessageHelper {
                             }
                         if (quote)
                             personal = "\"" + personal + "\"";
-                    }
+                    } else
+                        personal = Helper.transformMathematical(personal);
 
                     if (format == AddressFormat.NAME_EMAIL && !TextUtils.isEmpty(email))
                         formatted.add(personal + " <" + email + ">");