RTL fixes

app/src/main/java/org/thunderdog/challegram/U.java

@@ -2149,7 +2149,7 @@ public static float measureText (char[] in, int start, int end, @NonNull Paint p
       return 0;
     }
 
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+    if (Config.USE_TEXT_ADVANCE && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && !Strings.requiresBidi(in, start, end)) {
       /*
       getTextRunAdvances(char[] chars, int index, int count,
             int contextIndex, int contextCount, boolean isRtl, float[] advances,
@@ -2278,6 +2278,34 @@ private static float getRunAdvance (@NonNull CharSequence in, int start, int end
     }
   }*/
 
+  public static float measureTextRun (@Nullable CharSequence in, @NonNull Paint p, boolean isRtl) {
+    final int count;
+    if (in == null || (count = in.length()) == 0) {
+      return 0;
+    }
+
+    if (Config.USE_TEXT_ADVANCE && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+      return p.getRunAdvance(in, 0, count, 0, in.length(), isRtl, count);
+    }
+
+    return measureText(in, p);
+  }
+
+  public static float measureTextRun (@Nullable CharSequence in, int start, int end, @NonNull Paint p, boolean isRtl) {
+    final int count = end - start;
+
+    if (in == null || in.length() == 0 || count <= 0) {
+      return 0;
+    }
+
+    if (Config.USE_TEXT_ADVANCE && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+      return p.getRunAdvance(in, start, end, 0, in.length(), isRtl, end);
+    }
+
+    return measureText(in, start, end, p);
+  }
+
+  @Deprecated
   public static float measureText (@Nullable CharSequence in, int start, int end, @NonNull Paint p) {
     final int count = end - start;
 
@@ -2288,7 +2316,7 @@ public static float measureText (@Nullable CharSequence in, int start, int end,
     if (p == null)
       throw new IllegalArgumentException();
 
-    if (Config.USE_TEXT_ADVANCE && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && Strings.getTextDirection(in, start, end) != Strings.DIRECTION_RTL) {
+    if (Config.USE_TEXT_ADVANCE && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && !Strings.requiresBidi(in, start, end)) {
       return p.getRunAdvance(in, start, end, 0, in.length(), false, end);
     } else {
       float[] widths = pickWidths(count, true);

app/src/main/java/org/thunderdog/challegram/tool/Strings.java

@@ -88,6 +88,71 @@ public static boolean hostsEqual (String url1, String url2) {
     return false;
   }
 
+  public static boolean requiresBidi (CharSequence text, int start, int end) {
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+      // Source: android.icu.text.Bidi.requiresBidi
+      // but uses CharSequence instead of char[]
+
+      final int RTLMask = (1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_ARABIC_NUMBER);
+
+      for (int i = start; i < end; ++i) {
+        if (((1 << android.icu.lang.UCharacter.getDirection(text.charAt(i))) & RTLMask) != 0) {
+          return true;
+        }
+      }
+      return false;
+    } else {    // todo: test difference between UCharacter and Character
+      final int RTLMask = (1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT |
+        1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC |
+        1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING |
+        1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE |
+        1 << Character.DIRECTIONALITY_ARABIC_NUMBER);
+
+      for (int i = start; i < end; ++i) {
+        if (((1 << Character.getDirectionality(text.charAt(i))) & RTLMask) != 0) {
+          return true;
+        }
+      }
+      return false;
+    }
+  }
+
+  public static boolean requiresBidi (char[] text, int start, int end) {
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+      // Source: android.icu.text.Bidi.requiresBidi
+
+      final int RTLMask = (1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE |
+        1 << android.icu.lang.UCharacter.DIRECTIONALITY_ARABIC_NUMBER);
+
+      for (int i = start; i < end; ++i) {
+        if (((1 << android.icu.lang.UCharacter.getDirection(text[i])) & RTLMask) != 0) {
+          return true;
+        }
+      }
+      return false;
+    } else {
+      final int RTLMask = (1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT |
+        1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC |
+        1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING |
+        1 << Character.DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE |
+        1 << Character.DIRECTIONALITY_ARABIC_NUMBER);
+
+      for (int i = start; i < end; ++i) {
+        if (((1 << Character.getDirectionality(text[i])) & RTLMask) != 0) {
+          return true;
+        }
+      }
+      return false;
+    }
+  }
+
   public interface CharacterCounter {
     boolean accept (char c);
   }

app/src/main/java/org/thunderdog/challegram/ui/MessagesController.java

@@ -231,6 +231,7 @@
 import org.thunderdog.challegram.util.SenderPickerDelegate;
 import org.thunderdog.challegram.util.StringList;
 import org.thunderdog.challegram.util.Unlockable;
+import org.thunderdog.challegram.util.text.Text;
 import org.thunderdog.challegram.util.text.TextColorSets;
 import org.thunderdog.challegram.v.HeaderEditText;
 import org.thunderdog.challegram.v.MessagesLayoutManager;
@@ -400,6 +401,7 @@ public List<HapticMenuHelper.MenuItem> onCreateHapticMenu (View view) {
     }
     if (BuildConfig.DEBUG) {
       items.add(new HapticMenuHelper.MenuItem(R.id.btn_sendToast, "Show toast", R.drawable.baseline_warning_24));
+      items.add(new HapticMenuHelper.MenuItem(R.id.btn_debugLtrEmoji, "Send LTR emoji", R.drawable.baseline_warning_24));
     }
     if (canSelectSender()) {
       items.add(0, createHapticSenderItem(R.id.btn_openSendersMenu, chat.messageSenderId, false, false));
@@ -453,6 +455,8 @@ public boolean onHapticMenuItemClick (View view, View parentView, HapticMenuHelp
           send(modifiedSendOptions, true);
         }
       });
+    } else if (viewId == R.id.btn_debugLtrEmoji) {
+      pickDateOrProceed(Td.newSendOptions(), (sendOptions, disableMarkdown) -> send(new TdApi.InputMessageText(new TdApi.FormattedText(Text.bidiGenerateTestMessage(), new TdApi.TextEntity[0]), null, false), false, sendOptions, null));
     }
     return true;
   }