2 files changed, 32 insertions, 0 deletions
diff --git a/src/ScintillaBase.cxx b/src/ScintillaBase.cxx
index a95df76ae..e19f75d36 100644
--- a/src/ScintillaBase.cxx
+++ b/src/ScintillaBase.cxx
@@ -213,6 +213,30 @@ void ScintillaBase::ListNotify(ListBoxEvent *plbe) {
 	}
 }
 
+void ScintillaBase::MoveImeCarets(Sci::Position offset) noexcept {
+	// Move carets relatively by bytes.
+	for (size_t r = 0; r < sel.Count(); r++) {
+		const Sci::Position positionInsert = sel.Range(r).Start().Position();
+		sel.Range(r) = SelectionRange(positionInsert + offset);
+	}
+}
+
+void ScintillaBase::DrawImeIndicator(int indicator, Sci::Position len) {
+	// Emulate the visual style of IME characters with indicators.
+	// Draw an indicator on the character before caret by the character bytes of len
+	// so it should be called after InsertCharacter().
+	// It does not affect caret positions.
+	const IndicatorNumbers ind = static_cast<IndicatorNumbers>(indicator);
+	if (ind < IndicatorNumbers::Container || ind > IndicatorNumbers::Max) {
+		return;
+	}
+	pdoc->DecorationSetCurrentIndicator(indicator);
+	for (size_t r = 0; r < sel.Count(); r++) {
+		const Sci::Position positionInsert = sel.Range(r).Start().Position();
+		pdoc->DecorationFillRange(positionInsert - len, 1, len);
+	}
+}
+
 void ScintillaBase::AutoCompleteInsert(Sci::Position startPos, Sci::Position removeLen, std::string_view text) {
 	UndoGroup ug(pdoc);
 	if (multiAutoCMode == MultiAutoComplete::Once) {
diff --git a/src/ScintillaBase.h b/src/ScintillaBase.h
index bfeb5a3d9..d3a6e1ad6 100644
--- a/src/ScintillaBase.h
+++ b/src/ScintillaBase.h
@@ -14,6 +14,11 @@ namespace Scintilla::Internal {
 // blue, with different patterns.
 constexpr ColourRGBA colourIME(0x0, 0x0, 0xffU);
 
+constexpr int IndicatorInput = static_cast<int>(Scintilla::IndicatorNumbers::Ime);
+constexpr int IndicatorTarget = IndicatorInput + 1;
+constexpr int IndicatorConverted = IndicatorInput + 2;
+constexpr int IndicatorUnknown = IndicatorInput + 3;
+
 class LexState;
 /**
  */
@@ -61,6 +66,9 @@ protected:
 	void CancelModes() override;
 	int KeyCommand(Scintilla::Message iMessage) override;
 
+	void MoveImeCarets(Sci::Position offset) noexcept;
+	void DrawImeIndicator(int indicator, Sci::Position len);
+
 	void AutoCompleteInsert(Sci::Position startPos, Sci::Position removeLen, std::string_view text);
 	void AutoCompleteStart(Sci::Position lenEntered, const char *list);
 	void AutoCompleteCancel();