Implement replacement for IMEs which may help with actions like reconversion.

2 files changed, 15 insertions, 0 deletions

diff --git a/doc/ScintillaHistory.html b/doc/ScintillaHistory.html
index e84d43cb0..f60eb3933 100644
--- a/doc/ScintillaHistory.html
+++ b/doc/ScintillaHistory.html
@@ -601,6 +601,10 @@
 	On Qt, for IMEs, update micro focus when selection changes.
 	This may move the location of IME popups to align with the caret.
 	</li>
+	<li>
+	On Qt, implement replacement for IMEs which may help with actions like reconversion.
+	This is similar to delete-surrounding on GTK.
+	</li>
     </ul>
     <h3>
        <a href="https://www.scintilla.org/scintilla535.zip">Release 5.3.5</a>
diff --git a/qt/ScintillaEditBase/ScintillaEditBase.cpp b/qt/ScintillaEditBase/ScintillaEditBase.cpp
index b64070407..5072cd824 100644
--- a/qt/ScintillaEditBase/ScintillaEditBase.cpp
+++ b/qt/ScintillaEditBase/ScintillaEditBase.cpp
@@ -542,6 +542,17 @@ void ScintillaEditBase::inputMethodEvent(QInputMethodEvent *event)
 	sqt->view.imeCaretBlockOverride = false;
 	preeditPos = -1; // reset not to interrupt Qt::ImCursorRectangle.
 
+	const int rpLength = event->replacementLength();
+	if (rpLength != 0) {
+		// Qt has called setCommitString().
+		// Make room for the string to sit in.
+		const int rpStart = event->replacementStart();
+		const Scintilla::Position rpBase = sqt->CurrentPosition();
+		const Scintilla::Position start = sqt->pdoc->GetRelativePositionUTF16(rpBase, rpStart);
+		const Scintilla::Position end = sqt->pdoc->GetRelativePositionUTF16(start, rpLength);
+		sqt->pdoc->DeleteChars(start, end - start);
+	}
+
 	if (!event->commitString().isEmpty()) {
 		const QString &commitStr = event->commitString();
 		const int commitStrLen = commitStr.length();