Fix wrong preedit cursor position in Qt5

diff --git a/src/frontends/qt/GuiWorkArea.cpp b/src/frontends/qt/GuiWorkArea.cpp
index 3f7c34dc4d4e0702921d66953b39614c28ed93ac..558ab2311c5781f19b3709519c0bd3935667785e 100644 (file)
--- a/src/frontends/qt/GuiWorkArea.cpp
+++ b/src/frontends/qt/GuiWorkArea.cpp
@@ -1227,11 +1227,20 @@ void GuiWorkArea::Private::paintPreeditText(GuiPainter & pain)
        // get attributes of input method cursor.
        // cursor_pos : cursor position in preedit string.
        size_t cursor_pos = 0;
+
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
        bool cursor_is_visible = false;
+#endif
+
        for (auto const & attr : preedit_attr_) {
                if (attr.type == QInputMethodEvent::Cursor) {
+                       // in the completing mode, cursor_pos comes after the selected
+                       // snippet in Qt 5
+                       // in Qt 6, it comes at the head of the selected snippet
                        cursor_pos = size_t(attr.start);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
                        cursor_is_visible = attr.length != 0;
+#endif
                        break;
                }
        }
@@ -1244,21 +1253,34 @@ void GuiWorkArea::Private::paintPreeditText(GuiPainter & pain)
        size_t rStart = 0;
        // rLength : selected string length in IM.
        size_t rLength = 0;
-       if (cursor_pos < preedit_length) {
-               for (auto const & attr : preedit_attr_) {
-                       if (attr.type == QInputMethodEvent::TextFormat) {
-                               if (attr.start <= int(cursor_pos)
-                                       && int(cursor_pos) < attr.start + attr.length) {
-                                               rStart = size_t(attr.start);
-                                               rLength = size_t(attr.length);
-                                               if (!cursor_is_visible)
-                                                       cursor_pos += rLength;
-                                               break;
-                               }
+
+       for (auto const & attr : preedit_attr_) {
+               if (attr.type == QInputMethodEvent::TextFormat) {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+                       if (attr.start <= int(cursor_pos)
+                               && int(cursor_pos) < attr.start + attr.length) {
+                               // we are in the completing mode
+                               // (selecting the right chars from candidates)
+                               rStart = size_t(attr.start);
+                               rLength = size_t(attr.length);
+                               if (!cursor_is_visible)
+                                       cursor_pos += rLength;
+                               break;
+                       }
+#else
+                       if (attr.start < int(cursor_pos)
+                               && int(cursor_pos) <= attr.start + attr.length) {
+                               // we are in the completing mode
+                               // (selecting the right chars from candidates)
+                               rStart = size_t(attr.start);
+                               rLength = size_t(attr.length);
+                               break;
                        }
+#endif
                }
        }
-       else {
+       if (rStart == 0 && rLength == preedit_length) {
+               // we are in the composing mode (typing) as we didn't break above
                rStart = cursor_pos;
                rLength = 0;
        }
@@ -1290,9 +1312,9 @@ void GuiWorkArea::Private::paintPreeditText(GuiPainter & pain)
                        ps = Painter::preedit_selecting;
                }
 
-               if (pos == cursor_pos
-                       && (cursor_pos < rLength && rLength == preedit_length))
+               if (pos == cursor_pos && rLength == 0) {
                        ps = Painter::preedit_cursor;
+               }
 
                // draw one character and update cur_x.
                cur_x += pain.preeditText(cur_x, cur_y, typed_char, font, ps);