Merge remote branch 'qt-mainline/4.8'

17 files changed, 71 insertions, 116 deletions

diff --git a/src/gui/kernel/qkeysequence.cpp b/src/gui/kernel/qkeysequence.cpp
index 5fc72d4..469973f 100644
--- a/src/gui/kernel/qkeysequence.cpp
+++ b/src/gui/kernel/qkeysequence.cpp
@@ -1381,11 +1381,11 @@ QString QKeySequencePrivate::encodeString(int key, QKeySequence::SequenceFormat
     QString p;
 
     if (key && key < Qt::Key_Escape && key != Qt::Key_Space) {
-        if (key < 0x10000) {
-            p = QChar(key & 0xffff).toUpper();
+        if (!QChar::requiresSurrogates(key)) {
+            p = QChar(ushort(key)).toUpper();
         } else {
-            p = QChar((key-0x10000)/0x400+0xd800);
-            p += QChar((key-0x10000)%400+0xdc00);
+            p += QChar(QChar::highSurrogate(key));
+            p += QChar(QChar::lowSurrogate(key));
         }
     } else if (key >= Qt::Key_F1 && key <= Qt::Key_F35) {
             p = nativeText ? QShortcut::tr("F%1").arg(key - Qt::Key_F1 + 1)
@@ -1418,11 +1418,11 @@ NonSymbol:
             // Or else characters like Qt::Key_aring may not get displayed
             // (Really depends on you locale)
             if (!keyname[i].name) {
-                if (key < 0x10000) {
-                    p = QChar(key & 0xffff).toUpper();
+                if (!QChar::requiresSurrogates(key)) {
+                    p = QChar(ushort(key)).toUpper();
                 } else {
-                    p = QChar((key-0x10000)/0x400+0xd800);
-                    p += QChar((key-0x10000)%400+0xdc00);
+                    p += QChar(QChar::highSurrogate(key));
+                    p += QChar(QChar::lowSurrogate(key));
                 }
             }
         }
diff --git a/src/gui/styles/qcommonstyle.cpp b/src/gui/styles/qcommonstyle.cpp
index ad0e151..327bedf 100644
--- a/src/gui/styles/qcommonstyle.cpp
+++ b/src/gui/styles/qcommonstyle.cpp
@@ -837,14 +837,12 @@ static void drawArrow(const QStyle *style, const QStyleOptionToolButton *toolbut
 
 QSize QCommonStylePrivate::viewItemSize(const QStyleOptionViewItemV4 *option, int role) const
 {
-    Q_Q(const QCommonStyle);
-
     const QWidget *widget = option->widget;
     switch (role) {
     case Qt::CheckStateRole:
         if (option->features & QStyleOptionViewItemV2::HasCheckIndicator)
-            return QSize(q->pixelMetric(QStyle::PM_IndicatorWidth, option, widget),
-                         q->pixelMetric(QStyle::PM_IndicatorHeight, option, widget));
+            return QSize(proxyStyle->pixelMetric(QStyle::PM_IndicatorWidth, option, widget),
+                         proxyStyle->pixelMetric(QStyle::PM_IndicatorHeight, option, widget));
         break;
     case Qt::DisplayRole:
         if (option->features & QStyleOptionViewItemV2::HasDisplay) {
@@ -855,7 +853,7 @@ QSize QCommonStylePrivate::viewItemSize(const QStyleOptionViewItemV4 *option, in
             textLayout.setFont(option->font);
             textLayout.setText(option->text);
             const bool wrapText = option->features & QStyleOptionViewItemV2::WrapText;
-            const int textMargin = q->pixelMetric(QStyle::PM_FocusFrameHMargin, option, widget) + 1;
+            const int textMargin = proxyStyle->pixelMetric(QStyle::PM_FocusFrameHMargin, option, widget) + 1;
             QRect bounds = option->rect;
             switch (option->decorationPosition) {
             case QStyleOptionViewItem::Left:
@@ -919,9 +917,8 @@ static QSizeF viewItemTextLayout(QTextLayout &textLayout, int lineWidth)
 
 void QCommonStylePrivate::viewItemDrawText(QPainter *p, const QStyleOptionViewItemV4 *option, const QRect &rect) const
 {
-    Q_Q(const QCommonStyle);
     const QWidget *widget = option->widget;
-    const int textMargin = q->pixelMetric(QStyle::PM_FocusFrameHMargin, 0, widget) + 1;
+    const int textMargin = proxyStyle->pixelMetric(QStyle::PM_FocusFrameHMargin, 0, widget) + 1;
 
     QRect textRect = rect.adjusted(textMargin, 0, -textMargin, 0); // remove width padding
     const bool wrapText = option->features & QStyleOptionViewItemV2::WrapText;
@@ -999,7 +996,6 @@ void QCommonStylePrivate::viewItemDrawText(QPainter *p, const QStyleOptionViewIt
 void QCommonStylePrivate::viewItemLayout(const QStyleOptionViewItemV4 *opt,  QRect *checkRect,
                                          QRect *pixmapRect, QRect *textRect, bool sizehint) const
 {
-    Q_Q(const QCommonStyle);
     Q_ASSERT(checkRect && pixmapRect && textRect);
     *pixmapRect = QRect(QPoint(0, 0), viewItemSize(opt, Qt::DecorationRole));
     *textRect = QRect(QPoint(0, 0), viewItemSize(opt, Qt::DisplayRole));
@@ -1009,9 +1005,9 @@ void QCommonStylePrivate::viewItemLayout(const QStyleOptionViewItemV4 *opt,  QRe
     const bool hasCheck = checkRect->isValid();
     const bool hasPixmap = pixmapRect->isValid();
     const bool hasText = textRect->isValid();
-    const int textMargin = hasText ? q->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, widget) + 1 : 0;
-    const int pixmapMargin = hasPixmap ? q->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, widget) + 1 : 0;
-    const int checkMargin = hasCheck ? q->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, widget) + 1 : 0;
+    const int textMargin = hasText ? proxyStyle->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, widget) + 1 : 0;
+    const int pixmapMargin = hasPixmap ? proxyStyle->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, widget) + 1 : 0;
+    const int checkMargin = hasCheck ? proxyStyle->pixelMetric(QStyle::PM_FocusFrameHMargin, opt, widget) + 1 : 0;
     int x = opt->rect.left();
     int y = opt->rect.top();
     int w, h;
diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index 7056861..c9b672b 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -1337,8 +1337,7 @@ bool QFontEngineMulti::stringToCMap(const QChar *str, int len,
 
     int glyph_pos = 0;
     for (int i = 0; i < len; ++i) {
-        bool surrogate = (str[i].unicode() >= 0xd800 && str[i].unicode() < 0xdc00 && i < len-1
-                          && str[i+1].unicode() >= 0xdc00 && str[i+1].unicode() < 0xe000);
+        bool surrogate = (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate());
 
         if (glyphs->glyphs[glyph_pos] == 0 && str[i].category() != QChar::Separator_Line) {
             QGlyphLayoutInstance tmp = glyphs->instance(glyph_pos);
diff --git a/src/gui/text/qfontengine_ft.cpp b/src/gui/text/qfontengine_ft.cpp
index e3ab655..e20aa25 100644
--- a/src/gui/text/qfontengine_ft.cpp
+++ b/src/gui/text/qfontengine_ft.cpp
@@ -1422,15 +1422,12 @@ void QFontEngineFT::getUnscaledGlyph(glyph_t glyph, QPainterPath *path, glyph_me
 
 static inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 bool QFontEngineFT::canRender(const QChar *string, int len)
diff --git a/src/gui/text/qfontengine_mac.mm b/src/gui/text/qfontengine_mac.mm
index 9d9eaed..6186b2f 100644
--- a/src/gui/text/qfontengine_mac.mm
+++ b/src/gui/text/qfontengine_mac.mm
@@ -257,10 +257,8 @@ static OSStatus atsuPostLayoutCallback(ATSULayoutOperationSelector selector, ATS
 #if !defined(QT_NO_DEBUG)
         int surrogates = 0;
         const QChar *str = item->string;
-        for (int i = item->from; i < item->from + item->length - 1; ++i) {
-            surrogates += (str[i].unicode() >= 0xd800 && str[i].unicode() < 0xdc00
-                           && str[i+1].unicode() >= 0xdc00 && str[i+1].unicode() < 0xe000);
-        }
+        for (int i = item->from; i < item->from + item->length - 1; ++i)
+            surrogates += (str[i].isHighSurrogate() && str[i+1].isLowSurrogate());
 #endif
         for (nextCharStop = item->from; nextCharStop < item->from + item->length; ++nextCharStop)
             if (item->charAttributes[nextCharStop].charStop)
@@ -328,10 +326,8 @@ static OSStatus atsuPostLayoutCallback(ATSULayoutOperationSelector selector, ATS
             if (charOffset < item->length - 1) {
                 QChar current = item->string[item->from + charOffset];
                 QChar next = item->string[item->from + charOffset + 1];
-                if (current.unicode() >= 0xd800 && current.unicode() < 0xdc00
-                    && next.unicode() >= 0xdc00 && next.unicode() < 0xe000) {
+                if (current.isHighSurrogate() && next.isLowSurrogate())
                     item->log_clusters[charOffset + 1] = currentClusterGlyph;
-                }
             }
         }
     }
@@ -738,15 +734,12 @@ QFontEngineMac::~QFontEngineMac()
 
 static inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 // Not used directly for shaping, only used to calculate m_averageCharWidth
diff --git a/src/gui/text/qfontengine_qpa.cpp b/src/gui/text/qfontengine_qpa.cpp
index cb1e7d6..c829c2f 100644
--- a/src/gui/text/qfontengine_qpa.cpp
+++ b/src/gui/text/qfontengine_qpa.cpp
@@ -226,15 +226,12 @@ QVariant QFontEngineQPA::extractHeaderField(const uchar *data, HeaderTag request
 
 static inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 QFontEngineQPA::QFontEngineQPA(const QFontDef &def, const QByteArray &data)
diff --git a/src/gui/text/qfontengine_qpf.cpp b/src/gui/text/qfontengine_qpf.cpp
index 30a1623..3db5ce1 100644
--- a/src/gui/text/qfontengine_qpf.cpp
+++ b/src/gui/text/qfontengine_qpf.cpp
@@ -278,15 +278,12 @@ QList<QByteArray> QFontEngineQPF::cleanUpAfterClientCrash(const QList<int> &cras
 
 static inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 #ifdef QT_FONTS_ARE_RESOURCES
 QFontEngineQPF::QFontEngineQPF(const QFontDef &def, const uchar *bytes, int size)
diff --git a/src/gui/text/qfontengine_qws.cpp b/src/gui/text/qfontengine_qws.cpp
index 237842b..ade283f 100644
--- a/src/gui/text/qfontengine_qws.cpp
+++ b/src/gui/text/qfontengine_qws.cpp
@@ -83,15 +83,12 @@ QT_BEGIN_NAMESPACE
 
 static inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 #define FM_SMOOTH 1
diff --git a/src/gui/text/qfontengine_s60.cpp b/src/gui/text/qfontengine_s60.cpp
index b0824cb..203b6e1 100644
--- a/src/gui/text/qfontengine_s60.cpp
+++ b/src/gui/text/qfontengine_s60.cpp
@@ -233,15 +233,12 @@ bool QSymbianTypeFaceExtras::symbianFontTableApiAvailable()
 // duplicated from qfontengine_xyz.cpp
 static inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 extern QString qt_symbian_fontNameWithAppFontMarker(const QString &fontName); // qfontdatabase_s60.cpp
diff --git a/src/gui/text/qfontengine_win.cpp b/src/gui/text/qfontengine_win.cpp
index aef2145..fc11387 100644
--- a/src/gui/text/qfontengine_win.cpp
+++ b/src/gui/text/qfontengine_win.cpp
@@ -224,15 +224,12 @@ void QFontEngineWin::getCMap()
 
 inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4(ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 int QFontEngineWin::getGlyphIndexes(const QChar *str, int numChars, QGlyphLayout *glyphs, bool mirrored) const
diff --git a/src/gui/text/qfontengine_x11.cpp b/src/gui/text/qfontengine_x11.cpp
index 490866c..6e87f4c 100644
--- a/src/gui/text/qfontengine_x11.cpp
+++ b/src/gui/text/qfontengine_x11.cpp
@@ -358,9 +358,7 @@ bool QFontEngineXLFD::stringToCMap(const QChar *s, int len, QGlyphLayout *glyphs
     QVarLengthArray<ushort> _s(len);
     QChar *str = (QChar *)_s.data();
     for (int i = 0; i < len; ++i) {
-        if (i < len - 1
-            && s[i].unicode() >= 0xd800 && s[i].unicode() < 0xdc00
-            && s[i+1].unicode() >= 0xdc00 && s[i].unicode() < 0xe000) {
+        if (s[i].isHighSurrogate() && i < len-1 && s[i+1].isLowSurrogate()) {
             *str = QChar();
             ++i;
         } else {
diff --git a/src/gui/text/qfontenginedirectwrite.cpp b/src/gui/text/qfontenginedirectwrite.cpp
index d693273..5bac117 100644
--- a/src/gui/text/qfontenginedirectwrite.cpp
+++ b/src/gui/text/qfontenginedirectwrite.cpp
@@ -269,15 +269,12 @@ QFixed QFontEngineDirectWrite::emSquareSize() const
 
 inline unsigned int getChar(const QChar *str, int &i, const int len)
 {
-    unsigned int uc = str[i].unicode();
-    if (uc >= 0xd800 && uc < 0xdc00 && i < len-1) {
-        uint low = str[i+1].unicode();
-       if (low >= 0xdc00 && low < 0xe000) {
-            uc = (uc - 0xd800)*0x400 + (low - 0xdc00) + 0x10000;
-            ++i;
-        }
+    uint ucs4 = str[i].unicode();
+    if (str[i].isHighSurrogate() && i < len-1 && str[i+1].isLowSurrogate()) {
+        ++i;
+        ucs4 = QChar::surrogateToUcs4( ucs4, str[i].unicode());
     }
-    return uc;
+    return ucs4;
 }
 
 bool QFontEngineDirectWrite::stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs,
diff --git a/src/gui/text/qtextcontrol.cpp b/src/gui/text/qtextcontrol.cpp
index bde2c34..aeeef85 100644
--- a/src/gui/text/qtextcontrol.cpp
+++ b/src/gui/text/qtextcontrol.cpp
@@ -1638,16 +1638,13 @@ void QTextControlPrivate::mouseMoveEvent(QEvent *e, Qt::MouseButton button, cons
         return;
     }
 
-    if (!mousePressed)
-        return;
-
     const qreal mouseX = qreal(mousePos.x());
 
     int newCursorPos = q->hitTest(mousePos, Qt::FuzzyHit);
     if (newCursorPos == -1)
         return;
 
-    if (wordSelectionEnabled && !selectedWordOnDoubleClick.hasSelection()) {
+    if (mousePressed && wordSelectionEnabled && !selectedWordOnDoubleClick.hasSelection()) {
         selectedWordOnDoubleClick = cursor;
         selectedWordOnDoubleClick.select(QTextCursor::WordUnderCursor);
     }
@@ -1656,7 +1653,7 @@ void QTextControlPrivate::mouseMoveEvent(QEvent *e, Qt::MouseButton button, cons
         extendBlockwiseSelection(newCursorPos);
     else if (selectedWordOnDoubleClick.hasSelection())
         extendWordwiseSelection(newCursorPos, mouseX);
-    else
+    else if (mousePressed)
         setCursorPosition(newCursorPos, QTextCursor::KeepAnchor);
 
     if (interactionFlags & Qt::TextEditable) {
diff --git a/src/gui/text/qtextcursor.cpp b/src/gui/text/qtextcursor.cpp
index 7e7ca6c..acef9fa 100644
--- a/src/gui/text/qtextcursor.cpp
+++ b/src/gui/text/qtextcursor.cpp
@@ -1511,11 +1511,11 @@ void QTextCursor::deletePreviousChar()
     const QTextFragmentData * const frag = fragIt.value();
     int fpos = fragIt.position();
     QChar uc = d->priv->buffer().at(d->anchor - fpos + frag->stringPosition);
-    if (d->anchor > fpos && uc.unicode() >= 0xdc00 && uc.unicode() < 0xe000) {
+    if (d->anchor > fpos && uc.isLowSurrogate()) {
         // second half of a surrogate, check if we have the first half as well,
         // if yes delete both at once
         uc = d->priv->buffer().at(d->anchor - 1 - fpos + frag->stringPosition);
-        if (uc.unicode() >= 0xd800 && uc.unicode() < 0xdc00)
+        if (uc.isHighSurrogate())
             --d->anchor;
     }
 
diff --git a/src/gui/text/qtextengine.cpp b/src/gui/text/qtextengine.cpp
index a1b0cb0..2fc1dbd 100644
--- a/src/gui/text/qtextengine.cpp
+++ b/src/gui/text/qtextengine.cpp
@@ -993,8 +993,7 @@ static void heuristicSetGlyphAttributes(const QChar *uc, int length, QGlyphLayou
 
     int glyph_pos = 0;
     for (int i = 0; i < length; i++) {
-        if (uc[i].unicode() >= 0xd800 && uc[i].unicode() < 0xdc00 && i < length-1
-            && uc[i+1].unicode() >= 0xdc00 && uc[i+1].unicode() < 0xe000) {
+        if (uc[i].isHighSurrogate() && i < length-1 && uc[i+1].isLowSurrogate()) {
             logClusters[i] = glyph_pos;
             logClusters[++i] = glyph_pos;
         } else {
diff --git a/src/gui/text/qtexthtmlparser.cpp b/src/gui/text/qtexthtmlparser.cpp
index 5b60dfa..d130c61 100644
--- a/src/gui/text/qtexthtmlparser.cpp
+++ b/src/gui/text/qtexthtmlparser.cpp
@@ -820,15 +820,11 @@ QString QTextHtmlParser::parseEntity()
             if (uc >= 0x80 && uc < 0x80 + (sizeof(windowsLatin1ExtendedCharacters)/sizeof(windowsLatin1ExtendedCharacters[0])))
                 uc = windowsLatin1ExtendedCharacters[uc - 0x80];
             QString str;
-            if (uc > 0xffff) {
-                // surrogate pair
-                uc -= 0x10000;
-                ushort high = uc/0x400 + 0xd800;
-                ushort low = uc%0x400 + 0xdc00;
-                str.append(QChar(high));
-                str.append(QChar(low));
+            if (QChar::requiresSurrogates(uc)) {
+                str += QChar(QChar::highSurrogate(uc));
+                str += QChar(QChar::lowSurrogate(uc));
             } else {
-                str.append(QChar(uc));
+                str = QChar(uc);
             }
             return str;
         }
diff --git a/src/gui/widgets/qlinecontrol.cpp b/src/gui/widgets/qlinecontrol.cpp
index a8031e7..d58da37 100644
--- a/src/gui/widgets/qlinecontrol.cpp
+++ b/src/gui/widgets/qlinecontrol.cpp
@@ -198,12 +198,10 @@ void QLineControl::backspace()
             --m_cursor;
             if (m_maskData)
                 m_cursor = prevMaskBlank(m_cursor);
-            QChar uc = m_text.at(m_cursor);
-            if (m_cursor > 0 && uc.unicode() >= 0xdc00 && uc.unicode() < 0xe000) {
+            if (m_cursor > 0 && m_text.at(m_cursor).isLowSurrogate()) {
                 // second half of a surrogate, check if we have the first half as well,
                 // if yes delete both at once
-                uc = m_text.at(m_cursor - 1);
-                if (uc.unicode() >= 0xd800 && uc.unicode() < 0xdc00) {
+                if (m_text.at(m_cursor - 1).isHighSurrogate()) {
                     internalDelete(true);
                     --m_cursor;
                 }