Merge remote-tracking branch 'origin/5.7' into dev

Conflicts:
	src/corelib/kernel/qobject.cpp
	src/gui/painting/qpaintengine_raster.cpp

Change-Id: I74e1779832f43d033708dcfd6b666c7b4f0111fb

9 files changed, 165 insertions, 129 deletions

diff --git a/src/widgets/styles/qcommonstyle.cpp b/src/widgets/styles/qcommonstyle.cpp
index 63024360ae..437becbf70 100644
--- a/src/widgets/styles/qcommonstyle.cpp
+++ b/src/widgets/styles/qcommonstyle.cpp
@@ -803,10 +803,8 @@ static void drawArrow(const QStyle *style, const QStyleOptionToolButton *toolbut
     default:
         return;
     }
-    QStyleOption arrowOpt;
+    QStyleOption arrowOpt = *toolbutton;
     arrowOpt.rect = rect;
-    arrowOpt.palette = toolbutton->palette;
-    arrowOpt.state = toolbutton->state;
     style->drawPrimitive(pe, &arrowOpt, painter, widget);
 }
 #endif // QT_NO_TOOLBUTTON
@@ -3345,8 +3343,7 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 mflags |= State_Sunken;
             }
 
-            QStyleOption tool(0);
-            tool.palette = toolbutton->palette;
+            QStyleOption tool = *toolbutton;
             if (toolbutton->subControls & SC_ToolButton) {
                 if (bflags & (State_Sunken | State_On | State_Raised)) {
                     tool.rect = button;
@@ -3415,8 +3412,7 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
             bool down = false;
             QPixmap pm;
 
-            QStyleOption tool(0);
-            tool.palette = tb->palette;
+            QStyleOption tool = *tb;
             if (tb->subControls & SC_TitleBarCloseButton && tb->titleBarFlags & Qt::WindowSystemMenuHint) {
                 ir = proxy()->subControlRect(CC_TitleBar, tb, SC_TitleBarCloseButton, widget);
                 down = tb->activeSubControls & SC_TitleBarCloseButton && (opt->state & State_Sunken);
diff --git a/src/widgets/styles/qfusionstyle.cpp b/src/widgets/styles/qfusionstyle.cpp
index b15b9701d9..5b6e47e2c6 100644
--- a/src/widgets/styles/qfusionstyle.cpp
+++ b/src/widgets/styles/qfusionstyle.cpp
@@ -1649,7 +1649,7 @@ void QFusionStyle::drawControl(ControlElement element, const QStyleOption *optio
 
             QRect textRect(xpos, y + windowsItemVMargin, w - xm - windowsRightBorder - tab + 1, h - 2 * windowsItemVMargin);
             QRect vTextRect = visualRect(opt->direction, menuitem->rect, textRect);
-            QString s = menuitem->text;
+            QStringRef s(&menuitem->text);
             if (!s.isEmpty()) {                     // draw text
                 p->save();
                 int t = s.indexOf(QLatin1Char('\t'));
@@ -1660,12 +1660,13 @@ void QFusionStyle::drawControl(ControlElement element, const QStyleOption *optio
                 if (t >= 0) {
                     QRect vShortcutRect = visualRect(opt->direction, menuitem->rect,
                                                      QRect(textRect.topRight(), QPoint(menuitem->rect.right(), textRect.bottom())));
+                    const QString textToDraw = s.mid(t + 1).toString();
                     if (dis && !act && proxy()->styleHint(SH_EtchDisabledText, option, widget)) {
                         p->setPen(menuitem->palette.light().color());
-                        p->drawText(vShortcutRect.adjusted(1, 1, 1, 1), text_flags, s.mid(t + 1));
+                        p->drawText(vShortcutRect.adjusted(1, 1, 1, 1), text_flags, textToDraw);
                         p->setPen(discol);
                     }
-                    p->drawText(vShortcutRect, text_flags, s.mid(t + 1));
+                    p->drawText(vShortcutRect, text_flags, textToDraw);
                     s = s.left(t);
                 }
                 QFont font = menuitem->font;
@@ -1680,12 +1681,13 @@ void QFusionStyle::drawControl(ControlElement element, const QStyleOption *optio
                     font.setBold(true);
 
                 p->setFont(font);
+                const QString textToDraw = s.left(t).toString();
                 if (dis && !act && proxy()->styleHint(SH_EtchDisabledText, option, widget)) {
                     p->setPen(menuitem->palette.light().color());
-                    p->drawText(vTextRect.adjusted(1, 1, 1, 1), text_flags, s.left(t));
+                    p->drawText(vTextRect.adjusted(1, 1, 1, 1), text_flags, textToDraw);
                     p->setPen(discol);
                 }
-                p->drawText(vTextRect, text_flags, s.left(t));
+                p->drawText(vTextRect, text_flags, textToDraw);
                 p->restore();
             }
 
diff --git a/src/widgets/styles/qstyleanimation.cpp b/src/widgets/styles/qstyleanimation.cpp
index 67e2ee3225..0b8e32be19 100644
--- a/src/widgets/styles/qstyleanimation.cpp
+++ b/src/widgets/styles/qstyleanimation.cpp
@@ -273,6 +273,7 @@ static QImage blendedImage(const QImage &start, const QImage &end, float alpha)
     case 32:
         {
             blended = QImage(sw, sh, start.format());
+            blended.setDevicePixelRatio(start.devicePixelRatio());
             uchar *mixed_data = blended.bits();
             const uchar *back_data = start.bits();
             const uchar *front_data = end.bits();
diff --git a/src/widgets/styles/qstylesheetstyle.cpp b/src/widgets/styles/qstylesheetstyle.cpp
index 053820e459..44555c3058 100644
--- a/src/widgets/styles/qstylesheetstyle.cpp
+++ b/src/widgets/styles/qstylesheetstyle.cpp
@@ -3679,7 +3679,7 @@ void QStyleSheetStyle::drawControl(ControlElement ce, const QStyleOption *opt, Q
 
                 QRect textRect = subRule.contentsRect(opt->rect);
                 textRect.setWidth(textRect.width() - mi.tabWidth);
-                QString s = mi.text;
+                QStringRef s(&mi.text);
                 p->setPen(mi.palette.buttonText().color());
                 if (!s.isEmpty()) {
                     int text_flags = Qt::AlignLeft | Qt::AlignVCenter | Qt::TextShowMnemonic | Qt::TextDontClip | Qt::TextSingleLine;
@@ -3689,10 +3689,10 @@ void QStyleSheetStyle::drawControl(ControlElement ce, const QStyleOption *opt, Q
                     if (t >= 0) {
                         QRect vShortcutRect = visualRect(opt->direction, mi.rect,
                             QRect(textRect.topRight(), QPoint(mi.rect.right(), textRect.bottom())));
-                        p->drawText(vShortcutRect, text_flags, s.mid(t + 1));
+                        p->drawText(vShortcutRect, text_flags, s.mid(t + 1).toString());
                         s = s.left(t);
                     }
-                    p->drawText(textRect, text_flags, s.left(t));
+                    p->drawText(textRect, text_flags, s.left(t).toString());
                 }
 
                 if (mi.menuItemType == QStyleOptionMenuItem::SubMenu) {// draw sub menu arrow
diff --git a/src/widgets/styles/qwindowsstyle.cpp b/src/widgets/styles/qwindowsstyle.cpp
index fa1ba80402..e0e9d0f6f1 100644
--- a/src/widgets/styles/qwindowsstyle.cpp
+++ b/src/widgets/styles/qwindowsstyle.cpp
@@ -71,6 +71,8 @@
 #include <private/qstylehelper_p.h>
 #include <private/qstyleanimation_p.h>
 
+#include <algorithm>
+
 QT_BEGIN_NAMESPACE
 
 #if defined(Q_OS_WIN)
@@ -117,8 +119,6 @@ enum QSliderDirection { SlUp, SlDown, SlLeft, SlRight };
     \internal
 */
 
-int QWindowsStylePrivate::m_appDevicePixelRatio = 0;
-
 QWindowsStylePrivate::QWindowsStylePrivate()
     : alt_down(false), menuBarTimer(0)
 {
@@ -131,11 +131,9 @@ QWindowsStylePrivate::QWindowsStylePrivate()
 #endif
 }
 
-int QWindowsStylePrivate::appDevicePixelRatio()
+qreal QWindowsStylePrivate::appDevicePixelRatio()
 {
-    if (!QWindowsStylePrivate::m_appDevicePixelRatio)
-        QWindowsStylePrivate::m_appDevicePixelRatio = qRound(qApp->devicePixelRatio());
-    return QWindowsStylePrivate::m_appDevicePixelRatio;
+    return qApp->devicePixelRatio();
 }
 
 // Returns \c true if the toplevel parent of \a widget has seen the Alt-key
@@ -163,12 +161,11 @@ bool QWindowsStyle::eventFilter(QObject *o, QEvent *e)
 
             // Alt has been pressed - find all widgets that care
             QList<QWidget *> l = widget->findChildren<QWidget *>();
-            for (int pos=0 ; pos < l.size() ; ++pos) {
-                QWidget *w = l.at(pos);
-                if (w->isWindow() || !w->isVisible() ||
-                    w->style()->styleHint(SH_UnderlineShortcut, 0, w))
-                    l.removeAt(pos);
-            }
+            auto ignorable = [](QWidget *w) {
+                return w->isWindow() || !w->isVisible()
+                        || w->style()->styleHint(SH_UnderlineShortcut, 0, w);
+            };
+            l.erase(std::remove_if(l.begin(), l.end(), ignorable), l.end());
             // Update states before repainting
             d->seenAlt.append(widget);
             d->alt_down = true;
@@ -397,7 +394,7 @@ int QWindowsStyle::pixelMetric(PixelMetric pm, const QStyleOption *opt, const QW
 {
     int ret = QWindowsStylePrivate::pixelMetricFromSystemDp(pm, opt, widget);
     if (ret != QWindowsStylePrivate::InvalidMetric)
-        return ret / QWindowsStylePrivate::devicePixelRatio(widget);
+        return qRound(qreal(ret) / QWindowsStylePrivate::devicePixelRatio(widget));
 
     ret = QWindowsStylePrivate::fixedPixelMetric(pm);
     if (ret != QWindowsStylePrivate::InvalidMetric)
@@ -1183,7 +1180,7 @@ void QWindowsStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPai
             QRect textRect(xpos, y + QWindowsStylePrivate::windowsItemVMargin,
                            w - xm - QWindowsStylePrivate::windowsRightBorder - tab + 1, h - 2 * QWindowsStylePrivate::windowsItemVMargin);
             QRect vTextRect = visualRect(opt->direction, menuitem->rect, textRect);
-            QString s = menuitem->text;
+            QStringRef s(&menuitem->text);
             if (!s.isEmpty()) {                     // draw text
                 p->save();
                 int t = s.indexOf(QLatin1Char('\t'));
@@ -1194,24 +1191,26 @@ void QWindowsStyle::drawControl(ControlElement ce, const QStyleOption *opt, QPai
                 if (t >= 0) {
                     QRect vShortcutRect = visualRect(opt->direction, menuitem->rect,
                         QRect(textRect.topRight(), QPoint(menuitem->rect.right(), textRect.bottom())));
+                    const QString textToDraw = s.mid(t + 1).toString();
                     if (dis && !act && proxy()->styleHint(SH_EtchDisabledText, opt, widget)) {
                         p->setPen(menuitem->palette.light().color());
-                        p->drawText(vShortcutRect.adjusted(1,1,1,1), text_flags, s.mid(t + 1));
+                        p->drawText(vShortcutRect.adjusted(1, 1, 1, 1), text_flags, textToDraw);
                         p->setPen(discol);
                     }
-                    p->drawText(vShortcutRect, text_flags, s.mid(t + 1));
+                    p->drawText(vShortcutRect, text_flags, textToDraw);
                     s = s.left(t);
                 }
                 QFont font = menuitem->font;
                 if (menuitem->menuItemType == QStyleOptionMenuItem::DefaultItem)
                     font.setBold(true);
                 p->setFont(font);
+                const QString textToDraw = s.left(t).toString();
                 if (dis && !act && proxy()->styleHint(SH_EtchDisabledText, opt, widget)) {
                     p->setPen(menuitem->palette.light().color());
-                    p->drawText(vTextRect.adjusted(1,1,1,1), text_flags, s.left(t));
+                    p->drawText(vTextRect.adjusted(1, 1, 1, 1), text_flags, textToDraw);
                     p->setPen(discol);
                 }
-                p->drawText(vTextRect, text_flags, s.left(t));
+                p->drawText(vTextRect, text_flags, textToDraw);
                 p->restore();
             }
             if (menuitem->menuItemType == QStyleOptionMenuItem::SubMenu) {// draw sub menu arrow
diff --git a/src/widgets/styles/qwindowsstyle_p_p.h b/src/widgets/styles/qwindowsstyle_p_p.h
index 503cd2ca26..e6c44f401e 100644
--- a/src/widgets/styles/qwindowsstyle_p_p.h
+++ b/src/widgets/styles/qwindowsstyle_p_p.h
@@ -70,8 +70,8 @@ public:
     QWindowsStylePrivate();
     static int pixelMetricFromSystemDp(QStyle::PixelMetric pm, const QStyleOption *option = 0, const QWidget *widget = 0);
     static int fixedPixelMetric(QStyle::PixelMetric pm);
-    static int devicePixelRatio(const QWidget *widget = 0)
-        { return widget ? int(widget->devicePixelRatioF()) : QWindowsStylePrivate::appDevicePixelRatio(); }
+    static qreal devicePixelRatio(const QWidget *widget = 0)
+        { return widget ? widget->devicePixelRatioF() : QWindowsStylePrivate::appDevicePixelRatio(); }
 
     bool hasSeenAlt(const QWidget *widget) const;
     bool altDown() const { return alt_down; }
@@ -96,8 +96,7 @@ public:
     };
 
 private:
-    static int appDevicePixelRatio();
-    static int m_appDevicePixelRatio;
+    static qreal appDevicePixelRatio();
 };
 
 QT_END_NAMESPACE
diff --git a/src/widgets/styles/qwindowsvistastyle.cpp b/src/widgets/styles/qwindowsvistastyle.cpp
index a48417677a..2b2b919818 100644
--- a/src/widgets/styles/qwindowsvistastyle.cpp
+++ b/src/widgets/styles/qwindowsvistastyle.cpp
@@ -108,6 +108,15 @@ bool canAnimate(const QStyleOption *option) {
             && !option->styleObject->property("_q_no_animation").toBool();
 }
 
+static inline QImage createAnimationBuffer(const QStyleOption *option, const QWidget *widget)
+{
+    const int devicePixelRatio = widget ? widget->devicePixelRatio() : 1;
+    QImage result(option->rect.size() * devicePixelRatio, QImage::Format_ARGB32_Premultiplied);
+    result.setDevicePixelRatio(devicePixelRatio);
+    result.fill(0);
+    return result;
+}
+
 /* \internal
     Used by animations to clone a styleoption and shift its offset
 */
@@ -320,12 +329,10 @@ void QWindowsVistaStyle::drawPrimitive(PrimitiveElement element, const QStyleOpt
 
                     // We create separate images for the initial and final transition states and store them in the
                     // Transition object.
-                    QImage startImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                    startImage.fill(0);
+                    QImage startImage = createAnimationBuffer(option, widget);
                     QPainter startPainter(&startImage);
 
-                    QImage endImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                    endImage.fill(0);
+                    QImage endImage = createAnimationBuffer(option, widget);
                     QPainter endPainter(&endImage);
 
                     // If we have a running animation on the widget already, we will use that to paint the initial
@@ -425,8 +432,8 @@ void QWindowsVistaStyle::drawPrimitive(PrimitiveElement element, const QStyleOpt
                 XPThemeData themeSize = theme;
                 themeSize.partId = TVP_HOTGLYPH;
                 themeSize.stateId = GLPS_OPENED;
-                const QSize size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-                decoration_size = qMax(size.width(), size.height());
+                const QSizeF size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                decoration_size = qRound(qMax(size.width(), size.height()));
             }
             int mid_h = option->rect.x() + option->rect.width() / 2;
             int mid_v = option->rect.y() + option->rect.height() / 2;
@@ -873,8 +880,7 @@ void QWindowsVistaStyle::drawControl(ControlElement element, const QStyleOption
                 QStyleOption *styleOption = clonedAnimationStyleOption(option);
                 styleOption->state = (QStyle::State)oldState;
 
-                QImage startImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                startImage.fill(0);
+                QImage startImage = createAnimationBuffer(option, widget);
                 QPainter startPainter(&startImage);
 
                 // Use current state of existing animation if already one is running
@@ -886,8 +892,7 @@ void QWindowsVistaStyle::drawControl(ControlElement element, const QStyleOption
                 }
 
                 t->setStartImage(startImage);
-                QImage endImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                endImage.fill(0);
+                QImage endImage = createAnimationBuffer(option, widget);
                 QPainter endPainter(&endImage);
                 styleOption->state = option->state;
                 proxy()->drawControl(element, styleOption, &endPainter, widget);
@@ -949,10 +954,8 @@ void QWindowsVistaStyle::drawControl(ControlElement element, const QStyleOption
                     QWindowsVistaAnimation *anim = qobject_cast<QWindowsVistaAnimation *>(d->animation(styleObject(option)));
 
                     if (!anim) {
-                        QImage startImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                        startImage.fill(0);
-                        QImage alternateImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                        alternateImage.fill(0);
+                        QImage startImage = createAnimationBuffer(option, widget);
+                        QImage alternateImage = createAnimationBuffer(option, widget);
 
                         QWindowsVistaPulse *pulse = new QWindowsVistaPulse(styleObject(option));
 
@@ -991,10 +994,10 @@ void QWindowsVistaStyle::drawControl(ControlElement element, const QStyleOption
                 XPThemeData theme(widget, 0, QWindowsXPStylePrivate::ToolBarTheme,
                                   TP_DROPDOWNBUTTON);
                 if (theme.isValid()) {
-                    const QSize size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                    const QSizeF size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
                     if (!size.isEmpty()) {
-                        mbiw = size.width();
-                        mbih = size.height();
+                        mbiw = qRound(size.width());
+                        mbih = qRound(size.height());
                     }
                 }
                 QRect ir = subElementRect(SE_PushButtonContents, option, 0);
@@ -1178,17 +1181,18 @@ void QWindowsVistaStyle::drawControl(ControlElement element, const QStyleOption
     case CE_MenuItem:
         if (const QStyleOptionMenuItem *menuitem = qstyleoption_cast<const QStyleOptionMenuItem *>(option)) {
             // windows always has a check column, regardless whether we have an icon or not
-            int checkcol = 25 / QWindowsXPStylePrivate::devicePixelRatio(widget);
-            const int gutterWidth = 3 / QWindowsXPStylePrivate::devicePixelRatio(widget);
+            const qreal devicePixelRatio = QWindowsXPStylePrivate::devicePixelRatio(widget);
+            int checkcol = qRound(qreal(25) / devicePixelRatio);
+            const int gutterWidth = qRound(qreal(3) / devicePixelRatio);
             {
                 XPThemeData theme(widget, 0, QWindowsXPStylePrivate::MenuTheme,
                                   MENU_POPUPCHECKBACKGROUND, MBI_HOT);
                 XPThemeData themeSize = theme;
                 themeSize.partId = MENU_POPUPCHECK;
                 themeSize.stateId = 0;
-                const QSize size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-                const QMargins margins = themeSize.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-                checkcol = qMax(menuitem->maxIconWidth, gutterWidth + size.width() + margins.left() + margins.right());
+                const QSizeF size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                const QMarginsF margins = themeSize.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                checkcol = qMax(menuitem->maxIconWidth, qRound(gutterWidth + size.width() + margins.left() + margins.right()));
             }
             QRect rect = option->rect;
 
@@ -1245,17 +1249,17 @@ void QWindowsVistaStyle::drawControl(ControlElement element, const QStyleOption
                 XPThemeData themeSize = theme;
                 themeSize.partId = MENU_POPUPCHECK;
                 themeSize.stateId = 0;
-                const QSize size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-                const QMargins margins = themeSize.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-                QRect checkRect(0, 0, size.width() + margins.left() + margins.right(),
-                                size.height() + margins.bottom() + margins.top());
+                const QSizeF size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                const QMarginsF margins = themeSize.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                QRect checkRect(0, 0, qRound(size.width() + margins.left() + margins.right()),
+                                qRound(size.height() + margins.bottom() + margins.top()));
                 checkRect.moveCenter(vCheckRect.center());
                 theme.rect = checkRect;
 
                 d->drawBackground(theme);
 
                 if (menuitem->icon.isNull()) {
-                    checkRect = QRect(QPoint(0, 0), size);
+                    checkRect = QRect(QPoint(0, 0), size.toSize());
                     checkRect.moveCenter(theme.rect.center());
                     theme.rect = checkRect;
 
@@ -1549,13 +1553,10 @@ void QWindowsVistaStyle::drawComplexControl(ComplexControl control, const QStyle
             }
 
             if (doTransition) {
-
-                QImage startImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                startImage.fill(0);
+                QImage startImage = createAnimationBuffer(option, widget);
                 QPainter startPainter(&startImage);
 
-                QImage endImage(option->rect.size(), QImage::Format_ARGB32_Premultiplied);
-                endImage.fill(0);
+                QImage endImage = createAnimationBuffer(option, widget);
                 QPainter endPainter(&endImage);
 
                 QWindowsVistaAnimation *anim = qobject_cast<QWindowsVistaAnimation *>(d->animation(styleObject));
@@ -1861,10 +1862,10 @@ QSize QWindowsVistaStyle::sizeFromContents(ContentsType type, const QStyleOption
             XPThemeData themeSize = theme;
             themeSize.partId = MENU_POPUPCHECK;
             themeSize.stateId = 0;
-            const QSize size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-            const QMargins margins = themeSize.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
-            minimumHeight = qMax(size.height() + margins.bottom() + margins.top(), sz.height());
-            sz.rwidth() += size.width() + margins.left() + margins.right();
+            const QSizeF size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+            const QMarginsF margins = themeSize.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+            minimumHeight = qMax(qRound(size.height() + margins.bottom() + margins.top()), sz.height());
+            sz.rwidth() += qRound(size.width() + margins.left() + margins.right());
         }
 
         if (const QStyleOptionMenuItem *menuitem = qstyleoption_cast<const QStyleOptionMenuItem *>(option)) {
@@ -1972,10 +1973,10 @@ QRect QWindowsVistaStyle::subElementRect(SubElement element, const QStyleOption
             int arrowWidth = 13;
             int arrowHeight = 5;
             if (theme.isValid()) {
-                const QSize size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                const QSizeF size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
                 if (!size.isEmpty()) {
-                    arrowWidth = size.width();
-                    arrowHeight = size.height();
+                    arrowWidth = qRound(size.width());
+                    arrowHeight = qRound(size.height());
                 }
             }
             if (option->state & State_Horizontal) {
@@ -2516,7 +2517,7 @@ QIcon QWindowsVistaStyle::standardIcon(StandardPixmap standardIcon,
                               QWindowsXPStylePrivate::ButtonTheme,
                               BP_COMMANDLINKGLYPH, CMDLGS_NORMAL);
             if (theme.isValid()) {
-                const QSize size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                const QSize size = (theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget)).toSize();
                 QIcon linkGlyph;
                 QPixmap pm(size);
                 pm.fill(Qt::transparent);
diff --git a/src/widgets/styles/qwindowsxpstyle.cpp b/src/widgets/styles/qwindowsxpstyle.cpp
index c3072303de..1f910d41cb 100644
--- a/src/widgets/styles/qwindowsxpstyle.cpp
+++ b/src/widgets/styles/qwindowsxpstyle.cpp
@@ -431,7 +431,7 @@ const QPixmap *QWindowsXPStylePrivate::tabBody(QWidget *widget)
 {
     if (!tabbody) {
         XPThemeData theme(0, 0, QWindowsXPStylePrivate::TabTheme, TABP_BODY);
-        const QSize size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+        const QSize size = (theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget)).toSize();
 
         tabbody = new QPixmap(size.width(), QApplication::desktop()->screenGeometry().height());
         QPainter painter(tabbody);
@@ -712,6 +712,19 @@ bool QWindowsXPStylePrivate::swapAlphaChannel(const QRect &rect, bool allPixels)
     return valueChange;
 }
 
+enum TransformType { SimpleTransform, HighDpiScalingTransform, ComplexTransform };
+
+static inline TransformType transformType(const QTransform &transform, qreal devicePixelRatio)
+{
+    if (transform.type() <= QTransform::TxTranslate)
+        return SimpleTransform;
+    if (transform.type() > QTransform::TxScale)
+        return ComplexTransform;
+    return qFuzzyCompare(transform.m11(), devicePixelRatio)
+        && qFuzzyCompare(transform.m22(), devicePixelRatio)
+        ? HighDpiScalingTransform : ComplexTransform;
+}
+
 /*! \internal
     Main theme drawing function.
     Determines the correct lowlevel drawing method depending on several
@@ -735,21 +748,22 @@ bool QWindowsXPStylePrivate::drawBackground(XPThemeData &themeData)
 
     painter->save();
 
-    bool complexXForm = painter->deviceTransform().type() > QTransform::TxTranslate;
-
     // Access paintDevice via engine since the painter may
     // return the clip device which can still be a widget device in case of grabWidget().
 
     bool translucentToplevel = false;
     const QPaintDevice *paintDevice = painter->device();
+    const qreal aditionalDevicePixelRatio = themeData.widget ? themeData.widget->devicePixelRatio() : 1;
     if (paintDevice->devType() == QInternal::Widget) {
         const QWidget *window = static_cast<const QWidget *>(paintDevice)->window();
         translucentToplevel = window->testAttribute(Qt::WA_TranslucentBackground);
     }
 
+    const TransformType tt = transformType(painter->deviceTransform(), aditionalDevicePixelRatio);
+
     bool canDrawDirectly = false;
     if (themeData.widget && painter->opacity() == 1.0 && !themeData.rotate
-        && !complexXForm && !themeData.mirrorVertically
+        && tt != ComplexTransform && !themeData.mirrorVertically
         && (!themeData.mirrorHorizontally || pDrawThemeBackgroundEx)
         && !translucentToplevel) {
         // Draw on backing store DC only for real widgets or backing store images.
@@ -767,26 +781,44 @@ bool QWindowsXPStylePrivate::drawBackground(XPThemeData &themeData)
     }
 
     const HDC dc = canDrawDirectly ? hdcForWidgetBackingStore(themeData.widget) : HDC(0);
-    const bool result = dc ? drawBackgroundDirectly(themeData) : drawBackgroundThruNativeBuffer(themeData);
+    const bool result = dc
+        ? drawBackgroundDirectly(dc, themeData, qRound(aditionalDevicePixelRatio))
+        : drawBackgroundThruNativeBuffer(themeData, qRound(aditionalDevicePixelRatio));
     painter->restore();
     return result;
 }
 
+static inline QRect scaleRect(const QRect &r, int factor)
+{
+    return r.isValid() && factor > 1
+        ? QRect(r.topLeft() * factor, r.size() * factor)
+        : r;
+}
+
+static QRegion scaleRegion(const QRegion &region, int factor)
+{
+    if (region.isEmpty() || factor == 1)
+        return region;
+    if (region.rectCount() == 1)
+        return QRegion(scaleRect(region.boundingRect(), factor));
+    QRegion result;
+    foreach (const QRect &rect, region.rects())
+        result += QRect(rect.topLeft() * factor, rect.size() * factor);
+    return result;
+}
+
 /*! \internal
     This function draws the theme parts directly to the paintengines HDC.
     Do not use this if you need to perform other transformations on the
     resulting data.
 */
-bool QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
+bool QWindowsXPStylePrivate::drawBackgroundDirectly(HDC dc, XPThemeData &themeData, int additionalDevicePixelRatio)
 {
     QPainter *painter = themeData.painter;
-    HDC dc = 0;
-    if (themeData.widget)
-        dc = hdcForWidgetBackingStore(themeData.widget);
 
     QPoint redirectionDelta(int(painter->deviceMatrix().dx()),
                             int(painter->deviceMatrix().dy()));
-    QRect area = themeData.rect.translated(redirectionDelta);
+    QRect area = scaleRect(themeData.rect, additionalDevicePixelRatio).translated(redirectionDelta);
 
     QRegion sysRgn = painter->paintEngine()->systemClip();
     if (sysRgn.isEmpty())
@@ -794,7 +826,7 @@ bool QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
     else
         sysRgn &= area;
     if (painter->hasClipping())
-        sysRgn &= painter->clipRegion().translated(redirectionDelta);
+        sysRgn &= scaleRegion(painter->clipRegion(), additionalDevicePixelRatio).translated(redirectionDelta);
     HRGN hrgn = qt_hrgn_from_qregion(sysRgn);
     SelectClipRgn(dc, hrgn);
 
@@ -806,6 +838,7 @@ bool QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
 
     RECT drawRECT = themeData.toRECT(area);
     DTBGOPTS drawOptions;
+    memset(&drawOptions, 0, sizeof(drawOptions));
     drawOptions.dwSize = sizeof(drawOptions);
     drawOptions.rcClip = themeData.toRECT(sysRgn.boundingRect());
     drawOptions.dwFlags = DTBG_CLIPRECT
@@ -813,8 +846,9 @@ bool QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
                           | (themeData.noContent ? DTBG_OMITCONTENT : 0)
                           | (themeData.mirrorHorizontally ? DTBG_MIRRORDC : 0);
 
+    HRESULT result = S_FALSE;
     if (pDrawThemeBackgroundEx != 0) {
-        pDrawThemeBackgroundEx(themeData.handle(), dc, themeData.partId, themeData.stateId, &(drawRECT), &drawOptions);
+        result = pDrawThemeBackgroundEx(themeData.handle(), dc, themeData.partId, themeData.stateId, &(drawRECT), &drawOptions);
     } else {
         // We are running on a system where the uxtheme.dll does not have
         // the DrawThemeBackgroundEx function, so we need to clip away
@@ -848,11 +882,11 @@ bool QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
             }
         }
 
-        pDrawThemeBackground(themeData.handle(), dc, themeData.partId, themeData.stateId, &(drawRECT), &(drawOptions.rcClip));
+        result = pDrawThemeBackground(themeData.handle(), dc, themeData.partId, themeData.stateId, &(drawRECT), &(drawOptions.rcClip));
     }
     SelectClipRgn(dc, 0);
     DeleteObject(hrgn);
-    return true;
+    return SUCCEEDED(result);
 }
 
 /*! \internal
@@ -863,10 +897,11 @@ bool QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
     flips (horizonal mirroring only, vertical are handled by the theme
     engine).
 */
-bool QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(XPThemeData &themeData)
+bool QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(XPThemeData &themeData,
+                                                            int additionalDevicePixelRatio)
 {
     QPainter *painter = themeData.painter;
-    QRect rect = themeData.rect;
+    QRect rect = scaleRect(themeData.rect, additionalDevicePixelRatio);
 
     if ((themeData.rotate + 90) % 180 == 0) { // Catch 90,270,etc.. degree flips.
         rect = QRect(0, 0, rect.height(), rect.width());
@@ -898,6 +933,8 @@ bool QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(XPThemeData &themeDa
     pixmapCacheKey.append(QLatin1Char('w'));
     pixmapCacheKey.append(QString::number(h));
     pixmapCacheKey.append(QLatin1Char('h'));
+    pixmapCacheKey.append(QString::number(additionalDevicePixelRatio));
+    pixmapCacheKey.append(QLatin1Char('d'));
 
     QPixmap cachedPixmap;
     ThemeMapKey key(themeData);
@@ -1074,6 +1111,7 @@ bool QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(XPThemeData &themeDa
         printf("Image format is: %s\n", alphaType == RealAlpha ? "Real Alpha" : alphaType == MaskAlpha ? "Masked Alpha" : "No Alpha");
 #endif
         img = QImage(bufferPixels, bufferW, bufferH, format);
+        img.setDevicePixelRatio(additionalDevicePixelRatio);
     }
 
     // Blitting backing store
@@ -2007,7 +2045,7 @@ void QWindowsXPStyle::drawControl(ControlElement element, const QStyleOption *op
             themeNumber = QWindowsXPStylePrivate::StatusTheme;
             partId = SP_GRIPPER;
             XPThemeData theme(0, p, themeNumber, partId, 0);
-            QSize size = theme.size() / QWindowsStylePrivate::devicePixelRatio(widget);
+            QSize size = (theme.size() / QWindowsStylePrivate::devicePixelRatio(widget)).toSize();
             size.rheight()--;
             if (const QStyleOptionSizeGrip *sg = qstyleoption_cast<const QStyleOptionSizeGrip *>(option)) {
                 switch (sg->corner) {
@@ -2078,7 +2116,7 @@ void QWindowsXPStyle::drawControl(ControlElement element, const QStyleOption *op
                                   QWindowsXPStylePrivate::ToolBarTheme,
                                   TP_SPLITBUTTONDROPDOWN);
                 if (theme.isValid()) {
-                    const QSize size = theme.size() / QWindowsStylePrivate::devicePixelRatio(widget);
+                    const QSize size = (theme.size() / QWindowsStylePrivate::devicePixelRatio(widget)).toSize();
                     mbiw = size.width();
                     mbih = size.height();
                 }
@@ -2541,10 +2579,10 @@ void QWindowsXPStyle::drawControl(ControlElement element, const QStyleOption *op
 QRect QWindowsXPStylePrivate::scrollBarGripperBounds(QStyle::State flags, const QWidget *widget, XPThemeData *theme)
 {
     const bool horizontal = flags & QStyle::State_Horizontal;
-    const QMargins contentsMargin = theme->margins(theme->rect, TMT_SIZINGMARGINS)
-                                    / QWindowsStylePrivate::devicePixelRatio(widget);
+    const QMargins contentsMargin = (theme->margins(theme->rect, TMT_SIZINGMARGINS)
+                                     / QWindowsStylePrivate::devicePixelRatio(widget)).toMargins();
     theme->partId = horizontal ? SBP_GRIPPERHORZ : SBP_GRIPPERVERT;
-    const QSize size = theme->size() / QWindowsStylePrivate::devicePixelRatio(widget);
+    const QSize size = (theme->size() / QWindowsStylePrivate::devicePixelRatio(widget)).toSize();
 
     const int hSpace = theme->rect.width() - size.width();
     const int vSpace = theme->rect.height() - size.height();
@@ -3359,7 +3397,7 @@ int QWindowsXPStyle::pixelMetric(PixelMetric pm, const QStyleOption *option, con
 
     int res = QWindowsXPStylePrivate::pixelMetricFromSystemDp(pm, option, widget);
     if (res != QWindowsStylePrivate::InvalidMetric)
-        return res / QWindowsStylePrivate::devicePixelRatio(widget);
+        return qRound(qreal(res) / QWindowsStylePrivate::devicePixelRatio(widget));
 
     res = 0;
     switch (pm) {
@@ -3505,9 +3543,9 @@ QRect QWindowsXPStyle::subControlRect(ComplexControl cc, const QStyleOptionCompl
             const int height = tb->rect.height();
             const int width = tb->rect.width();
             const int buttonMargin = int(QStyleHelper::dpiScaled(4));
-            int buttonHeight = GetSystemMetrics(SM_CYSIZE) / QWindowsStylePrivate::devicePixelRatio(widget)
+            int buttonHeight = qRound(qreal(GetSystemMetrics(SM_CYSIZE)) / QWindowsStylePrivate::devicePixelRatio(widget))
                 - buttonMargin;
-            int buttonWidth = GetSystemMetrics(SM_CXSIZE) / QWindowsStylePrivate::devicePixelRatio(widget)
+            int buttonWidth = qRound(qreal(GetSystemMetrics(SM_CXSIZE)) / QWindowsStylePrivate::devicePixelRatio(widget))
                 - buttonMargin;
             const int delta = buttonWidth + 2;
             int controlTop = option->rect.bottom() - buttonHeight - 2;
@@ -3702,10 +3740,10 @@ QSize QWindowsXPStyle::sizeFromContents(ContentsType ct, const QStyleOption *opt
         {
             XPThemeData buttontheme(widget, 0, QWindowsXPStylePrivate::ButtonTheme, BP_PUSHBUTTON, PBS_NORMAL);
             if (buttontheme.isValid()) {
-                const QMargins borderSize = buttontheme.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                const QMarginsF borderSize = buttontheme.margins() / QWindowsXPStylePrivate::devicePixelRatio(widget);
                 if (!borderSize.isNull()) {
-                    sz.rwidth() += borderSize.left() + borderSize.right() - 2;
-                    sz.rheight() += borderSize.bottom() + borderSize.top() - 2;
+                    sz.rwidth() += qRound(borderSize.left() + borderSize.right() - 2);
+                    sz.rheight() += qRound(borderSize.bottom() + borderSize.top() - 2);
                 }
                 const int textMargins = 2*(proxy()->pixelMetric(PM_FocusFrameHMargin) + 1);
                 sz += QSize(qMax(pixelMetric(QStyle::PM_ScrollBarExtent, option, widget)
@@ -3875,7 +3913,7 @@ QPixmap QWindowsXPStyle::standardPixmap(StandardPixmap standardPixmap, const QSt
             if (widget && widget->isWindow()) {
                 XPThemeData theme(widget, 0, QWindowsXPStylePrivate::WindowTheme, WP_SMALLCLOSEBUTTON, CBS_NORMAL);
                 if (theme.isValid()) {
-                    const QSize size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                    const QSize size = (theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget)).toSize();
                     return QIcon(QWindowsStyle::standardPixmap(standardPixmap, option, widget)).pixmap(size);
                 }
             }
@@ -3909,7 +3947,7 @@ QIcon QWindowsXPStyle::standardIcon(StandardPixmap standardIcon,
                 XPThemeData theme(0, 0, QWindowsXPStylePrivate::WindowTheme,
                                   WP_MAXBUTTON, MAXBS_NORMAL);
                 if (theme.isValid()) {
-                    const QSize size = themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                    const QSize size = (themeSize.size() / QWindowsXPStylePrivate::devicePixelRatio(widget)).toSize();
                     QPixmap pm(size);
                     pm.fill(Qt::transparent);
                     QPainter p(&pm);
@@ -3943,7 +3981,7 @@ QIcon QWindowsXPStyle::standardIcon(StandardPixmap standardIcon,
                 XPThemeData theme(0, 0, QWindowsXPStylePrivate::WindowTheme,
                                   WP_SMALLCLOSEBUTTON, CBS_NORMAL);
                 if (theme.isValid()) {
-                    const QSize size = theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget);
+                    const QSize size = (theme.size() / QWindowsXPStylePrivate::devicePixelRatio(widget)).toSize();
                     QPixmap pm(size);
                     pm.fill(Qt::transparent);
                     QPainter p(&pm);
@@ -3979,7 +4017,7 @@ QIcon QWindowsXPStyle::standardIcon(StandardPixmap standardIcon,
                 XPThemeData theme(0, 0, QWindowsXPStylePrivate::WindowTheme,
                                   WP_RESTOREBUTTON, RBS_NORMAL);
                 if (theme.isValid()) {
-                    const QSize size = themeSize.size() / QWindowsStylePrivate::devicePixelRatio(widget);
+                    const QSize size = (themeSize.size() / QWindowsStylePrivate::devicePixelRatio(widget)).toSize();
                     QPixmap pm(size);
                     pm.fill(Qt::transparent);
                     QPainter p(&pm);
diff --git a/src/widgets/styles/qwindowsxpstyle_p_p.h b/src/widgets/styles/qwindowsxpstyle_p_p.h
index 31977304fe..68aa10e12a 100644
--- a/src/widgets/styles/qwindowsxpstyle_p_p.h
+++ b/src/widgets/styles/qwindowsxpstyle_p_p.h
@@ -208,15 +208,15 @@ public:
     static RECT toRECT(const QRect &qr);
     bool isValid();
 
-    QSize size();
-    QMargins margins(const QRect &rect, int propId = TMT_CONTENTMARGINS);
-    QMargins margins(int propId = TMT_CONTENTMARGINS);
+    QSizeF size();
+    QMarginsF margins(const QRect &rect, int propId = TMT_CONTENTMARGINS);
+    QMarginsF margins(int propId = TMT_CONTENTMARGINS);
 
-    static QSize themeSize(const QWidget *w = 0, QPainter *p = 0, int themeIn = -1, int part = 0, int state = 0);
-    static QMargins themeMargins(const QRect &rect, const QWidget *w = 0, QPainter *p = 0, int themeIn = -1,
-                                 int part = 0, int state = 0, int propId = TMT_CONTENTMARGINS);
-    static QMargins themeMargins(const QWidget *w = 0, QPainter *p = 0, int themeIn = -1,
-                                 int part = 0, int state = 0, int propId = TMT_CONTENTMARGINS);
+    static QSizeF themeSize(const QWidget *w = 0, QPainter *p = 0, int themeIn = -1, int part = 0, int state = 0);
+    static QMarginsF themeMargins(const QRect &rect, const QWidget *w = 0, QPainter *p = 0, int themeIn = -1,
+                                  int part = 0, int state = 0, int propId = TMT_CONTENTMARGINS);
+    static QMarginsF themeMargins(const QWidget *w = 0, QPainter *p = 0, int themeIn = -1,
+                                  int part = 0, int state = 0, int propId = TMT_CONTENTMARGINS);
 
     const QWidget *widget;
     QPainter *painter;
@@ -393,8 +393,8 @@ public:
 
     void setTransparency(QWidget *widget, XPThemeData &themeData);
     bool drawBackground(XPThemeData &themeData);
-    bool drawBackgroundThruNativeBuffer(XPThemeData &themeData);
-    bool drawBackgroundDirectly(XPThemeData &themeData);
+    bool drawBackgroundThruNativeBuffer(XPThemeData &themeData, int aditionalDevicePixelRatio);
+    bool drawBackgroundDirectly(HDC dc, XPThemeData &themeData, int aditionalDevicePixelRatio);
 
     bool hasAlphaChannel(const QRect &rect);
     bool fixAlphaChannel(const QRect &rect);
@@ -433,9 +433,9 @@ private:
     static HTHEME m_themes[NThemes];
 };
 
-inline QSize XPThemeData::size()
+inline QSizeF XPThemeData::size()
 {
-    QSize result(0, 0);
+    QSizeF result(0, 0);
     if (isValid()) {
         SIZE size;
         if (SUCCEEDED(QWindowsXPStylePrivate::pGetThemePartSize(handle(), 0, partId, stateId, 0, TS_TRUE, &size)))
@@ -444,9 +444,9 @@ inline QSize XPThemeData::size()
     return result;
 }
 
-inline QMargins XPThemeData::margins(const QRect &qRect, int propId)
+inline QMarginsF XPThemeData::margins(const QRect &qRect, int propId)
 {
-    QMargins result(0, 0, 0 ,0);
+    QMarginsF result(0, 0, 0 ,0);
     if (isValid()) {
         MARGINS margins;
         RECT rect = XPThemeData::toRECT(qRect);
@@ -456,9 +456,9 @@ inline QMargins XPThemeData::margins(const QRect &qRect, int propId)
     return result;
 }
 
-inline QMargins XPThemeData::margins(int propId)
+inline QMarginsF XPThemeData::margins(int propId)
 {
-    QMargins result(0, 0, 0 ,0);
+    QMarginsF result(0, 0, 0 ,0);
     if (isValid()) {
         MARGINS margins;
         if (SUCCEEDED(QWindowsXPStylePrivate::pGetThemeMargins(handle(), 0, partId, stateId, propId, NULL, &margins)))
@@ -467,21 +467,21 @@ inline QMargins XPThemeData::margins(int propId)
     return result;
 }
 
-inline QSize XPThemeData::themeSize(const QWidget *w, QPainter *p, int themeIn, int part, int state)
+inline QSizeF XPThemeData::themeSize(const QWidget *w, QPainter *p, int themeIn, int part, int state)
 {
     XPThemeData theme(w, p, themeIn, part, state);
     return theme.size();
 }
 
-inline QMargins XPThemeData::themeMargins(const QRect &rect, const QWidget *w, QPainter *p, int themeIn,
-                                          int part, int state, int propId)
+inline QMarginsF XPThemeData::themeMargins(const QRect &rect, const QWidget *w, QPainter *p, int themeIn,
+                                           int part, int state, int propId)
 {
     XPThemeData theme(w, p, themeIn, part, state);
     return theme.margins(rect, propId);
 }
 
-inline QMargins XPThemeData::themeMargins(const QWidget *w, QPainter *p, int themeIn,
-                                          int part, int state, int propId)
+inline QMarginsF XPThemeData::themeMargins(const QWidget *w, QPainter *p, int themeIn,
+                                           int part, int state, int propId)
 {
     XPThemeData theme(w, p, themeIn, part, state);
     return theme.margins(propId);