QStyle/QWidget: Avoid repetitive invocation of QStyleHelper::dpiScaled()

Store the result of QStyleHelper::dpiScaled() or functions dependent on it
in a variable, preparing the addition of a DPI parameter.

Task-number: QTBUG-45055
Change-Id: Ic70d65b590793c29a4b1f7a7a5312dd169517fc5
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

src/plugins/styles/windowsvista/qwindowsxpstyle.cpp

@@ -1486,11 +1486,13 @@ case PE_Frame:
 
                 // Inner white border
                 p->setPen(QPen(option->palette.base().color(), 0));
-                p->drawRect(QRectF(option->rect).adjusted(QStyleHelper::dpiScaled(0.5), QStyleHelper::dpiScaled(0.5),
+                const auto topLevelAdjustment = QStyleHelper::dpiScaled(0.5);
-                                                          QStyleHelper::dpiScaled(-1), QStyleHelper::dpiScaled(-1)));
+                const auto bottomRightAdjustment = QStyleHelper::dpiScaled(-1);
+                p->drawRect(QRectF(option->rect).adjusted(topLevelAdjustment, topLevelAdjustment,
+                                                          bottomRightAdjustment, bottomRightAdjustment));
                 // Outer dark border
                 p->setPen(QPen(bordercolor, 0));
-                p->drawRect(QRectF(option->rect).adjusted(0, 0, QStyleHelper::dpiScaled(-0.5), QStyleHelper::dpiScaled(-0.5)));
+                p->drawRect(QRectF(option->rect).adjusted(0, 0, -topLevelAdjustment, -topLevelAdjustment));
                 p->setPen(oldPen);
                 return;
             } else if (fillType == BT_NONE) {
@@ -3534,9 +3536,12 @@ QRect QWindowsXPStyle::subControlRect(ComplexControl cc, const QStyleOptionCompl
                              qRound(QStyleHelper::dpiScaled(16)), he - qRound(QStyleHelper::dpiScaled(2)));
                 break;
 
-            case SC_ComboBoxEditField:
+            case SC_ComboBoxEditField: {
-                rect = QRect(x + qRound(QStyleHelper::dpiScaled(2)), y + qRound(QStyleHelper::dpiScaled(2)),
+                const int frame = qRound(QStyleHelper::dpiScaled(2));
-                             wi - qRound(QStyleHelper::dpiScaled(3 + 16)), he - qRound(QStyleHelper::dpiScaled(4)));
+                rect = QRect(x + frame, y + frame,
+                             wi - qRound(QStyleHelper::dpiScaled(3 + 16)),
+                             he - qRound(QStyleHelper::dpiScaled(4)));
+            }
                 break;
 
             case SC_ComboBoxListBoxPopup:

src/widgets/dialogs/qwizard.cpp

@@ -1595,23 +1595,25 @@ bool QWizardPrivate::handleAeroStyleChange()
     bool vistaMargins = false;
 
     if (isVistaThemeEnabled()) {
+        const int topOffset = vistaHelper->topOffset();
+        const int topPadding = vistaHelper->topPadding();
         if (isVistaThemeEnabled(QVistaHelper::VistaAero)) {
             if (isWindow) {
                 vistaHelper->setDWMTitleBar(QVistaHelper::ExtendedTitleBar);
                 q->installEventFilter(vistaHelper);
             }
             q->setMouseTracking(true);
-            antiFlickerWidget->move(0, vistaHelper->titleBarSize() + vistaHelper->topOffset());
+            antiFlickerWidget->move(0, vistaHelper->titleBarSize() + topOffset);
             vistaHelper->backButton()->move(
-                0, vistaHelper->topOffset() // ### should ideally work without the '+ 1'
+                0, topOffset // ### should ideally work without the '+ 1'
-                - qMin(vistaHelper->topOffset(), vistaHelper->topPadding() + 1));
+                - qMin(topOffset, topPadding + 1));
             vistaMargins = true;
             vistaHelper->backButton()->show();
         } else {
             if (isWindow)
                 vistaHelper->setDWMTitleBar(QVistaHelper::NormalTitleBar);
             q->setMouseTracking(true);
-            antiFlickerWidget->move(0, vistaHelper->topOffset());
+            antiFlickerWidget->move(0, topOffset);
             vistaHelper->backButton()->move(0, -1); // ### should ideally work with (0, 0)
         }
         if (isWindow)

src/widgets/dialogs/qwizard_win.cpp

@@ -293,9 +293,9 @@ void QVistaHelper::drawTitleBar(QPainter *painter)
     int glowOffset = 0;
 
     if (vistaState() == VistaAero) {
-        textHeight += 2 * glowSize();
-        textWidth += 2 * glowSize();
         glowOffset = glowSize();
+        textHeight += 2 * glowOffset;
+        textWidth += 2 * glowOffset;
     }
 
     const int titleLeft = (wizard->layoutDirection() == Qt::LeftToRight

src/widgets/styles/qwindowsstyle.cpp

@@ -802,8 +802,10 @@ void QWindowsStyle::drawPrimitive(PrimitiveElement pe, const QStyleOption *opt,
         QPen oldPen = p->pen();
         p->setPen(QPen(opt->palette.shadow().color(), 0));
         QRectF rect = opt->rect;
-        rect.adjust(QStyleHelper::dpiScaled(0.5), QStyleHelper::dpiScaled(0.5),
+        const qreal topLevelAdjustment = QStyleHelper::dpiScaled(0.5);
-                    QStyleHelper::dpiScaled(-1.5), QStyleHelper::dpiScaled(-1.5));
+        const qreal bottomRightAdjustment = QStyleHelper::dpiScaled(-1.5);
+        rect.adjust(topLevelAdjustment, topLevelAdjustment,
+                    bottomRightAdjustment, bottomRightAdjustment);
         p->drawRect(rect);
         p->setPen(oldPen);
         break;