Widget style: Use per-screen DPI in QStyleHelper::dpiScaled()

Pass the style option to dpiScaled() in order to get
the correct screen DPI. The style option contains the
font, which again contains the current DPI value.

Add QFontMetrics::fontDpi() accessors to get the DPI
from the QFont. This DPI will/should be updated on screen
change.

Replace hardcoded Q_OS_MAC DPI with hardcoded base
DPI. This makes per-screen DPI testable on macOS, too.

Task-number: QTBUG-45055
Change-Id: I75f8b37d45eb50c3334b46b8469a546d29712f1b
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

1 files changed, 58 insertions, 57 deletions

diff --git a/src/widgets/styles/qcommonstyle.cpp b/src/widgets/styles/qcommonstyle.cpp
index 7b53f5272c..3db85ca07a 100644
--- a/src/widgets/styles/qcommonstyle.cpp
+++ b/src/widgets/styles/qcommonstyle.cpp
@@ -4247,10 +4247,11 @@ QRect QCommonStyle::subControlRect(ComplexControl cc, const QStyleOptionComplex
 #if QT_CONFIG(combobox)
     case CC_ComboBox:
         if (const QStyleOptionComboBox *cb = qstyleoption_cast<const QStyleOptionComboBox *>(opt)) {
+            const qreal dpi = QStyleHelper::dpi(opt);
             const int x = cb->rect.x(), y = cb->rect.y(), wi = cb->rect.width(), he = cb->rect.height();
-            const int margin = cb->frame ? qRound(QStyleHelper::dpiScaled(3)) : 0;
-            const int bmarg = cb->frame ? qRound(QStyleHelper::dpiScaled(2)) : 0;
-            const int xpos = x + wi - bmarg - qRound(QStyleHelper::dpiScaled(16));
+            const int margin = cb->frame ? qRound(QStyleHelper::dpiScaled(3, dpi)) : 0;
+            const int bmarg = cb->frame ? qRound(QStyleHelper::dpiScaled(2, dpi)) : 0;
+            const int xpos = x + wi - bmarg - qRound(QStyleHelper::dpiScaled(16, dpi));
 
 
             switch (sc) {
@@ -4258,10 +4259,10 @@ QRect QCommonStyle::subControlRect(ComplexControl cc, const QStyleOptionComplex
                 ret = cb->rect;
                 break;
             case SC_ComboBoxArrow:
-                ret.setRect(xpos, y + bmarg, qRound(QStyleHelper::dpiScaled(16)), he - 2*bmarg);
+                ret.setRect(xpos, y + bmarg, qRound(QStyleHelper::dpiScaled(16, opt)), he - 2*bmarg);
                 break;
             case SC_ComboBoxEditField:
-                ret.setRect(x + margin, y + margin, wi - 2 * margin - qRound(QStyleHelper::dpiScaled(16)), he - 2 * margin);
+                ret.setRect(x + margin, y + margin, wi - 2 * margin - qRound(QStyleHelper::dpiScaled(16, dpi)), he - 2 * margin);
                 break;
             case SC_ComboBoxListBoxPopup:
                 ret = cb->rect;
@@ -4505,13 +4506,13 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         ret = 0;
         break;
     case PM_DialogButtonsSeparator:
-        ret = int(QStyleHelper::dpiScaled(5.));
+        ret = int(QStyleHelper::dpiScaled(5, opt));
         break;
     case PM_DialogButtonsButtonWidth:
-        ret = int(QStyleHelper::dpiScaled(70.));
+        ret = int(QStyleHelper::dpiScaled(70, opt));
         break;
     case PM_DialogButtonsButtonHeight:
-        ret = int(QStyleHelper::dpiScaled(30.));
+        ret = int(QStyleHelper::dpiScaled(30, opt));
         break;
     case PM_TitleBarHeight: {
         if (const QStyleOptionTitleBar *tb = qstyleoption_cast<const QStyleOptionTitleBar *>(opt)) {
@@ -4519,33 +4520,33 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
                 ret = qMax(widget ? widget->fontMetrics().height() : opt->fontMetrics.height(), 16);
 #if QT_CONFIG(dockwidget)
             } else if (qobject_cast<const QDockWidget*>(widget)) {
-                ret = qMax(widget->fontMetrics().height(), int(QStyleHelper::dpiScaled(13)));
+                ret = qMax(widget->fontMetrics().height(), int(QStyleHelper::dpiScaled(13, opt)));
 #endif
             } else {
                 ret = qMax(widget ? widget->fontMetrics().height() : opt->fontMetrics.height(), 18);
             }
         } else {
-            ret = int(QStyleHelper::dpiScaled(18.));
+            ret = int(QStyleHelper::dpiScaled(18., opt));
         }
 
         break; }
     case PM_TitleBarButtonSize:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16., opt));
         break;
     case PM_TitleBarButtonIconSize:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16., opt));
         break;
 
     case PM_ScrollBarSliderMin:
-        ret = int(QStyleHelper::dpiScaled(9.));
+        ret = int(QStyleHelper::dpiScaled(9., opt));
         break;
 
     case PM_ButtonMargin:
-        ret = int(QStyleHelper::dpiScaled(6.));
+        ret = int(QStyleHelper::dpiScaled(6., opt));
         break;
 
     case PM_DockWidgetTitleBarButtonMargin:
-        ret = int(QStyleHelper::dpiScaled(2.));
+        ret = int(QStyleHelper::dpiScaled(2., opt));
         break;
 
     case PM_ButtonDefaultIndicator:
@@ -4553,7 +4554,7 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
 
     case PM_MenuButtonIndicator:
-        ret = int(QStyleHelper::dpiScaled(12.));
+        ret = int(QStyleHelper::dpiScaled(12, opt));
         break;
 
     case PM_ButtonShiftHorizontal:
@@ -4568,15 +4569,15 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
     case PM_MenuPanelWidth:
     case PM_TabBarBaseOverlap:
     case PM_TabBarBaseHeight:
-        ret = proxy()->pixelMetric(PM_DefaultFrameWidth, opt, widget);
+        ret = proxy()->pixelMetric(PM_DefaultFrameWidth, opt);
         break;
 
     case PM_MdiSubWindowFrameWidth:
-        ret = int(QStyleHelper::dpiScaled(4.));
+        ret = int(QStyleHelper::dpiScaled(4, opt));
         break;
 
     case PM_MdiSubWindowMinimizedWidth:
-        ret = int(QStyleHelper::dpiScaled(196.));
+        ret = int(QStyleHelper::dpiScaled(196, opt));
         break;
 
 #if QT_CONFIG(scrollbar)
@@ -4587,7 +4588,7 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
                     : QApplication::globalStrut().width();
             ret = qMax(16, s);
         } else {
-            ret = int(QStyleHelper::dpiScaled(16.));
+            ret = int(QStyleHelper::dpiScaled(16, opt));
         }
         break;
 #endif
@@ -4597,7 +4598,7 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
 
 #if QT_CONFIG(slider)
     case PM_SliderThickness:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16, opt));
         break;
 
     case PM_SliderTickmarkOffset:
@@ -4631,11 +4632,11 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
 #endif // QT_CONFIG(slider)
 #if QT_CONFIG(dockwidget)
     case PM_DockWidgetSeparatorExtent:
-        ret = int(QStyleHelper::dpiScaled(6.));
+        ret = int(QStyleHelper::dpiScaled(6, opt));
         break;
 
     case PM_DockWidgetHandleExtent:
-        ret = int(QStyleHelper::dpiScaled(8.));
+        ret = int(QStyleHelper::dpiScaled(8, opt));
         break;
     case PM_DockWidgetTitleMargin:
         ret = 0;
@@ -4664,19 +4665,19 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
 
     case PM_ToolBarItemSpacing:
-        ret = int(QStyleHelper::dpiScaled(4.));
+        ret = int(QStyleHelper::dpiScaled(4, opt));
         break;
 
     case PM_ToolBarHandleExtent:
-        ret = int(QStyleHelper::dpiScaled(8.));
+        ret = int(QStyleHelper::dpiScaled(8, opt));
         break;
 
     case PM_ToolBarSeparatorExtent:
-        ret = int(QStyleHelper::dpiScaled(6.));
+        ret = int(QStyleHelper::dpiScaled(6, opt));
         break;
 
     case PM_ToolBarExtensionExtent:
-        ret = int(QStyleHelper::dpiScaled(12.));
+        ret = int(QStyleHelper::dpiScaled(12, opt));
         break;
 #endif // QT_CONFIG(toolbar)
 
@@ -4686,7 +4687,7 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
 
     case PM_TabBarTabHSpace:
-        ret = int(QStyleHelper::dpiScaled(24.));
+        ret = int(QStyleHelper::dpiScaled(24, opt));
         break;
 
     case PM_TabBarTabShiftHorizontal:
@@ -4715,27 +4716,27 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
 
     case PM_IndicatorWidth:
-        ret = int(QStyleHelper::dpiScaled(13.));
+        ret = int(QStyleHelper::dpiScaled(13, opt));
         break;
 
     case PM_IndicatorHeight:
-        ret = int(QStyleHelper::dpiScaled(13.));
+        ret = int(QStyleHelper::dpiScaled(13, opt));
         break;
 
     case PM_ExclusiveIndicatorWidth:
-        ret = int(QStyleHelper::dpiScaled(12.));
+        ret = int(QStyleHelper::dpiScaled(12, opt));
         break;
 
     case PM_ExclusiveIndicatorHeight:
-        ret = int(QStyleHelper::dpiScaled(12.));
+        ret = int(QStyleHelper::dpiScaled(12, opt));
         break;
 
     case PM_MenuTearoffHeight:
-        ret = int(QStyleHelper::dpiScaled(10.));
+        ret = int(QStyleHelper::dpiScaled(10, opt));
         break;
 
     case PM_MenuScrollerHeight:
-        ret = int(QStyleHelper::dpiScaled(10.));
+        ret = int(QStyleHelper::dpiScaled(10, opt));
         break;
 
     case PM_MenuDesktopFrameWidth:
@@ -4745,22 +4746,22 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
 
     case PM_HeaderMargin:
-        ret = int(QStyleHelper::dpiScaled(4.));
+        ret = int(QStyleHelper::dpiScaled(4, opt));
         break;
     case PM_HeaderMarkSize:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16, opt));
         break;
     case PM_HeaderGripMargin:
-        ret = int(QStyleHelper::dpiScaled(4.));
+        ret = int(QStyleHelper::dpiScaled(4, opt));
         break;
     case PM_HeaderDefaultSectionSizeHorizontal:
-        ret = int(QStyleHelper::dpiScaled(100.));
+        ret = int(QStyleHelper::dpiScaled(100, opt));
         break;
     case PM_HeaderDefaultSectionSizeVertical:
-        ret = int(QStyleHelper::dpiScaled(30.));
+        ret = int(QStyleHelper::dpiScaled(30, opt));
         break;
     case PM_TabBarScrollButtonWidth:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16, opt));
         break;
     case PM_LayoutLeftMargin:
     case PM_LayoutTopMargin:
@@ -4782,13 +4783,13 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
 
     case PM_DefaultTopLevelMargin:
-        ret = int(QStyleHelper::dpiScaled(11.));
+        ret = int(QStyleHelper::dpiScaled(11, opt));
         break;
     case PM_DefaultChildMargin:
-        ret = int(QStyleHelper::dpiScaled(9.));
+        ret = int(QStyleHelper::dpiScaled(9, opt));
         break;
     case PM_DefaultLayoutSpacing:
-        ret = int(QStyleHelper::dpiScaled(6.));
+        ret = int(QStyleHelper::dpiScaled(6, opt));
         break;
 
     case PM_ToolBarIconSize:
@@ -4796,31 +4797,31 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         if (const QPlatformTheme *theme = QGuiApplicationPrivate::platformTheme())
             ret = theme->themeHint(QPlatformTheme::ToolBarIconSize).toInt();
         if (ret <= 0)
-            ret =  int(QStyleHelper::dpiScaled(24.));
+            ret =  int(QStyleHelper::dpiScaled(24, opt));
         break;
 
     case PM_TabBarIconSize:
-        ret = proxy()->pixelMetric(PM_SmallIconSize, opt, widget);
+        ret = proxy()->pixelMetric(PM_SmallIconSize, opt);
         break;
     case PM_ListViewIconSize:
 #if QT_CONFIG(filedialog)
         if (qobject_cast<const QSidebar *>(widget))
-            ret = int(QStyleHelper::dpiScaled(24.));
+            ret = int(QStyleHelper::dpiScaled(24., opt));
         else
 #endif
-            ret = proxy()->pixelMetric(PM_SmallIconSize, opt, widget);
+            ret = proxy()->pixelMetric(PM_SmallIconSize, opt);
         break;
 
     case PM_ButtonIconSize:
     case PM_SmallIconSize:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16, opt));
         break;
     case PM_IconViewIconSize:
-        ret = proxy()->pixelMetric(PM_LargeIconSize, opt, widget);
+        ret = proxy()->pixelMetric(PM_LargeIconSize, opt);
         break;
 
     case PM_LargeIconSize:
-        ret = int(QStyleHelper::dpiScaled(32.));
+        ret = int(QStyleHelper::dpiScaled(32, opt));
         break;
 
     case PM_ToolTipLabelFrameWidth:
@@ -4828,10 +4829,10 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
     case PM_CheckBoxLabelSpacing:
     case PM_RadioButtonLabelSpacing:
-        ret = int(QStyleHelper::dpiScaled(6.));
+        ret = int(QStyleHelper::dpiScaled(6, opt));
         break;
     case PM_SizeGripSize:
-        ret = int(QStyleHelper::dpiScaled(13.));
+        ret = int(QStyleHelper::dpiScaled(13, opt));
         break;
     case PM_MessageBoxIconSize:
 #ifdef Q_OS_MAC
@@ -4840,7 +4841,7 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         } else
 #endif
         {
-            ret = int(QStyleHelper::dpiScaled(32.));
+            ret = int(QStyleHelper::dpiScaled(32, opt));
         }
         break;
     case PM_TextCursorWidth:
@@ -4851,19 +4852,19 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         break;
     case PM_TabCloseIndicatorWidth:
     case PM_TabCloseIndicatorHeight:
-        ret = int(QStyleHelper::dpiScaled(16.));
+        ret = int(QStyleHelper::dpiScaled(16, opt));
         break;
     case PM_ScrollView_ScrollBarSpacing:
-        ret = 2 * proxy()->pixelMetric(PM_DefaultFrameWidth, opt, widget);
+        ret = 2 * proxy()->pixelMetric(PM_DefaultFrameWidth, opt);
         break;
     case PM_ScrollView_ScrollBarOverlap:
         ret = 0;
         break;
     case PM_SubMenuOverlap:
-        ret = -proxy()->pixelMetric(QStyle::PM_MenuPanelWidth, opt, widget);
+        ret = -proxy()->pixelMetric(QStyle::PM_MenuPanelWidth, opt);
         break;
     case PM_TreeViewIndentation:
-        ret = int(QStyleHelper::dpiScaled(20.));
+        ret = int(QStyleHelper::dpiScaled(20, opt));
         break;
     default:
         ret = 0;