Take the size and the icon size for MDI buttons from a style

This way they can be DPI-dependent.

Change-Id: I117c337aaa3e2bf6fb85cb3b04bbbccd9db41070
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>

src/widgets/styles/qcommonstyle.cpp

@@ -3724,6 +3724,8 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
             btnOpt.state &= ~State_MouseOver;
             int bsx = 0;
             int bsy = 0;
+            const int buttonIconMetric = proxy()->pixelMetric(PM_TitleBarButtonIconSize, &btnOpt, widget);
+            const QSize buttonIconSize(buttonIconMetric, buttonIconMetric);
             if (opt->subControls & QStyle::SC_MdiCloseButton) {
                 if (opt->activeSubControls & QStyle::SC_MdiCloseButton && (opt->state & State_Sunken)) {
                     btnOpt.state |= State_Sunken;
@@ -3738,7 +3740,7 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 }
                 btnOpt.rect = proxy()->subControlRect(CC_MdiControls, opt, SC_MdiCloseButton, widget);
                 proxy()->drawPrimitive(PE_PanelButtonCommand, &btnOpt, p, widget);
-                QPixmap pm = proxy()->standardIcon(SP_TitleBarCloseButton).pixmap(qt_getWindow(widget), QSize(16, 16));
+                QPixmap pm = proxy()->standardIcon(SP_TitleBarCloseButton).pixmap(qt_getWindow(widget), buttonIconSize);
                 proxy()->drawItemPixmap(p, btnOpt.rect.translated(bsx, bsy), Qt::AlignCenter, pm);
             }
             if (opt->subControls & QStyle::SC_MdiNormalButton) {
@@ -3755,7 +3757,7 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 }
                 btnOpt.rect = proxy()->subControlRect(CC_MdiControls, opt, SC_MdiNormalButton, widget);
                 proxy()->drawPrimitive(PE_PanelButtonCommand, &btnOpt, p, widget);
-                QPixmap pm = proxy()->standardIcon(SP_TitleBarNormalButton).pixmap(qt_getWindow(widget), QSize(16, 16));
+                QPixmap pm = proxy()->standardIcon(SP_TitleBarNormalButton).pixmap(qt_getWindow(widget), buttonIconSize);
                 proxy()->drawItemPixmap(p, btnOpt.rect.translated(bsx, bsy), Qt::AlignCenter, pm);
             }
             if (opt->subControls & QStyle::SC_MdiMinButton) {
@@ -3772,7 +3774,7 @@ void QCommonStyle::drawComplexControl(ComplexControl cc, const QStyleOptionCompl
                 }
                 btnOpt.rect = proxy()->subControlRect(CC_MdiControls, opt, SC_MdiMinButton, widget);
                 proxy()->drawPrimitive(PE_PanelButtonCommand, &btnOpt, p, widget);
-                QPixmap pm = proxy()->standardIcon(SP_TitleBarMinButton).pixmap(qt_getWindow(widget), QSize(16, 16));
+                QPixmap pm = proxy()->standardIcon(SP_TitleBarMinButton).pixmap(qt_getWindow(widget), buttonIconSize);
                 proxy()->drawItemPixmap(p, btnOpt.rect.translated(bsx, bsy), Qt::AlignCenter, pm);
             }
         }
@@ -4393,6 +4395,13 @@ int QCommonStyle::pixelMetric(PixelMetric m, const QStyleOption *opt, const QWid
         }
 
         break; }
+    case PM_TitleBarButtonSize:
+        ret = int(QStyleHelper::dpiScaled(16.));
+        break;
+    case PM_TitleBarButtonIconSize:
+        ret = int(QStyleHelper::dpiScaled(16.));
+        break;
+
     case PM_ScrollBarSliderMin:
         ret = int(QStyleHelper::dpiScaled(9.));
         break;
@@ -4845,16 +4854,18 @@ QSize QCommonStyle::sizeFromContents(ContentsType ct, const QStyleOption *opt,
 #endif // QT_NO_GROUPBOX
     case CT_MdiControls:
         if (const QStyleOptionComplex *styleOpt = qstyleoption_cast<const QStyleOptionComplex *>(opt)) {
+            const int buttonSize = proxy()->pixelMetric(PM_TitleBarButtonSize, styleOpt, widget);
             int width = 1;
             if (styleOpt->subControls & SC_MdiMinButton)
-                width += 16 + 1;
+                width += buttonSize + 1;
             if (styleOpt->subControls & SC_MdiNormalButton)
-                width += 16 + 1;
+                width += buttonSize + 1;
             if (styleOpt->subControls & SC_MdiCloseButton)
-                width += 16 + 1;
+                width += buttonSize + 1;
-            sz = QSize(width, 16);
+            sz = QSize(width, buttonSize);
         } else {
-            sz = QSize(52, 16);
+            const int buttonSize = proxy()->pixelMetric(PM_TitleBarButtonSize, opt, widget);
+            sz = QSize(1 + 3 * (buttonSize + 1), buttonSize);
         }
         break;
 #ifndef QT_NO_ITEMVIEWS

src/widgets/styles/qfusionstyle.cpp

@@ -3102,6 +3102,9 @@ int QFusionStyle::pixelMetric(PixelMetric metric, const QStyleOption *option, co
     case PM_DockWidgetTitleBarButtonMargin:
         val = 2;
         break;
+    case PM_TitleBarButtonSize:
+        val = 19;
+        break;
     case PM_MaximumDragDistance:
         return -1; // Do not dpi-scale because the value is magic
     case PM_TabCloseIndicatorWidth:
@@ -3225,18 +3228,7 @@ QSize QFusionStyle::sizeFromContents(ContentsType type, const QStyleOption *opti
         newSize += QSize(4, 4);
         break;
     case CT_MdiControls:
-        if (const QStyleOptionComplex *styleOpt = qstyleoption_cast<const QStyleOptionComplex *>(option)) {
+        newSize -= QSize(1, 0);
-            int width = 0;
-            if (styleOpt->subControls & SC_MdiMinButton)
-                width += 19 + 1;
-            if (styleOpt->subControls & SC_MdiNormalButton)
-                width += 19 + 1;
-            if (styleOpt->subControls & SC_MdiCloseButton)
-                width += 19 + 1;
-            newSize = QSize(width, 19);
-        } else {
-            newSize = QSize(60, 19);
-        }
         break;
     default:
         break;

src/widgets/styles/qstyle.cpp

@@ -1494,6 +1494,11 @@ void QStyle::drawItemPixmap(QPainter *painter, const QRect &rect, int alignment,
     \value PM_HeaderDefaultSectionSizeVertical The default size of sections
            in a vertical header. This enum value has been introduced in Qt 5.5.
 
+    \value PM_TitleBarButtonIconSize The size of button icons on a title bar.
+           This enum value has been introduced in Qt 5.8.
+    \value PM_TitleBarButtonSize The size of buttons on a title bar.
+           This enum value has been introduced in Qt 5.8.
+
     \value PM_CustomBase Base value for custom pixel metrics.  Custom
     values must be greater than this value.
 

src/widgets/styles/qstyle.h

@@ -570,6 +570,9 @@ public:
         PM_HeaderDefaultSectionSizeHorizontal,
         PM_HeaderDefaultSectionSizeVertical,
 
+        PM_TitleBarButtonIconSize,
+        PM_TitleBarButtonSize,
+
         // do not add any values below/greater than this
         PM_CustomBase = 0xf0000000
     };

src/widgets/widgets/qmdisubwindow.cpp

@@ -412,6 +412,10 @@ bool ControlLabel::event(QEvent *event)
 {
     if (event->type() == QEvent::WindowIconChange)
         updateWindowIcon();
+    else if (event->type() == QEvent::StyleChange) {
+        updateWindowIcon();
+        setFixedSize(label.size());
+    }
 #ifndef QT_NO_TOOLTIP
     else if (event->type() == QEvent::ToolTip) {
         QStyleOptionTitleBar options;
@@ -480,7 +484,8 @@ void ControlLabel::updateWindowIcon()
     QIcon menuIcon = windowIcon();
     if (menuIcon.isNull())
         menuIcon = style()->standardIcon(QStyle::SP_TitleBarMenuButton, 0, parentWidget());
-    label = menuIcon.pixmap(16, 16);
+    const int iconSize = style()->pixelMetric(QStyle::PM_TitleBarButtonIconSize, 0, parentWidget());
+    label = menuIcon.pixmap(iconSize);
     update();
 }
 
@@ -556,7 +561,8 @@ QSize ControllerWidget::sizeHint() const
     ensurePolished();
     QStyleOptionComplex opt;
     initStyleOption(&opt);
-    QSize size(48, 16);
+    const int buttonSize = style()->pixelMetric(QStyle::PM_TitleBarButtonSize, &opt, mdiArea);
+    QSize size(3 * buttonSize, buttonSize);
     return style()->sizeFromContents(QStyle::CT_MdiControls, &opt, size, mdiArea);
 }