Utils: Make the "shadow" under toolbar icons optional

In preparation od a "Flat Light" theme, where shadows under the icons
would have a negative impact.

Change-Id: I2d9d3563c90336640513c1a970a432898dd63cfc
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@theqtcompany.com>

share/qtcreator/themes/dark.creatortheme

@@ -188,6 +188,7 @@ ApplyThemePaletteGlobally=true
 FlatSideBarIcons=true
 FlatProjectsMode=true
 FlatMenuBar=true
+ToolBarIconShadow=true
 
 [Gradients]
 DetailsWidgetHeaderGradient\1\color=0

share/qtcreator/themes/default.creatortheme

@@ -182,6 +182,7 @@ ApplyThemePaletteGlobally=false
 FlatSideBarIcons=false
 FlatProjectsMode=false
 FlatMenuBar=false
+ToolBarIconShadow=true
 
 [Gradients]
 DetailsWidgetHeaderGradient\1\color=ffffff

share/qtcreator/themes/flat.creatortheme

@@ -192,6 +192,7 @@ ApplyThemePaletteGlobally=false
 FlatSideBarIcons=true
 FlatProjectsMode=false
 FlatMenuBar=false
+ToolBarIconShadow=true
 
 [Gradients]
 DetailsWidgetHeaderGradient\1\color=0

src/libs/utils/icon.cpp

@@ -129,7 +129,7 @@ static QPixmap masksToIcon(const MasksAndColors &masks, const QPixmap &combinedM
         p.drawPixmap(0, 0, maskToColorAndAlpha((*maskImage).first, (*maskImage).second));
     }
 
-    if (style & Icon::DropShadow) {
+    if (style & Icon::DropShadow && creatorTheme()->flag(Theme::ToolBarIconShadow)) {
         const QPixmap shadowMask = maskToColorAndAlpha(combinedMask, Qt::black);
         p.setCompositionMode(QPainter::CompositionMode_DestinationOver);
         p.setOpacity(0.05);

src/libs/utils/stylehelper.cpp

@@ -315,6 +315,7 @@ void StyleHelper::drawArrow(QStyle::PrimitiveElement element, QPainter *painter,
         if (!enabled) {
             drawCommonStyleArrow(image.rect(), creatorTheme()->color(Theme::IconsDisabledColor));
         } else {
+            if (creatorTheme()->flag(Theme::ToolBarIconShadow))
                 drawCommonStyleArrow(image.rect().translated(0, devicePixelRatio), toolBarDropShadowColor());
             drawCommonStyleArrow(image.rect(), creatorTheme()->color(Theme::IconsBaseColor));
         }
@@ -393,7 +394,7 @@ void StyleHelper::drawIconWithShadow(const QIcon &icon, const QRect &rect,
             const bool hasDisabledState = icon.availableSizes(QIcon::Disabled).contains(px.size());
             if (!hasDisabledState)
                 px = disabledSideBarIcon(icon.pixmap(window, rect.size()));
-        } else {
+        } else if (creatorTheme()->flag(Theme::ToolBarIconShadow)) {
             // Draw shadow
             QImage tmp(px.size() + QSize(radius * 2, radius * 2 + 1), QImage::Format_ARGB32_Premultiplied);
             tmp.fill(Qt::transparent);

src/libs/utils/theme/theme.h

@@ -274,7 +274,8 @@ public:
         ApplyThemePaletteGlobally,
         FlatSideBarIcons,
         FlatProjectsMode,
-        FlatMenuBar
+        FlatMenuBar,
+        ToolBarIconShadow
     };
 
     enum WidgetStyle {