DRY-ed some code by adding a static Component::getApproximateScaleFactorForComponent() method

modules/juce_gui_basics/components/juce_Component.cpp

@@ -1288,6 +1288,21 @@ AffineTransform Component::getTransform() const
     return affineTransform != nullptr ? *affineTransform : AffineTransform();
 }
 
+float Component::getApproximateScaleFactorForComponent (Component* targetComponent)
+{
+    AffineTransform transform;
+
+    for (auto* target = targetComponent; target != nullptr; target = target->getParentComponent())
+    {
+        transform = transform.followedBy (target->getTransform());
+
+        if (target->isOnDesktop())
+            transform = transform.scaled (target->getDesktopScaleFactor());
+    }
+
+    return (transform.getScaleFactor() / Desktop::getInstance().getGlobalScaleFactor());
+}
+
 //==============================================================================
 bool Component::hitTest (int x, int y)
 {

modules/juce_gui_basics/components/juce_Component.h

@@ -590,6 +590,11 @@ public:
     */
     bool isTransformed() const noexcept;
 
+    /** Returns the approximate scale factor for a given component by traversing its parent hierarchy
+        and applying each transform and finally scaling this by the global scale factor.
+    */
+    static float JUCE_CALLTYPE getApproximateScaleFactorForComponent (Component* targetComponent);
+
     //==============================================================================
     /** Returns a proportion of the component's width.
         This is a handy equivalent of (getWidth() * proportion).

modules/juce_gui_basics/menus/juce_PopupMenu.cpp

@@ -218,7 +218,7 @@ struct MenuWindow  : public Component
 
         if (parentComponent == nullptr && parentWindow == nullptr && lf.shouldPopupMenuScaleWithTargetComponent (options))
             if (auto* targetComponent = options.getTargetComponent())
-                scaleFactor = getApproximateScaleFactorForTargetComponent (targetComponent);
+                scaleFactor = Component::getApproximateScaleFactorForComponent (targetComponent);
 
         setOpaque (lf.findColour (PopupMenu::backgroundColourId).isOpaque()
                      || ! Desktop::canUseSemiTransparentWindows());
@@ -969,22 +969,6 @@ struct MenuWindow  : public Component
     bool isTopScrollZoneActive() const noexcept     { return canScroll() && childYOffset > 0; }
     bool isBottomScrollZoneActive() const noexcept  { return canScroll() && childYOffset < contentHeight - windowPos.getHeight(); }
 
-    //==============================================================================
-    static float getApproximateScaleFactorForTargetComponent (Component* targetComponent)
-    {
-        AffineTransform transform;
-
-        for (auto* target = targetComponent; target != nullptr; target = target->getParentComponent())
-        {
-            transform = transform.followedBy (target->getTransform());
-
-            if (target->isOnDesktop())
-                transform = transform.scaled (target->getDesktopScaleFactor());
-        }
-
-        return (transform.getScaleFactor() / Desktop::getInstance().getGlobalScaleFactor());
-    }
-
     //==============================================================================
     MenuWindow* parent;
     const Options options;

modules/juce_gui_basics/widgets/juce_Slider.cpp

@@ -1298,7 +1298,7 @@ public:
               font (s.getLookAndFeel().getSliderPopupFont (s))
         {
             if (isOnDesktop)
-                setTransform (AffineTransform::scale (getApproximateScaleFactor (&s)));
+                setTransform (AffineTransform::scale (Component::getApproximateScaleFactorForComponent (&s)));
 
             setAlwaysOnTop (true);
             setAllowedPlacement (owner.getLookAndFeel().getSliderPopupPlacement (s));
@@ -1338,21 +1338,6 @@ public:
         }
 
     private:
-        static float getApproximateScaleFactor (Component* targetComponent)
-        {
-            AffineTransform transform;
-
-            for (Component* target = targetComponent; target != nullptr; target = target->getParentComponent())
-            {
-                transform = transform.followedBy (target->getTransform());
-
-                if (target->isOnDesktop())
-                    transform = transform.scaled (target->getDesktopScaleFactor());
-            }
-
-            return (transform.getScaleFactor() / Desktop::getInstance().getGlobalScaleFactor());
-        }
-
         //==============================================================================
         Slider& owner;
         Font font;