BMenu: Make margins/padding more HiDPI-aware.

This greatly improves the appearance of menus under font-scaled systems.
The computations are written such that the margins should be unchanged
under a 12pt font size.

src/kits/interface/Menu.cpp

@@ -228,7 +228,6 @@ BMenu::BMenu(const char* name, menu_layout layout)
 	:
 	BView(BRect(0, 0, 0, 0), name, 0, B_WILL_DRAW),
 	fChosenItem(NULL),
-	fPad(std::max(14.0f, be_plain_font->Size() + 2.0f), 2.0f, 20.0f, 0.0f),
 	fSelected(NULL),
 	fCachedMenuWindow(NULL),
 	fSuper(NULL),
@@ -255,6 +254,9 @@ BMenu::BMenu(const char* name, menu_layout layout)
 	fHasSubmenus(false),
 	fAttachAborted(false)
 {
+	const float fontSize = be_plain_font->Size();
+	fPad = BRect(fontSize * 1.15f, fontSize / 6.0f, fontSize * 1.7f, 0.0f);
+
 	_InitData(NULL);
 }
 

src/kits/interface/MenuBar.cpp

@@ -741,9 +741,12 @@ BMenuBar::_RestoreFocus()
 void
 BMenuBar::_InitData(menu_layout layout)
 {
+	const float fontSize = be_plain_font->Size();
+	float lr = fontSize * 2.0f / 3.0f, tb = fontSize / 6.0f;
+	SetItemMargins(lr, tb, lr, tb);
+
 	fBorders = BControlLook::B_ALL_BORDERS;
 	fLastBounds = new BRect(Bounds());
-	SetItemMargins(8.0f, 2.0f, 8.0f, 2.0f);
 	_SetIgnoreHidden(true);
 	SetLowUIColor(B_MENU_BACKGROUND_COLOR);
 	SetViewColor(B_TRANSPARENT_COLOR);