vcl: use std::optional in PhysicalFontFace

Otherwise when a font does not, say, support variations or color
palettes, we keep querying the font each time they are requested.

Change-Id: I3a41bc73dd814b25af3a8b5b009632ecf7ef27ab
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/142963
Tested-by: Jenkins
Reviewed-by: خالد حسني <khaled@aliftype.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/vcl/inc/font/PhysicalFontFace.hxx b/vcl/inc/font/PhysicalFontFace.hxx
index ae0e6ad7d5bf..6e99ae4a098c 100644
--- a/vcl/inc/font/PhysicalFontFace.hxx
+++ b/vcl/inc/font/PhysicalFontFace.hxx
@@ -194,16 +194,15 @@ public:
         return nullptr;
     }
 
-    virtual std::vector<hb_variation_t> GetVariations() const { return {}; };
+    virtual const std::vector<hb_variation_t>& GetVariations() const;
 
 protected:
     mutable hb_face_t* mpHbFace;
     mutable hb_font_t* mpHbUnscaledFont;
     mutable FontCharMapRef mxCharMap;
-    mutable vcl::FontCapabilities maFontCapabilities;
-    mutable bool mbFontCapabilitiesRead;
-    mutable std::vector<ColorPalette> maColorPalettes;
-    mutable std::vector<hb_variation_t> m_aVariations;
+    mutable std::optional<vcl::FontCapabilities> mxFontCapabilities;
+    mutable std::optional<std::vector<ColorPalette>> mxColorPalettes;
+    mutable std::optional<std::vector<hb_variation_t>> mxVariations;
 
     explicit PhysicalFontFace(const FontAttributes&);