Codechange: Scale sprite font height once on init instead of every call to GetHeight().

Scaling is not expensive, but it does not change either, and this avoids the need for a virtual method call. This cascades back to all GetCharacterHeight(FS_xxx) and FONT_HEIGHT_xxx calls.

(cherry picked from commit 9c6c0a0966)

src/fontcache.cpp

@@ -76,7 +76,6 @@ public:
 	virtual void ClearFontCache();
 	virtual const Sprite *GetGlyph(GlyphID key);
 	virtual uint GetGlyphWidth(GlyphID key);
-	virtual int GetHeight() const;
 	virtual bool GetDrawGlyphShadow();
 	virtual GlyphID MapCharToGlyph(WChar key) { assert(IsPrintable(key)); return SPRITE_GLYPH | key; }
 	virtual const void *GetFontTable(uint32 tag, size_t &length) { length = 0; return nullptr; }
@@ -91,6 +90,7 @@ public:
 SpriteFontCache::SpriteFontCache(FontSize fs) : FontCache(fs), glyph_to_spriteid_map(nullptr)
 {
 	this->InitializeUnicodeGlyphMap();
+	this->height = ScaleFontTrad(this->GetDefaultFontHeight(this->fs));
 }
 
 /**
@@ -167,6 +167,7 @@ void SpriteFontCache::ClearGlyphToSpriteMap()
 void SpriteFontCache::ClearFontCache()
 {
 	Layouter::ResetFontCache(this->fs);
+	this->height = ScaleFontTrad(this->GetDefaultFontHeight(this->fs));
 }
 
 const Sprite *SpriteFontCache::GetGlyph(GlyphID key)
@@ -183,11 +184,6 @@ uint SpriteFontCache::GetGlyphWidth(GlyphID key)
 	return SpriteExists(sprite) ? GetSprite(sprite, ST_FONT)->width + ScaleFontTrad(this->fs != FS_NORMAL ? 1 : 0) : 0;
 }
 
-int SpriteFontCache::GetHeight() const
-{
-	return ScaleFontTrad(this->height);
-}
-
 bool SpriteFontCache::GetDrawGlyphShadow()
 {
 	return false;

src/fontcache.h

@@ -49,7 +49,7 @@ public:
 	 * Get the height of the font.
 	 * @return The height of the font.
 	 */
-	virtual int GetHeight() const { return this->height; }
+	inline int GetHeight() const { return this->height; }
 
 	/**
 	 * Get the ascender value of the font.