Use Skia to load external (TTF/OTF) fonts

Related to aseprite/aseprite#4362

text/font_mgr.cpp

@@ -39,12 +39,12 @@ FontRef FontMgr::loadSpriteSheetFont(const char* filename, int scale)
   return font;
 }
 
-FontRef FontMgr::loadTrueTypeFont(const char* filename, int height)
+FontRef FontMgr::loadTrueTypeFont(const char* filename, float size)
 {
 #if LAF_FREETYPE
   if (!m_ft)
     m_ft.reset(new ft::Lib());
-  return FreeTypeFont::LoadFont(*m_ft.get(), filename, height);
+  return FreeTypeFont::LoadFont(*m_ft.get(), filename, size);
 #else
   return nullptr;
 #endif

text/font_mgr.h

@@ -23,7 +23,7 @@ namespace text {
     static FontMgrRef Make();
 
     FontRef loadSpriteSheetFont(const char* filename, int scale);
-    FontRef loadTrueTypeFont(const char* filename, int height);
+    virtual FontRef loadTrueTypeFont(const char* filename, float size);
     virtual FontRef makeFont(const TypefaceRef& typeface) = 0;
     virtual FontRef makeFont(const TypefaceRef& typeface, float size) = 0;
 

text/skia_font_mgr.cpp

@@ -109,6 +109,19 @@ SkiaFontMgr::~SkiaFontMgr()
 {
 }
 
+FontRef SkiaFontMgr::loadTrueTypeFont(const char* filename, float size)
+{
+  // Use the native impl from Skia to load the font file
+  sk_sp<SkTypeface> face = m_skFontMgr->makeFromFile(filename);
+  if (!face) {
+    // In other case try the FreeType impl
+    return FontMgr::loadTrueTypeFont(filename, size);
+  }
+
+  SkFont skFont(face, size);
+  return base::make_ref<SkiaFont>(skFont);
+}
+
 FontRef SkiaFontMgr::defaultFont(float size) const
 {
   sk_sp<SkTypeface> face =

text/skia_font_mgr.h

@@ -51,6 +51,8 @@ class SkiaFontMgr : public FontMgr {
   SkiaFontMgr();
   ~SkiaFontMgr();
 
+  FontRef loadTrueTypeFont(const char* filename, float size) override;
+
   FontRef defaultFont(float size) const override;
   FontRef makeFont(const TypefaceRef& typeface) override;
   FontRef makeFont(const TypefaceRef& typeface, float size) override;