Load GPOS table only when selecting font features tab to speedup font usage

2 files changed, 16 insertions, 8 deletions

diff --git a/src/libnrtype/FontInstance.cpp b/src/libnrtype/FontInstance.cpp
index 2253b49c8..5a3d5aa9f 100644
--- a/src/libnrtype/FontInstance.cpp
+++ b/src/libnrtype/FontInstance.cpp
@@ -113,7 +113,8 @@ font_instance::font_instance() :
     maxGlyph(0),
     glyphs(nullptr),
     theFace(nullptr),
-    fontHasSVG(false)
+    fontHasSVG(false),
+    fulloaded(false)
 {
     //printf("font instance born\n");
     _ascent  = _ascent_max  = 0.8;
@@ -186,10 +187,12 @@ void font_instance::Unref()
     }
 }
 
-void font_instance::InitTheFace()
+void font_instance::InitTheFace(bool loadgsub)
 {
-    if (theFace == nullptr && pFont != nullptr) {
-
+    if (pFont != nullptr && (theFace == nullptr || (loadgsub && !fulloaded))) {
+        if (theFace) {
+            theFace = nullptr;
+        }
 #ifdef USE_PANGO_WIN32
 
         LOGFONT *lf=pango_win32_font_logfont(pFont);
@@ -213,8 +216,10 @@ void font_instance::InitTheFace()
 #endif
 
 #ifndef USE_PANGO_WIN32
-
-        readOpenTypeGsubTable( theFace, openTypeTables );
+        if (loadgsub) {
+            readOpenTypeGsubTable( theFace, openTypeTables );
+            fulloaded = true;
+        }
         readOpenTypeFvarAxes(  theFace, openTypeVarAxes );
         readOpenTypeSVGTable(  theFace, openTypeSVGGlyphs );
 
diff --git a/src/libnrtype/font-instance.h b/src/libnrtype/font-instance.h
index 0dc9c40d0..b30652bdd 100644
--- a/src/libnrtype/font-instance.h
+++ b/src/libnrtype/font-instance.h
@@ -47,8 +47,12 @@ public:
     // common glyph definitions for all the rasterfonts
     std::map<int, int>    id_to_no;
     int                   nbGlyph, maxGlyph;
+
     font_glyph*           glyphs;
 
+    // font is loaded with GSUB in 2 pass
+    bool    fulloaded;    
+
     // Map of OpenType tables found in font.
     std::map<Glib::ustring, OTSubstitution> openTypeTables;
 
@@ -71,7 +75,7 @@ public:
     void                 InstallFace(PangoFont* iFace); // utility; should reset the pFont field if loading failed
     // in case the PangoFont is a bitmap font, for example. that way, the calling function
     // will be able to check the validity of the font before installing it in loadedFaces
-    void                 InitTheFace();
+    void                 InitTheFace(bool loadgsub = false);
 
     int                  MapUnicodeChar(gunichar c); // calls the relevant unicode->glyph index function
     void                 LoadGlyph(int glyph_id);    // the main backend-dependent function
@@ -124,7 +128,6 @@ public:
 #endif
 
 private:
-
     // Font metrics in em-box units
     double  _ascent;       // Typographic ascent.
     double  _descent;      // Typographic descent.