Faster fill/strokeText

src/CanvasRenderingContext2d.cc

@@ -2457,35 +2457,16 @@ Context2d::paintText(const Napi::CallbackInfo& info, bool stroke) {
     double fontSize = state->fontProperties.size;
     double toPx = fontSize / 1000;
 
-    FT_Face ftface;
-    FT_Error newFaceResult = FT_New_Memory_Face(
-      data->ft,
-      reinterpret_cast<const FT_Byte *>(run.face->data.get()),
-      run.face->data_len,
-      run.face->index,
-      &ftface
-    );
-
-    if (newFaceResult != 0) continue;
-
-    cairo_font_face_t* crface = cairo_ft_font_face_create_for_ft_face(ftface, 0);
-
-    static const cairo_user_data_key_t key{0};
-    cairo_status_t setDataResult = cairo_font_face_set_user_data(
-      crface,
-      &key,
-      ftface,
-      (cairo_destroy_func_t) FT_Done_Face
-    );
-
-    if (setDataResult) {
-      cairo_font_face_destroy(crface);
-      FT_Done_Face (ftface);
-      continue;
-    }
-
+    cairo_font_face_t* crface = cairo_ft_font_face_create_for_ft_face(run.face->ftface.get(), 0);
     cairo_set_font_face(context(), crface);
-    cairo_set_font_size(context(), fontSize);
+
+    // Be shy about cairo_set_font_size. This always recreates a scaled font,
+    // which destroys lots of caching. Scaled fonts are associated with the
+    // font's matrix, which is both for scaling from em to Cairo space and for
+    // fake italics. Just checking xx should therefore be reliable.
+    cairo_matrix_t m;
+    cairo_get_font_matrix(context(), &m);
+    if (m.xx != fontSize) cairo_set_font_size(context(), fontSize);
 
     size_t hbGlyphIndex = 0;
     while (hbGlyphIndex < run.glyphs.size()) {

src/Font.h

@@ -8,6 +8,8 @@
 
 #include <hb.h>
 #include <hb-ot.h>
+#include <freetype/freetype.h>
+#include <type_traits>
 
 enum class FontStyle {
   Normal,
@@ -42,6 +44,14 @@ struct HbFontDeleter {
   }
 };
 
+struct FT_FaceDeleter {
+  void operator()(FT_Face face) {
+    FT_Done_Face(face);
+  }
+};
+
+using FT_Face_Type = std::remove_pointer<FT_Face>::type;
+
 // Descriptors describe real fonts on the OS
 struct FontDescriptor : FontBase {
   std::unique_ptr<char[]> family;
@@ -53,6 +63,7 @@ struct FontDescriptor : FontBase {
   std::unique_ptr<file_char[]> url = nullptr;
   std::unique_ptr<uint8_t[]> data = nullptr;
   std::unique_ptr<hb_font_t, HbFontDeleter> hbfont = nullptr;
+  std::unique_ptr<FT_Face_Type, FT_FaceDeleter> ftface = nullptr;
   size_t data_len = 0;
   size_t index = 0;
   FontStatus status = FontStatus::Unloaded;
@@ -95,6 +106,22 @@ struct FontDescriptor : FontBase {
     hb_font_set_scale(hbfont.get(), 1000, 1000);
   }
 
+  void loadFtFont(FT_Library ft) {
+    FT_Face ftface;
+    FT_Error newFaceResult = FT_New_Memory_Face(
+      ft,
+      reinterpret_cast<const FT_Byte *>(data.get()),
+      data_len,
+      index,
+      &ftface
+    );
+    if (newFaceResult) {
+      status = FontStatus::Error;
+    } else {
+      this->ftface = std::unique_ptr<FT_Face_Type, FT_FaceDeleter>(ftface);
+    }
+  }
+
   void loadData() {
     FILE* file = nullptr;
     long file_size = 0;
@@ -134,9 +161,12 @@ struct FontDescriptor : FontBase {
     if (file) fclose(file);
   }
 
-  void load() {
+  void load(FT_Library ft) {
     if (status == FontStatus::Unloaded) loadData();
-    if (status == FontStatus::Loaded && hbfont == nullptr) loadHbFont();
+    if (status == FontStatus::Loaded && hbfont == nullptr) {
+      loadHbFont();
+      loadFtFont(ft);
+    }
   }
 };
 

src/FontLayout.cc

@@ -417,7 +417,7 @@ layoutText(
 
     while (shapingWorkList.size() && matchIndex < matches.size()) {
       auto face = matches[matchIndex];
-      face->load();
+      face->load(data->ft());
       if (!face->hbfont) {
         matchIndex++;
         continue;

src/InstanceData.h

@@ -15,6 +15,16 @@ using PlatformFontManager = FontManagerMacos;
 using PlatformFontManager = FontManagerLinux;
 #endif
 
+struct FT_Wrapper {
+  FT_Library ft;
+  FT_Wrapper() {
+    FT_Init_FreeType(&ft);
+  }
+  ~FT_Wrapper() {
+    FT_Done_FreeType(ft);
+  }
+};
+
 struct InstanceData {
   Napi::FunctionReference CanvasCtor;
   Napi::FunctionReference CanvasGradientCtor;
@@ -27,14 +37,10 @@ struct InstanceData {
   Napi::FunctionReference FontFaceCtor;
   Napi::ObjectReference jsFontSet;
   FontFaceSet* cppFontSet;
-  FT_Library ft;
+  // FT_Wrapper exists because, and it is located here so that, FT_Done_FreeType
+  // is called after ~PlatformFontManager. FT_Faces are all freed in
+  // FT_Done_FreeType. That can't happen before their backing buffers are freed.
+  FT_Wrapper _ft;
+  inline FT_Library ft() { return _ft.ft; }
   PlatformFontManager fontManager;
-
-  InstanceData() {
-    FT_Init_FreeType(&ft);
-  }
-
-  ~InstanceData() {
-    FT_Done_FreeType(ft);
-  }
 };