Add support for CPAL / COLR tables color emoji

Require freetype 2.10, emoji can be Windows 10 Segoe UI Emoji for
example

src/font/font_manager.cpp

@@ -408,8 +408,11 @@ void FontManager::shape(const std::u32string& text,
                 }
             }
             prev_face = cur_face;
-            if (!FT_HAS_COLOR(cur_face))
+            if (!FT_HAS_COLOR(cur_face) ||
+                (FT_HAS_COLOR(cur_face) && cur_face->num_fixed_sizes == 0))
             {
+                // Handle color emoji with CPAL / COLR tables
+                // (num_fixed_sizes == 0)
                 checkFTError(FT_Set_Pixel_Sizes(cur_face, 0,
                     m_shaping_dpi), "setting DPI");
             }
@@ -574,18 +577,55 @@ FT_Face FontManager::loadColorEmoji()
         return NULL;
     }
 
-    if (!FT_HAS_COLOR(face) || face->num_fixed_sizes == 0)
+    if (!FT_HAS_COLOR(face))
     {
         Log::error("FontManager", "Bad %s color emoji, ignored.",
             GUIEngine::getSkin()->getColorEmojiTTF().c_str());
         checkFTError(FT_Done_Face(face), "removing faces for emoji");
         return NULL;
     }
-    // Use the largest size available, it will be scaled to regular face ttf
+    if (face->num_fixed_sizes != 0)
-    // when loading the glyph, so it can reduce the blurring effect
+    {
-    m_shaping_dpi = face->available_sizes[face->num_fixed_sizes - 1].height;
+        // Use the largest size available, it will be scaled to regular face ttf
-    checkFTError(FT_Select_Size(face, face->num_fixed_sizes - 1),
+        // when loading the glyph, so it can reduce the blurring effect
-        "setting color emoji size");
+        m_shaping_dpi = face->available_sizes[face->num_fixed_sizes - 1].height;
+        checkFTError(FT_Select_Size(face, face->num_fixed_sizes - 1),
+            "setting color emoji size");
+    }
+
+    uint32_t smiley = 0x1f603;
+    uint32_t glyph_index = FT_Get_Char_Index(face, smiley);
+    if (glyph_index == 0)
+    {
+        Log::error("FontManager", "%s doesn't make 0x1f603 smiley, ignored.",
+            GUIEngine::getSkin()->getColorEmojiTTF().c_str());
+        checkFTError(FT_Done_Face(face), "removing faces for emoji");
+        return NULL;
+    }
+    FT_GlyphSlot slot = face->glyph;
+    if (FT_HAS_COLOR(face) && face->num_fixed_sizes != 0)
+    {
+        checkFTError(FT_Load_Glyph(face, glyph_index,
+            FT_LOAD_DEFAULT | FT_LOAD_COLOR), "loading a glyph");
+    }
+    else
+    {
+        checkFTError(FT_Set_Pixel_Sizes(face, 0, 16), "setting DPI");
+        checkFTError(FT_Load_Glyph(face, glyph_index,
+            FT_LOAD_DEFAULT | FT_LOAD_COLOR), "loading a glyph");
+        checkFTError(FT_Render_Glyph(slot,
+            FT_RENDER_MODE_NORMAL), "rendering a glyph to bitmap");
+    }
+
+    FT_Bitmap* bits = &(slot->bitmap);
+    if (!bits || bits->pixel_mode != FT_PIXEL_MODE_BGRA)
+    {
+        Log::error("FontManager", "%s doesn't have color, ignored.",
+            GUIEngine::getSkin()->getColorEmojiTTF().c_str());
+        checkFTError(FT_Done_Face(face), "removing faces for emoji");
+        return NULL;
+    }
+
     m_has_color_emoji = true;
     return face;
 }   // loadColorEmoji
@@ -602,10 +642,11 @@ void FontManager::loadFonts()
     std::vector<FT_Face> normal_ttf = loadTTF(
         GUIEngine::getSkin()->getNormalTTF());
     std::vector<FT_Face> bold_ttf = normal_ttf;
+    FT_Face color_emoji = NULL;
     if (!ProfileWorld::isNoGraphics())
     {
         assert(!normal_ttf.empty());
-        FT_Face color_emoji = loadColorEmoji();
+        color_emoji = loadColorEmoji();
         if (!normal_ttf.empty() && color_emoji != NULL)
         {
             // Put color emoji after 1st default font so can use it before wqy
@@ -634,6 +675,17 @@ void FontManager::loadFonts()
     regular->getFaceTTF()->loadTTF(normal_ttf);
 #endif
     regular->init();
+
+#ifndef SERVER_ONLY
+    if (color_emoji && color_emoji->num_fixed_sizes == 0)
+    {
+        // This color emoji has CPAL / COLR tables so it's scalable
+        m_shaping_dpi = regular->getDPI();
+        // Update inverse shaping from m_shaping_dpi
+        regular->setDPI();
+    }
+#endif
+
     m_fonts.push_back(regular);
     m_font_type_map[std::type_index(typeid(RegularFace))] = font_loaded++;
 

src/font/font_with_face.cpp

@@ -195,7 +195,7 @@ void FontWithFace::insertGlyph(unsigned font_number, unsigned glyph_index)
     FT_Face cur_face = m_face_ttf->getFace(font_number);
     FT_GlyphSlot slot = cur_face->glyph;
 
-    if (FT_HAS_COLOR(cur_face))
+    if (FT_HAS_COLOR(cur_face) && cur_face->num_fixed_sizes != 0)
     {
         font_manager->checkFTError(FT_Load_Glyph(cur_face, glyph_index,
             FT_LOAD_DEFAULT | FT_LOAD_COLOR), "loading a glyph");
@@ -207,8 +207,10 @@ void FontWithFace::insertGlyph(unsigned font_number, unsigned glyph_index)
         font_manager->checkFTError(FT_Set_Pixel_Sizes(cur_face, 0, getDPI()),
             "setting DPI");
 
+        unsigned flag = FT_HAS_COLOR(cur_face) ?
+            (FT_LOAD_DEFAULT | FT_LOAD_COLOR) : FT_LOAD_DEFAULT;
         font_manager->checkFTError(FT_Load_Glyph(cur_face, glyph_index,
-            FT_LOAD_DEFAULT), "loading a glyph");
+            flag), "loading a glyph");
 
         font_manager->checkFTError(shapeOutline(&(slot->outline)),
             "shaping outline");

src/font/font_with_face.hpp

@@ -216,8 +216,6 @@ private:
     /** Add a character into \ref m_new_char_holder for lazy loading later. */
     void addLazyLoadChar(wchar_t c)            { m_new_char_holder.insert(c); }
     // ------------------------------------------------------------------------
-    void setDPI();
-    // ------------------------------------------------------------------------
     /** Override it if sub-class should not do lazy loading characters. */
     virtual bool supportLazyLoadChar() const                   { return true; }
     // ------------------------------------------------------------------------
@@ -307,6 +305,8 @@ public:
     float getInverseShaping() const               { return m_inverse_shaping; }
     // ------------------------------------------------------------------------
     virtual bool useColorGlyphPage() const                    { return false; }
+    // ------------------------------------------------------------------------
+    void setDPI();
 };   // FontWithFace
 
 #endif