add is italic check for font file

src/libslic3r/Emboss.cpp

@@ -45,12 +45,12 @@ std::optional<stbtt_fontinfo> Private::load_font_info(const Emboss::Font &font)
 {
     int font_offset = stbtt_GetFontOffsetForIndex(font.buffer.data(), font.index);
     if (font_offset < 0) {
-        std::cerr << "Font index("<<font.index<<") doesn't exist.";
+        std::cerr << "Font index("<<font.index<<") doesn't exist." << std::endl;
         return {};        
     }
     stbtt_fontinfo font_info;
     if (stbtt_InitFont(&font_info, font.buffer.data(), font_offset) == 0) {
-        std::cerr << "Can't initialize font.";
+        std::cerr << "Can't initialize font." << std::endl;
         return {};
     }
     return font_info;
@@ -437,7 +437,7 @@ std::optional<Emboss::Font> Emboss::load_font(std::vector<unsigned char> data)
     --index; // last one is bad
     // at least one font must be inside collection
     if (index < 1) {
-        std::cerr << "There is no font collection inside data.";
+        std::cerr << "There is no font collection inside data." << std::endl;
         return {};
     }
     // select default font on index 0
@@ -457,18 +457,18 @@ std::optional<Emboss::Font> Emboss::load_font(const char *file_path)
 {
     FILE *file = fopen(file_path, "rb");
     if (file == nullptr) {
-        std::cerr << "Couldn't open " << file_path << " for reading.";
+        std::cerr << "Couldn't open " << file_path << " for reading." << std::endl;
         return {};
     }
 
     // find size of file
     if (fseek(file, 0L, SEEK_END) != 0) {
-        std::cerr << "Couldn't fseek file " << file_path << " for size measure.";
+        std::cerr << "Couldn't fseek file " << file_path << " for size measure." << std::endl;
         return {};
     }
     size_t size = ftell(file);
     if (size == 0) {
-        std::cerr << "Size of font file is zero. Can't read.";
+        std::cerr << "Size of font file is zero. Can't read." << std::endl;
         return {};    
     }
     rewind(file);
@@ -476,7 +476,7 @@ std::optional<Emboss::Font> Emboss::load_font(const char *file_path)
     std::vector<unsigned char> buffer(size);
     size_t count_loaded_bytes = fread((void *) &buffer.front(), 1, size, file);
     if (count_loaded_bytes != size) {
-        std::cerr << "Different loaded(from file) data size.";
+        std::cerr << "Different loaded(from file) data size." << std::endl;
         return {};
     }
     return load_font(std::move(buffer));
@@ -488,7 +488,7 @@ std::optional<Emboss::Font> Emboss::load_font(HFONT hfont)
 {
     HDC hdc = ::CreateCompatibleDC(NULL);
     if (hdc == NULL) {
-        std::cerr << "Can't create HDC by CreateCompatibleDC(NULL).";
+        std::cerr << "Can't create HDC by CreateCompatibleDC(NULL)." << std::endl;
         return {};
     }
 
@@ -506,7 +506,7 @@ std::optional<Emboss::Font> Emboss::load_font(HFONT hfont)
     }
 
     if (size == 0 || size == GDI_ERROR) {
-        std::cerr << "HFONT doesn't have size.";
+        std::cerr << "HFONT doesn't have size." << std::endl;
         ::DeleteDC(hdc);
         return {};    
     }
@@ -515,7 +515,7 @@ std::optional<Emboss::Font> Emboss::load_font(HFONT hfont)
     size_t loaded_size = ::GetFontData(hdc, dwTable, dwOffset, buffer.data(), size);
     ::DeleteDC(hdc);
     if (size != loaded_size) {
-        std::cerr << "Different loaded(from HFONT) data size.";
+        std::cerr << "Different loaded(from HFONT) data size." << std::endl;
         return {};    
     }
 
@@ -601,6 +601,43 @@ ExPolygons Emboss::text2shapes(Font &          font,
     return Private::dilate_to_unique_points(result);
 }
 
+bool Emboss::is_italic(Font &font) { 
+    std::optional<stbtt_fontinfo> font_info_opt = 
+        Private::load_font_info(font);
+
+    if (!font_info_opt.has_value()) return false;
+    stbtt_fontinfo *info = &(*font_info_opt);
+
+    // https://docs.microsoft.com/cs-cz/typography/opentype/spec/name
+    // https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6name.html
+    // 2 ==> Style / Subfamily name
+    int name_id = 2;
+    int length;
+    const char* value = stbtt_GetFontNameString(info, &length,
+                                               STBTT_PLATFORM_ID_MICROSOFT,
+                                               STBTT_MS_EID_UNICODE_BMP,
+                                               STBTT_MS_LANG_ENGLISH,                            
+                                               name_id);
+
+    // value is big endian utf-16 i need extract only normal chars
+    std::string value_str;
+    value_str.reserve(length / 2);
+    for (int i = 1; i < length; i += 2)
+        value_str.push_back(value[i]);
+
+    // lower case
+    std::transform(value_str.begin(), value_str.end(), value_str.begin(),
+                   [](unsigned char c) { return std::tolower(c); });
+
+    const std::vector<std::string> italics({"italic", "oblique"});
+    for (const std::string &it : italics) { 
+        if (value_str.find(it) != std::string::npos) { 
+            return true; 
+        }
+    }
+    return false; 
+}
+
 indexed_triangle_set Emboss::polygons2model(const ExPolygons &shape2d,
                                             const IProject &projection)
 {