Constness improvmenet of Emboss::FontFile / FontManager.

FontFile is returned by shared_ptr<const FontFile>, which makes it clear
that the FontFile must not be modified.
Because FontFile caches glyphs, a global mutex for all FontFile instances
was added guarding the glyph cache.
FIXME change true type font index in collection atomically, by duplicating the font!
         font_file->index = i;

src/libslic3r/Emboss.cpp

@@ -24,9 +24,8 @@ public:
 
     static std::optional<stbtt_fontinfo> load_font_info(const Emboss::FontFile &font);
     static std::optional<stbtt_fontinfo> load_font_info(const unsigned char *data, unsigned int index = 0);
-    static std::optional<Emboss::Glyph> get_glyph(stbtt_fontinfo &font_info, int unicode_letter, float flatness);
-    static std::optional<Emboss::Glyph> get_glyph(int unicode, const Emboss::FontFile &font, const FontProp &font_prop, 
-        Emboss::Glyphs &cache, std::optional<stbtt_fontinfo> &font_info_opt);
+    static std::optional<Emboss::Glyph> get_glyph(const stbtt_fontinfo &font_info, int unicode_letter, float flatness);
+    static std::optional<Emboss::Glyph> get_glyph(int unicode, const Emboss::FontFile &font, const FontProp &font_prop, std::optional<stbtt_fontinfo> &font_info_opt);
 
     static FontItem create_font_item(std::wstring name, std::wstring path);
 
@@ -63,7 +62,7 @@ std::optional<stbtt_fontinfo> Private::load_font_info(
     return font_info;
 }
 
-std::optional<Emboss::Glyph> Private::get_glyph(stbtt_fontinfo &font_info, int unicode_letter, float flatness)
+std::optional<Emboss::Glyph> Private::get_glyph(const stbtt_fontinfo &font_info, int unicode_letter, float flatness)
 {
     int glyph_index = stbtt_FindGlyphIndex(&font_info, unicode_letter);
     if (glyph_index == 0) {
@@ -128,13 +127,9 @@ std::optional<Emboss::Glyph> Private::get_glyph(
     int                            unicode,
     const Emboss::FontFile &       font,
     const FontProp &               font_prop,
-    Emboss::Glyphs &               cache,
     std::optional<stbtt_fontinfo> &font_info_opt)
 {
     const double RESOLUTION = 0.0125; // TODO: read from printer configuration
-    auto glyph_item = cache.find(unicode);
-    if (glyph_item != cache.end())
-        return glyph_item->second;
     
     if (!font_info_opt.has_value()) {
         font_info_opt = Private::load_font_info(font);
@@ -182,8 +177,6 @@ std::optional<Emboss::Glyph> Private::get_glyph(
     // unify multipoints with similar position. Could appear after union
     dilate_to_unique_points(glyph_opt->shape); 
 
-    cache[unicode] = *glyph_opt;
-
     return glyph_opt;
 }
 
@@ -593,7 +586,7 @@ std::optional<Emboss::Glyph> Emboss::letter2glyph(const FontFile &font,
     return Private::get_glyph(*font_info_opt, letter, flatness);
 }
 
-ExPolygons Emboss::text2shapes(FontFile &      font,
+ExPolygons Emboss::text2shapes(const FontFile &font,
                                const char *    text,
                                const FontProp &font_prop)
 {
@@ -617,14 +610,26 @@ ExPolygons Emboss::text2shapes(FontFile &      font,
         if (wc == '\t') {
             // '\t' = 4*space => same as imgui
             const int count_spaces = 4;
-            std::optional<Glyph> space_opt = Private::get_glyph(int(' '), font, font_prop, font.cache, font_info_opt);
+            auto space = int(' ');
+            std::optional<Glyph> space_opt = font.get_glyph(space);
+            if (! space_opt) {
+                space_opt = Private::get_glyph(space, font, font_prop, font_info_opt);
+                if (space_opt)
+                    font.cache_glyph(space, *space_opt);
+            }
             if (!space_opt.has_value()) continue;
             cursor.x() += count_spaces * space_opt->advance_width;
             continue;
         }
 
         int unicode = static_cast<int>(wc);
-        std::optional<Glyph> glyph_opt = Private::get_glyph(unicode, font, font_prop, font.cache, font_info_opt);
+        std::optional<Glyph> glyph_opt = font.get_glyph(unicode);
+        if (! glyph_opt) {
+            glyph_opt = Private::get_glyph(unicode, font, font_prop, font_info_opt);
+            if (glyph_opt)
+                font.cache_glyph(unicode, *glyph_opt);
+        }
+
         if (!glyph_opt.has_value()) continue;
         
         // move glyph to cursor position
@@ -652,7 +657,7 @@ void Emboss::apply_transformation(const FontProp &font_prop,
     }
 }
 
-bool Emboss::is_italic(FontFile &font) { 
+bool Emboss::is_italic(const FontFile &font) { 
     std::optional<stbtt_fontinfo> font_info_opt = 
         Private::load_font_info(font);
 
@@ -814,3 +819,32 @@ Transform3d Emboss::create_transformation_onto_surface(const Vec3f &position,
     transform.rotate(up_rot);
     return transform;
 }
+
+static std::mutex FontFile_cache_mutex;
+
+std::optional<Emboss::Glyph> Emboss::FontFile::get_glyph(int unicode) const
+{
+    std::lock_guard<std::mutex> guard(FontFile_cache_mutex);
+    auto glyph_item = m_cache.find(unicode);
+    if (glyph_item != m_cache.end())
+        return glyph_item->second;
+    return {};
+}
+
+void Emboss::FontFile::cache_glyph(int unicode, Emboss::Glyph glyph) const
+{
+    std::lock_guard<std::mutex> guard(FontFile_cache_mutex);
+    m_cache[unicode] = std::move(glyph);
+}
+
+void Emboss::FontFile::clear_glyph_cache() const
+{
+    std::lock_guard<std::mutex> guard(FontFile_cache_mutex);
+    m_cache.clear();
+}
+
+size_t Emboss::FontFile::glyph_cache_size() const
+{
+    std::lock_guard<std::mutex> guard(FontFile_cache_mutex);
+    return m_cache.size();
+}

src/libslic3r/Emboss.hpp

@@ -5,6 +5,7 @@
 #include <set>
 #include <optional>
 #include <memory>
+#include <mutex>
 #include <admesh/stl.h> // indexed_triangle_set
 #include "Polygon.hpp"
 #include "ExPolygon.hpp"
@@ -75,8 +76,6 @@ public:
         // for convert font units to pixel
         int unit_per_em;
 
-        Emboss::Glyphs cache; // cache of glyphs
-
         FontFile(std::vector<unsigned char> &&buffer,
                  unsigned int                 count,
                  int                          ascent,
@@ -97,6 +96,17 @@ public:
                    buffer.size() == other.buffer.size() &&
                    buffer == other.buffer;
         }
+
+        std::optional<Emboss::Glyph> get_glyph(int unicode) const;
+        // These two methods modifying cache are marked as const, because their
+        // access to the cache is guarded by a global mutex specific to all FontFile instances.
+        void                         cache_glyph(int unicode, Emboss::Glyph glyph) const;
+        void                         clear_glyph_cache() const;
+        size_t                       glyph_cache_size() const;
+
+    private:
+        // Cache of glyphs, guarded by a global mutex specific to all FontFile instances.
+        mutable Emboss::Glyphs m_cache;
     };
 
     /// <summary>
@@ -130,7 +140,7 @@ public:
     /// <param name="text">Characters to convert</param>
     /// <param name="font_prop">User defined property of the font</param>
     /// <returns>Inner polygon cw(outer ccw)</returns>
-    static ExPolygons text2shapes(FontFile & font,
+    static ExPolygons text2shapes(const FontFile &font,
                                   const char *    text,
                                   const FontProp &font_prop);
 
@@ -149,7 +159,7 @@ public:
     /// </summary>
     /// <param name="font">Selector of font</param>
     /// <returns>True when the font description contains italic/obligue otherwise False</returns>
-    static bool is_italic(FontFile &font);
+    static bool is_italic(const FontFile &font);
 
     /// <summary>
     /// Project 2d point into space

src/slic3r/GUI/Gizmos/GLGizmoEmboss.cpp

@@ -662,7 +662,7 @@ bool GLGizmoEmboss::process()
     if (m_volume == nullptr) return false;
 
     // exist loaded font?
-    std::shared_ptr<Emboss::FontFile>& font_file = m_font_manager.get_font_file();
+    std::shared_ptr<const Emboss::FontFile>& font_file = m_font_manager.get_font_file();
     if (font_file == nullptr) return false;
     auto data = std::make_unique<EmbossDataUpdate>(font_file,
                                              create_configuration(),
@@ -1224,7 +1224,7 @@ void GLGizmoEmboss::draw_style_list() {
 bool GLGizmoEmboss::italic_button()
 {
     std::optional<wxFont> &wx_font = m_font_manager.get_wx_font(); 
-    std::shared_ptr<Emboss::FontFile> &font_file = m_font_manager.get_font_file();
+    std::shared_ptr<const Emboss::FontFile> &font_file = m_font_manager.get_font_file();
     if (!wx_font.has_value() || font_file == nullptr) { 
         draw_icon(IconType::italic, IconState::disabled);
         return false;
@@ -1266,7 +1266,7 @@ bool GLGizmoEmboss::italic_button()
 
 bool GLGizmoEmboss::bold_button() {
     std::optional<wxFont> &wx_font = m_font_manager.get_wx_font();
-    std::shared_ptr<Emboss::FontFile> &font_file = m_font_manager.get_font_file();
+    std::shared_ptr<const Emboss::FontFile> &font_file = m_font_manager.get_font_file();
     if (!wx_font.has_value() || font_file==nullptr) {
         draw_icon(IconType::bold, IconState::disabled);
         return false;
@@ -1576,7 +1576,7 @@ void GLGizmoEmboss::do_rotate(float relative_z_angle)
 
 void GLGizmoEmboss::draw_advanced()
 {
-    std::shared_ptr<Emboss::FontFile>& font_file = m_font_manager.get_font_file();
+    std::shared_ptr<const Emboss::FontFile>& font_file = m_font_manager.get_font_file();
     if (font_file == nullptr) { 
         ImGui::Text("%s", _u8L("Advanced font options could be change only for corect font.\nStart with select correct font.").c_str());
         return;
@@ -1589,7 +1589,7 @@ void GLGizmoEmboss::draw_advanced()
         ", descent=" + std::to_string(font_file->descent) +
         ", lineGap=" + std::to_string(font_file->linegap) +
         ", unitPerEm=" + std::to_string(font_file->unit_per_em) +
-        ", cache(" + std::to_string(font_file->cache.size()) + " glyphs)";
+        ", cache(" + std::to_string(font_file->glyph_cache_size()) + " glyphs)";
     if (font_file->count > 1) ff_property += 
         ", collect=" + std::to_string(font_file->index + 1) + "/" + std::to_string(font_file->count);
     m_imgui->text_colored(ImGuiWrapper::COL_GREY_DARK, ff_property);
@@ -1698,7 +1698,8 @@ void GLGizmoEmboss::draw_advanced()
                 ImGui::PushID(1 << (10 + i));
                 bool is_selected = i == font_file->index;
                 if (ImGui::Selectable(std::to_string(i).c_str(), is_selected)) {
-                    font_file->index = i;
+//FIXME change true type font index in collection atomically, by duplicating the font!
+//                    font_file->index = i;
                     exist_change = true;
                 }
                 ImGui::PopID();

src/slic3r/GUI/Jobs/EmbossJob.cpp

@@ -240,10 +240,10 @@ TriangleMesh EmbossCreateJob::create_default_mesh()
     return triangle_mesh;
 }
 
-TriangleMesh EmbossCreateJob::create_mesh(const char *      text,
-                                          Emboss::FontFile &font,
-                                          const FontProp &  font_prop,
-                                          Ctl &             ctl)
+TriangleMesh EmbossCreateJob::create_mesh(const char *            text,
+                                          const Emboss::FontFile &font,
+                                          const FontProp &        font_prop,
+                                          Ctl &                   ctl)
 {
     ExPolygons shapes = Emboss::text2shapes(font, text, font_prop);
     if (shapes.empty()) return {};

src/slic3r/GUI/Jobs/EmbossJob.hpp

@@ -46,10 +46,10 @@ public:
     /// <param name="font_prop">Property of font</param>
     /// <param name="ctl">Control for job, check of cancelation</param>
     /// <returns>Triangle mesh model</returns>
-    static TriangleMesh create_mesh(const char *      text,
-                                    Emboss::FontFile &font,
-                                    const FontProp &  font_prop,
-                                    Ctl &             ctl);
+    static TriangleMesh create_mesh(const char *            text,
+                                    const Emboss::FontFile &font,
+                                    const FontProp &        font_prop,
+                                    Ctl &                   ctl);
 
 private:
     static TriangleMesh create_default_mesh();
@@ -62,14 +62,14 @@ private:
 struct EmbossDataBase
 {
     // Pointer on Data of font (glyph shapes)
-    std::shared_ptr<Emboss::FontFile> font_file;
+    std::shared_ptr<const Emboss::FontFile> font_file;
     // font item is not used for create object
     TextConfiguration text_configuration;
     // new volume name created from text
     std::string volume_name;
-    EmbossDataBase(std::shared_ptr<Emboss::FontFile> font_file,
-                   TextConfiguration                 text_configuration,
-                   std::string                       volume_name)
+    EmbossDataBase(std::shared_ptr<const Emboss::FontFile> font_file,
+                   TextConfiguration                       text_configuration,
+                   std::string                             volume_name)
         : font_file(std::move(font_file))
         , text_configuration(text_configuration)
         , volume_name(volume_name)
@@ -88,10 +88,10 @@ struct EmbossDataUpdate : public EmbossDataBase
     // unique identifier of volume to change
     // Change of volume change id, last change could disapear
     // ObjectID     volume_id;
-    EmbossDataUpdate(std::shared_ptr<Emboss::FontFile> font_file,
-                     TextConfiguration                 text_configuration,
-                     std::string                       volume_name,
-                     ModelVolume *                     volume)
+    EmbossDataUpdate(std::shared_ptr<const Emboss::FontFile> font_file,
+                     TextConfiguration                       text_configuration,
+                     std::string                             volume_name,
+                     ModelVolume *                           volume)
         : EmbossDataBase(std::move(font_file), text_configuration, volume_name)
         , volume(volume)
     {}
@@ -125,7 +125,7 @@ struct EmbossDataCreate: public EmbossDataBase
     // It is inside of GLGizmoEmboss object,
     // so I hope it will survive
 
-    EmbossDataCreate(std::shared_ptr<Emboss::FontFile> font_file,
+    EmbossDataCreate(std::shared_ptr<const Emboss::FontFile> font_file,
                      const TextConfiguration &         text_configuration,
                      const std::string &               volume_name,
                      ModelVolumeType                   volume_type,

src/slic3r/Utils/FontManager.cpp

@@ -146,7 +146,7 @@ void FontManager::add_fonts(FontList font_list)
         add_font(fi);
 }
 
-std::shared_ptr<Emboss::FontFile> &FontManager::get_font_file()
+std::shared_ptr<const Emboss::FontFile> &FontManager::get_font_file()
 {
     // TODO: fix not selected font
     //if (!is_activ_font()) return nullptr;
@@ -367,7 +367,7 @@ void FontManager::create_texture(size_t index, const std::string &text, GLuint&
     if (index >= m_font_list.size()) return;
     Item &item = m_font_list[index];
     const FontProp &font_prop = item.font_item.prop;
-    std::shared_ptr<Emboss::FontFile> &font_file = item.font_file;
+    std::shared_ptr<const Emboss::FontFile> &font_file = item.font_file;
     if (font_file == nullptr && !set_up_font_file(index)) return;
     ExPolygons shapes = Emboss::text2shapes(*font_file, text.c_str(), font_prop);
 
@@ -415,7 +415,7 @@ void FontManager::init_style_images(int max_width) {
     for (Item &item : m_font_list) {
         FontItem &        font_item = item.font_item;
         const FontProp &  font_prop = font_item.prop;
-        std::shared_ptr<Emboss::FontFile> &font_file = item.font_file;
+        std::shared_ptr<const Emboss::FontFile> &font_file = item.font_file;
         size_t index = &item - &m_font_list.front();
         if (font_file == nullptr && !set_up_font_file(index)) continue;
         if (font_file == nullptr) continue;
@@ -520,10 +520,10 @@ void FontManager::init_style_images(int max_width) {
 
 void FontManager::free_style_images() {
     if (!is_activ_font()) return;
-    std::shared_ptr<Emboss::FontFile> &font_file =
+    std::shared_ptr<const Emboss::FontFile> &font_file =
         m_font_list[m_font_selected].font_file;
-    if(font_file != nullptr)
-        font_file->cache.clear();
+    if (font_file != nullptr)
+        font_file->clear_glyph_cache();
 
     if (!m_exist_style_images) return;
     GLuint tex_id = (GLuint) (intptr_t) m_font_list.front().image->texture_id;

src/slic3r/Utils/FontManager.hpp

@@ -72,7 +72,7 @@ public:
     void add_fonts(FontList font_list);
 
     // getter on active font file for access to glyphs
-    std::shared_ptr<Emboss::FontFile> &get_font_file();
+    std::shared_ptr<const Emboss::FontFile> &get_font_file();
 
     // getter on active font item for access to font property
     const FontItem &get_font_item() const;
@@ -137,7 +137,7 @@ public:
         std::string truncated_name; 
 
         // share font file data with emboss job thread
-        std::shared_ptr<Emboss::FontFile> font_file = nullptr;
+        std::shared_ptr<const Emboss::FontFile> font_file;
 
         std::optional<size_t> imgui_font_index;