Add support for multiple fonts

include/config.hpp

@@ -37,15 +37,15 @@ class Config
     // They can be overwritten from CLI arguments
     struct config_file_t
     {
-        std::string ocr_path;
-        std::string ocr_model;
-        std::string font;
-        int         delay            = -1;
-        bool        allow_out_edit   = false;
-        bool        real_full_screen = false;
-        bool        show_text_tools  = true;
-        bool        enable_vsync     = true;
-        bool        render_anns      = true;
+        std::string              ocr_path;
+        std::string              ocr_model;
+        std::vector<std::string> fonts;
+        int                      delay            = -1;
+        bool                     allow_out_edit   = false;
+        bool                     real_full_screen = false;
+        bool                     show_text_tools  = true;
+        bool                     enable_vsync     = true;
+        bool                     render_anns      = true;
     } File;
 
     // Only from CLI arguments
@@ -190,9 +190,11 @@ show-text-tools = true
 # or only when saving the selection (false)
 annotations-in-text-tools = true
 
-# Default font (absolute path or just name) for the whole application.
-# Leave/Make it empty, or commment it, to use ImGUI default font.
-font = "Arial.ttf"
+# Fonts to use for the application. Can be an absolute path, or just a name.
+# You can combine multiple fonts for multiple language support.
+# for example, using `Roboto-Regular.ttf` and `RobotoCJK-Regular.ttc` for Chinese, Japanese, and Korean support alongside English support.
+# If empty, or non-existent (commented out), oshot will use the default font for ImGUI.
+fonts = ["Arial.ttf"]
 )#";
 
 inline constexpr std::string_view oshot_help = (R"(Usage: oshot [OPTIONS]...

src/config.cpp

@@ -42,9 +42,41 @@ void Config::LoadConfigFile(const std::string& filename)
             err.source().begin.column);
     }
 
+    // Fonts
+    auto fonts = m_tbl.at_path("default.fonts");
+    if (fonts.is_array())
+    {
+        toml::array* font_arr = fonts.as_array();
+        if (font_arr)
+        {
+            File.fonts.reserve(font_arr->size());
+
+            size_t idx = 0;
+            for (auto&& font : *font_arr)
+            {
+                std::optional<std::string> font_opt = font.value<std::string>();
+
+                if (!font_opt.has_value())
+                {
+                    warn("Font at index {} is not a string!", idx);
+                    idx++;
+                    continue;
+                }
+
+                File.fonts.push_back(font_opt.value());
+                idx++;
+            }
+        }
+    }
+
+    auto font = m_tbl.at_path("default.font").value<std::string>();
+    if (font.has_value())
+    {
+        File.fonts.push_back(font.value());
+    }
+
     File.ocr_path         = GetValue<std::string>("default.ocr-path", "/usr/share/tessdata");
     File.ocr_model        = GetValue<std::string>("default.ocr-model", "eng");
-    File.font             = GetValue<std::string>("default.font", "");
     File.delay            = GetValue<int>("default.delay", -1);
     File.show_text_tools  = GetValue<bool>("default.show-text-tools", true);
     File.enable_vsync     = GetValue<bool>("default.vsync", true);

src/main_tool_metal.mm

@@ -172,17 +172,22 @@ int run_main_tool(const std::string& imgui_ini_path)
     io.IniFilename = imgui_ini_path.c_str();
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
 
-    if (!g_config->File.font.empty())
-    {
-        const auto& path = get_font_path(g_config->File.font);
-        if (!path.empty())
-            io.FontDefault =
-                io.Fonts->AddFontFromFileTTF(path.string().c_str(), 16.0f, nullptr, io.Fonts->GetGlyphRangesDefault());
-    }
-
     ImGui_ImplGlfw_InitForOther(window, true);  // "Other" = non-GL backend
     ImGui_ImplMetal_Init(device);
 
+    ImFontConfig font_cfg;
+
+    for (const std::string& font : g_config->File.fonts)
+    {
+        const fs::path& path = get_font_path(font);
+        io.Fonts->AddFontFromFileTTF(path.string().c_str(), 16.0f, &font_cfg);
+
+        // this value is false by default, and we can't set it to true without adding atleast one font first.
+        // so, after we add the first font, this will be true (and will stay true).
+        // MergeMode fills the gap in previous fonts with glyphs from this font, for example, adding Arabic glyphs to a non-Arabic font.
+        font_cfg.MergeMode = true;
+    }
+
     {
         const Result<>& res = ss_tool.StartWindow();
         if (!res.ok())

src/main_tool_opengl3.cpp

@@ -211,18 +211,23 @@ int run_main_tool(const std::string& imgui_ini_path)
     io.IniFilename = imgui_ini_path.c_str();
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
 
-    if (!g_config->File.font.empty())
-    {
-        const fs::path& path = get_font_path(g_config->File.font);
-        if (fs::exists(path))
-            io.FontDefault =
-                io.Fonts->AddFontFromFileTTF(path.string().c_str(), 16.0f, nullptr, io.Fonts->GetGlyphRangesDefault());
-    }
-
     // Setup Platform/Renderer backends
     ImGui_ImplGlfw_InitForOpenGL(window, true);
     ImGui_ImplOpenGL3_Init(glsl_version);
 
+    ImFontConfig font_cfg;
+
+    for (const std::string& font : g_config->File.fonts)
+    {
+        const fs::path& path = get_font_path(font);
+        io.Fonts->AddFontFromFileTTF(path.string().c_str(), 16.0f, &font_cfg);
+
+        // this value is false by default, and we can't set it to true without adding atleast one font first.
+        // so, after we add the first font, this will be true (and will stay true).
+        // MergeMode fills the gap in previous fonts with glyphs from this font, for example, adding Arabic glyphs to a non-Arabic font.
+        font_cfg.MergeMode = true;
+    }
+
     {
         const Result<>& res = ss_tool.StartWindow();
         if (!res.ok())

src/screenshot_tool.cpp

@@ -238,7 +238,7 @@ Result<> ScreenshotTool::StartWindow()
     m_io    = ImGui::GetIO();
     m_state = ToolState::Selecting;
 
-    m_inputs.ann_font = g_config->File.font;
+    m_inputs.ann_font = g_config->File.fonts.size() > 0 ? g_config->File.fonts[0] : "";
     m_show_text_tools = g_config->File.show_text_tools;
 
     fit_to_screen(m_screenshot);