Added Noto Sans as default font.

private/raid/application.cpp

@@ -161,6 +161,35 @@ int Application::run(int argc, char** argv)
     return 0;
 }
 
+bool Application::loadFont(const fs::path& path)
+{
+    ImGuiIO& imguiIO = ImGui::GetIO();
+
+    std::unique_ptr<mijin::Stream> fontFile;
+    if (const mijin::StreamError error = mFS.open(path, mijin::FileOpenMode::READ, fontFile);
+            error != mijin::StreamError::SUCCESS)
+    {
+        msgError("Error opening font file {}: {}.", path.generic_string(), mijin::errorName(error));
+        return false;
+    }
+
+    mijin::TypelessBuffer data;
+    if (const mijin::StreamError readError = fontFile->readRest(data); readError != mijin::StreamError::SUCCESS)
+    {
+        msgError("Error reading font data from {}: {}.", path.generic_string(), mijin::errorName(readError));
+        return false;
+    }
+
+    // by default ImGui takes ownership of the data, that's now what we want
+    ImFontConfig config;
+    config.FontDataOwnedByAtlas = false;
+    imguiIO.Fonts->AddFontFromMemoryTTF(data.data(), static_cast<int>(data.byteSize()), 20, &config);
+
+    // but in that case Build() has to be run before the data gets deleted
+    imguiIO.Fonts->Build();
+    return true;
+}
+
 void Application::handleMessage(const Message& message)
 {
     switch (message.severity)
@@ -271,7 +300,15 @@ bool Application::initImGui()
     }
 
     // init font
-    imguiIO.Fonts->AddFontDefault();
+    if (imguiIO.Fonts->Fonts.empty())
+    {
+        static const char* const DEFAULT_FONT = "/data/fonts/NotoSans-Regular.ttf";
+        if (!loadFont(DEFAULT_FONT))
+        {
+            imguiIO.Fonts->AddFontDefault();
+        }
+    }
+
 
     return true;
 }