_LoadFontImpl: fill debug ImFontConfig->Name (cf pthom/imgui_bundle#263)

src/hello_imgui/impl/hello_imgui_font.cpp

@@ -10,6 +10,8 @@
 #endif
 
 #include <vector>
+#include <cstring>
+#include <cmath>
 
 #ifdef IOS
 #include "hello_imgui/internal/platform/getAppleBundleResourcePath.h"
@@ -122,12 +124,46 @@ namespace HelloImGui
             return 1.f;
     }
 
+    // Fills ImFontConfig->Name with the base filename of the font file + the font size
+    // (ImFontConfig->Name is only used for debugging purposes, and displayed in the Style Editor)
+    static void Priv_CopyDebugFontNameToFontConfig(
+        const std::string& fontFilename,
+        float fontSize,
+        ImFontConfig* dstFontConfig)
+    {
+        // Step 1: Extract the base filename without path
+        std::string filename = fontFilename;
+        size_t lastSlash = filename.find_last_of("/\\");
+        if (lastSlash != std::string::npos) {
+            filename = filename.substr(lastSlash + 1);
+        }
+
+        // Step 2: Remove the extension
+        size_t lastDot = filename.find_last_of('.');
+        if (lastDot != std::string::npos) {
+            filename = filename.substr(0, lastDot);
+        }
+
+        // Step 3: Round fontSize to the nearest integer
+        int roundedSize = static_cast<int>(std::lround(fontSize));
+
+        // Step 4: Create the name string (e.g., "Arial 10")
+        std::string nameWithSize = filename + " " + std::to_string(roundedSize);
+
+        // Step 5: Copy the result into dstFontConfig->Name, ensuring no overflow
+        int bufferSize = sizeof(dstFontConfig->Name);
+        std::strncpy(dstFontConfig->Name, nameWithSize.c_str(), bufferSize - 1);
+        dstFontConfig->Name[bufferSize - 1] = '\0'; // Ensure null termination
+    }
+
     ImFont* _LoadFontImpl(const std::string & fontFilename, float fontSize_, const FontLoadingParams& params_)
     {
         gDidCallHelloImGuiLoadFontTTF = true;
 
         FontLoadingParams params = params_;
 
+        Priv_CopyDebugFontNameToFontConfig(fontFilename, fontSize_, &params.fontConfig);
+
         // Font oversampling (set by dpiAwareParams)
         {
             const auto& dpiAwareParams = HelloImGui::GetDpiAwareParams();