[UI] Allow loading custom font

- Unified font size to 12. This causes default UI to look a bit bigger
- Set oversample to 2 to make font more readable (especially custom fonts)

Author: Gliniak

src/xenia/ui/imgui_drawer.cc

@@ -21,6 +21,15 @@
 #include "xenia/ui/ui_event.h"
 #include "xenia/ui/window.h"
 
+#if XE_PLATFORM_WIN32
+#include <ShlObj_core.h>
+#endif
+
+DEFINE_path(
+    custom_font_path, "",
+    "Allows user to load custom font and use it instead of default one.",
+    "General");
+
 namespace xe {
 namespace ui {
 
@@ -98,38 +107,7 @@ void ImGuiDrawer::Initialize() {
   internal_state_ = ImGui::CreateContext();
   ImGui::SetCurrentContext(internal_state_);
 
-  auto& io = ImGui::GetIO();
-
-  // TODO(gibbed): disable imgui.ini saving for now,
-  // imgui assumes paths are char* so we can't throw a good path at it on
-  // Windows.
-  io.IniFilename = nullptr;
-
-  // Setup the font glyphs.
-  ImFontConfig font_config;
-  font_config.OversampleH = font_config.OversampleV = 1;
-  font_config.PixelSnapH = true;
-  static const ImWchar font_glyph_ranges[] = {
-      0x0020,
-      0x00FF,  // Basic Latin + Latin Supplement
-      0,
-  };
-  io.Fonts->AddFontFromMemoryCompressedBase85TTF(
-      kProggyTinyCompressedDataBase85, 10.0f, &font_config, font_glyph_ranges);
-  // TODO(benvanik): jp font on other platforms?
-  // https://github.com/Koruri/kibitaki looks really good, but is 1.5MiB.
-  const char* jp_font_path = "C:\\Windows\\Fonts\\msgothic.ttc";
-  if (std::filesystem::exists(jp_font_path)) {
-    ImFontConfig jp_font_config;
-    jp_font_config.MergeMode = true;
-    jp_font_config.OversampleH = jp_font_config.OversampleV = 1;
-    jp_font_config.PixelSnapH = true;
-    jp_font_config.FontNo = 0;
-    io.Fonts->AddFontFromFileTTF(jp_font_path, 12.0f, &jp_font_config,
-                                 io.Fonts->GetGlyphRangesJapanese());
-  } else {
-    XELOGW("Unable to load Japanese font; JP characters will be boxes");
-  }
+  InitializeFonts();
 
   auto& style = ImGui::GetStyle();
   style.ScrollbarRounding = 0;
@@ -218,6 +196,68 @@ std::optional<ImGuiKey> ImGuiDrawer::VirtualKeyToImGuiKey(VirtualKey vkey) {
   }
 }
 
+void ImGuiDrawer::InitializeFonts() {
+  auto& io = ImGui::GetIO();
+
+  const float default_font_size = 12.0f;
+  // TODO(gibbed): disable imgui.ini saving for now,
+  // imgui assumes paths are char* so we can't throw a good path at it on
+  // Windows.
+  io.IniFilename = nullptr;
+
+  // Setup the font glyphs.
+  ImFontConfig font_config;
+  font_config.OversampleH = font_config.OversampleV = 2;
+  font_config.PixelSnapH = true;
+
+  if (!cvars::custom_font_path.empty() &&
+      std::filesystem::exists(cvars::custom_font_path)) {
+    const std::string font_path = xe::path_to_utf8(cvars::custom_font_path);
+    ImFont* font = io.Fonts->AddFontFromFileTTF(
+        font_path.c_str(), default_font_size, &font_config,
+        io.Fonts->GetGlyphRangesDefault());
+
+    io.Fonts->Build();
+    // Something went wrong while loading custom font. Probably corrupted.
+    if (!font->IsLoaded()) {
+      XELOGE("Failed to load custom font: {}", font_path);
+      io.Fonts->Clear();
+    }
+  }
+
+  if (io.Fonts->Fonts.empty()) {
+    io.Fonts->AddFontFromMemoryCompressedBase85TTF(
+        kProggyTinyCompressedDataBase85, default_font_size, &font_config,
+        io.Fonts->GetGlyphRangesDefault());
+  }
+
+  // TODO(benvanik): jp font on other platforms?
+#if XE_PLATFORM_WIN32
+  PWSTR fonts_dir;
+  HRESULT result = SHGetKnownFolderPath(FOLDERID_Fonts, 0, NULL, &fonts_dir);
+  if (FAILED(result)) {
+    XELOGW("Unable to find Windows fonts directory");
+    return;
+  }
+
+  std::filesystem::path jp_font_path = std::wstring(fonts_dir);
+  jp_font_path.append("msgothic.ttc");
+  if (std::filesystem::exists(jp_font_path)) {
+    ImFontConfig jp_font_config;
+    jp_font_config.MergeMode = true;
+    jp_font_config.OversampleH = jp_font_config.OversampleV = 2;
+    jp_font_config.PixelSnapH = true;
+    jp_font_config.FontNo = 0;
+    io.Fonts->AddFontFromFileTTF(xe::path_to_utf8(jp_font_path).c_str(),
+                                 default_font_size, &jp_font_config,
+                                 io.Fonts->GetGlyphRangesJapanese());
+  } else {
+    XELOGW("Unable to load Japanese font; JP characters will be boxes");
+  }
+  CoTaskMemFree(static_cast<void*>(fonts_dir));
+#endif
+}
+
 void ImGuiDrawer::SetupFontTexture() {
   if (font_texture_ || !immediate_drawer_) {
     return;

src/xenia/ui/imgui_drawer.h

@@ -66,6 +66,7 @@ class ImGuiDrawer : public WindowInputListener, public UIDrawer {
 
  private:
   void Initialize();
+  void InitializeFonts();
 
   void SetupFontTexture();