Save/restore window size in UX settings.

PiperOrigin-RevId: 913695007
Change-Id: I3366b11a5de53292d4ffe0e4c46f866381624788

src/experimental/platform/hal/window.cc

@@ -177,6 +177,18 @@ void Window::SetTitle(std::string_view title) {
   SDL_SetWindowTitle(sdl_window_, title.data());
 }
 
+void Window::Resize(int width, int height) {
+  SDL_SetWindowSize(sdl_window_, width, height);
+  SDL_SetWindowPosition(sdl_window_, SDL_WINDOWPOS_CENTERED,
+                        SDL_WINDOWPOS_CENTERED);
+
+  SDL_GetWindowSize(sdl_window_, &width_, &height_);
+  int drawable_width = width_;
+  int drawable_height = height_;
+  SDL_GL_GetDrawableSize(sdl_window_, &drawable_width, &drawable_height);
+  scale_ = (float)drawable_width / (float)width_;
+}
+
 void Window::DisableWindowResizing() {
   SDL_SetWindowResizable(sdl_window_, SDL_FALSE);
 }

src/experimental/platform/hal/window.h

@@ -79,6 +79,9 @@ class Window {
   // Returns the graphics configuration of the window.
   GraphicsMode GetGraphicsMode() const;
 
+  // Resizes the window to the given width and height.
+  void Resize(int width, int height);
+
   // Enables window resizing.
   void EnableWindowResizing();
 

src/experimental/studio/app.cc

@@ -104,6 +104,11 @@ void App::SwitchGraphicsMode(int width, int height,
                                                window_config);
   renderer_ = std::make_unique<platform::Renderer>(
       window_->GetNativeWindowHandle(), gfx_mode_);
+
+  LoadSettings();
+  if (ui_.window_width > 0 && ui_.window_height > 0) {
+    window_->Resize(ui_.window_width, ui_.window_height);
+  }
 }
 
 void App::Recompile() {
@@ -791,6 +796,10 @@ void App::LoadSettings() {
 void App::SaveSettings() {
   if (!ini_path_.empty()) {
     std::string settings = ImGui::SaveIniSettingsToMemory();
+    if (window_) {
+      ui_.window_width = window_->GetWidth();
+      ui_.window_height = window_->GetHeight();
+    }
     platform::AppendIniSection(settings, "[Studio][UX]", ui_.ToDict());
 
     platform::KeyValues plugin_names;
@@ -1839,12 +1848,18 @@ App::UiState::Dict App::UiState::ToDict() const {
   return {
       {"theme", std::to_string(static_cast<int>(theme))},
       {"font_scale", std::to_string(font_scale)},
+      {"window_width", std::to_string(window_width)},
+      {"window_height", std::to_string(window_height)},
   };
 }
 
 void App::UiState::FromDict(const Dict& dict) {
+  using platform::ReadIniValue;
+
   *this = UiState();
   theme = ReadIniValue(dict, "theme", theme);
-  font_scale = platform::ReadIniValue(dict, "font_scale", font_scale);
+  window_width = ReadIniValue(dict, "window_width", window_width);
+  window_height = ReadIniValue(dict, "window_height", window_height);
+  font_scale = ReadIniValue(dict, "font_scale", font_scale);
 }
 }  // namespace mujoco::studio

src/experimental/studio/app.h

@@ -106,6 +106,8 @@ class App {
     int key_idx = 0;
     platform::GuiTheme theme = platform::GuiTheme::kLight;
     float font_scale = 1.0f;
+    int window_width = 0;
+    int window_height = 0;
 
     using Dict = std::unordered_map<std::string, std::string>;
     Dict ToDict() const;