SDL: Support high-dpi displays

src/duckstation-sdl/CMakeLists.txt

@@ -17,6 +17,7 @@ if(WIN32)
   target_sources(duckstation-sdl PRIVATE
     d3d11_host_display.cpp
     d3d11_host_display.h
+    duckstation-sdl.manifest
   )
   target_link_libraries(duckstation-sdl PRIVATE d3d11.lib dxgi.lib ${SDL2MAIN_LIBRARIES})
 endif()

src/duckstation-sdl/d3d11_host_display.cpp

@@ -156,10 +156,6 @@ std::tuple<u32, u32> D3D11HostDisplay::GetWindowSize() const
 
 void D3D11HostDisplay::WindowResized()
 {
-  SDL_GetWindowSize(m_window, &m_window_width, &m_window_height);
-  ImGui::GetIO().DisplaySize.x = static_cast<float>(m_window_width);
-  ImGui::GetIO().DisplaySize.y = static_cast<float>(m_window_height);
-
   m_swap_chain_rtv.Reset();
 
   HRESULT hr = m_swap_chain->ResizeBuffers(0, 0, 0, DXGI_FORMAT_UNKNOWN,
@@ -169,6 +165,15 @@ void D3D11HostDisplay::WindowResized()
 
   if (!CreateSwapChainRTV())
     Panic("Failed to recreate swap chain RTV after resize");
+
+  DXGI_SWAP_CHAIN_DESC desc;
+  if (SUCCEEDED(m_swap_chain->GetDesc(&desc)))
+  {
+    m_window_width = static_cast<int>(desc.BufferDesc.Width);
+    m_window_height = static_cast<int>(desc.BufferDesc.Height);
+    ImGui::GetIO().DisplaySize.x = static_cast<float>(m_window_width);
+    ImGui::GetIO().DisplaySize.y = static_cast<float>(m_window_height);
+  }
 }
 
 bool D3D11HostDisplay::CreateD3DDevice(bool debug_device)
@@ -334,6 +339,9 @@ bool D3D11HostDisplay::CreateD3DResources()
 
 bool D3D11HostDisplay::CreateImGuiContext()
 {
+  ImGui::GetIO().DisplaySize.x = static_cast<float>(m_window_width);
+  ImGui::GetIO().DisplaySize.y = static_cast<float>(m_window_height);
+
   if (!ImGui_ImplSDL2_InitForD3D(m_window) || !ImGui_ImplDX11_Init(m_device.Get(), m_context.Get()))
     return false;
 

src/duckstation-sdl/duckstation-sdl.manifest

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <asmv3:application>
+    <asmv3:windowsSettings>
+      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2</dpiAwareness>
+      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true</dpiAware>
+    </asmv3:windowsSettings>
+  </asmv3:application>
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/>
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/>
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
+    </application>
+  </compatibility>
+</assembly>

src/duckstation-sdl/duckstation-sdl.vcxproj

@@ -66,6 +66,9 @@
     <ClInclude Include="sdl_host_interface.h" />
     <ClInclude Include="sdl_settings_interface.h" />
   </ItemGroup>
+  <ItemGroup>
+    <Manifest Include="duckstation-sdl.manifest" />
+  </ItemGroup>
   <PropertyGroup Label="Globals">
     <ProjectGuid>{DAA8F93D-9C17-4DE2-BD0B-57891E0FF0D9}</ProjectGuid>
     <Keyword>Win32Proj</Keyword>

src/duckstation-sdl/duckstation-sdl.vcxproj.filters

@@ -15,4 +15,7 @@
     <ClInclude Include="sdl_settings_interface.h" />
     <ClInclude Include="imgui_impl_sdl.h" />
   </ItemGroup>
+  <ItemGroup>
+    <Manifest Include="duckstation-sdl.manifest" />
+  </ItemGroup>
 </Project>

src/duckstation-sdl/imgui_impl_sdl.cpp

@@ -388,15 +388,6 @@ void ImGui_ImplSDL2_NewFrame(SDL_Window* window)
     ImGuiIO& io = ImGui::GetIO();
     IM_ASSERT(io.Fonts->IsBuilt() && "Font atlas not built! It is generally built by the renderer back-end. Missing call to renderer _NewFrame() function? e.g. ImGui_ImplOpenGL3_NewFrame().");
 
-    // Setup display size (every frame to accommodate for window resizing)
-    int w, h;
-    int display_w, display_h;
-    SDL_GetWindowSize(window, &w, &h);
-    SDL_GL_GetDrawableSize(window, &display_w, &display_h);
-    io.DisplaySize = ImVec2((float)w, (float)h);
-    if (w > 0 && h > 0)
-        io.DisplayFramebufferScale = ImVec2((float)display_w / w, (float)display_h / h);
-
     // Setup time step (we don't use SDL_GetTicks() because it is using millisecond resolution)
     static Uint64 frequency = SDL_GetPerformanceFrequency();
     Uint64 current_time = SDL_GetPerformanceCounter();

src/duckstation-sdl/opengl_host_display.cpp

@@ -138,7 +138,7 @@ std::tuple<u32, u32> OpenGLHostDisplay::GetWindowSize() const
 
 void OpenGLHostDisplay::WindowResized()
 {
-  SDL_GetWindowSize(m_window, &m_window_width, &m_window_height);
+  SDL_GL_GetDrawableSize(m_window, &m_window_width, &m_window_height);
   ImGui::GetIO().DisplaySize.x = static_cast<float>(m_window_width);
   ImGui::GetIO().DisplaySize.y = static_cast<float>(m_window_height);
 }
@@ -264,6 +264,9 @@ bool OpenGLHostDisplay::CreateGLContext(bool debug_device)
     glEnable(GL_DEBUG_OUTPUT_SYNCHRONOUS);
   }
 
+  // this can change due to retina scaling on macos?
+  SDL_GL_GetDrawableSize(m_window, &m_window_width, &m_window_height);
+
   // start with vsync on
   SDL_GL_SetSwapInterval(1);
   return true;
@@ -271,6 +274,9 @@ bool OpenGLHostDisplay::CreateGLContext(bool debug_device)
 
 bool OpenGLHostDisplay::CreateImGuiContext()
 {
+  ImGui::GetIO().DisplaySize.x = static_cast<float>(m_window_width);
+  ImGui::GetIO().DisplaySize.y = static_cast<float>(m_window_height);
+
   if (!ImGui_ImplSDL2_InitForOpenGL(m_window, m_gl_context) || !ImGui_ImplOpenGL3_Init(GetGLSLVersionString()))
     return false;
 

src/duckstation-sdl/sdl_host_interface.cpp

@@ -43,17 +43,60 @@ SDLHostInterface::~SDLHostInterface()
     DestroySDLWindow();
 }
 
+float SDLHostInterface::GetDPIScaleFactor(SDL_Window* window)
+{
+#ifdef __APPLE__
+  static constexpr float DEFAULT_DPI = 72.0f;
+#else
+  static constexpr float DEFAULT_DPI = 96.0f;
+#endif
+
+  if (!window)
+  {
+    SDL_Window* dummy_window = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 1, 1,
+                                                SDL_WINDOW_ALLOW_HIGHDPI | SDL_WINDOW_HIDDEN);
+    if (!dummy_window)
+      return 1.0f;
+
+    const float scale = GetDPIScaleFactor(dummy_window);
+
+    SDL_DestroyWindow(dummy_window);
+
+    return scale;
+  }
+
+  int display_index = SDL_GetWindowDisplayIndex(window);
+  float display_dpi = DEFAULT_DPI;
+  if (SDL_GetDisplayDPI(display_index, &display_dpi, nullptr, nullptr) != 0)
+    return 1.0f;
+
+  return display_dpi / DEFAULT_DPI;
+}
+
 bool SDLHostInterface::CreateSDLWindow()
 {
-  constexpr u32 DEFAULT_WINDOW_WIDTH = 900;
+  static constexpr u32 DEFAULT_WINDOW_WIDTH = 900;
-  constexpr u32 DEFAULT_WINDOW_HEIGHT = 700;
+  static constexpr u32 DEFAULT_WINDOW_HEIGHT = 700;
 
   // Create window.
   const u32 window_flags =
     SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI | (UseOpenGLRenderer() ? SDL_WINDOW_OPENGL : 0);
 
-  m_window = SDL_CreateWindow("DuckStation", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, DEFAULT_WINDOW_WIDTH,
+  u32 window_width = DEFAULT_WINDOW_WIDTH;
-                              DEFAULT_WINDOW_HEIGHT, window_flags);
+  u32 window_height = DEFAULT_WINDOW_HEIGHT;
+
+  // macOS does DPI scaling differently..
+#ifndef __APPLE__
+  {
+    // scale by default monitor's DPI
+    float scale = GetDPIScaleFactor(nullptr);
+    window_width = static_cast<u32>(std::round(static_cast<float>(window_width) * scale));
+    window_height = static_cast<u32>(std::round(static_cast<float>(window_height) * scale));
+  }
+#endif
+
+  m_window = SDL_CreateWindow("DuckStation", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, window_width,
+                              window_height, window_flags);
   if (!m_window)
     return false;
 
@@ -113,12 +156,24 @@ void SDLHostInterface::DestroyDisplay()
 
 void SDLHostInterface::CreateImGuiContext()
 {
+  const float framebuffer_scale = GetDPIScaleFactor(m_window);
+
   ImGui::CreateContext();
   ImGui::GetIO().IniFilename = nullptr;
   ImGui::GetIO().ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
+  ImGui::GetIO().DisplayFramebufferScale.x = framebuffer_scale;
+  ImGui::GetIO().DisplayFramebufferScale.y = framebuffer_scale;
+  ImGui::GetStyle().ScaleAllSizes(framebuffer_scale);
 
   ImGui::StyleColorsDarker();
-  ImGui::AddRobotoRegularFont();
+  ImGui::AddRobotoRegularFont(15.0f * framebuffer_scale);
+}
+
+void SDLHostInterface::UpdateFramebufferScale()
+{
+  const float framebuffer_scale = GetDPIScaleFactor(m_window);
+  ImGui::GetIO().DisplayFramebufferScale.x = framebuffer_scale;
+  ImGui::GetIO().DisplayFramebufferScale.y = framebuffer_scale;
 }
 
 bool SDLHostInterface::AcquireHostDisplay()
@@ -315,7 +370,14 @@ void SDLHostInterface::HandleSDLEvent(const SDL_Event* event)
     case SDL_WINDOWEVENT:
     {
       if (event->window.event == SDL_WINDOWEVENT_RESIZED)
+      {
         m_display->WindowResized();
+        UpdateFramebufferScale();
+      }
+      else if (event->window.event == SDL_WINDOWEVENT_MOVED)
+      {
+        UpdateFramebufferScale();
+      }
     }
     break;
 
@@ -722,9 +784,11 @@ void SDLHostInterface::DrawMainMenuBar()
 
   if (m_system)
   {
+    const float framebuffer_scale = ImGui::GetIO().DisplayFramebufferScale.x;
+
     if (!m_paused)
     {
-      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - 210.0f);
+      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - (210.0f * framebuffer_scale));
 
       const float speed = m_system->GetEmulationSpeed();
       const u32 rounded_speed = static_cast<u32>(std::round(speed));
@@ -735,15 +799,15 @@ void SDLHostInterface::DrawMainMenuBar()
       else
         ImGui::TextColored(ImVec4(0.4f, 1.0f, 0.4f, 1.0f), "%u%%", rounded_speed);
 
-      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - 165.0f);
+      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - (165.0f * framebuffer_scale));
       ImGui::Text("FPS: %.2f", m_system->GetFPS());
 
-      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - 80.0f);
+      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - (80.0f * framebuffer_scale));
       ImGui::Text("VPS: %.2f", m_system->GetVPS());
     }
     else
     {
-      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - 50.0f);
+      ImGui::SetCursorPosX(ImGui::GetIO().DisplaySize.x - (50.0f * framebuffer_scale));
       ImGui::TextColored(ImVec4(1.0f, 1.0f, 0.0f, 1.0f), "Paused");
     }
   }
@@ -875,12 +939,14 @@ void SDLHostInterface::DrawDebugMenu()
 
 void SDLHostInterface::DrawPoweredOffWindow()
 {
-  constexpr int WINDOW_WIDTH = 400;
+  static constexpr int WINDOW_WIDTH = 400;
-  constexpr int WINDOW_HEIGHT = 650;
+  static constexpr int WINDOW_HEIGHT = 650;
-  constexpr int BUTTON_WIDTH = 200;
+  static constexpr int BUTTON_WIDTH = 200;
-  constexpr int BUTTON_HEIGHT = 40;
+  static constexpr int BUTTON_HEIGHT = 40;
+  const float framebuffer_scale = ImGui::GetIO().DisplayFramebufferScale.x;
 
-  ImGui::SetNextWindowSize(ImVec2(WINDOW_WIDTH, WINDOW_HEIGHT));
+  ImGui::SetNextWindowSize(ImVec2(static_cast<float>(WINDOW_WIDTH) * framebuffer_scale,
+                                  static_cast<float>(WINDOW_HEIGHT) * framebuffer_scale));
   ImGui::SetNextWindowPos(ImVec2(ImGui::GetIO().DisplaySize.x * 0.5f, ImGui::GetIO().DisplaySize.y * 0.5f),
                           ImGuiCond_Always, ImVec2(0.5f, 0.5f));
 
@@ -892,15 +958,17 @@ void SDLHostInterface::DrawPoweredOffWindow()
     ImGui::End();
   }
 
-  ImGui::SetCursorPosX((WINDOW_WIDTH - APP_ICON_WIDTH) / 2);
+  ImGui::SetCursorPosX(static_cast<float>((WINDOW_WIDTH - APP_ICON_WIDTH) / 2) * framebuffer_scale);
-  ImGui::Image(m_app_icon_texture->GetHandle(), ImVec2(APP_ICON_WIDTH, APP_ICON_HEIGHT));
+  ImGui::Image(m_app_icon_texture->GetHandle(), ImVec2(static_cast<float>(APP_ICON_WIDTH) * framebuffer_scale,
-  ImGui::SetCursorPosY(APP_ICON_HEIGHT + 32);
+                                                       static_cast<float>(APP_ICON_HEIGHT) * framebuffer_scale));
+  ImGui::SetCursorPosY(static_cast<float>(APP_ICON_HEIGHT + 32) * framebuffer_scale);
 
-  static const ImVec2 button_size(static_cast<float>(BUTTON_WIDTH), static_cast<float>(BUTTON_HEIGHT));
+  const ImVec2 button_size(static_cast<float>(BUTTON_WIDTH) * framebuffer_scale,
-  constexpr float button_left = static_cast<float>((WINDOW_WIDTH - BUTTON_WIDTH) / 2);
+                           static_cast<float>(BUTTON_HEIGHT) * framebuffer_scale);
+  const float button_left = static_cast<float>((WINDOW_WIDTH - BUTTON_WIDTH) / 2) * framebuffer_scale;
 
-  ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, 8.0f);
+  ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, 8.0f * framebuffer_scale);
-  ImGui::PushStyleVar(ImGuiStyleVar_FrameBorderSize, 1.0f);
+  ImGui::PushStyleVar(ImGuiStyleVar_FrameBorderSize, 1.0f * framebuffer_scale);
   ImGui::PushStyleColor(ImGuiCol_Button, 0xFF202020);
   ImGui::PushStyleColor(ImGuiCol_ButtonActive, 0xFF808080);
   ImGui::PushStyleColor(ImGuiCol_ButtonHovered, 0xFF575757);
@@ -972,9 +1040,11 @@ static bool DrawSettingsSectionHeader(const char* title)
 
 void SDLHostInterface::DrawSettingsWindow()
 {
+  const float framebuffer_scale = ImGui::GetIO().DisplayFramebufferScale.x;
+
   ImGui::SetNextWindowPos(ImVec2(ImGui::GetIO().DisplaySize.x * 0.5f, ImGui::GetIO().DisplaySize.y * 0.5f),
                           ImGuiCond_FirstUseEver, ImVec2(0.5f, 0.5f));
-  ImGui::SetNextWindowSize(ImVec2(500, 400), ImGuiCond_FirstUseEver);
+  ImGui::SetNextWindowSize(ImVec2(500 * framebuffer_scale, 400.0f * framebuffer_scale), ImGuiCond_FirstUseEver);
 
   if (!ImGui::Begin("Settings", &m_settings_window_open, ImGuiWindowFlags_NoResize))
   {
@@ -986,7 +1056,7 @@ void SDLHostInterface::DrawSettingsWindow()
 
   if (ImGui::BeginTabBar("SettingsTabBar", 0))
   {
-    const float indent = 150.0f;
+    const float indent = 150.0f * framebuffer_scale;
 
     if (ImGui::BeginTabItem("General"))
     {
@@ -1203,12 +1273,6 @@ void SDLHostInterface::DrawSettingsWindow()
     ImGui::EndTabBar();
   }
 
-  const auto window_size = ImGui::GetWindowSize();
-  ImGui::SetCursorPosX(window_size.x - 50.0f);
-  ImGui::SetCursorPosY(window_size.y - 30.0f);
-  if (ImGui::Button("Close"))
-    m_settings_window_open = false;
-
   ImGui::End();
 
   if (settings_changed)
@@ -1222,6 +1286,8 @@ void SDLHostInterface::DrawSettingsWindow()
 
 void SDLHostInterface::DrawAboutWindow()
 {
+  const float framebuffer_scale = ImGui::GetIO().DisplayFramebufferScale.x;
+
   ImGui::SetNextWindowPos(ImVec2(ImGui::GetIO().DisplaySize.x * 0.5f, ImGui::GetIO().DisplaySize.y * 0.5f),
                           ImGuiCond_Appearing, ImVec2(0.5f, 0.5f));
 
@@ -1243,8 +1309,8 @@ void SDLHostInterface::DrawAboutWindow()
 
   ImGui::NewLine();
 
-  ImGui::SetCursorPosX((ImGui::GetWindowSize().x - 60.0f) / 2.0f);
+  ImGui::SetCursorPosX((ImGui::GetWindowSize().x - (60.0f * framebuffer_scale)) / 2.0f);
-  if (ImGui::Button("Close", ImVec2(60.0f, 20.0f)))
+  if (ImGui::Button("Close", ImVec2(60.0f * framebuffer_scale, 20.0f * framebuffer_scale)))
     m_about_window_open = false;
 
   ImGui::EndPopup();
@@ -1252,11 +1318,13 @@ void SDLHostInterface::DrawAboutWindow()
 
 bool SDLHostInterface::DrawFileChooser(const char* label, std::string* path, const char* filter /* = nullptr */)
 {
-  ImGui::SetNextItemWidth(ImGui::CalcItemWidth() - 50.0f);
+  const float framebuffer_scale = ImGui::GetIO().DisplayFramebufferScale.x;
+
+  ImGui::SetNextItemWidth((ImGui::CalcItemWidth() - 50.0f) * framebuffer_scale);
   bool result = ImGui::InputText(label, path);
   ImGui::SameLine();
 
-  ImGui::SetNextItemWidth(50.0f);
+  ImGui::SetNextItemWidth(50.0f * framebuffer_scale);
   if (ImGui::Button("..."))
   {
     nfdchar_t* out_path = nullptr;

src/duckstation-sdl/sdl_host_interface.h

@@ -78,11 +78,14 @@ private:
   bool UseOpenGLRenderer() const { return true; }
 #endif
 
+  static float GetDPIScaleFactor(SDL_Window* window);
+
   bool CreateSDLWindow();
   void DestroySDLWindow();
   bool CreateDisplay();
   void DestroyDisplay();
   void CreateImGuiContext();
+  void UpdateFramebufferScale();
 
   /// Executes a callback later, after the UI has finished rendering. Needed to boot while rendering ImGui.
   void RunLater(std::function<void()> callback);