From fa65dcf24cee01dc25c1abb304d8fae80114d3dc Mon Sep 17 00:00:00 2001
From: RT2 <contact@rt2.fr>
Date: Sat, 17 Aug 2024 13:13:10 +0200
Subject: [PATCH] Backends: SDL2, SDL3: Replace Win32 hack with
 SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN hint. (#7896)

---
 backends/imgui_impl_sdl2.cpp | 6 +++++-
 backends/imgui_impl_sdl3.cpp | 8 +-------
 docs/CHANGELOG.txt           | 3 +++
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/backends/imgui_impl_sdl2.cpp b/backends/imgui_impl_sdl2.cpp
index d038cb80d..eeef0c788 100644
--- a/backends/imgui_impl_sdl2.cpp
+++ b/backends/imgui_impl_sdl2.cpp
@@ -116,6 +116,7 @@
 #define SDL_HAS_PER_MONITOR_DPI             SDL_VERSION_ATLEAST(2,0,4)
 #define SDL_HAS_VULKAN                      SDL_VERSION_ATLEAST(2,0,6)
 #define SDL_HAS_DISPLAY_EVENT               SDL_VERSION_ATLEAST(2,0,9)
+#define SDL_HAS_SHOW_WINDOW_ACTIVATION_HINT SDL_VERSION_ATLEAST(2,0,18)
 #if !SDL_HAS_VULKAN
 static const Uint32 SDL_WINDOW_VULKAN = 0x10000000;
 #endif
@@ -1012,7 +1013,11 @@ static void ImGui_ImplSDL2_ShowWindow(ImGuiViewport* viewport)
         ex_style |= WS_EX_TOOLWINDOW;
         ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
     }
+#endif
 
+#if SDL_HAS_SHOW_WINDOW_ACTIVATION_HINT
+    SDL_SetHint(SDL_HINT_WINDOW_NO_ACTIVATION_WHEN_SHOWN, (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing) ? "1" : "0");
+#elif defined(_WIN32)
     // SDL hack: SDL always activate/focus windows :/
     if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
     {
@@ -1020,7 +1025,6 @@ static void ImGui_ImplSDL2_ShowWindow(ImGuiViewport* viewport)
         return;
     }
 #endif
-
     SDL_ShowWindow(vd->Window);
 }
 
diff --git a/backends/imgui_impl_sdl3.cpp b/backends/imgui_impl_sdl3.cpp
index c54589487..035ee7b17 100644
--- a/backends/imgui_impl_sdl3.cpp
+++ b/backends/imgui_impl_sdl3.cpp
@@ -952,15 +952,9 @@ static void ImGui_ImplSDL3_ShowWindow(ImGuiViewport* viewport)
         ex_style |= WS_EX_TOOLWINDOW;
         ::SetWindowLong(hwnd, GWL_EXSTYLE, ex_style);
     }
-
-    // SDL hack: SDL always activate/focus windows :/
-    if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
-    {
-        ::ShowWindow(hwnd, SW_SHOWNA);
-        return;
-    }
 #endif
 
+    SDL_SetHint(SDL_HINT_WINDOW_ACTIVATE_WHEN_SHOWN, (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing) ? "0" : "1");
     SDL_ShowWindow(vd->Window);
 }
 
diff --git a/docs/CHANGELOG.txt b/docs/CHANGELOG.txt
index 380217c41..8f0076efd 100644
--- a/docs/CHANGELOG.txt
+++ b/docs/CHANGELOG.txt
@@ -58,6 +58,9 @@ Docking+Viewports Branch:
   to allow backends to alter the default per-viewport work-area. (#7823)
 - Backends: don't report monitors with DpiScale of 0, which seemed to be reported
   for virtual monitors instead by accessibility drivers. (#7902) [@nicolasnoble]
+- Backends: SDL2, SDL3: using SDL_HINT_WINDOW_NO_ACTIVATION_WHEN_SHOWN to support the
+  ImGuiViewportFlags_NoFocusOnAppearing flag, instead of using a Win32-specific hack.
+  (#7896) [@RT2Code]
 
 
 -----------------------------------------------------------------------