Store the current window display ID on the window

src/events/SDL_windowevents.c

@@ -191,11 +191,11 @@ bool SDL_SendWindowEvent(SDL_Window *window, SDL_EventType windowevent, int data
         window->flags &= ~SDL_WINDOW_INPUT_FOCUS;
         break;
     case SDL_EVENT_WINDOW_DISPLAY_CHANGED:
-        if (data1 == 0 || (SDL_DisplayID)data1 == window->last_displayID) {
+        if (data1 == 0 || (SDL_DisplayID)data1 == window->displayID) {
             return false;
         }
         window->update_fullscreen_on_display_changed = true;
-        window->last_displayID = (SDL_DisplayID)data1;
+        window->displayID = (SDL_DisplayID)data1;
         break;
     case SDL_EVENT_WINDOW_OCCLUDED:
         if (window->flags & SDL_WINDOW_OCCLUDED) {

src/video/SDL_sysvideo.h

@@ -60,7 +60,7 @@ struct SDL_Window
     bool external_graphics_context;
     bool fullscreen_exclusive;  // The window is currently fullscreen exclusive
     SDL_DisplayID last_fullscreen_exclusive_display;  // The last fullscreen_exclusive display
-    SDL_DisplayID last_displayID;
+    SDL_DisplayID displayID;
     SDL_DisplayID pending_displayID;
 
     /* Stored position and size for the window in the non-fullscreen state,

src/video/SDL_video.c

@@ -1150,7 +1150,7 @@ void SDL_SetDisplayContentScale(SDL_VideoDisplay *display, float scale)
 
         // Check the windows on this display
         for (window = _this->windows; window; window = window->next) {
-            if (display->id == window->last_displayID) {
+            if (display->id == window->displayID) {
                 SDL_CheckWindowDisplayScaleChanged(window);
             }
         }
@@ -1800,7 +1800,7 @@ static void SDL_CheckWindowDisplayChanged(SDL_Window *window)
 
     SDL_DisplayID displayID = SDL_GetDisplayForWindowPosition(window);
 
-    if (displayID != window->last_displayID) {
+    if (displayID != window->displayID) {
         int i, display_index;
 
         // Sanity check our fullscreen windows
@@ -1862,7 +1862,7 @@ static void SDL_CheckWindowDisplayScaleChanged(SDL_Window *window)
         display_scale = _this->GetWindowContentScale(_this, window);
     } else {
         const float pixel_density = SDL_GetWindowPixelDensity(window);
-        const float content_scale = SDL_GetDisplayContentScale(SDL_GetDisplayForWindowPosition(window));
+        const float content_scale = SDL_GetDisplayContentScale(window->displayID);
 
         display_scale = pixel_density * content_scale;
     }
@@ -2524,7 +2524,7 @@ SDL_Window *SDL_CreateWindowWithProperties(SDL_PropertiesID props)
     window->opacity = 1.0f;
     window->next = _this->windows;
     window->is_destroying = false;
-    window->last_displayID = SDL_GetDisplayForWindow(window);
+    window->displayID = SDL_GetDisplayForWindow(window);
     window->external_graphics_context = external_graphics_context;
     window->constrain_popup = SDL_GetBooleanProperty(props, SDL_PROP_WINDOW_CREATE_CONSTRAIN_POPUP_BOOLEAN, true);
 

src/video/windows/SDL_windowsevents.c

@@ -1715,7 +1715,7 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
     case WM_WINDOWPOSCHANGED:
     {
         SDL_Window *win;
-        const SDL_DisplayID original_displayID = data->last_displayID;
+        const SDL_DisplayID original_displayID = data->window->displayID;
         const WINDOWPOS *windowpos = (WINDOWPOS *)lParam;
         bool iconic;
         bool zoomed;
@@ -1790,9 +1790,7 @@ LRESULT CALLBACK WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lPara
         WIN_UpdateClipCursor(data->window);
 
         // Update the window display position
-        data->last_displayID = SDL_GetDisplayForWindow(data->window);
-
-        if (data->last_displayID != original_displayID) {
+        if (data->window->displayID != original_displayID) {
             // Display changed, check ICC profile
             WIN_UpdateWindowICCProfile(data->window, true);
         }

src/video/windows/SDL_windowswindow.c

@@ -391,7 +391,6 @@ static bool SetupWindowData(SDL_VideoDevice *_this, SDL_Window *window, HWND hwn
     data->last_pointer_update = (LPARAM)-1;
     data->videodata = videodata;
     data->initializing = true;
-    data->last_displayID = window->last_displayID;
     data->hint_erase_background_mode = GetEraseBackgroundModeHint();
 
 

src/video/windows/SDL_windowswindow.h

@@ -91,7 +91,6 @@ struct SDL_WindowData
     RECT cursor_ctrlock_rect; // this is Windows-specific, but probably does not need to be per-window
     bool mouse_tracked;
     bool destroy_parent_with_window;
-    SDL_DisplayID last_displayID;
     WCHAR *ICMFileName;
     SDL_WindowEraseBackgroundMode hint_erase_background_mode;
     bool taskbar_button_created;

src/video/x11/SDL_x11window.c

@@ -742,7 +742,7 @@ bool X11_CreateWindow(SDL_VideoDevice *_this, SDL_Window *window, SDL_Properties
     }
 
     if (window->undefined_x && window->undefined_y &&
-        window->last_displayID == SDL_GetPrimaryDisplay()) {
+        window->displayID == SDL_GetPrimaryDisplay()) {
         undefined_position = true;
     }