Clarify that a window being 'hidden' means that it is unmapped/ordered out

SDL considers a hidden window to be unmapped and blocks or defers certain operations until the window is shown again, however, the X11 and Cocoa backends would set the hidden flag when the window was minimized, which blocked the functionality of SDL_RestoreWindow().

Specify that a window with the hidden flag set is unmapped and not visible on the desktop or in the dock/taskbar without a call to SDL_ShowWindow(), and don't set the hidden flag in the X11 and Cocoa backends when the window is in the minimized state, but still mapped to the desktop.

include/SDL3/SDL_video.h

@@ -132,7 +132,7 @@ typedef enum
     SDL_WINDOW_FULLSCREEN           = 0x00000001,   /**< window is in fullscreen mode */
     SDL_WINDOW_OPENGL               = 0x00000002,   /**< window usable with OpenGL context */
     SDL_WINDOW_OCCLUDED             = 0x00000004,   /**< window is occluded */
-    SDL_WINDOW_HIDDEN               = 0x00000008,   /**< window is not visible */
+    SDL_WINDOW_HIDDEN               = 0x00000008,   /**< window is neither mapped onto the desktop nor shown in the taskbar/dock/window list; SDL_ShowWindow() is required for it to become visible */
     SDL_WINDOW_BORDERLESS           = 0x00000010,   /**< no window decoration */
     SDL_WINDOW_RESIZABLE            = 0x00000020,   /**< window can be resized */
     SDL_WINDOW_MINIMIZED            = 0x00000040,   /**< window is minimized */

src/video/cocoa/SDL_cocoawindow.m

@@ -643,7 +643,7 @@ static void Cocoa_SendExposedEventIfVisible(SDL_Window *window)
         int newVisibility = [[change objectForKey:@"new"] intValue];
         if (newVisibility) {
             SDL_SendWindowEvent(_data.window, SDL_EVENT_WINDOW_SHOWN, 0, 0);
-        } else {
+        } else if (![_data.nswindow isMiniaturized]) {
             SDL_SendWindowEvent(_data.window, SDL_EVENT_WINDOW_HIDDEN, 0, 0);
         }
     }
@@ -662,7 +662,7 @@ static void Cocoa_SendExposedEventIfVisible(SDL_Window *window)
     if (wasVisible != isVisible) {
         if (isVisible) {
             SDL_SendWindowEvent(_data.window, SDL_EVENT_WINDOW_SHOWN, 0, 0);
-        } else {
+        } else if (![_data.nswindow isMiniaturized]) {
             SDL_SendWindowEvent(_data.window, SDL_EVENT_WINDOW_HIDDEN, 0, 0);
         }
 

src/video/x11/SDL_x11events.c

@@ -1579,12 +1579,19 @@ static void X11_DispatchEvent(SDL_VideoDevice *_this, XEvent *xevent)
                 }
             }
 
-            if (changed & SDL_WINDOW_MAXIMIZED) {
-                if (flags & SDL_WINDOW_MAXIMIZED) {
-                    SDL_SendWindowEvent(data->window, SDL_EVENT_WINDOW_MAXIMIZED, 0, 0);
-                } else {
-                    SDL_SendWindowEvent(data->window, SDL_EVENT_WINDOW_RESTORED, 0, 0);
-                }
+            if ((changed & SDL_WINDOW_MAXIMIZED) && ((flags & SDL_WINDOW_MAXIMIZED) && !(flags & SDL_WINDOW_MINIMIZED))) {
+                SDL_SendWindowEvent(data->window, SDL_EVENT_WINDOW_MAXIMIZED, 0, 0);
+            }
+            if ((changed & SDL_WINDOW_MINIMIZED) && (flags & SDL_WINDOW_MINIMIZED)) {
+                SDL_SendWindowEvent(data->window, SDL_EVENT_WINDOW_MINIMIZED, 0, 0);
+            }
+            if (((changed & SDL_WINDOW_MAXIMIZED) || (changed & SDL_WINDOW_MINIMIZED)) &&
+                (!(flags & SDL_WINDOW_MAXIMIZED) && !(flags & SDL_WINDOW_MINIMIZED))) {
+                SDL_SendWindowEvent(data->window, SDL_EVENT_WINDOW_RESTORED, 0, 0);
+            }
+
+            if (changed & SDL_WINDOW_OCCLUDED) {
+                SDL_SendWindowEvent(data->window, (flags & SDL_WINDOW_OCCLUDED) ? SDL_EVENT_WINDOW_OCCLUDED : SDL_EVENT_WINDOW_EXPOSED, 0, 0);
             }
         } else if (xevent->xproperty.atom == videodata->XKLAVIER_STATE) {
             /* Hack for Ubuntu 12.04 (etc) that doesn't send MappingNotify

src/video/x11/SDL_x11window.c

@@ -238,7 +238,7 @@ Uint32 X11_GetNetWMState(SDL_VideoDevice *_this, SDL_Window *window, Window xwin
 
         for (i = 0; i < numItems; ++i) {
             if (atoms[i] == _NET_WM_STATE_HIDDEN) {
-                flags |= SDL_WINDOW_HIDDEN;
+                flags |= SDL_WINDOW_MINIMIZED | SDL_WINDOW_OCCLUDED;
             } else if (atoms[i] == _NET_WM_STATE_FOCUSED) {
                 flags |= SDL_WINDOW_INPUT_FOCUS;
             } else if (atoms[i] == _NET_WM_STATE_MAXIMIZED_VERT) {