[rcore][GLFW] Fix GetClipboardImage() creating new connection under X11 (#5871)

* Improve GetClipboardImage implementation under X11

* Remove code for creating new connection, handle selection in GLFW connection instead.

* `GetClipboardImage()`: Small fix to remove unnecessary boolean

Author: steampuker

src/platforms/rcore_desktop_glfw.c

@@ -1042,11 +1042,6 @@ const char *GetClipboardText(void)
     return glfwGetClipboardString(platform.handle);
 }
 
-#if SUPPORT_CLIPBOARD_IMAGE && defined(__linux__) && defined(_GLFW_X11)
-    #include <X11/Xlib.h>
-    #include <X11/Xatom.h>
-#endif
-
 // Get clipboard image
 Image GetClipboardImage(void)
 {
@@ -1066,51 +1061,46 @@ Image GetClipboardImage(void)
     else image = LoadImageFromMemory(".bmp", (const unsigned char *)bmpData, (int)dataSize);
 
 #elif defined(__linux__) && defined(_GLFW_X11)
-
     // REF: https://github.com/ColleagueRiley/Clipboard-Copy-Paste/blob/main/x11.c
-    Display *dpy = XOpenDisplay(NULL);
-    if (!dpy) return image;
-
-    Window root = DefaultRootWindow(dpy);
-    Window win = XCreateSimpleWindow(
-        dpy,      // The connection to the X Server
-        root,     // The 'Parent' window (usually the desktop/root)
-        0, 0,     // X and Y position on the screen
-        1, 1,     // Width and Height (1x1 pixel)
-        0,        // Border width
-        0,        // Border color
-        0         // Background color
-    );
-
-    Atom clipboard = XInternAtom(dpy, "CLIPBOARD", False);
-    Atom targetType = XInternAtom(dpy, "image/png", False); // Ask for PNG
-    Atom property = XInternAtom(dpy, "RAYLIB_CLIPBOARD_MANAGER", False);
-
-    // Request the data: "Convert whatever is in CLIPBOARD to image/png and put it in RAYLIB_CLIPBOARD_MANAGER"
-    XConvertSelection(dpy, clipboard, targetType, property, win, CurrentTime);
-
-    // Wait for the SelectionNotify event
+
+    static Atom clipboard = 0;
+    static Atom targetType = 0;
+    static Atom property = 0;
+
+    Display *display = glfwGetX11Display();
+    XID window = glfwGetX11Window(platform.handle);
+
+    // Lazy-load X11 atoms
+    if(clipboard == 0)
+    {
+        clipboard = XInternAtom(display, "CLIPBOARD", False);
+        targetType = XInternAtom(display, "image/png", False);
+        property = XInternAtom(display, "RAYLIB_CLIPBOARD_MANAGER", False);
+    }
+
+    XConvertSelection(display, clipboard, targetType, property, window, CurrentTime);
+    XSync(display, 0);
+
     XEvent ev = { 0 };
-    XNextEvent(dpy, &ev);
+
+    // Keep calling until we get SelectionNotify
+    while (XCheckTypedEvent(display, SelectionNotify, &ev) == False);
 
     Atom actualType = { 0 };
     int actualFormat = 0;
     unsigned long nitems = 0;
     unsigned long bytesAfter = 0;
     unsigned char *data = NULL;
 
-    // Read the data from our ghost window's property
-    XGetWindowProperty(dpy, win, property, 0, ~0L, False, AnyPropertyType,
-        &actualType, &actualFormat, &nitems, &bytesAfter, &data);
+    XGetWindowProperty(display, window, property, 0, ~0L, False, AnyPropertyType,
+                       &actualType, &actualFormat, &nitems, &bytesAfter, &data);
 
     if (data != NULL)
     {
         image = LoadImageFromMemory(".png", data, (int)nitems);
         XFree(data);
     }
 
-    XDestroyWindow(dpy, win);
-    XCloseDisplay(dpy);
 #else
     TRACELOG(LOG_WARNING, "GetClipboardImage() not implemented on target platform");
 #endif // _WIN32