From 72396f7ecd385cf514a229e1b44191cdf590d0c1 Mon Sep 17 00:00:00 2001
From: ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
Date: Wed, 18 Mar 2026 16:36:52 +0100
Subject: [PATCH] Wayland: fix computation of wld_scale parameter for GL
 subwindows - cont'd (#1382)

---
 src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx | 11 ++++++++---
 src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx    | 12 +++++++++---
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
index 0dd315002..0a1e79d9d 100644
--- a/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
@@ -1,7 +1,7 @@
 //
 // Class Fl_Wayland_Gl_Window_Driver for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2021-2023 by Bill Spitzak and others.
+// Copyright 2021-2026 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -266,6 +266,10 @@ void Fl_Wayland_Gl_Window_Driver::make_current_before() {
   if (!egl_window) {
     struct wld_window *win = fl_wl_xid(pWindow);
     struct wl_surface *surface = win->wl_surface;
+    if (pWindow->parent()) { // force toplevel win to enter its display before sizing GL subwin
+      win = fl_wl_xid(pWindow->top_window());
+      while (wl_list_empty(&win->outputs)) wl_display_dispatch(fl_wl_display());
+    }
     int W = pWindow->pixel_w();
     int H = pWindow->pixel_h();
     int scale = Fl_Wayland_Window_Driver::driver(pWindow)->wld_scale();
@@ -280,8 +284,9 @@ void Fl_Wayland_Gl_Window_Driver::make_current_before() {
     // Tested apps: shape, glpuzzle, cube, fractals, gl_overlay, fullscreen, unittests,
     //   OpenGL3-glut-test, OpenGL3test.
     // Tested wayland compositors: mutter, kde-plasma, weston, sway on FreeBSD.
-    if (pWindow->parent()) win = fl_wl_xid(pWindow->top_window());
-    while (wl_list_empty(&win->outputs)) wl_display_dispatch(fl_wl_display());
+    if (!pWindow->parent()) {
+      while (wl_list_empty(&win->outputs)) wl_display_dispatch(fl_wl_display());
+    }
   }
 }
 
diff --git a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
index cb28755f7..ad7284b1f 100644
--- a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
@@ -1,7 +1,7 @@
 //
 // Implementation of the Wayland window driver.
 //
-// Copyright 1998-2024 by Bill Spitzak and others.
+// Copyright 1998-2026 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -723,7 +723,7 @@ static void surface_enter(void *data, struct wl_surface *wl_surface,
   while (e->next != &window->outputs) e = e->next; // move e to end of linked list
   wl_list_insert(e, &surface_output->link);
 //printf("window %p enters screen id=%d length=%d\n", window->fl_win, output->id, wl_list_length(&window->outputs));
-  if (list_was_empty && (!window->fl_win->parent() || window->fl_win->as_gl_window()) && !window->fl_win->menu_window()) {
+  if (list_was_empty && !window->fl_win->parent() && !window->fl_win->menu_window()) {
     change_scale(output, window, pre_scale);
   }
 }
@@ -2122,7 +2122,13 @@ int Fl_Wayland_Window_Driver::wld_scale() {
   Fl_X *flx = Fl_X::flx(pWindow->top_window());
   struct wld_window *xid = (flx ? (struct wld_window *)flx->xid : NULL);
   if (!xid || wl_list_empty(&xid->outputs)) {
-    return 1;
+    int scale = 1;
+    Fl_Wayland_Screen_Driver *scr_driver = (Fl_Wayland_Screen_Driver*)Fl::screen_driver();
+    Fl_Wayland_Screen_Driver::output *output;
+    wl_list_for_each(output, &(scr_driver->outputs), link) {
+      scale = fl_max(scale, output->wld_scale);
+    }
+    return scale;
   }
   struct surface_output *s_output;
   s_output = wl_container_of(xid->outputs.next, s_output, link);