commit 1f53b9e203b41ca0614c51534df9bac4177a451c
Author:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
AuthorDate: Wed Aug 17 09:26:40 2022 +0200
Commit:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
CommitDate: Wed Aug 17 09:26:40 2022 +0200

    Wayland platform: improve Fl_Gl_Window resize operations.

 src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.H  |  2 +-
 .../Wayland/Fl_Wayland_Gl_Window_Driver.cxx        | 28 ++++++++++++----------
 2 files changed, 16 insertions(+), 14 deletions(-)

diff --git src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.H src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.H
index 2241c5e..2dcc0c2 100644
--- src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.H
+++ src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.H
@@ -36,7 +36,7 @@ Consequently, FL_DOUBLE is enforced in all Fl_Gl_Window::mode_ values under Wayl
 class Fl_Wayland_Gl_Window_Driver : public Fl_Gl_Window_Driver {
   friend Fl_Gl_Window_Driver* Fl_Gl_Window_Driver::newGlWindowDriver(Fl_Gl_Window *);
   friend class Fl_Wayland_Gl_Plugin;
-  bool egl_resize_in_progress;
+  bool egl_swap_in_progress;
   Fl_Wayland_Gl_Window_Driver(Fl_Gl_Window *win);
   virtual float pixels_per_unit();
   virtual void make_current_before();
diff --git src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
index 10b6d61..ce969b3 100644
--- src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
+++ src/drivers/Wayland/Fl_Wayland_Gl_Window_Driver.cxx
@@ -64,7 +64,7 @@ Fl_Wayland_Gl_Window_Driver::Fl_Wayland_Gl_Window_Driver(Fl_Gl_Window *win) : Fl
   if (egl_display == EGL_NO_DISPLAY) init();
   egl_window = NULL;
   egl_surface = NULL;
-  egl_resize_in_progress = false;
+  egl_swap_in_progress = false;
 }
 
 
@@ -322,19 +322,16 @@ void Fl_Wayland_Gl_Window_Driver::swap_buffers() {
     if (!overlay_buffer) return; // don't call eglSwapBuffers until overlay has been drawn
   }
 
-  if (egl_surface) {
+  if (egl_surface && !egl_swap_in_progress) {
+    egl_swap_in_progress = true;
     //eglSwapInterval(egl_display, 0); // doesn't seem to have any effect in this context
-    if (!egl_resize_in_progress) {
-      while (wl_display_prepare_read(Fl_Wayland_Screen_Driver::wl_display) != 0) {
-        wl_display_dispatch_pending(Fl_Wayland_Screen_Driver::wl_display);
-      }
-      wl_display_read_events(Fl_Wayland_Screen_Driver::wl_display);
-      wl_display_dispatch_queue_pending(Fl_Wayland_Screen_Driver::wl_display,  gl_event_queue);
+    while (wl_display_prepare_read(Fl_Wayland_Screen_Driver::wl_display) != 0) {
+      wl_display_dispatch_pending(Fl_Wayland_Screen_Driver::wl_display);
     }
-    if (!egl_resize_in_progress || pWindow->parent()) {
-       eglSwapBuffers(Fl_Wayland_Gl_Window_Driver::egl_display, egl_surface);
-    }
-    egl_resize_in_progress = false;
+    wl_display_read_events(Fl_Wayland_Screen_Driver::wl_display);
+    wl_display_dispatch_queue_pending(Fl_Wayland_Screen_Driver::wl_display,  gl_event_queue);
+    eglSwapBuffers(Fl_Wayland_Gl_Window_Driver::egl_display, egl_surface);
+    egl_swap_in_progress = false;
   }
 }
 
@@ -366,6 +363,9 @@ public:
 
 static Fl_Wayland_Gl_Plugin Gl_Overlay_Plugin;
 
+static void delayed_flush(Fl_Gl_Window *win) {
+  win->flush();
+}
 
 void Fl_Wayland_Gl_Window_Driver::resize(int is_a_resize, int W, int H) {
   if (!egl_window) return;
@@ -378,7 +378,9 @@ void Fl_Wayland_Gl_Window_Driver::resize(int is_a_resize, int W, int H) {
   if (W2 != W || H2 != H) {
     wl_egl_window_resize(egl_window, W, H, 0, 0);
     //fprintf(stderr, "Fl_Wayland_Gl_Window_Driver::resize to %dx%d\n", W, H);
-    if (!Fl_Window::is_a_rescale()) egl_resize_in_progress = true;
+    if (!pWindow->parent()) {
+        Fl::add_timeout(0.01, (Fl_Timeout_Handler)delayed_flush, pWindow);
+    }
   }
 }