Wayland: support move/resize of subwindow independently from parent (#1003)

1 files changed, 77 insertions, 15 deletions

diff --git a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
index 2c45df2c8..3c9fb3c65 100644
--- a/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
+++ b/src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
@@ -1771,7 +1771,36 @@ int Fl_Wayland_Window_Driver::set_cursor_4args(const Fl_RGB_Image *rgb, int hotx
 }
 
 
+struct xid_and_rect {
+  struct wld_window *xid;
+  Fl_Window *win;
+  int X, Y, W, H;
+  bool need_resize;
+};
+
+
+static void surface_frame_done(void *data, struct wl_callback *cb, uint32_t time) {
+  struct xid_and_rect *xid_rect = (xid_and_rect *)data;
+  wl_callback_destroy(cb);
+  xid_rect->xid->frame_cb = NULL;
+  if (xid_rect->need_resize) {
+    xid_rect->win->Fl_Group::resize(xid_rect->X, xid_rect->Y, xid_rect->W, xid_rect->H);
+    xid_rect->win->redraw();
+  } else {
+    xid_rect->win->Fl_Widget::resize(xid_rect->X, xid_rect->Y, xid_rect->W, xid_rect->H);
+    wl_surface_commit(xid_rect->xid->wl_surface);
+  }
+  delete xid_rect;
+}
+
+
+static const struct wl_callback_listener surface_frame_listener = {
+  .done = surface_frame_done,
+};
+
+
 void Fl_Wayland_Window_Driver::resize(int X, int Y, int W, int H) {
+  static int depth = 0;
   struct wld_window *fl_win = fl_wl_xid(pWindow);
   if (fl_win && fl_win->kind == DECORATED && !xdg_toplevel()) {
     pWindow->wait_for_expose();
@@ -1789,20 +1818,32 @@ void Fl_Wayland_Window_Driver::resize(int X, int Y, int W, int H) {
   int is_a_resize = (W != w() || H != h() || true_rescale);
   if (is_a_move) force_position(1);
   else if (!is_a_resize && !is_a_move) return;
+  depth++;
   if (shown() && !(parent() || popup_window())) {
     X = Y = 0;
   }
-  if (is_a_resize) {
-    if (pWindow->parent()) {
-      if (W < 1) W = 1;
-      if (H < 1) H = 1;
+  struct wld_window *parent_xid = parent() ? fl_wl_xid(pWindow->window()) : NULL;
+  xid_and_rect *xid_rect = NULL;
+  if (parent_xid && parent_xid->frame_cb && wl_proxy_get_listener((struct wl_proxy*)parent_xid->frame_cb) == &surface_frame_listener) {
+    xid_rect = (xid_and_rect*)wl_callback_get_user_data(parent_xid->frame_cb);
+    if (xid_rect->win != pWindow) xid_rect = NULL;
+  }
+  // When moving or resizing a non-GL subwindow independently from its parent, this condition
+  // delays application of X,Y,W,H values until the compositor signals
+  // it's ready for a new frame using the frame callback mechanism.
+  if (depth > 1 || pWindow->as_gl_window() || !parent_xid || wait_for_expose_value || (parent_xid->frame_cb && !xid_rect)) {
+    if (is_a_resize) {
+      if (pWindow->parent()) {
+        if (W < 1) W = 1;
+        if (H < 1) H = 1;
+      }
+      pWindow->Fl_Group::resize(X,Y,W,H);
+      //fprintf(stderr, "resize: win=%p to %dx%d\n", pWindow, W, H);
+      if (shown()) {pWindow->redraw();}
+    } else {
+      x(X); y(Y);
+      //fprintf(stderr, "move win=%p to %dx%d\n", pWindow, X, Y);
     }
-    pWindow->Fl_Group::resize(X,Y,W,H);
-    //fprintf(stderr, "resize: win=%p to %dx%d\n", pWindow, W, H);
-    if (shown()) {pWindow->redraw();}
-  } else {
-    x(X); y(Y);
-    //fprintf(stderr, "move win=%p to %dx%d\n", pWindow, X, Y);
   }
 
   if (shown()) {
@@ -1860,14 +1901,35 @@ void Fl_Wayland_Window_Driver::resize(int X, int Y, int W, int H) {
     }
   }
 
-  struct wld_window *parent_xid = parent() ? fl_wl_xid(pWindow->window()) : NULL;
   if (fl_win && parent_xid) {
-    if (pWindow->as_gl_window() && fl_win->frame_cb) {
-      wl_callback_destroy(fl_win->frame_cb);
-      fl_win->frame_cb = NULL;
-    } else wl_surface_commit(parent_xid->wl_surface);
+    if (pWindow->as_gl_window()) {
+      if (fl_win->frame_cb) {
+        wl_callback_destroy(fl_win->frame_cb);
+        fl_win->frame_cb = NULL;
+      }
+      Fl_Wayland_Graphics_Driver::buffer_commit(parent_xid);
+    } else {
+      if (!parent_xid->frame_cb) {
+        // use the frame callback mechanism and memorize current X,Y,W,H values
+        xid_rect = new xid_and_rect;
+        xid_rect->xid = parent_xid;
+        xid_rect->win = pWindow;
+        parent_xid->frame_cb = wl_surface_frame(parent_xid->wl_surface);
+        wl_callback_add_listener(parent_xid->frame_cb, &surface_frame_listener, xid_rect);
+        xid_rect->X = X; xid_rect->Y = Y; xid_rect->W = W; xid_rect->H = H;
+        xid_rect->need_resize = is_a_resize;
+        wl_surface_commit(parent_xid->wl_surface);
+      } else if (xid_rect) {
+        // update the active frame callback with new X,Y,W,H values
+        xid_rect->X = X; xid_rect->Y = Y; xid_rect->W = W; xid_rect->H = H;
+        xid_rect->need_resize |= is_a_resize;
+      } else {
+        wl_surface_commit(parent_xid->wl_surface);
+      }
+    }
     checkSubwindowFrame(); // make sure subwindow doesn't leak outside parent
   }
+  depth--;
 }