From cdcf0faa5ff21589ff23e32e2d38cea8efbc23c4 Mon Sep 17 00:00:00 2001
From: Olivier Goffart <ogoffart@sixtyfps.io>
Date: Thu, 8 Apr 2021 08:26:51 +0200
Subject: [PATCH] Set the size to the Window element when it is shown, when the
 size would otherwise be empty

---
 .../rendering_backends/gl/graphics_window.rs   | 18 ++++++++++++++----
 .../rendering_backends/qt/qt_window.rs         | 18 +++++++++++++++---
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/sixtyfps_runtime/rendering_backends/gl/graphics_window.rs b/sixtyfps_runtime/rendering_backends/gl/graphics_window.rs
index ecf0b173c..d41f9d41d 100644
--- a/sixtyfps_runtime/rendering_backends/gl/graphics_window.rs
+++ b/sixtyfps_runtime/rendering_backends/gl/graphics_window.rs
@@ -424,10 +424,20 @@ impl PlatformWindow for GraphicsWindow {
                 let backend = window.backend.borrow();
                 let winit_window = backend.window();
                 winit_window.set_title(&window_item.title());
-                let size: winit::dpi::PhysicalSize<u32> =
-                    (window_item.width(), window_item.height()).into();
-                if size.width > 0 && size.height > 0 {
-                    winit_window.set_inner_size(size);
+                let mut size = winit_window.inner_size();
+                let mut must_resize = false;
+                let mut apply = |r: &mut u32, v| {
+                    if v > 0. {
+                        *r = v as _
+                    } else {
+                        must_resize = true
+                    }
+                };
+                apply(&mut size.width, window_item.width());
+                apply(&mut size.height, window_item.height());
+                winit_window.set_inner_size(size);
+                if must_resize {
+                    self.set_geometry(size.width as _, size.height as _)
                 }
             }
         }
diff --git a/sixtyfps_runtime/rendering_backends/qt/qt_window.rs b/sixtyfps_runtime/rendering_backends/qt/qt_window.rs
index 216738108..90bf872d0 100644
--- a/sixtyfps_runtime/rendering_backends/qt/qt_window.rs
+++ b/sixtyfps_runtime/rendering_backends/qt/qt_window.rs
@@ -933,14 +933,26 @@ impl PlatformWindow for QtWindow {
     fn apply_window_properties(&self, window_item: Pin<&items::Window>) {
         let widget_ptr = self.widget_ptr();
         let title: qttypes::QString = window_item.title().as_str().into();
-        let size = qttypes::QSize {
+        let mut size = qttypes::QSize {
             width: window_item.width().ceil() as _,
             height: window_item.height().ceil() as _,
         };
+        if size.width == 0 || size.height == 0 {
+            let existing_size = cpp!(unsafe [widget_ptr as "QWidget*"] -> qttypes::QSize as "QSize" {
+                return widget_ptr->size();
+            });
+            if size.width == 0 {
+                window_item.width.set(existing_size.width as _);
+                size.width = existing_size.width;
+            }
+            if size.height == 0 {
+                window_item.height.set(existing_size.height as _);
+                size.height = existing_size.height;
+            }
+        }
         let background: u32 = window_item.background().as_argb_encoded();
         cpp! {unsafe [widget_ptr as "QWidget*",  title as "QString", size as "QSize", background as "QRgb"] {
-            if (!size.isEmpty())
-                widget_ptr->resize(size);
+            widget_ptr->resize(size);
             widget_ptr->setWindowTitle(title);
             auto pal = widget_ptr->palette();
             pal.setColor(QPalette::Window, QColor::fromRgba(background));