From 98a6149b4fe584cda9c2ba0736b513044a3e893e Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sat, 26 Oct 2019 12:27:01 +0200
Subject: [PATCH] LibGUI: Make GWindow drive relayout and do it recursively

Instead of only doing a relayout in the widget you're invalidating,
we now do a recursive top-down relayout so everything gets updated.

This fixes invalid results after updating a preferred size in some
situations with nested layouts.
---
 Libraries/LibGUI/GWidget.cpp | 19 ++++++-------------
 Libraries/LibGUI/GWidget.h   |  3 ++-
 Libraries/LibGUI/GWindow.cpp | 13 +++++++++++++
 Libraries/LibGUI/GWindow.h   |  3 +++
 4 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/Libraries/LibGUI/GWidget.cpp b/Libraries/LibGUI/GWidget.cpp
index 07b2fe98e02..a5004de332f 100644
--- a/Libraries/LibGUI/GWidget.cpp
+++ b/Libraries/LibGUI/GWidget.cpp
@@ -146,6 +146,10 @@ void GWidget::set_layout(OwnPtr<GLayout>&& layout)
 
 void GWidget::do_layout()
 {
+    for_each_child_widget([&](auto& child) {
+        child.do_layout();
+        return IterationDecision::Continue;
+    });
     custom_layout();
     if (!m_layout)
         return;
@@ -434,19 +438,8 @@ void GWidget::set_size_policy(SizePolicy horizontal_policy, SizePolicy vertical_
 
 void GWidget::invalidate_layout()
 {
-    if (m_layout_dirty)
-        return;
-    m_layout_dirty = true;
-    deferred_invoke([this](auto&) {
-        m_layout_dirty = false;
-        auto* w = window();
-        if (!w)
-            return;
-        if (!w->main_widget())
-            return;
-        do_layout();
-        w->main_widget()->do_layout();
-    });
+    if (window())
+        window()->schedule_relayout();
 }
 
 void GWidget::set_visible(bool visible)
diff --git a/Libraries/LibGUI/GWidget.h b/Libraries/LibGUI/GWidget.h
index c5f459e6901..b7acaa773b5 100644
--- a/Libraries/LibGUI/GWidget.h
+++ b/Libraries/LibGUI/GWidget.h
@@ -201,6 +201,8 @@ public:
 
     virtual void save_to(AK::JsonObject&) override;
 
+    void do_layout();
+
 protected:
     explicit GWidget(GWidget* parent = nullptr);
 
@@ -234,7 +236,6 @@ private:
     void handle_mouseup_event(GMouseEvent&);
     void handle_enter_event(CEvent&);
     void handle_leave_event(CEvent&);
-    void do_layout();
     void focus_previous_widget();
     void focus_next_widget();
 
diff --git a/Libraries/LibGUI/GWindow.cpp b/Libraries/LibGUI/GWindow.cpp
index 7620f30acc4..bd03ef61d34 100644
--- a/Libraries/LibGUI/GWindow.cpp
+++ b/Libraries/LibGUI/GWindow.cpp
@@ -736,3 +736,16 @@ void GWindow::set_fullscreen(bool fullscreen)
     request.value = fullscreen;
     GWindowServerConnection::the().sync_request(request, WSAPI_ServerMessage::Type::DidSetFullscreen);
 }
+
+void GWindow::schedule_relayout()
+{
+    if (m_layout_pending)
+        return;
+    m_layout_pending = true;
+    deferred_invoke([this](auto&) {
+        if (main_widget())
+            main_widget()->do_layout();
+        update();
+        m_layout_pending = false;
+    });
+}
diff --git a/Libraries/LibGUI/GWindow.h b/Libraries/LibGUI/GWindow.h
index b33b62dfb1c..ff11e7e10a9 100644
--- a/Libraries/LibGUI/GWindow.h
+++ b/Libraries/LibGUI/GWindow.h
@@ -131,6 +131,8 @@ public:
 
     virtual void save_to(AK::JsonObject&) override;
 
+    void schedule_relayout();
+
 protected:
     GWindow(CObject* parent = nullptr);
     virtual void wm_event(GWMEvent&);
@@ -175,4 +177,5 @@ private:
     String m_entered_keybind;
     int m_max_keybind_length { 0 };
     HashMap<String, WeakPtr<GWidget>> m_keyboard_activation_targets;
+    bool m_layout_pending { false };
 };