From 6f89fd3d215744762b6cc3d48040780126ce4d58 Mon Sep 17 00:00:00 2001
From: falkTX <falktx@falktx.com>
Date: Mon, 13 Sep 2021 10:37:03 +0100
Subject: [PATCH] Better handling of transient windows, using
 ScopedGraphicsContext

---
 dgl/StandaloneWindow.hpp      |  8 ++++----
 dgl/Window.hpp                |  7 ++++++-
 dgl/src/Window.cpp            | 21 ++++++++++++++++++---
 dgl/src/WindowPrivateData.cpp |  5 -----
 4 files changed, 28 insertions(+), 13 deletions(-)

diff --git a/dgl/StandaloneWindow.hpp b/dgl/StandaloneWindow.hpp
index 6502f3ae..f86e4c39 100644
--- a/dgl/StandaloneWindow.hpp
+++ b/dgl/StandaloneWindow.hpp
@@ -37,12 +37,12 @@ public:
         sgc((Window&)*this) {}
 
    /**
-      Constructor with parent window, typically used to run as modal.
+      Constructor with a transient parent window, typically used to run as modal.
     */
-    StandaloneWindow(Application& app, Window& parentWindow)
-      : Window(app, parentWindow),
+    StandaloneWindow(Application& app, Window& transientParentWindow)
+      : Window(app, transientParentWindow),
         TopLevelWidget((Window&)*this),
-        sgc((Window&)*this) {}
+        sgc((Window&)*this, transientParentWindow) {}
 
    /**
       Clear current graphics context.
diff --git a/dgl/Window.hpp b/dgl/Window.hpp
index 8c646777..744f7f2d 100644
--- a/dgl/Window.hpp
+++ b/dgl/Window.hpp
@@ -49,6 +49,8 @@ class TopLevelWidget;
  */
 class Window
 {
+   struct PrivateData;
+
 public:
 #ifndef DGL_FILE_BROWSER_DISABLED
    /**
@@ -131,6 +133,9 @@ public:
         /** Constructor that will make the @a window graphics context the current one */
         explicit ScopedGraphicsContext(Window& window);
 
+        /** Overloaded constructor, gives back context to its transient parent when done */
+        explicit ScopedGraphicsContext(Window& window, Window& transientParentWindow);
+
         /** Desstructor for clearing current context, if not done yet */
         ~ScopedGraphicsContext();
 
@@ -142,6 +147,7 @@ public:
 
     private:
         Window& window;
+        Window::PrivateData* ppData;
         bool active;
     };
 
@@ -451,7 +457,6 @@ protected:
 #endif
 
 private:
-    struct PrivateData;
     PrivateData* const pData;
     friend class Application;
     friend class PluginWindow;
diff --git a/dgl/src/Window.cpp b/dgl/src/Window.cpp
index 154c4974..b418fdad 100644
--- a/dgl/src/Window.cpp
+++ b/dgl/src/Window.cpp
@@ -25,20 +25,35 @@ START_NAMESPACE_DGL
 
 Window::ScopedGraphicsContext::ScopedGraphicsContext(Window& win)
     : window(win),
+      ppData(nullptr),
       active(puglBackendEnter(window.pData->view)) {}
 
+Window::ScopedGraphicsContext::ScopedGraphicsContext(Window& win, Window& transientWin)
+    : window(win),
+      ppData(transientWin.pData),
+      active(false)
+{
+    puglBackendLeave(ppData->view);
+    active = puglBackendEnter(window.pData->view);
+}
+
 Window::ScopedGraphicsContext::~ScopedGraphicsContext()
 {
-    if (active)
-        puglBackendLeave(window.pData->view);
+    done();
 }
 
 void Window::ScopedGraphicsContext::done()
 {
     if (active)
     {
-        active = false;
         puglBackendLeave(window.pData->view);
+        active = false;
+    }
+
+    if (ppData != nullptr)
+    {
+        puglBackendEnter(ppData->view);
+        ppData = nullptr;
     }
 }
 
diff --git a/dgl/src/WindowPrivateData.cpp b/dgl/src/WindowPrivateData.cpp
index e2dddeb4..eed5c04d 100644
--- a/dgl/src/WindowPrivateData.cpp
+++ b/dgl/src/WindowPrivateData.cpp
@@ -123,7 +123,6 @@ Window::PrivateData::PrivateData(Application& a, Window* const s, PrivateData* c
 #endif
       modal(ppData)
 {
-    puglBackendLeave(transientParentView);
     puglSetTransientFor(view, puglGetNativeWindow(transientParentView));
 
     initPre(DEFAULT_WIDTH, DEFAULT_HEIGHT, false);
@@ -266,10 +265,6 @@ bool Window::PrivateData::initPost()
         puglShow(view);
     }
 
-    // give context back to transient parent window
-    if (transientParentView != nullptr)
-        puglBackendEnter(transientParentView);
-
     return true;
 }