Fix GL context issues when using ImageAboutWindow

Signed-off-by: falkTX <falktx@falktx.com>

dgl/StandaloneWindow.hpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2022 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -53,6 +53,15 @@ public:
         sgc.done();
     }
 
+   /**
+      Get a graphics context back again.
+      Called when a valid graphics context is needed outside the constructor.
+    */
+    void reinit()
+    {
+        sgc.reinit();
+    }
+
    /**
       Overloaded functions to ensure they apply to the Window class.
     */

dgl/Window.hpp

@@ -105,13 +105,17 @@ public:
         /** Early context clearing, useful for standalone windows not created by you. */
         void done();
 
+        /** Get a valid context back again. */
+        void reinit();
+
         DISTRHO_DECLARE_NON_COPYABLE(ScopedGraphicsContext)
         DISTRHO_PREVENT_HEAP_ALLOCATION
 
     private:
         Window& window;
-        Window::PrivateData* ppData;
+        Window::PrivateData* const ppData;
         bool active;
+        bool reenter;
     };
 
    /**

dgl/src/ImageBaseWidgets.cpp

@@ -1,6 +1,6 @@
 /*
  * DISTRHO Plugin Framework (DPF)
- * Copyright (C) 2012-2021 Filipe Coelho <falktx@falktx.com>
+ * Copyright (C) 2012-2022 Filipe Coelho <falktx@falktx.com>
  *
  * Permission to use, copy, modify, and/or distribute this software for any purpose with
  * or without fee is hereby granted, provided that the above copyright notice and this
@@ -61,13 +61,20 @@ void ImageBaseAboutWindow<ImageType>::setImage(const ImageType& image)
     if (img == image)
         return;
 
-    img = image;
-
     if (image.isInvalid())
+    {
+        img = image;
         return;
+    }
+
+    reinit();
+
+    img = image;
 
     setSize(image.getSize());
     setGeometryConstraints(image.getWidth(), image.getHeight(), true, true);
+
+    done();
 }
 
 template <class ImageType>

dgl/src/Window.cpp

@@ -27,12 +27,16 @@ START_NAMESPACE_DGL
 Window::ScopedGraphicsContext::ScopedGraphicsContext(Window& win)
     : window(win),
       ppData(nullptr),
-      active(puglBackendEnter(window.pData->view)) {}
+      active(puglBackendEnter(window.pData->view)),
+      reenter(false)
+{
+}
 
 Window::ScopedGraphicsContext::ScopedGraphicsContext(Window& win, Window& transientWin)
     : window(win),
       ppData(transientWin.pData),
-      active(false)
+      active(false),
+      reenter(true)
 {
     puglBackendLeave(ppData->view);
     active = puglBackendEnter(window.pData->view);
@@ -51,13 +55,26 @@ void Window::ScopedGraphicsContext::done()
         active = false;
     }
 
-    if (ppData != nullptr)
+    if (reenter)
     {
+        reenter = false;
+        DISTRHO_SAFE_ASSERT_RETURN(ppData != nullptr,);
+
         puglBackendEnter(ppData->view);
-        ppData = nullptr;
     }
 }
 
+void Window::ScopedGraphicsContext::reinit()
+{
+    DISTRHO_SAFE_ASSERT_RETURN(!active,);
+    DISTRHO_SAFE_ASSERT_RETURN(!reenter,);
+    DISTRHO_SAFE_ASSERT_RETURN(ppData != nullptr,);
+
+    reenter = true;
+    puglBackendLeave(ppData->view);
+    active = puglBackendEnter(window.pData->view);
+}
+
 // -----------------------------------------------------------------------
 // Window