--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Platforms/WebAssembly/WebAssemblyViewport.h	Sat Jan 29 12:47:32 2022 +0100
@@ -0,0 +1,181 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2022 Osimis S.A., Belgium
+ * Copyright (C) 2021-2022 Sebastien Jodogne, ICTEAM UCLouvain, Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program. If not, see
+ * <http://www.gnu.org/licenses/>.
+ **/
+
+
+#pragma once
+
+#include "../../../OrthancStone/Sources/OrthancStone.h"
+
+#if !defined(ORTHANC_ENABLE_WASM)
+#  error Macro ORTHANC_ENABLE_WASM must be defined
+#endif
+
+#if ORTHANC_ENABLE_WASM != 1
+#  error This file can only be used if targeting WebAssembly
+#endif
+
+#include "../../../OrthancStone/Sources/Viewport/IViewport.h"
+#include "../../../OrthancStone/Sources/Viewport/IViewportInteractor.h"
+
+#include <Compatibility.h>
+
+#include <emscripten.h>
+#include <emscripten/html5.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+#include <boost/enable_shared_from_this.hpp>
+
+namespace OrthancStone
+{
+  class WebAssemblyViewport : public IViewport,
+                              public boost::enable_shared_from_this<WebAssemblyViewport>
+
+  {
+  private:
+    class WasmLock;
+    
+    std::string                           canvasId_;
+    std::string                           canvasCssSelector_;
+    std::unique_ptr<ICompositor>          compositor_;
+    std::unique_ptr<ViewportController>   controller_;
+    std::unique_ptr<IViewportInteractor>  interactor_;
+    bool                                  enableEmscriptenMouseEvents_;
+    unsigned int                          canvasWidth_;
+    unsigned int                          canvasHeight_;
+
+    static EM_BOOL OnRequestAnimationFrame(double time, void *userData);
+    
+    static EM_BOOL OnResize(int eventType, const EmscriptenUiEvent *uiEvent, void *userData);
+
+    static EM_BOOL OnMouseDown(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
+    
+    static EM_BOOL OnMouseMove(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
+    
+    static EM_BOOL OnMouseUp(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData);
+
+  protected:
+    void Invalidate();
+    
+    void ClearCompositor()
+    {
+      compositor_.reset();
+    }
+
+    bool HasCompositor() const
+    {
+      return compositor_.get() != NULL;
+    }
+
+    void AcquireCompositor(ICompositor* compositor /* takes ownership */);
+
+    virtual void Paint(ICompositor& compositor,
+                       ViewportController& controller) = 0;
+
+    /**
+    The second argument is temporary and should be deleted once the migration 
+    to interactors is finished. It should be set to "true" for new applications.
+    */
+    WebAssemblyViewport(const std::string& canvasId, 
+                        bool enableEmscriptenMouseEvents);
+
+    void PostConstructor();
+
+
+    /**
+     * This method can be called to retrieve a cookie that can be passed to 
+     * C-style callbacks that expect the object to be passed as a void*
+     * 
+     * This cookie is a resource and must be freed when it is guaranteed 
+     * not to be used anymore, with ReleaseObjectCookie
+     */
+    void* CreateObjectCookie();
+
+    /**
+     * This static method can be used to dereference a cookie (i.e. retrieve 
+     * a pointer to the underlying object) that has been created with 
+     * WebAssemblyViewport::CreateObjectCookie()
+     * 
+     * If this method returns NULL, it basically means that the 
+     * WebAssemblyViewport has already been deleted and that you should NOT 
+     * attempt to use it!
+     * 
+     * This method never releases the cookie (for other in-flight callbacks
+     * could possibly require to cookie to be valid)
+     * 
+     * If this method is called AFTER ReleaseObjectCookie has been called on
+     * the same cookie, the behavior is undefined and things will CERTAINLY
+     * go wrong.
+     * 
+     * NEVER call this method on a void* that has not been generated by the
+     * CreateObjectCookie method of this class
+     */
+    static WebAssemblyViewport* DereferenceObjectCookie(void* cookie);
+
+    /**
+     * This method must be used when the object cookie will not be used anymore.
+     * 
+     * You must call it when you are certain that no entity will attempt to 
+     * dereference the cookie.
+     */
+    static void ReleaseObjectCookie(void* cookie);
+
+    void RefreshCanvasSize();
+
+    unsigned int GetCanvasWidth() const
+    {
+      return canvasWidth_;
+    }
+    
+    unsigned int GetCanvasHeight()
+    {
+      return canvasHeight_;
+    }
+
+  public:
+    virtual ILock* Lock() ORTHANC_OVERRIDE;
+
+    ~WebAssemblyViewport();
+
+    /**
+    This method takes ownership
+    */
+    void AcquireInteractor(IViewportInteractor* interactor);
+
+    const std::string& GetCanvasId() const
+    {
+      return canvasId_;
+    }
+
+    /**
+    emscripten functions requires the css selector for the canvas. This is 
+    different from the canvas id (the syntax is '#mycanvasid')
+    */
+    const std::string& GetCanvasCssSelector() const
+    {
+      return canvasCssSelector_;
+    }
+
+    void FitForPrint();
+  };
+}