--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Applications/Platforms/WebAssembly/WebAssemblyViewport.cpp	Fri Oct 23 13:15:03 2020 +0200
@@ -0,0 +1,399 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2020 Osimis S.A., Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero 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
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#if defined(ORTHANC_BUILDING_STONE_LIBRARY) && ORTHANC_BUILDING_STONE_LIBRARY == 1
+#  include "WebAssemblyViewport.h"
+#  include "../../../OrthancStone/Sources/Scene2DViewport/ViewportController.h"
+#  include "../../../OrthancStone/Sources/Toolbox/GenericToolbox.h"
+#  include "../../../OrthancStone/Sources/Viewport/DefaultViewportInteractor.h"
+#else
+// This is the case when using the WebAssembly side module, and this
+// source file must be compiled within the WebAssembly main module
+#  include <Viewport/WebAssemblyViewport.h>
+#  include <Toolbox/GenericToolbox.h>
+#  include <Scene2DViewport/ViewportController.h>
+#  include <Viewport/DefaultViewportInteractor.h>
+#endif
+
+
+#include <OrthancException.h>
+
+#include <boost/make_shared.hpp>
+#include <boost/enable_shared_from_this.hpp>
+#include <boost/math/special_functions/round.hpp>
+
+namespace OrthancStone
+{
+  static void ConvertMouseEvent(PointerEvent& target,
+                                const EmscriptenMouseEvent& source,
+                                const ICompositor& compositor)
+  {
+    int x = static_cast<int>(source.targetX);
+    int y = static_cast<int>(source.targetY);
+
+    switch (source.button)
+    {
+      case 0:
+        target.SetMouseButton(MouseButton_Left);
+        break;
+
+      case 1:
+        target.SetMouseButton(MouseButton_Middle);
+        break;
+
+      case 2:
+        target.SetMouseButton(MouseButton_Right);
+        break;
+
+      default:
+        target.SetMouseButton(MouseButton_None);
+        break;
+    }
+      
+    target.AddPosition(compositor.GetPixelCenterCoordinates(x, y));
+    target.SetAltModifier(source.altKey);
+    target.SetControlModifier(source.ctrlKey);
+    target.SetShiftModifier(source.shiftKey);
+  }
+
+
+  class WebAssemblyViewport::WasmLock : public ILock
+  {
+  private:
+    WebAssemblyViewport& that_;
+
+  public:
+    WasmLock(WebAssemblyViewport& that) :
+      that_(that)
+    {
+    }
+
+    virtual bool HasCompositor() const ORTHANC_OVERRIDE
+    {
+      return that_.compositor_.get() != NULL;
+    }
+
+    virtual ICompositor& GetCompositor() ORTHANC_OVERRIDE
+    {
+      if (that_.compositor_.get() == NULL)
+      {
+        throw Orthanc::OrthancException(Orthanc::ErrorCode_BadSequenceOfCalls);
+      }
+      else
+      {
+        return *that_.compositor_;
+      }
+    }
+
+    virtual ViewportController& GetController() ORTHANC_OVERRIDE
+    {
+      assert(that_.controller_);
+      return *that_.controller_;
+    }
+
+    virtual void Invalidate() ORTHANC_OVERRIDE
+    {
+      that_.Invalidate();
+    }
+
+    virtual void RefreshCanvasSize() ORTHANC_OVERRIDE
+    {
+      that_.RefreshCanvasSize();
+    }
+  };
+
+
+  EM_BOOL WebAssemblyViewport::OnRequestAnimationFrame(double time, void *userData)
+  {
+    LOG(TRACE) << __func__;
+    WebAssemblyViewport* that = reinterpret_cast<WebAssemblyViewport*>(userData);
+
+    if (that->compositor_.get() != NULL &&
+        that->controller_ /* should always be true */)
+    {
+      that->Paint(*that->compositor_, *that->controller_);
+    }
+      
+    LOG(TRACE) << "Exiting: " << __func__;
+    return true;
+  }
+
+  EM_BOOL WebAssemblyViewport::OnResize(int eventType, const EmscriptenUiEvent *uiEvent, void *userData)
+  {
+    LOG(TRACE) << __func__;
+    WebAssemblyViewport* that = reinterpret_cast<WebAssemblyViewport*>(userData);
+
+    if (that->compositor_.get() != NULL)
+    {
+      that->RefreshCanvasSize();
+      that->Invalidate();
+    }
+      
+    LOG(TRACE) << "Exiting: " << __func__;
+    return true;
+  }
+
+
+  EM_BOOL WebAssemblyViewport::OnMouseDown(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData)
+  {
+    WebAssemblyViewport* that = reinterpret_cast<WebAssemblyViewport*>(userData);
+
+    LOG(TRACE) << "mouse down: " << that->GetCanvasCssSelector();      
+
+    if (that->compositor_.get() != NULL &&
+        that->interactor_.get() != NULL)
+    {
+      PointerEvent pointer;
+      ConvertMouseEvent(pointer, *mouseEvent, *that->compositor_);
+
+      that->controller_->HandleMousePress(*that->interactor_, pointer,
+                                         that->compositor_->GetCanvasWidth(),
+                                         that->compositor_->GetCanvasHeight());        
+      that->Invalidate();
+    }
+
+    LOG(TRACE) << "Exiting: " << __func__;
+    return true;
+  }
+
+    
+  EM_BOOL WebAssemblyViewport::OnMouseMove(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData)
+  {
+    WebAssemblyViewport* that = reinterpret_cast<WebAssemblyViewport*>(userData);
+
+    if (that->compositor_.get() != NULL &&
+        that->controller_->HasActiveTracker())
+    {
+      PointerEvent pointer;
+      ConvertMouseEvent(pointer, *mouseEvent, *that->compositor_);
+      if (that->controller_->HandleMouseMove(pointer))
+      {
+        that->Invalidate();
+      }
+    }
+
+    LOG(TRACE) << "Exiting: " << __func__;
+    return true;
+  }
+    
+  EM_BOOL WebAssemblyViewport::OnMouseUp(int eventType, const EmscriptenMouseEvent *mouseEvent, void *userData)
+  {
+    LOG(TRACE) << __func__;
+    WebAssemblyViewport* that = reinterpret_cast<WebAssemblyViewport*>(userData);
+
+    if (that->compositor_.get() != NULL)
+    {
+      PointerEvent pointer;
+      ConvertMouseEvent(pointer, *mouseEvent, *that->compositor_);
+      that->controller_->HandleMouseRelease(pointer);
+      that->Invalidate();
+    }
+
+    LOG(TRACE) << "Exiting: " << __func__;
+    return true;
+  }
+
+  void WebAssemblyViewport::Invalidate()
+  {
+    emscripten_request_animation_frame(OnRequestAnimationFrame, reinterpret_cast<void*>(this));
+  }
+
+  void WebAssemblyViewport::FitForPrint()
+  {
+    if (compositor_.get() != NULL &&
+        controller_ /* should always be true */)
+    {
+      RefreshCanvasSize();
+      compositor_->FitContent(controller_->GetScene());
+      OnRequestAnimationFrame(0, reinterpret_cast<void*>(this));  // Mandatory to work with Firefox
+    }
+  }
+
+  void WebAssemblyViewport::AcquireCompositor(ICompositor* compositor /* takes ownership */)
+  {
+    if (compositor == NULL)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_NullPointer);
+    }
+    else
+    {
+      compositor_.reset(compositor);
+    }
+  }
+
+#if DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR == 1
+// everything OK..... we're using the new setting
+#else
+#pragma message("WARNING: DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR is not defined or equal to 0. Stone will use the OLD Emscripten rules for DOM element selection.")
+#endif
+
+  WebAssemblyViewport::WebAssemblyViewport(
+    const std::string& canvasId, bool enableEmscriptenMouseEvents) :
+    canvasId_(canvasId),
+#if DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR == 1
+    canvasCssSelector_("#" + canvasId),
+#else
+    canvasCssSelector_(canvasId),
+#endif
+    interactor_(new DefaultViewportInteractor),
+    enableEmscriptenMouseEvents_(enableEmscriptenMouseEvents),
+    canvasWidth_(0),
+    canvasHeight_(0)
+  {
+  }
+
+  void WebAssemblyViewport::PostConstructor()
+  {
+    boost::shared_ptr<IViewport> viewport = shared_from_this();
+    controller_.reset(new ViewportController(viewport));
+
+    LOG(INFO) << "Initializing Stone viewport on HTML canvas: " 
+              << canvasId_;
+
+    if (canvasId_.empty() ||
+        canvasId_[0] == '#')
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_ParameterOutOfRange,
+        "The canvas identifier must not start with '#'");
+    }
+
+    // Disable right-click on the canvas (i.e. context menu)
+    EM_ASM({
+        document.getElementById(UTF8ToString($0)).oncontextmenu = 
+        function(event)
+        {
+          event.preventDefault();
+        }
+      },
+      canvasId_.c_str()   // $0
+      );
+
+    // It is not possible to monitor the resizing of individual
+    // canvas, so we track the full window of the browser
+    emscripten_set_resize_callback(EMSCRIPTEN_EVENT_TARGET_WINDOW,
+                                   reinterpret_cast<void*>(this),
+                                   false,
+                                   OnResize);
+
+    if (enableEmscriptenMouseEvents_)
+    {
+
+      // if any of this function causes an error in the console, please
+      // make sure you are using the new (as of 1.39.x) version of 
+      // emscripten element lookup rules( pass 
+      // "-s DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR=1" to the linker.
+
+      emscripten_set_mousedown_callback(canvasCssSelector_.c_str(),
+                                        reinterpret_cast<void*>(this),
+                                        false,
+                                        OnMouseDown);
+
+      emscripten_set_mousemove_callback(canvasCssSelector_.c_str(),
+                                        reinterpret_cast<void*>(this),
+                                        false,
+                                        OnMouseMove);
+
+      emscripten_set_mouseup_callback(canvasCssSelector_.c_str(),
+                                      reinterpret_cast<void*>(this),
+                                      false,
+                                      OnMouseUp);
+    }
+  }
+
+  WebAssemblyViewport::~WebAssemblyViewport()
+  {
+    emscripten_set_resize_callback(EMSCRIPTEN_EVENT_TARGET_WINDOW,
+                                   reinterpret_cast<void*>(this),
+                                   false,
+                                   NULL);
+
+    if (enableEmscriptenMouseEvents_)
+    {
+
+      emscripten_set_mousedown_callback(canvasCssSelector_.c_str(),
+                                        reinterpret_cast<void*>(this),
+                                        false,
+                                        NULL);
+
+      emscripten_set_mousemove_callback(canvasCssSelector_.c_str(),
+                                        reinterpret_cast<void*>(this),
+                                        false,
+                                        NULL);
+
+      emscripten_set_mouseup_callback(canvasCssSelector_.c_str(),
+                                      reinterpret_cast<void*>(this),
+                                      false,
+                                      NULL);
+    }
+  }
+  
+  IViewport::ILock* WebAssemblyViewport::Lock()
+  {
+    return new WasmLock(*this);
+  }
+  
+  void WebAssemblyViewport::AcquireInteractor(IViewportInteractor* interactor)
+  {
+    if (interactor == NULL)
+    {
+      throw Orthanc::OrthancException(Orthanc::ErrorCode_NullPointer);
+    }
+    else
+    {
+      interactor_.reset(interactor);
+    }
+  }
+
+
+  void WebAssemblyViewport::RefreshCanvasSize()
+  {
+    double w, h;
+    emscripten_get_element_css_size(GetCanvasCssSelector().c_str(), &w, &h);
+
+    /**
+     * Emscripten has the function emscripten_get_element_css_size()
+     * to query the width and height of a named HTML element. I'm
+     * calling this first to get the initial size of the canvas DOM
+     * element, and then call emscripten_set_canvas_size() to
+     * initialize the framebuffer size of the canvas to the same
+     * size as its DOM element.
+     * https://floooh.github.io/2017/02/22/emsc-html.html
+     **/
+    if (w > 0 &&
+        h > 0)
+    {
+      canvasWidth_ = static_cast<unsigned int>(boost::math::iround(w));
+      canvasHeight_ = static_cast<unsigned int>(boost::math::iround(h));
+    }
+    else
+    {
+      canvasWidth_ = 0;
+      canvasHeight_ = 0;
+    }
+
+    emscripten_set_canvas_element_size(GetCanvasCssSelector().c_str(), canvasWidth_, canvasHeight_);
+
+    if (compositor_.get() != NULL)
+    {
+      compositor_->SetCanvasSize(canvasWidth_, canvasHeight_);
+    }
+  }
+}