GlobalKeyboardHook.h

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/*
 * Copyright (c) 2019 pongasoft
 *
 * Licensed under the Apache License, Version 2.0 or the MIT license,
 * at your option. You may not use this file except in compliance with
 * one of these licenses. You may obtain copies of the licenses at:
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 * https://opensource.org/licenses/MIT
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *
 * @author Yan Pujante
 */
#pragma once
 
#include <vstgui4/vstgui/lib/cframe.h>
#include <vstgui4/vstgui/lib/events.h>
#include <pongasoft/VST/GUI/Types.h>
#include "SelfContainedViewListener.h"
 
namespace pongasoft::VST::GUI::Views {
 
using namespace VSTGUI;

class GlobalKeyboardHook : public SelfContainedViewListener, protected IKeyboardHook
{
public:
  std::shared_ptr<GlobalKeyboardHook> onKeyboardEvent(KeyboardEventCallback iOnKeyboardEventCallback)
  {
    fOnKeyboardEventCallback = std::move(iOnKeyboardEventCallback);
    return std::dynamic_pointer_cast<GlobalKeyboardHook>(shared_from_this());
  }

  static std::shared_ptr<GlobalKeyboardHook> create(CView *iView)
  {
    return SelfContainedViewListener::create<GlobalKeyboardHook>(iView);
  }

  std::shared_ptr<SelfContainedViewListener> registerView(CView *iView) override
  {
    auto res = SelfContainedViewListener::registerView(iView);
    maybeRegisterKeyboardHook();
    return res;
  }
 
protected:
  void viewAttached(CView *iView) override
  {
    DCHECK_F(iView == fView);
    maybeRegisterKeyboardHook();
  }

  void viewRemoved(CView *iView) override
  {
    DCHECK_F(iView == fView);
    maybeUnregisterKeyboardHook();
  }
 
public:
  void unregister() override
  {
    maybeUnregisterKeyboardHook();
    SelfContainedViewListener::unregister();
  }

  GlobalKeyboardHook() = default;
 
protected:
  // maybeRegisterKeyboardHook
  void maybeRegisterKeyboardHook()
  {
    if(!fFrame)
    {
      fFrame = fView->getFrame();
      if(fFrame)
      {
        fFrame->registerKeyboardHook(this);
      }
    }
  }
 
  // maybeUnregisterKeyboardHook
  void maybeUnregisterKeyboardHook()
  {
    if(fFrame)
    {
      fFrame->unregisterKeyboardHook(this);
      fFrame = nullptr;
    }
  }

  void onKeyboardEvent(KeyboardEvent &event, CFrame *frame) override
  {
    if(fOnKeyboardEventCallback)
      fOnKeyboardEventCallback(event);
  }
 
protected:
  CFrame *fFrame{};
  KeyboardEventCallback fOnKeyboardEventCallback{};
};

inline std::shared_ptr<GlobalKeyboardHook> registerGlobalKeyboardHook(CView *iView) { return GlobalKeyboardHook::create(iView); }
 
}