text: #ifndef KRUST_IO_PUBLIC_API_APPLICATION_COMPONENT_H_
  #define KRUST_IO_PUBLIC_API_APPLICATION_COMPONENT_H_
  
  // Copyright (c) 2021 Andrew Helge Cox
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in all
  // copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  // SOFTWARE.
  
  namespace Krust {
  namespace IO {
  
  class Application;
  
  /**
   * @brief Abstract base class for components which expose some reusable Vulkan
   * machinery that needs to know about the application lifecycle.
   */
  class ApplicationComponent {
  public:
    ApplicationComponent(Application& app);
    /**
     * @brief Called once Vulkan and a window are up and running so any extra
     * initialisation of the component can be done.
     */
    virtual bool Init(Application& app) = 0;
  
    /**
     * @brief Called while Vulkan and a window are still up and running so
     * the component can cleanup before the Application base class does.
     */
    virtual bool DeInit(Application& app) = 0;
  
    /**
     * @brief Called after the application base class has responded to the window
     * resizing and before the derived concrete application has.
     */
    virtual void OnResize(Application& app, unsigned width, unsigned height) = 0;
  };
  
  } /* namespace IO */
  } /* namespace Krust */
  
  #endif /* KRUST_IO_PUBLIC_API_APPLICATION_COMPONENT_H_ */
  