1#ifndef RUNNER_WIN32_WINDOW_H_
  2#define RUNNER_WIN32_WINDOW_H_
  3
  4#include <windows.h>
  5
  6#include <functional>
  7#include <memory>
  8#include <string>
  9
 10// A class abstraction for a high DPI-aware Win32 Window. Intended to be
 11// inherited from by classes that wish to specialize with custom
 12// rendering and input handling
 13class Win32Window {
 14 public:
 15  struct Point {
 16    unsigned int x;
 17    unsigned int y;
 18    Point(unsigned int x, unsigned int y) : x(x), y(y) {}
 19  };
 20
 21  struct Size {
 22    unsigned int width;
 23    unsigned int height;
 24    Size(unsigned int width, unsigned int height)
 25        : width(width), height(height) {}
 26  };
 27
 28  Win32Window();
 29  virtual ~Win32Window();
 30
 31  // Creates a win32 window with |title| that is positioned and sized using
 32  // |origin| and |size|. New windows are created on the default monitor. Window
 33  // sizes are specified to the OS in physical pixels, hence to ensure a
 34  // consistent size this function will scale the inputted width and height as
 35  // as appropriate for the default monitor. The window is invisible until
 36  // |Show| is called. Returns true if the window was created successfully.
 37  bool Create(const std::wstring& title, const Point& origin, const Size& size);
 38
 39  // Show the current window. Returns true if the window was successfully shown.
 40  bool Show();
 41
 42  // Release OS resources associated with window.
 43  void Destroy();
 44
 45  // Inserts |content| into the window tree.
 46  void SetChildContent(HWND content);
 47
 48  // Returns the backing Window handle to enable clients to set icon and other
 49  // window properties. Returns nullptr if the window has been destroyed.
 50  HWND GetHandle();
 51
 52  // If true, closing this window will quit the application.
 53  void SetQuitOnClose(bool quit_on_close);
 54
 55  // Return a RECT representing the bounds of the current client area.
 56  RECT GetClientArea();
 57
 58 protected:
 59  // Processes and route salient window messages for mouse handling,
 60  // size change and DPI. Delegates handling of these to member overloads that
 61  // inheriting classes can handle.
 62  virtual LRESULT MessageHandler(HWND window,
 63                                 UINT const message,
 64                                 WPARAM const wparam,
 65                                 LPARAM const lparam) noexcept;
 66
 67  // Called when CreateAndShow is called, allowing subclass window-related
 68  // setup. Subclasses should return false if setup fails.
 69  virtual bool OnCreate();
 70
 71  // Called when Destroy is called.
 72  virtual void OnDestroy();
 73
 74 private:
 75  friend class WindowClassRegistrar;
 76
 77  // OS callback called by message pump. Handles the WM_NCCREATE message which
 78  // is passed when the non-client area is being created and enables automatic
 79  // non-client DPI scaling so that the non-client area automatically
 80  // responsponds to changes in DPI. All other messages are handled by
 81  // MessageHandler.
 82  static LRESULT CALLBACK WndProc(HWND const window,
 83                                  UINT const message,
 84                                  WPARAM const wparam,
 85                                  LPARAM const lparam) noexcept;
 86
 87  // Retrieves a class instance pointer for |window|
 88  static Win32Window* GetThisFromHandle(HWND const window) noexcept;
 89
 90  // Update the window frame's theme to match the system theme.
 91  static void UpdateTheme(HWND const window);
 92
 93  bool quit_on_close_ = false;
 94
 95  // window handle for top level window.
 96  HWND window_handle_ = nullptr;
 97
 98  // window handle for hosted content.
 99  HWND child_content_ = nullptr;
100};
101
102#endif  // RUNNER_WIN32_WINDOW_H_