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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef FLUTTER_SHELL_PLATFORM_WINDOWS_FLUTTER_WIN32_WINDOW_H_
#define FLUTTER_SHELL_PLATFORM_WINDOWS_FLUTTER_WIN32_WINDOW_H_
#include <Windows.h>
#include <Windowsx.h>
#include <memory>
#include <string>
namespace flutter {
// A class abstraction for a high DPI aware Win32 Window. Intended to be
// inherited from by classes that wish to specialize with custom
// rendering and input handling.
class Win32Window {
public:
Win32Window();
virtual ~Win32Window();
// Initializes as a child window with size using |width| and |height| and
// |title| to identify the windowclass. Does not show window, window must be
// parented into window hierarchy by caller.
void InitializeChild(const char* title,
unsigned int width,
unsigned int height);
HWND GetWindowHandle();
protected:
// Converts a c string to a wide unicode string.
std::wstring NarrowToWide(const char* source);
// Registers a window class with default style attributes, cursor and
// icon.
WNDCLASS RegisterWindowClass(std::wstring& title);
// OS callback called by message pump. Handles the WM_NCCREATE message which
// is passed when the non-client area is being created and enables automatic
// non-client DPI scaling so that the non-client area automatically
// responsponds to changes in DPI. All other messages are handled by
// MessageHandler.
static LRESULT CALLBACK WndProc(HWND const window,
UINT const message,
WPARAM const wparam,
LPARAM const lparam) noexcept;
// Processes and route salient window messages for mouse handling,
// size change and DPI. Delegates handling of these to member overloads that
// inheriting classes can handle.
LRESULT
HandleMessage(UINT const message,
WPARAM const wparam,
LPARAM const lparam) noexcept;
// When WM_DPICHANGE process it using |hWnd|, |wParam|. If
// |top_level| is set, extract the suggested new size from |lParam| and resize
// the window to the new suggested size. If |top_level| is not set, the
// |lParam| will not contain a suggested size hence ignore it.
LRESULT
HandleDpiChange(HWND hWnd, WPARAM wParam, LPARAM lParam, bool top_level);
// Called when the DPI changes either when a
// user drags the window between monitors of differing DPI or when the user
// manually changes the scale factor.
virtual void OnDpiScale(UINT dpi) = 0;
// Called when a resize occurs.
virtual void OnResize(UINT width, UINT height) = 0;
// Called when the pointer moves within the
// window bounds.
virtual void OnPointerMove(double x, double y) = 0;
// Called when the a mouse button, determined by |button|, goes down.
virtual void OnPointerDown(double x, double y, UINT button) = 0;
// Called when the a mouse button, determined by |button|, goes from
// down to up
virtual void OnPointerUp(double x, double y, UINT button) = 0;
// Called when the mouse leaves the window.
virtual void OnPointerLeave() = 0;
// Called when the cursor should be set for the client area.
virtual void OnSetCursor() = 0;
// Called when text input occurs.
virtual void OnText(const std::u16string& text) = 0;
// Called when raw keyboard input occurs.
virtual void OnKey(int key, int scancode, int action, char32_t character) = 0;
// Called when mouse scrollwheel input occurs.
virtual void OnScroll(double delta_x, double delta_y) = 0;
UINT GetCurrentDPI();
UINT GetCurrentWidth();
UINT GetCurrentHeight();
private:
// Release OS resources asociated with window.
void Destroy();
// Activates tracking for a "mouse leave" event.
void TrackMouseLeaveEvent(HWND hwnd);
// Stores new width and height and calls |OnResize| to notify inheritors
void HandleResize(UINT width, UINT height);
// Retrieves a class instance pointer for |window|
static Win32Window* GetThisFromHandle(HWND const window) noexcept;
int current_dpi_ = 0;
int current_width_ = 0;
int current_height_ = 0;
// WM_DPICHANGED_BEFOREPARENT defined in more recent Windows
// SDK
const static long kWmDpiChangedBeforeParent = 0x02E2;
// Member variable to hold window handle.
HWND window_handle_ = nullptr;
// Member variable to hold the window title.
std::wstring window_class_name_;
// Set to true to be notified when the mouse leaves the window.
bool tracking_mouse_leave_ = false;
// Keeps track of the last key code produced by a WM_KEYDOWN or WM_SYSKEYDOWN
// message.
int keycode_for_char_message_ = 0;
};
} // namespace flutter
#endif // FLUTTER_SHELL_PLATFORM_WINDOWS_FLUTTER_WIN32_WINDOW_H_