chromium/ui/base/ime/input_method.h

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_BASE_IME_INPUT_METHOD_H_
#define UI_BASE_IME_INPUT_METHOD_H_

#include <stdint.h>

#include "build/build_config.h"
#include "ui/base/ime/text_input_mode.h"
#include "ui/base/ime/text_input_type.h"
#include "ui/base/ime/virtual_keyboard_controller.h"
#include "ui/events/event_dispatcher.h"
#include "ui/events/platform_event.h"
#include "ui/gfx/geometry/rect.h"

namespace ui {

class VirtualKeyboardController;
class InputMethodObserver;
class KeyEvent;
class ImeKeyEventDispatcher;
class TextInputClient;

// An interface implemented by an object that encapsulates a native input method
// service provided by the underlying operating system, and acts as a "system
// wide" input method for all Chrome windows. A class that implements this
// interface should behave as follows:
// - Receives a keyboard event directly from a message dispatcher for the
//   system through the InputMethod::DispatchKeyEvent API, and forwards it to
//   an underlying input method for the OS.
// - The input method should handle the key event either of the following ways:
//   1) Send the original key down event to the focused window, which is e.g.
//      a NativeWidgetAura (NWA) or a RenderWidgetHostViewAura (RWHVA), using
//      ImeKeyEventDispatcher API, then send a Char event using
//      TextInputClient::InsertChar API to a text input client, which is, again,
//      e.g. NWA or RWHVA, and then send the original key up event to the same
//      window.
//   2) Send VKEY_PROCESSKEY event to the window using the DispatchKeyEvent API,
//      then update IME status (e.g. composition text) using TextInputClient,
//      and then send the original key up event to the window.
// - Keeps track of the focused TextInputClient to see which client can call
//   APIs, OnTextInputTypeChanged, OnCaretBoundsChanged, and CancelComposition,
//   that change the state of the input method.
// In Aura environment, aura::WindowTreeHost creates an instance of
// ui::InputMethod and owns it.
class InputMethod { … };

}  // namespace ui

#endif  // UI_BASE_IME_INPUT_METHOD_H_