1// Copyright (c) 2011 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef UI_EVENTS_KEYCODES_KEYBOARD_CODE_CONVERSION_H_ 6#define UI_EVENTS_KEYCODES_KEYBOARD_CODE_CONVERSION_H_ 7 8#include "base/basictypes.h" 9#include "ui/events/events_base_export.h" 10#include "ui/events/keycodes/keyboard_codes.h" 11 12namespace ui { 13 14// A helper function to get the character generated by a key event in a 15// platform independent way. It supports control characters as well. 16// It assumes a US keyboard layout is used, so it may only be used when there 17// is no native event or no better way to get the character. 18// For example, if a virtual keyboard implementation can only generate key 19// events with key_code and flags information, then there is no way for us to 20// determine the actual character that should be generate by the key. Because 21// a key_code only represents a physical key on the keyboard, it has nothing 22// to do with the actual character printed on that key. In such case, the only 23// thing we can do is to assume that we are using a US keyboard and get the 24// character according to US keyboard layout definition. 25// If a virtual keyboard implementation wants to support other keyboard 26// layouts, that may generate different text for a certain key than on a US 27// keyboard, a special native event object should be introduced to carry extra 28// information to help determine the correct character. 29// Take XKeyEvent as an example, it contains not only keycode and modifier 30// flags but also group and other extra XKB information to help determine the 31// correct character. That's why we can use XLookupString() function to get 32// the correct text generated by a X key event (See how is GetCharacter() 33// implemented in event_x.cc). 34EVENTS_BASE_EXPORT uint16 GetCharacterFromKeyCode(KeyboardCode key_code, 35 int flags); 36 37} // namespace ui 38 39#endif // UI_EVENTS_KEYCODES_KEYBOARD_CODE_CONVERSION_H_ 40