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 12 namespace 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). 34 EVENTS_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