1 // Copyright 2013 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_BASE_IME_CHROMEOS_CHARACTER_COMPOSER_H_ 6 #define UI_BASE_IME_CHROMEOS_CHARACTER_COMPOSER_H_ 7 8 #include <vector> 9 10 #include "base/strings/string_util.h" 11 #include "ui/base/ui_base_export.h" 12 13 namespace ui { 14 class KeyEvent; 15 16 // A class to recognize compose and dead key sequence. 17 // Outputs composed character. 18 class UI_BASE_EXPORT CharacterComposer { 19 public: 20 CharacterComposer(); 21 ~CharacterComposer(); 22 23 void Reset(); 24 25 // Filters keypress. 26 // Returns true if the keypress is recognized as a part of composition 27 // sequence. 28 // Fabricated events which don't have the native event, are not supported. 29 bool FilterKeyPress(const ui::KeyEvent& event); 30 31 // Returns a string consisting of composed character. 32 // Empty string is returned when there is no composition result. composed_character()33 const base::string16& composed_character() const { 34 return composed_character_; 35 } 36 37 // Returns the preedit string. preedit_string()38 const base::string16& preedit_string() const { return preedit_string_; } 39 40 private: 41 friend class CharacterComposerTest; 42 43 // An enum to describe composition mode. 44 enum CompositionMode { 45 // This is the initial state. 46 // Composite a character with dead-keys and compose-key. 47 KEY_SEQUENCE_MODE, 48 // Composite a character with a hexadecimal unicode sequence. 49 HEX_MODE, 50 }; 51 52 // Filters keypress using IBus defined value. 53 // Returns true if the keypress is recognized as a part of composition 54 // sequence. 55 // |keyval| must be a GDK_KEY_* constant. 56 // |keycode| must be a X key code. 57 // |flags| must be a combination of ui::EF_* flags. 58 // 59 // composed_character() returns non empty string when there is a character 60 // composed after this method returns true. 61 // preedit_string() returns non empty string when there is a preedit string 62 // after this method returns true. 63 // Return values of preedit_string() is empty after this method returns false. 64 // composed_character() may have some characters which are consumed in this 65 // composing session. 66 // 67 // 68 // TODO(nona): Actually a X KeySym is passed to |keyval|, so we should use 69 // XK_* rather than GDK_KEY_*. 70 bool FilterKeyPressInternal(unsigned int keyval, unsigned int keycode, 71 int flags); 72 73 // Filters keypress in key sequence mode. 74 bool FilterKeyPressSequenceMode(unsigned int keyval, int flags); 75 76 // Filters keypress in hexadecimal mode. 77 bool FilterKeyPressHexMode(unsigned int keyval, unsigned int keycode, 78 int flags); 79 80 // Commit a character composed from hexadecimal uncode sequence 81 void CommitHex(); 82 83 // Updates preedit string in hexadecimal mode. 84 void UpdatePreeditStringHexMode(); 85 86 // Remembers keypresses previously filtered. 87 std::vector<unsigned int> compose_buffer_; 88 89 // A string representing the composed character. 90 base::string16 composed_character_; 91 92 // Preedit string. 93 base::string16 preedit_string_; 94 95 // Composition mode which this instance is in. 96 CompositionMode composition_mode_; 97 98 DISALLOW_COPY_AND_ASSIGN(CharacterComposer); 99 }; 100 101 } // namespace ui 102 103 #endif // UI_BASE_IME_CHROMEOS_CHARACTER_COMPOSER_H_ 104