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text_input_model.h
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1 // Copyright 2013 The Flutter 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 FLUTTER_SHELL_PLATFORM_COMMON_TEXT_INPUT_MODEL_H_
6 #define FLUTTER_SHELL_PLATFORM_COMMON_TEXT_INPUT_MODEL_H_
7
8 #include <memory>
9 #include <string>
10
11 #include "flutter/shell/platform/common/text_range.h"
12
13 namespace flutter {
14
15 // Handles underlying text input state, using a simple ASCII model.
16 //
17 // Ignores special states like "insert mode" for now.
18 class TextInputModel {
19 public:
20 TextInputModel();
21 virtual ~TextInputModel();
22
23 // Sets the text, as well as the selection and the composing region.
24 //
25 // This method is typically used to update the TextInputModel's editing state
26 // when the Flutter framework sends its latest text editing state.
27 bool SetText(const std::string& text,
28 const TextRange& selection = TextRange(0),
29 const TextRange& composing_range = TextRange(0));
30
31 // Attempts to set the text selection.
32 //
33 // Returns false if the selection is not within the bounds of the text.
34 // While in composing mode, the selection is restricted to the composing
35 // range; otherwise, it is restricted to the length of the text.
36 //
37 // To update both the text and the selection/composing range within the text
38 // (for instance, when the framework sends its latest text editing state),
39 // call |SetText| instead.
40 bool SetSelection(const TextRange& range);
41
42 // Attempts to set the composing range.
43 //
44 // Returns false if the range or offset are out of range for the text, or if
45 // the offset is outside the composing range.
46 //
47 // To update both the text and the selection/composing range within the text
48 // (for instance, when the framework sends its latest text editing state),
49 // call |SetText| instead.
50 bool SetComposingRange(const TextRange& range, size_t cursor_offset);
51
52 // Begins IME composing mode.
53 //
54 // Resets the composing base and extent to the selection start. The existing
55 // selection is preserved in case composing is aborted with no changes. Until
56 // |EndComposing| is called, any further changes to selection base and extent
57 // are restricted to the composing range.
58 void BeginComposing();
59
60 // Replaces the composing range with new UTF-16 text, and sets the selection.
61 //
62 // The given |text| replaces text within the current composing range, or the
63 // current selection if the text wasn't composing. The composing range is
64 // adjusted to the length of |text|, and the |selection| describes the new
65 // selection range, relative to the start of the new composing range.
66 void UpdateComposingText(const std::u16string& text,
67 const TextRange& selection);
68
69 // Replaces the composing range with new UTF-16 text and sets the selection to
70 // the end of the composing text.
71 void UpdateComposingText(const std::u16string& text);
72
73 // Replaces the composing range with new UTF-8 text.
74 //
75 // If a selection of non-zero length exists, it is deleted if the composing
76 // text is non-empty. The composing range is adjusted to the length of
77 // |text| and the selection base and offset are set to the end of the
78 // composing range.
79 void UpdateComposingText(const std::string& text);
80
81 // Commits composing range to the string.
82 //
83 // Causes the composing base and extent to be collapsed to the end of the
84 // range.
85 void CommitComposing();
86
87 // Ends IME composing mode.
88 //
89 // Collapses the composing base and offset to 0.
90 void EndComposing();
91
92 // Adds a Unicode code point.
93 //
94 // Either appends after the cursor (when selection base and extent are the
95 // same), or deletes the selected text, replacing it with the given
96 // code point.
97 void AddCodePoint(char32_t c);
98
99 // Adds UTF-16 text.
100 //
101 // Either appends after the cursor (when selection base and extent are the
102 // same), or deletes the selected text, replacing it with the given text.
103 void AddText(const std::u16string& text);
104
105 // Adds UTF-8 text.
106 //
107 // Either appends after the cursor (when selection base and extent are the
108 // same), or deletes the selected text, replacing it with the given text.
109 void AddText(const std::string& text);
110
111 // Deletes either the selection, or one character ahead of the cursor.
112 //
113 // Deleting one character ahead of the cursor occurs when the selection base
114 // and extent are the same. When composing is active, deletions are
115 // restricted to text between the composing base and extent.
116 //
117 // Returns true if any deletion actually occurred.
118 bool Delete();
119
120 // Deletes text near the cursor.
121 //
122 // A section is made starting at |offset_from_cursor| code points past the
123 // cursor (negative values go before the cursor). |count| code points are
124 // removed. The selection may go outside the bounds of the available text and
125 // will result in only the part selection that covers the available text
126 // being deleted. The existing selection is ignored and removed after this
127 // operation. When composing is active, deletions are restricted to the
128 // composing range.
129 //
130 // Returns true if any deletion actually occurred.
131 bool DeleteSurrounding(int offset_from_cursor, int count);
132
133 // Deletes either the selection, or one character behind the cursor.
134 //
135 // Deleting one character behind the cursor occurs when the selection base
136 // and extent are the same. When composing is active, deletions are
137 // restricted to the text between the composing base and extent.
138 //
139 // Returns true if any deletion actually occurred.
140 bool Backspace();
141
142 // Attempts to move the cursor backward.
143 //
144 // Returns true if the cursor could be moved. If a selection is active, moves
145 // to the start of the selection. If composing is active, motion is
146 // restricted to the composing range.
147 bool MoveCursorBack();
148
149 // Attempts to move the cursor forward.
150 //
151 // Returns true if the cursor could be moved. If a selection is active, moves
152 // to the end of the selection. If composing is active, motion is restricted
153 // to the composing range.
154 bool MoveCursorForward();
155
156 // Attempts to move the cursor to the beginning.
157 //
158 // If composing is active, the cursor is moved to the beginning of the
159 // composing range; otherwise, it is moved to the beginning of the text. If
160 // composing is active, motion is restricted to the composing range.
161 //
162 // Returns true if the cursor could be moved.
163 bool MoveCursorToBeginning();
164
165 // Attempts to move the cursor to the end.
166 //
167 // If composing is active, the cursor is moved to the end of the composing
168 // range; otherwise, it is moved to the end of the text. If composing is
169 // active, motion is restricted to the composing range.
170 //
171 // Returns true if the cursor could be moved.
172 bool MoveCursorToEnd();
173
174 // Attempts to select text from the cursor position to the beginning.
175 //
176 // If composing is active, the selection is applied to the beginning of the
177 // composing range; otherwise, it is applied to the beginning of the text.
178 //
179 // Returns true if the selection could be applied.
180 bool SelectToBeginning();
181
182 // Attempts to select text from the cursor position to the end.
183 //
184 // If composing is active, the selection is applied to the end of the
185 // composing range; otherwise, it is moved to the end of the text.
186 //
187 // Returns true if the selection could be applied.
188 bool SelectToEnd();
189
190 // Gets the current text as UTF-8.
191 std::string GetText() const;
192
193 // Gets the cursor position as a byte offset in UTF-8 string returned from
194 // GetText().
195 int GetCursorOffset() const;
196
197 // Returns a range covering the entire text.
198 TextRange text_range() const { return TextRange(0, text_.length()); }
199
200 // The current selection.
201 TextRange selection() const { return selection_; }
202
203 // The composing range.
204 //
205 // If not in composing mode, returns a collapsed range at position 0.
206 TextRange composing_range() const { return composing_range_; }
207
208 // Whether multi-step input composing mode is active.
209 bool composing() const { return composing_; }
210
211 private:
212 // Deletes the current selection, if any.
213 //
214 // Returns true if any text is deleted. The selection base and extent are
215 // reset to the start of the selected range.
216 bool DeleteSelected();
217
218 // Returns the currently editable text range.
219 //
220 // In composing mode, returns the composing range; otherwise, returns a range
221 // covering the entire text.
222 TextRange editable_range() const {
223 return composing_ ? composing_range_ : text_range();
224 }
225
226 std::u16string text_;
227 TextRange selection_ = TextRange(0);
228 TextRange composing_range_ = TextRange(0);
229 bool composing_ = false;
230 };
231
232 } // namespace flutter
233
234 #endif // FLUTTER_SHELL_PLATFORM_COMMON_TEXT_INPUT_MODEL_H_
flutter::TextInputModel
Definition: text_input_model.h:18
flutter::TextInputModel::composing
bool composing() const
Definition: text_input_model.h:209
flutter::TextInputModel::MoveCursorForward
bool MoveCursorForward()
Definition: text_input_model.cc:265
flutter::TextInputModel::selection
TextRange selection() const
Definition: text_input_model.h:201
flutter::TextInputModel::SelectToBeginning
bool SelectToBeginning()
Definition: text_input_model.cc:247
flutter::TextInputModel::MoveCursorToBeginning
bool MoveCursorToBeginning()
Definition: text_input_model.cc:229
flutter::TextInputModel::GetText
std::string GetText() const
Definition: text_input_model.cc:297
flutter::TextInputModel::DeleteSurrounding
bool DeleteSurrounding(int offset_from_cursor, int count)
Definition: text_input_model.cc:188
flutter::TextInputModel::CommitComposing
void CommitComposing()
Definition: text_input_model.cc:94
flutter::TextInputModel::~TextInputModel
virtual ~TextInputModel()
flutter::TextInputModel::AddText
void AddText(const std::u16string &text)
Definition: text_input_model.cc:136
flutter::TextInputModel::MoveCursorBack
bool MoveCursorBack()
Definition: text_input_model.cc:281
flutter::TextInputModel::AddCodePoint
void AddCodePoint(char32_t c)
Definition: text_input_model.cc:122
flutter::TextInputModel::MoveCursorToEnd
bool MoveCursorToEnd()
Definition: text_input_model.cc:238
flutter::TextInputModel::SetComposingRange
bool SetComposingRange(const TextRange &range, size_t cursor_offset)
Definition: text_input_model.cc:57
flutter::TextInputModel::GetCursorOffset
int GetCursorOffset() const
Definition: text_input_model.cc:301
flutter::TextInputModel::BeginComposing
void BeginComposing()
Definition: text_input_model.cc:67
flutter::TextInputModel::Backspace
bool Backspace()
Definition: text_input_model.cc:153
flutter::TextInputModel::text_range
TextRange text_range() const
Definition: text_input_model.h:198
flutter::TextInputModel::composing_range
TextRange composing_range() const
Definition: text_input_model.h:206
flutter::TextInputModel::Delete
bool Delete()
Definition: text_input_model.cc:171
flutter::TextInputModel::SelectToEnd
bool SelectToEnd()
Definition: text_input_model.cc:256
flutter::TextInputModel::SetSelection
bool SetSelection(const TextRange &range)
Definition: text_input_model.cc:46
flutter::TextInputModel::EndComposing
void EndComposing()
Definition: text_input_model.cc:103
flutter::TextInputModel::SetText
bool SetText(const std::string &text, const TextRange &selection=TextRange(0), const TextRange &composing_range=TextRange(0))
Definition: text_input_model.cc:31
flutter::TextInputModel::UpdateComposingText
void UpdateComposingText(const std::u16string &text, const TextRange &selection)
Definition: text_input_model.cc:72
flutter::TextInputModel::TextInputModel
TextInputModel()
flutter::TextRange
Definition: text_range.h:19
flutter
Definition: accessibility_bridge.cc:14
text_range.h