iced_widget/text_input/
cursor.rs

1//! Track the cursor of a text input.
2use crate::text_input::Value;
3
4/// The cursor of a text input.
5#[derive(Debug, Copy, Clone, PartialEq, Eq)]
6pub struct Cursor {
7    state: State,
8}
9
10/// The state of a [`Cursor`].
11#[derive(Debug, Copy, Clone, PartialEq, Eq)]
12pub enum State {
13    /// Cursor without a selection
14    Index(usize),
15
16    /// Cursor selecting a range of text
17    Selection {
18        /// The start of the selection
19        start: usize,
20        /// The end of the selection
21        end: usize,
22    },
23}
24
25impl Default for Cursor {
26    fn default() -> Self {
27        Cursor {
28            state: State::Index(0),
29        }
30    }
31}
32
33impl Cursor {
34    /// Returns the [`State`] of the [`Cursor`].
35    pub fn state(&self, value: &Value) -> State {
36        match self.state {
37            State::Index(index) => State::Index(index.min(value.len())),
38            State::Selection { start, end } => {
39                let start = start.min(value.len());
40                let end = end.min(value.len());
41
42                if start == end {
43                    State::Index(start)
44                } else {
45                    State::Selection { start, end }
46                }
47            }
48        }
49    }
50
51    /// Returns the current selection of the [`Cursor`] for the given [`Value`].
52    ///
53    /// `start` is guaranteed to be <= than `end`.
54    pub fn selection(&self, value: &Value) -> Option<(usize, usize)> {
55        match self.state(value) {
56            State::Selection { start, end } => Some((start.min(end), start.max(end))),
57            State::Index(_) => None,
58        }
59    }
60
61    pub(crate) fn move_to(&mut self, position: usize) {
62        self.state = State::Index(position);
63    }
64
65    pub(crate) fn move_right(&mut self, value: &Value) {
66        self.move_right_by_amount(value, 1);
67    }
68
69    pub(crate) fn move_right_by_words(&mut self, value: &Value) {
70        self.move_to(value.next_end_of_word(self.right(value)));
71    }
72
73    pub(crate) fn move_right_by_amount(&mut self, value: &Value, amount: usize) {
74        match self.state(value) {
75            State::Index(index) => {
76                self.move_to(index.saturating_add(amount).min(value.len()));
77            }
78            State::Selection { start, end } => self.move_to(end.max(start)),
79        }
80    }
81
82    pub(crate) fn move_left(&mut self, value: &Value) {
83        match self.state(value) {
84            State::Index(index) if index > 0 => self.move_to(index - 1),
85            State::Selection { start, end } => self.move_to(start.min(end)),
86            State::Index(_) => self.move_to(0),
87        }
88    }
89
90    pub(crate) fn move_left_by_words(&mut self, value: &Value) {
91        self.move_to(value.previous_start_of_word(self.left(value)));
92    }
93
94    pub(crate) fn select_range(&mut self, start: usize, end: usize) {
95        if start == end {
96            self.state = State::Index(start);
97        } else {
98            self.state = State::Selection { start, end };
99        }
100    }
101
102    pub(crate) fn select_left(&mut self, value: &Value) {
103        match self.state(value) {
104            State::Index(index) if index > 0 => {
105                self.select_range(index, index - 1);
106            }
107            State::Selection { start, end } if end > 0 => {
108                self.select_range(start, end - 1);
109            }
110            _ => {}
111        }
112    }
113
114    pub(crate) fn select_right(&mut self, value: &Value) {
115        match self.state(value) {
116            State::Index(index) if index < value.len() => {
117                self.select_range(index, index + 1);
118            }
119            State::Selection { start, end } if end < value.len() => {
120                self.select_range(start, end + 1);
121            }
122            _ => {}
123        }
124    }
125
126    pub(crate) fn select_left_by_words(&mut self, value: &Value) {
127        match self.state(value) {
128            State::Index(index) => {
129                self.select_range(index, value.previous_start_of_word(index));
130            }
131            State::Selection { start, end } => {
132                self.select_range(start, value.previous_start_of_word(end));
133            }
134        }
135    }
136
137    pub(crate) fn select_right_by_words(&mut self, value: &Value) {
138        match self.state(value) {
139            State::Index(index) => {
140                self.select_range(index, value.next_end_of_word(index));
141            }
142            State::Selection { start, end } => {
143                self.select_range(start, value.next_end_of_word(end));
144            }
145        }
146    }
147
148    pub(crate) fn select_all(&mut self, value: &Value) {
149        self.select_range(0, value.len());
150    }
151
152    pub(crate) fn start(&self, value: &Value) -> usize {
153        let start = match self.state {
154            State::Index(index) => index,
155            State::Selection { start, .. } => start,
156        };
157
158        start.min(value.len())
159    }
160
161    pub(crate) fn end(&self, value: &Value) -> usize {
162        let end = match self.state {
163            State::Index(index) => index,
164            State::Selection { end, .. } => end,
165        };
166
167        end.min(value.len())
168    }
169
170    fn left(&self, value: &Value) -> usize {
171        match self.state(value) {
172            State::Index(index) => index,
173            State::Selection { start, end } => start.min(end),
174        }
175    }
176
177    fn right(&self, value: &Value) -> usize {
178        match self.state(value) {
179            State::Index(index) => index,
180            State::Selection { start, end } => start.max(end),
181        }
182    }
183}
iced_widget/text_input/cursor.rs

iced_widget/text_input/
cursor.rs
