ratatui 0.26.2

A library that's all about cooking up terminal user interfaces
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220

use std::error::Error;

use ratatui::{
    assert_buffer_eq,
    backend::{Backend, TestBackend},
    layout::Rect,
    prelude::Buffer,
    widgets::{Paragraph, Widget},
    Terminal, TerminalOptions, Viewport,
};

#[test]
fn terminal_buffer_size_should_be_limited() {
    let backend = TestBackend::new(400, 400);
    let terminal = Terminal::new(backend).unwrap();
    let size = terminal.backend().size().unwrap();
    assert_eq!(size.width, 255);
    assert_eq!(size.height, 255);
}

#[test]
fn swap_buffer_clears_prev_buffer() {
    let backend = TestBackend::new(100, 50);
    let mut terminal = Terminal::new(backend).unwrap();
    terminal
        .current_buffer_mut()
        .set_string(0, 0, "Hello", ratatui::style::Style::reset());
    assert_eq!(terminal.current_buffer_mut().content()[0].symbol(), "H");
    terminal.swap_buffers();
    assert_eq!(terminal.current_buffer_mut().content()[0].symbol(), " ");
}

#[test]
fn terminal_draw_returns_the_completed_frame() -> Result<(), Box<dyn Error>> {
    let backend = TestBackend::new(10, 10);
    let mut terminal = Terminal::new(backend)?;
    let frame = terminal.draw(|f| {
        let paragraph = Paragraph::new("Test");
        f.render_widget(paragraph, f.size());
    })?;
    assert_eq!(frame.buffer.get(0, 0).symbol(), "T");
    assert_eq!(frame.area, Rect::new(0, 0, 10, 10));
    terminal.backend_mut().resize(8, 8);
    let frame = terminal.draw(|f| {
        let paragraph = Paragraph::new("test");
        f.render_widget(paragraph, f.size());
    })?;
    assert_eq!(frame.buffer.get(0, 0).symbol(), "t");
    assert_eq!(frame.area, Rect::new(0, 0, 8, 8));
    Ok(())
}

#[test]
fn terminal_draw_increments_frame_count() -> Result<(), Box<dyn Error>> {
    let backend = TestBackend::new(10, 10);
    let mut terminal = Terminal::new(backend)?;
    let frame = terminal.draw(|f| {
        assert_eq!(f.count(), 0);
        let paragraph = Paragraph::new("Test");
        f.render_widget(paragraph, f.size());
    })?;
    assert_eq!(frame.count, 0);
    let frame = terminal.draw(|f| {
        assert_eq!(f.count(), 1);
        let paragraph = Paragraph::new("test");
        f.render_widget(paragraph, f.size());
    })?;
    assert_eq!(frame.count, 1);
    let frame = terminal.draw(|f| {
        assert_eq!(f.count(), 2);
        let paragraph = Paragraph::new("test");
        f.render_widget(paragraph, f.size());
    })?;
    assert_eq!(frame.count, 2);
    Ok(())
}

#[test]
fn terminal_insert_before_moves_viewport() -> Result<(), Box<dyn Error>> {
    // When we have a terminal with 5 lines, and a single line viewport, if we insert a
    // number of lines less than the `terminal height - viewport height` it should move
    // viewport down to accommodate the new lines.

    let backend = TestBackend::new(20, 5);
    let mut terminal = Terminal::with_options(
        backend,
        TerminalOptions {
            viewport: Viewport::Inline(1),
        },
    )?;

    // insert_before cannot guarantee the contents of the viewport remain unharmed
    // by potential scrolling as such it is necessary to call draw afterwards to
    // redraw the contents of the viewport over the newly designated area.
    terminal.insert_before(2, |buf| {
        Paragraph::new(vec![
            "------ Line 1 ------".into(),
            "------ Line 2 ------".into(),
        ])
        .render(buf.area, buf);
    })?;

    terminal.draw(|f| {
        let paragraph = Paragraph::new("[---- Viewport ----]");
        f.render_widget(paragraph, f.size());
    })?;

    assert_buffer_eq!(
        terminal.backend().buffer().clone(),
        Buffer::with_lines(vec![
            "------ Line 1 ------",
            "------ Line 2 ------",
            "[---- Viewport ----]",
            "                    ",
            "                    ",
        ])
    );

    Ok(())
}

#[test]
fn terminal_insert_before_scrolls_on_large_input() -> Result<(), Box<dyn Error>> {
    // When we have a terminal with 5 lines, and a single line viewport, if we insert many
    // lines before the viewport (greater than `terminal height - viewport height`) it should
    // move the viewport down to the bottom of the terminal and scroll all lines above the viewport
    // until all have been added to the buffer.

    let backend = TestBackend::new(20, 5);
    let mut terminal = Terminal::with_options(
        backend,
        TerminalOptions {
            viewport: Viewport::Inline(1),
        },
    )?;

    terminal.insert_before(5, |buf| {
        Paragraph::new(vec![
            "------ Line 1 ------".into(),
            "------ Line 2 ------".into(),
            "------ Line 3 ------".into(),
            "------ Line 4 ------".into(),
            "------ Line 5 ------".into(),
        ])
        .render(buf.area, buf);
    })?;

    terminal.draw(|f| {
        let paragraph = Paragraph::new("[---- Viewport ----]");
        f.render_widget(paragraph, f.size());
    })?;

    assert_buffer_eq!(
        terminal.backend().buffer().clone(),
        Buffer::with_lines(vec![
            "------ Line 2 ------",
            "------ Line 3 ------",
            "------ Line 4 ------",
            "------ Line 5 ------",
            "[---- Viewport ----]",
        ])
    );

    Ok(())
}

#[test]
fn terminal_insert_before_scrolls_on_many_inserts() -> Result<(), Box<dyn Error>> {
    // This test ensures similar behaviour to `terminal_insert_before_scrolls_on_large_input`
    // but covers a bug previously present whereby multiple small insertions
    // (less than `terminal height - viewport height`) would have disparate behaviour to one large
    // insertion. This was caused by an undocumented cap on the height to be inserted, which has now
    // been removed.

    let backend = TestBackend::new(20, 5);
    let mut terminal = Terminal::with_options(
        backend,
        TerminalOptions {
            viewport: Viewport::Inline(1),
        },
    )?;

    terminal.insert_before(1, |buf| {
        Paragraph::new(vec!["------ Line 1 ------".into()]).render(buf.area, buf);
    })?;

    terminal.insert_before(1, |buf| {
        Paragraph::new(vec!["------ Line 2 ------".into()]).render(buf.area, buf);
    })?;

    terminal.insert_before(1, |buf| {
        Paragraph::new(vec!["------ Line 3 ------".into()]).render(buf.area, buf);
    })?;

    terminal.insert_before(1, |buf| {
        Paragraph::new(vec!["------ Line 4 ------".into()]).render(buf.area, buf);
    })?;

    terminal.insert_before(1, |buf| {
        Paragraph::new(vec!["------ Line 5 ------".into()]).render(buf.area, buf);
    })?;

    terminal.draw(|f| {
        let paragraph = Paragraph::new("[---- Viewport ----]");
        f.render_widget(paragraph, f.size());
    })?;

    assert_buffer_eq!(
        terminal.backend().buffer().clone(),
        Buffer::with_lines(vec![
            "------ Line 2 ------",
            "------ Line 3 ------",
            "------ Line 4 ------",
            "------ Line 5 ------",
            "[---- Viewport ----]",
        ])
    );

    Ok(())
}