retroglyph_widgets/widget/
text.rs

1//! [`Text`]: a single line of plain text in one [`Style`].
2use retroglyph_core::{Backend, Rect, Style, Terminal};
3use unicode_width::UnicodeWidthStr;
4
5use super::Widget;
6use crate::Align;
7use crate::text::truncate as truncate_to_cols;
8
9/// A single line of text in one [`Style`], clipped (not wrapped) to
10/// `area.width()` columns. Only the first row of `area` is used.
11///
12/// The plain-content cousin of [`PrintLine`](super::PrintLine) (which
13/// prints a multi-span [`Line`](retroglyph_core::text::Line), for mixed
14/// styling within one line) and [`Paragraph`](super::Paragraph) (which
15/// word-wraps across multiple lines, and needs the `egc` feature): reach
16/// for `Text` for a single already-one-line label or readout in a single
17/// style, with no wrapping and no per-span styling. `style` defaults to
18/// [`Style::new()`] and `align` to [`Align::Left`]; set them with
19/// [`Text::style`]/[`Text::align`].
20#[derive(Clone, Copy, Debug)]
21pub struct Text<'a> {
22    content: &'a str,
23    style: Style,
24    align: Align,
25}
26
27impl<'a> Text<'a> {
28    /// A line of `content` in the default style, left-aligned.
29    #[must_use]
30    pub fn new(content: &'a str) -> Self {
31        Self {
32            content,
33            style: Style::new(),
34            align: Align::Left,
35        }
36    }
37
38    /// Set the text's style.
39    #[must_use]
40    pub const fn style(mut self, style: Style) -> Self {
41        self.style = style;
42        self
43    }
44
45    /// Set how the line is aligned within `area.width()` columns.
46    #[must_use]
47    pub const fn align(mut self, align: Align) -> Self {
48        self.align = align;
49        self
50    }
51}
52
53impl<B: Backend> Widget<B> for Text<'_> {
54    fn render(self, area: Rect, term: &mut Terminal<B>) {
55        if area.width() == 0 {
56            return;
57        }
58        let text = truncate_to_cols(self.content, area.width_usize());
59        let x = area.left() + self.align.offset(area.width(), text.width() as u16);
60        term.reset_style()
61            .fg(self.style.foreground())
62            .bg(self.style.background());
63        term.print(x, area.top(), &text);
64        term.reset_style();
65    }
66}
67
68#[cfg(test)]
69mod tests {
70    use retroglyph_core::{Color, Headless};
71
72    use super::*;
73
74    #[test]
75    fn prints_the_content_in_the_given_style() {
76        let area = Rect::new(0, 0, 10, 1);
77        let mut term = Terminal::new(Headless::new(10, 1));
78        Text::new("hi")
79            .style(Style::new().fg(Color::WHITE))
80            .render(area, &mut term);
81
82        assert_eq!(term.grid().get(0, 0).glyph(), 'h');
83        assert_eq!(term.grid().get(1, 0).glyph(), 'i');
84        assert_eq!(term.grid().get(0, 0).style().foreground(), Color::WHITE);
85    }
86
87    #[test]
88    fn clips_to_area_width() {
89        let area = Rect::new(0, 0, 5, 1);
90        let mut term = Terminal::new(Headless::new(5, 1));
91        Text::new("a much longer message than fits").render(area, &mut term);
92
93        assert_eq!(term.grid().get(4, 0).glyph(), 'c'); // "a muc"
94    }
95
96    #[test]
97    fn right_align_places_text_against_the_right_edge() {
98        let area = Rect::new(0, 0, 10, 1);
99        let mut term = Terminal::new(Headless::new(10, 1));
100        Text::new("hi").align(Align::Right).render(area, &mut term);
101
102        // "hi" (2 cols) in 10 cols, right-aligned: starts at column 8.
103        assert_eq!(term.grid().get(8, 0).glyph(), 'h');
104        assert_eq!(term.grid().get(9, 0).glyph(), 'i');
105        assert_eq!(term.grid().get(7, 0).glyph(), ' ');
106    }
107
108    #[test]
109    fn center_align_centers_text() {
110        let area = Rect::new(0, 0, 10, 1);
111        let mut term = Terminal::new(Headless::new(10, 1));
112        Text::new("hi").align(Align::Center).render(area, &mut term);
113
114        // 8 cols slack, 4 on the left: "hi" starts at column 4.
115        assert_eq!(term.grid().get(4, 0).glyph(), 'h');
116        assert_eq!(term.grid().get(5, 0).glyph(), 'i');
117    }
118
119    #[test]
120    fn zero_width_is_a_no_op() {
121        let area = Rect::new(0, 0, 0, 1);
122        let mut term = Terminal::new(Headless::new(1, 1));
123        Text::new("hi").render(area, &mut term);
124        assert_eq!(term.grid().get(0, 0).glyph(), ' ');
125    }
126}
retroglyph_widgets/widget/text.rs

retroglyph_widgets/widget/
text.rs
