egui/widgets/
checkbox.rs

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
use crate::{
    epaint, pos2, vec2, NumExt, Response, Sense, Shape, TextStyle, Ui, Vec2, Widget, WidgetInfo,
    WidgetText, WidgetType,
};

// TODO(emilk): allow checkbox without a text label
/// Boolean on/off control with text label.
///
/// Usually you'd use [`Ui::checkbox`] instead.
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// # let mut my_bool = true;
/// // These are equivalent:
/// ui.checkbox(&mut my_bool, "Checked");
/// ui.add(egui::Checkbox::new(&mut my_bool, "Checked"));
/// # });
/// ```
#[must_use = "You should put this widget in a ui with `ui.add(widget);`"]
pub struct Checkbox<'a> {
    checked: &'a mut bool,
    text: WidgetText,
    indeterminate: bool,
}

impl<'a> Checkbox<'a> {
    pub fn new(checked: &'a mut bool, text: impl Into<WidgetText>) -> Self {
        Checkbox {
            checked,
            text: text.into(),
            indeterminate: false,
        }
    }

    pub fn without_text(checked: &'a mut bool) -> Self {
        Self::new(checked, WidgetText::default())
    }

    /// Display an indeterminate state (neither checked nor unchecked)
    ///
    /// This only affects the checkbox's appearance. It will still toggle its boolean value when
    /// clicked.
    #[inline]
    pub fn indeterminate(mut self, indeterminate: bool) -> Self {
        self.indeterminate = indeterminate;
        self
    }
}

impl<'a> Widget for Checkbox<'a> {
    fn ui(self, ui: &mut Ui) -> Response {
        let Checkbox {
            checked,
            text,
            indeterminate,
        } = self;

        let spacing = &ui.spacing();
        let icon_width = spacing.icon_width;
        let icon_spacing = spacing.icon_spacing;

        let (galley, mut desired_size) = if text.is_empty() {
            (None, vec2(icon_width, 0.0))
        } else {
            let total_extra = vec2(icon_width + icon_spacing, 0.0);

            let wrap_width = ui.available_width() - total_extra.x;
            let galley = text.into_galley(ui, None, wrap_width, TextStyle::Button);

            let mut desired_size = total_extra + galley.size();
            desired_size = desired_size.at_least(spacing.interact_size);

            (Some(galley), desired_size)
        };

        desired_size = desired_size.at_least(Vec2::splat(spacing.interact_size.y));
        desired_size.y = desired_size.y.max(icon_width);
        let (rect, mut response) = ui.allocate_exact_size(desired_size, Sense::click());

        if response.clicked() {
            *checked = !*checked;
            response.mark_changed();
        }
        response.widget_info(|| {
            if indeterminate {
                WidgetInfo::labeled(
                    WidgetType::Checkbox,
                    ui.is_enabled(),
                    galley.as_ref().map_or("", |x| x.text()),
                )
            } else {
                WidgetInfo::selected(
                    WidgetType::Checkbox,
                    ui.is_enabled(),
                    *checked,
                    galley.as_ref().map_or("", |x| x.text()),
                )
            }
        });

        if ui.is_rect_visible(rect) {
            // let visuals = ui.style().interact_selectable(&response, *checked); // too colorful
            let visuals = ui.style().interact(&response);
            let (small_icon_rect, big_icon_rect) = ui.spacing().icon_rectangles(rect);
            ui.painter().add(epaint::RectShape::new(
                big_icon_rect.expand(visuals.expansion),
                visuals.rounding,
                visuals.bg_fill,
                visuals.bg_stroke,
            ));

            if indeterminate {
                // Horizontal line:
                ui.painter().add(Shape::hline(
                    small_icon_rect.x_range(),
                    small_icon_rect.center().y,
                    visuals.fg_stroke,
                ));
            } else if *checked {
                // Check mark:
                ui.painter().add(Shape::line(
                    vec![
                        pos2(small_icon_rect.left(), small_icon_rect.center().y),
                        pos2(small_icon_rect.center().x, small_icon_rect.bottom()),
                        pos2(small_icon_rect.right(), small_icon_rect.top()),
                    ],
                    visuals.fg_stroke,
                ));
            }
            if let Some(galley) = galley {
                let text_pos = pos2(
                    rect.min.x + icon_width + icon_spacing,
                    rect.center().y - 0.5 * galley.size().y,
                );
                ui.painter().galley(text_pos, galley, visuals.text_color());
            }
        }

        response
    }
}