armas_basic/layout/
aspect_ratio.rs

1use egui::{Response, Ui, Vec2};
2
3/// Maintain aspect ratio wrapper
4///
5/// Constrains content to a specific aspect ratio.
6/// Inspired by `SwiftUI`'s aspectRatio modifier.
7///
8/// # Example
9///
10/// ```rust,no_run
11/// # use egui::Ui;
12/// # fn example(ui: &mut Ui) {
13/// use armas_basic::layout::AspectRatio;
14///
15/// // 16:9 aspect ratio
16/// AspectRatio::new(16.0 / 9.0)
17///     .show(ui, |ui| {
18///         ui.label("16:9 content");
19///     });
20///
21/// // Square (1:1)
22/// AspectRatio::square()
23///     .show(ui, |ui| {
24///         ui.label("Square content");
25///     });
26/// # }
27/// ```
28pub struct AspectRatio {
29    ratio: f32,
30    content_mode: ContentMode,
31}
32
33/// How content should be sized within the aspect ratio container
34#[derive(Debug, Clone, Copy, PartialEq, Eq)]
35pub enum ContentMode {
36    /// Content fills available space (may be cropped)
37    Fill,
38    /// Content fits within available space (may have empty space)
39    Fit,
40}
41
42impl AspectRatio {
43    /// Create aspect ratio constraint (width / height)
44    #[must_use]
45    pub const fn new(ratio: f32) -> Self {
46        Self {
47            ratio,
48            content_mode: ContentMode::Fit,
49        }
50    }
51
52    /// Create a square aspect ratio (1:1)
53    #[must_use]
54    pub const fn square() -> Self {
55        Self::new(1.0)
56    }
57
58    /// Create 16:9 aspect ratio (widescreen)
59    #[must_use]
60    pub fn widescreen() -> Self {
61        Self::new(16.0 / 9.0)
62    }
63
64    /// Create 4:3 aspect ratio (standard)
65    #[must_use]
66    pub fn standard() -> Self {
67        Self::new(4.0 / 3.0)
68    }
69
70    /// Set content mode (fill or fit)
71    #[must_use]
72    pub const fn content_mode(mut self, mode: ContentMode) -> Self {
73        self.content_mode = mode;
74        self
75    }
76
77    /// Show the aspect ratio container with the given content
78    pub fn show<R>(self, ui: &mut Ui, content: impl FnOnce(&mut Ui) -> R) -> Response {
79        let available = ui.available_size();
80
81        // Calculate size maintaining aspect ratio (ratio = width / height)
82        let size = match self.content_mode {
83            ContentMode::Fit => {
84                // If available height is 0 or very small, use width to calculate both dimensions
85                if available.y < 1.0 {
86                    let height = available.x / self.ratio;
87                    Vec2::new(available.x, height)
88                } else {
89                    // Calculate what height we'd get if we use full width
90                    let height_from_width = available.x / self.ratio;
91                    // Calculate what width we'd get if we use full height
92                    let width_from_height = available.y * self.ratio;
93
94                    if height_from_width <= available.y {
95                        // Width is the limiting factor - use full width
96                        Vec2::new(available.x, height_from_width)
97                    } else {
98                        // Height is the limiting factor - use full height
99                        Vec2::new(width_from_height, available.y)
100                    }
101                }
102            }
103            ContentMode::Fill => {
104                // If available height is 0 or very small, use width to calculate both dimensions
105                if available.y < 1.0 {
106                    let height = available.x / self.ratio;
107                    Vec2::new(available.x, height)
108                } else {
109                    let height_from_width = available.x / self.ratio;
110                    let width_from_height = available.y * self.ratio;
111
112                    if height_from_width >= available.y {
113                        // Width gives us more - use it
114                        Vec2::new(available.x, height_from_width)
115                    } else {
116                        // Height gives us more - use it
117                        Vec2::new(width_from_height, available.y)
118                    }
119                }
120            }
121        };
122
123        let (rect, response) = ui.allocate_exact_size(size, egui::Sense::hover());
124
125        ui.scope_builder(egui::UiBuilder::new().max_rect(rect), |ui| content(ui));
126
127        response
128    }
129}
130
131impl Default for AspectRatio {
132    fn default() -> Self {
133        Self::new(1.0)
134    }
135}
armas_basic/layout/aspect_ratio.rs

armas_basic/layout/
aspect_ratio.rs
