iced_native/widget/
image.rs

1//! Display images in your user interface.
2pub mod viewer;
3pub use viewer::Viewer;
4
5use crate::image;
6use crate::layout;
7use crate::renderer;
8use crate::widget::Tree;
9use crate::{
10    ContentFit, Element, Layout, Length, Point, Rectangle, Size, Vector, Widget,
11};
12
13use std::hash::Hash;
14
15/// Creates a new [`Viewer`] with the given image `Handle`.
16pub fn viewer<Handle>(handle: Handle) -> Viewer<Handle> {
17    Viewer::new(handle)
18}
19
20/// A frame that displays an image while keeping aspect ratio.
21///
22/// # Example
23///
24/// ```
25/// # use iced_native::widget::Image;
26/// # use iced_native::image;
27/// #
28/// let image = Image::<image::Handle>::new("resources/ferris.png");
29/// ```
30///
31/// <img src="https://github.com/iced-rs/iced/blob/9712b319bb7a32848001b96bd84977430f14b623/examples/resources/ferris.png?raw=true" width="300">
32#[derive(Debug)]
33pub struct Image<Handle> {
34    handle: Handle,
35    width: Length,
36    height: Length,
37    content_fit: ContentFit,
38}
39
40impl<Handle> Image<Handle> {
41    /// Creates a new [`Image`] with the given path.
42    pub fn new<T: Into<Handle>>(handle: T) -> Self {
43        Image {
44            handle: handle.into(),
45            width: Length::Shrink,
46            height: Length::Shrink,
47            content_fit: ContentFit::Contain,
48        }
49    }
50
51    /// Sets the width of the [`Image`] boundaries.
52    pub fn width(mut self, width: impl Into<Length>) -> Self {
53        self.width = width.into();
54        self
55    }
56
57    /// Sets the height of the [`Image`] boundaries.
58    pub fn height(mut self, height: impl Into<Length>) -> Self {
59        self.height = height.into();
60        self
61    }
62
63    /// Sets the [`ContentFit`] of the [`Image`].
64    ///
65    /// Defaults to [`ContentFit::Contain`]
66    pub fn content_fit(self, content_fit: ContentFit) -> Self {
67        Self {
68            content_fit,
69            ..self
70        }
71    }
72}
73
74/// Computes the layout of an [`Image`].
75pub fn layout<Renderer, Handle>(
76    renderer: &Renderer,
77    limits: &layout::Limits,
78    handle: &Handle,
79    width: Length,
80    height: Length,
81    content_fit: ContentFit,
82) -> layout::Node
83where
84    Renderer: image::Renderer<Handle = Handle>,
85{
86    // The raw w/h of the underlying image
87    let image_size = {
88        let Size { width, height } = renderer.dimensions(handle);
89
90        Size::new(width as f32, height as f32)
91    };
92
93    // The size to be available to the widget prior to `Shrink`ing
94    let raw_size = limits.width(width).height(height).resolve(image_size);
95
96    // The uncropped size of the image when fit to the bounds above
97    let full_size = content_fit.fit(image_size, raw_size);
98
99    // Shrink the widget to fit the resized image, if requested
100    let final_size = Size {
101        width: match width {
102            Length::Shrink => f32::min(raw_size.width, full_size.width),
103            _ => raw_size.width,
104        },
105        height: match height {
106            Length::Shrink => f32::min(raw_size.height, full_size.height),
107            _ => raw_size.height,
108        },
109    };
110
111    layout::Node::new(final_size)
112}
113
114/// Draws an [`Image`]
115pub fn draw<Renderer, Handle>(
116    renderer: &mut Renderer,
117    layout: Layout<'_>,
118    handle: &Handle,
119    content_fit: ContentFit,
120) where
121    Renderer: image::Renderer<Handle = Handle>,
122    Handle: Clone + Hash,
123{
124    let Size { width, height } = renderer.dimensions(handle);
125    let image_size = Size::new(width as f32, height as f32);
126
127    let bounds = layout.bounds();
128    let adjusted_fit = content_fit.fit(image_size, bounds.size());
129
130    let render = |renderer: &mut Renderer| {
131        let offset = Vector::new(
132            (bounds.width - adjusted_fit.width).max(0.0) / 2.0,
133            (bounds.height - adjusted_fit.height).max(0.0) / 2.0,
134        );
135
136        let drawing_bounds = Rectangle {
137            width: adjusted_fit.width,
138            height: adjusted_fit.height,
139            ..bounds
140        };
141
142        renderer.draw(handle.clone(), drawing_bounds + offset)
143    };
144
145    if adjusted_fit.width > bounds.width || adjusted_fit.height > bounds.height
146    {
147        renderer.with_layer(bounds, render);
148    } else {
149        render(renderer)
150    }
151}
152
153impl<Message, Renderer, Handle> Widget<Message, Renderer> for Image<Handle>
154where
155    Renderer: image::Renderer<Handle = Handle>,
156    Handle: Clone + Hash,
157{
158    fn width(&self) -> Length {
159        self.width
160    }
161
162    fn height(&self) -> Length {
163        self.height
164    }
165
166    fn layout(
167        &self,
168        renderer: &Renderer,
169        limits: &layout::Limits,
170    ) -> layout::Node {
171        layout(
172            renderer,
173            limits,
174            &self.handle,
175            self.width,
176            self.height,
177            self.content_fit,
178        )
179    }
180
181    fn draw(
182        &self,
183        _state: &Tree,
184        renderer: &mut Renderer,
185        _theme: &Renderer::Theme,
186        _style: &renderer::Style,
187        layout: Layout<'_>,
188        _cursor_position: Point,
189        _viewport: &Rectangle,
190    ) {
191        draw(renderer, layout, &self.handle, self.content_fit)
192    }
193}
194
195impl<'a, Message, Renderer, Handle> From<Image<Handle>>
196    for Element<'a, Message, Renderer>
197where
198    Renderer: image::Renderer<Handle = Handle>,
199    Handle: Clone + Hash + 'a,
200{
201    fn from(image: Image<Handle>) -> Element<'a, Message, Renderer> {
202        Element::new(image)
203    }
204}
iced_native/widget/image.rs

iced_native/widget/
image.rs
