1use crate::{size, DevicePixels, Result, SharedString, Size};
 2use smallvec::SmallVec;
 3
 4use image::{Delay, Frame};
 5use std::{
 6    borrow::Cow,
 7    fmt,
 8    hash::Hash,
 9    sync::atomic::{AtomicUsize, Ordering::SeqCst},
10};
11
12/// A source of assets for this app to use.
13pub trait AssetSource: 'static + Send + Sync {
14    /// Load the given asset from the source path.
15    fn load(&self, path: &str) -> Result<Option<Cow<'static, [u8]>>>;
16
17    /// List the assets at the given path.
18    fn list(&self, path: &str) -> Result<Vec<SharedString>>;
19}
20
21impl AssetSource for () {
22    fn load(&self, _path: &str) -> Result<Option<Cow<'static, [u8]>>> {
23        Ok(None)
24    }
25
26    fn list(&self, _path: &str) -> Result<Vec<SharedString>> {
27        Ok(vec![])
28    }
29}
30
31/// A unique identifier for the image cache
32#[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
33pub struct ImageId(usize);
34
35#[derive(PartialEq, Eq, Hash, Clone)]
36pub(crate) struct RenderImageParams {
37    pub(crate) image_id: ImageId,
38    pub(crate) frame_index: usize,
39}
40
41/// A cached and processed image.
42pub struct ImageData {
43    /// The ID associated with this image
44    pub id: ImageId,
45    data: SmallVec<[Frame; 1]>,
46}
47
48impl ImageData {
49    /// Create a new image from the given data.
50    pub fn new(data: impl Into<SmallVec<[Frame; 1]>>) -> Self {
51        static NEXT_ID: AtomicUsize = AtomicUsize::new(0);
52
53        Self {
54            id: ImageId(NEXT_ID.fetch_add(1, SeqCst)),
55            data: data.into(),
56        }
57    }
58
59    /// Convert this image into a byte slice.
60    pub fn as_bytes(&self, frame_index: usize) -> &[u8] {
61        &self.data[frame_index].buffer()
62    }
63
64    /// Get the size of this image, in pixels.
65    pub fn size(&self, frame_index: usize) -> Size<DevicePixels> {
66        let (width, height) = self.data[frame_index].buffer().dimensions();
67        size(width.into(), height.into())
68    }
69
70    /// Get the delay of this frame from the previous
71    pub fn delay(&self, frame_index: usize) -> Delay {
72        self.data[frame_index].delay()
73    }
74
75    /// Get the number of frames for this image.
76    pub fn frame_count(&self) -> usize {
77        self.data.len()
78    }
79}
80
81impl fmt::Debug for ImageData {
82    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
83        f.debug_struct("ImageData")
84            .field("id", &self.id)
85            .field("size", &self.size(0))
86            .finish()
87    }
88}