egui/crates/egui_extras/src/loaders/gif_loader.rs

135 lines
4.4 KiB
Rust

use ahash::HashMap;
use egui::{
decode_animated_image_uri, has_gif_magic_header,
load::{BytesPoll, ImageLoadResult, ImageLoader, ImagePoll, LoadError, SizeHint},
mutex::Mutex,
ColorImage, FrameDurations, Id,
};
use image::AnimationDecoder as _;
use std::{io::Cursor, mem::size_of, sync::Arc, time::Duration};
/// Array of Frames and the duration for how long each frame should be shown
#[derive(Debug, Clone)]
pub struct AnimatedImage {
frames: Vec<Arc<ColorImage>>,
frame_durations: FrameDurations,
}
impl AnimatedImage {
fn load_gif(data: &[u8]) -> Result<Self, String> {
let decoder = image::codecs::gif::GifDecoder::new(Cursor::new(data))
.map_err(|err| format!("Failed to decode gif: {err}"))?;
let mut images = vec![];
let mut durations = vec![];
for frame in decoder.into_frames() {
let frame = frame.map_err(|err| format!("Failed to decode gif: {err}"))?;
let img = frame.buffer();
let pixels = img.as_flat_samples();
let delay: Duration = frame.delay().into();
images.push(Arc::new(ColorImage::from_rgba_unmultiplied(
[img.width() as usize, img.height() as usize],
pixels.as_slice(),
)));
durations.push(delay);
}
Ok(Self {
frames: images,
frame_durations: FrameDurations::new(durations),
})
}
}
impl AnimatedImage {
pub fn byte_len(&self) -> usize {
size_of::<Self>()
+ self
.frames
.iter()
.map(|image| {
image.pixels.len() * size_of::<egui::Color32>() + size_of::<Duration>()
})
.sum::<usize>()
}
/// Gets image at index
pub fn get_image(&self, index: usize) -> Arc<ColorImage> {
self.frames[index % self.frames.len()].clone()
}
}
type Entry = Result<Arc<AnimatedImage>, String>;
#[derive(Default)]
pub struct GifLoader {
cache: Mutex<HashMap<String, Entry>>,
}
impl GifLoader {
pub const ID: &'static str = egui::generate_loader_id!(GifLoader);
}
impl ImageLoader for GifLoader {
fn id(&self) -> &str {
Self::ID
}
fn load(&self, ctx: &egui::Context, frame_uri: &str, _: SizeHint) -> ImageLoadResult {
let (image_uri, frame_index) =
decode_animated_image_uri(frame_uri).map_err(|_err| LoadError::NotSupported)?;
let mut cache = self.cache.lock();
if let Some(entry) = cache.get(image_uri).cloned() {
match entry {
Ok(image) => Ok(ImagePoll::Ready {
image: image.get_image(frame_index),
}),
Err(err) => Err(LoadError::Loading(err)),
}
} else {
match ctx.try_load_bytes(image_uri) {
Ok(BytesPoll::Ready { bytes, .. }) => {
if !has_gif_magic_header(&bytes) {
return Err(LoadError::NotSupported);
}
log::trace!("started loading {image_uri:?}");
let result = AnimatedImage::load_gif(&bytes).map(Arc::new);
if let Ok(v) = &result {
ctx.data_mut(|data| {
*data.get_temp_mut_or_default(Id::new(image_uri)) =
v.frame_durations.clone();
});
}
log::trace!("finished loading {image_uri:?}");
cache.insert(image_uri.into(), result.clone());
match result {
Ok(image) => Ok(ImagePoll::Ready {
image: image.get_image(frame_index),
}),
Err(err) => Err(LoadError::Loading(err)),
}
}
Ok(BytesPoll::Pending { size }) => Ok(ImagePoll::Pending { size }),
Err(err) => Err(err),
}
}
}
fn forget(&self, uri: &str) {
let _ = self.cache.lock().remove(uri);
}
fn forget_all(&self) {
self.cache.lock().clear();
}
fn byte_size(&self) -> usize {
self.cache
.lock()
.values()
.map(|v| match v {
Ok(v) => v.byte_len(),
Err(e) => e.len(),
})
.sum()
}
}