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Animate image fade in in markdown example
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@hecrj
hecrj committed Feb 4, 2025
1 parent 24cf355 commit a6e64ea
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Showing 2 changed files with 104 additions and 51 deletions.
151 changes: 102 additions & 49 deletions examples/markdown/src/main.rs
View file
Original file line number Diff line number Diff line change
@@ -1,12 +1,13 @@
use iced::animation;
use iced::highlighter;
use iced::time::{self, milliseconds};
use iced::task;
use iced::time::{self, milliseconds, Instant};
use iced::widget::{
self, center_x, horizontal_space, hover, image, markdown, pop, right, row,
scrollable, text_editor, toggler,
};
use iced::{Element, Fill, Font, Subscription, Task, Theme};

use tokio::task;
use iced::window;
use iced::{Animation, Element, Fill, Font, Subscription, Task, Theme};

use std::collections::HashMap;
use std::io;
Expand All @@ -20,23 +21,27 @@ pub fn main() -> iced::Result {
}

struct Markdown {
content: text_editor::Content,
content: markdown::Content,
raw: text_editor::Content,
images: HashMap<markdown::Url, Image>,
mode: Mode,
theme: Theme,
now: Instant,
}

enum Mode {
Preview(Vec<markdown::Item>),
Stream {
pending: String,
parsed: markdown::Content,
},
Preview,
Stream { pending: String },
}

enum Image {
Loading,
Ready(image::Handle),
Loading {
_download: task::Handle,
},
Ready {
handle: image::Handle,
fade_in: Animation<bool>,
},
#[allow(dead_code)]
Errored(Error),
}
Expand All @@ -49,20 +54,21 @@ enum Message {
ImageDownloaded(markdown::Url, Result<image::Handle, Error>),
ToggleStream(bool),
NextToken,
Animate(Instant),
}

impl Markdown {
fn new() -> (Self, Task<Message>) {
const INITIAL_CONTENT: &str = include_str!("../overview.md");

let theme = Theme::TokyoNight;

(
Self {
content: text_editor::Content::with_text(INITIAL_CONTENT),
content: markdown::Content::parse(INITIAL_CONTENT),
raw: text_editor::Content::with_text(INITIAL_CONTENT),
images: HashMap::new(),
mode: Mode::Preview(markdown::parse(INITIAL_CONTENT).collect()),
theme,
mode: Mode::Preview,
theme: Theme::TokyoNight,
now: Instant::now(),
},
widget::focus_next(),
)
Expand All @@ -73,12 +79,14 @@ impl Markdown {
Message::Edit(action) => {
let is_edit = action.is_edit();

self.content.perform(action);
self.raw.perform(action);

if is_edit {
self.mode = Mode::Preview(
markdown::parse(&self.content.text()).collect(),
);
self.content = markdown::Content::parse(&self.raw.text());
self.mode = Mode::Preview;

let images = self.content.images();
self.images.retain(|url, _image| images.contains(url));
}

Task::none()
Expand All @@ -93,81 +101,103 @@ impl Markdown {
return Task::none();
}

let _ = self.images.insert(url.clone(), Image::Loading);
let (download_image, handle) = Task::future({
let url = url.clone();

Task::perform(download_image(url.clone()), move |result| {
async move {
// Wait half a second for further editions before attempting download
tokio::time::sleep(milliseconds(500)).await;
download_image(url).await
}
})
.abortable();

let _ = self.images.insert(
url.clone(),
Image::Loading {
_download: handle.abort_on_drop(),
},
);

download_image.map(move |result| {
Message::ImageDownloaded(url.clone(), result)
})
}
Message::ImageDownloaded(url, result) => {
let _ = self.images.insert(
url,
result.map(Image::Ready).unwrap_or_else(Image::Errored),
result
.map(|handle| Image::Ready {
handle,
fade_in: Animation::new(false)
.quick()
.easing(animation::Easing::EaseInOut)
.go(true),
})
.unwrap_or_else(Image::Errored),
);

Task::none()
}
Message::ToggleStream(enable_stream) => {
if enable_stream {
self.mode = Mode::Stream {
pending: self.content.text(),
parsed: markdown::Content::new(),
pending: self.raw.text(),
};

scrollable::snap_to(
"preview",
scrollable::RelativeOffset::END,
)
} else {
self.mode = Mode::Preview(
markdown::parse(&self.content.text()).collect(),
);
self.mode = Mode::Preview;

Task::none()
}
}
Message::NextToken => {
match &mut self.mode {
Mode::Preview(_) => {}
Mode::Stream { pending, parsed } => {
Mode::Preview => {}
Mode::Stream { pending } => {
if pending.is_empty() {
self.mode = Mode::Preview(parsed.items().to_vec());
self.mode = Mode::Preview;
} else {
let mut tokens = pending.split(' ');

if let Some(token) = tokens.next() {
parsed.push_str(&format!("{token} "));
self.content.push_str(&format!("{token} "));
}

*pending = tokens.collect::<Vec<_>>().join(" ");
}
}
}

Task::none()
}
Message::Animate(now) => {
self.now = now;

Task::none()
}
}
}

fn view(&self) -> Element<Message> {
let editor = text_editor(&self.content)
let editor = text_editor(&self.raw)
.placeholder("Type your Markdown here...")
.on_action(Message::Edit)
.height(Fill)
.padding(10)
.font(Font::MONOSPACE)
.highlight("markdown", highlighter::Theme::Base16Ocean);

let items = match &self.mode {
Mode::Preview(items) => items.as_slice(),
Mode::Stream { parsed, .. } => parsed.items(),
};

let preview = markdown::view_with(
items,
self.content.items(),
&self.theme,
&MarkdownViewer {
images: &self.images,
now: self.now,
},
);

Expand Down Expand Up @@ -197,17 +227,33 @@ impl Markdown {
}

fn subscription(&self) -> Subscription<Message> {
match self.mode {
Mode::Preview(_) => Subscription::none(),
let listen_stream = match self.mode {
Mode::Preview => Subscription::none(),
Mode::Stream { .. } => {
time::every(milliseconds(10)).map(|_| Message::NextToken)
}
}
};

let animate = {
let is_animating = self.images.values().any(|image| match image {
Image::Ready { fade_in, .. } => fade_in.is_animating(self.now),
_ => false,
});

if is_animating {
window::frames().map(Message::Animate)
} else {
Subscription::none()
}
};

Subscription::batch([listen_stream, animate])
}
}

struct MarkdownViewer<'a> {
images: &'a HashMap<markdown::Url, Image>,
now: Instant,
}

impl<'a> markdown::Viewer<'a, Message> for MarkdownViewer<'a> {
Expand All @@ -221,10 +267,15 @@ impl<'a> markdown::Viewer<'a, Message> for MarkdownViewer<'a> {
_title: &markdown::Text,
url: &'a markdown::Url,
) -> Element<'a, Message> {
if let Some(Image::Ready(handle)) = self.images.get(url) {
center_x(image(handle)).into()
if let Some(Image::Ready { handle, fade_in }) = self.images.get(url) {
center_x(
image(handle)
.opacity(fade_in.interpolate(0.0, 1.0, self.now))
.scale(fade_in.interpolate(1.2, 1.0, self.now)),
)
.into()
} else {
pop(horizontal_space().width(0))
pop(horizontal_space())
.key(url.as_str())
.on_show(|_size| Message::ImageShown(url.clone()))
.into()
Expand All @@ -236,6 +287,8 @@ async fn download_image(url: markdown::Url) -> Result<image::Handle, Error> {
use std::io;
use tokio::task;

println!("Trying to download image: {url}");

let client = reqwest::Client::new();

let bytes = client
Expand Down Expand Up @@ -267,7 +320,7 @@ async fn download_image(url: markdown::Url) -> Result<image::Handle, Error> {
pub enum Error {
RequestFailed(Arc<reqwest::Error>),
IOFailed(Arc<io::Error>),
JoinFailed(Arc<task::JoinError>),
JoinFailed(Arc<tokio::task::JoinError>),
ImageDecodingFailed(Arc<::image::ImageError>),
}

Expand All @@ -283,8 +336,8 @@ impl From<io::Error> for Error {
}
}

impl From<task::JoinError> for Error {
fn from(error: task::JoinError) -> Self {
impl From<tokio::task::JoinError> for Error {
fn from(error: tokio::task::JoinError) -> Self {
Self::JoinFailed(Arc::new(error))
}
}
Expand Down
4 changes: 2 additions & 2 deletions widget/src/markdown.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -167,8 +167,8 @@ impl Content {
}

/// Returns the URLs of the Markdown images present in the [`Content`].
pub fn images(&self) -> impl Iterator<Item = &Url> {
self.state.images.iter()
pub fn images(&self) -> &HashSet<Url> {
&self.state.images
}
}

Expand Down

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