Struct ThemeWatcher 

pub struct ThemeWatcher { /* private fields */ }

Available on crate features serde and theme-watch only.

A non-blocking filesystem watcher that hot-reloads a TOML theme file.

Requires the theme-watch feature. The watcher runs notify’s own background thread and buffers change events on a channel; poll drains the channel, re-reads the file, and returns the freshly parsed ThemeFile. On a parse error it logs context to stderr and keeps the last good theme, so a half-saved edit never breaks the running app.

Designed for SLT’s immediate-mode loop: call poll once per frame and apply the result via crate::Context::set_theme.

Example

use slt::ThemeWatcher;

let mut watcher = ThemeWatcher::new("theme.toml").unwrap();
slt::run(move |ui| {
    if let Some(tf) = watcher.poll() {
        ui.set_theme(tf.theme);
    }
    ui.button("Themed");
})
.unwrap();

Implementations

impl ThemeWatcher

pub fn new(path: impl AsRef<Path>) -> Result<ThemeWatcher, ThemeLoadError>

Start watching the theme file at path, loading it once up front.

Errors

Returns ThemeLoadError::Io if the initial read fails or the watch cannot be registered, or ThemeLoadError::Parse if the initial file is not valid TOML.

Example

use slt::ThemeWatcher;

let watcher = ThemeWatcher::new("theme.toml").unwrap();

pub fn current(&self) -> &ThemeFile

The most recently parsed theme (the initial load, or the last good hot-reload). Never returns a theme from a failed parse.

pub fn poll(&mut self) -> Option<ThemeFile>

Non-blocking poll for a hot-reloaded theme.

Drains pending filesystem events; if any occurred, re-reads and parses the watched file. Returns Some(theme) only when the file changed and parsed cleanly. Returns None when nothing changed, or when the new contents failed to parse — in which case the previous theme is retained (accessible via ThemeWatcher::current) and a message is logged to stderr.

Example

use slt::ThemeWatcher;

let mut watcher = ThemeWatcher::new("theme.toml").unwrap();
if let Some(tf) = watcher.poll() {
    println!("reloaded: {:?}", tf.theme.primary);
}