Styling

ProgressStyle combines a parsed template, progress characters, spinner frames, optional line color, and custom keys.

Template Variables

Variable	Format Spec	Description	Example Output
`{bar}`	`:40`, `:40.#/-`	Progress bar	`########>-------`
`{wide_bar}`	none	Width-adaptive progress bar	fills remaining columns
`{pos}`	none	Current position	`42`
`{count}`	none	Compact current position	`1.2k`
`{human_pos}`	none	Alias for compact position	`1.2k`
`{len}`	none	Total length or `?`	`100`
`{total_count}`	none	Compact total length	`1.5M`
`{human_len}`	none	Alias for compact total length	`1.5M`
`{remaining}`	none	Remaining units	`58`
`{human_remaining}`	none	Compact remaining units	`58.0k`
`{ratio}`	`:.3`	Completion ratio	`0.420`
`{percent}`	`:.2`	Percentage without `%`	`42` or `42.50`
`{elapsed}`	none	Human elapsed time	`3m 14s`
`{elapsed_precise}`	none	Precise elapsed time	`00:03:14`
`{elapsed_millis}`	none	Millisecond elapsed time	`00:03:14.123`
`{eta}`	none	Estimated remaining time	`~12s`
`{eta_precise}`	none	Precise ETA	`00:00:12`
`{eta_millis}`	none	Millisecond ETA	`00:00:12.345`
`{per_sec}`	`:.2`	Average rate	`123.45`
`{rate}`	none	Formatted item rate	`1.23k items/s`
`{bytes}`	none	Position as bytes	`1.00 MB`
`{total_bytes}`	none	Length as bytes	`50.00 MB`
`{bytes_per_sec}`	none	Byte throughput	`1.23 MB/s`
`{spinner}`	none	Current spinner frame	`-`
`{msg}`	`:20`, `:>20`, `:^20`	Message with optional padding/truncation	`downloading`
`{prefix}`	`:10`, `:>10`, `:^10`	Prefix with optional padding/truncation	`task`
`{postfix}`	`:10`, `:>10`, `:^10`	Postfix with optional padding/truncation	`ok`
`{status}`	`:10`, `:>10`, `:^10`	`running`, `spinning`, `finished`, or `abandoned`	`running`
`{wide_msg}`	none, `:20`, `:>20`, `:^20`	Terminal-width or explicit-width message field	terminal-width text

{bar:N} sets the width. {bar:N.fill/empty} sets fill and empty characters. Color words inside a template are accepted for compatibility with terminal-style templates; whole-line color is configured with ColorSpec.

{wide_bar} uses the active draw target width. Width detection uses terminal APIs and falls back to COLUMNS/LINES or safe defaults when a TTY is not available.

#![allow(unused)]
fn main() {
let style = loaders::ProgressStyle::with_template(
    "{prefix} [{bar:30.#/-}] {percent:.1}% {msg}",
)?;
Ok::<(), loaders::bar::template::TemplateError>(())
}

Reusable Progress Characters

ProgressChars stores fill, head, and empty characters as a reusable value.

#![allow(unused)]
fn main() {
use loaders::{ProgressChars, ProgressStyle};

let style = ProgressStyle::default_bar()
    .progress_chars_set(ProgressChars::blocks());
}

Use try_progress_chars when parsing user configuration and invalid inputs should return an error.

Text Padding and Truncation

String variables support width specs for alignment and fixed width:

:20 left-aligned width 20
:>20 right-aligned width 20
:^20 centered width 20

When the content is longer than the width it is truncated to fit.

Colors

#![allow(unused)]
fn main() {
use loaders::{Color, ColorSpec, ProgressStyle};

let style = ProgressStyle::default_bar()
    .color(ColorSpec::new().set_fg(Color::Cyan).set_bold(true));
}

Custom Keys

#![allow(unused)]
fn main() {
let style = loaders::ProgressStyle::with_template("{phase} {bar:20}")?
    .with_key("phase", |state| format!("phase {}", state.pos / 10 + 1));
Ok::<(), loaders::bar::template::TemplateError>(())
}

Loaders