Struct env_logger::fmt::Style

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pub struct Style { /* private fields */ }
Expand description

A set of styles to apply to the terminal output.

Call Formatter::style to get a Style and use the builder methods to set styling properties, like color and weight. To print a value using the style, wrap it in a call to value when the log record is formatted.

Examples

Create a bold, red colored style and use it to print the log level:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut level_style = buf.style();

    level_style.set_color(Color::Red).set_bold(true);

    writeln!(buf, "{}: {}",
        level_style.value(record.level()),
        record.args())
});

Styles can be re-used to output multiple values:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut bold = buf.style();

    bold.set_bold(true);

    writeln!(buf, "{}: {} {}",
        bold.value(record.level()),
        bold.value("some bold text"),
        record.args())
});

Implementations§

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impl Style

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pub fn set_color(&mut self, color: Color) -> &mut Style

Set the text color.

Examples

Create a style with red text:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_color(Color::Red);

    writeln!(buf, "{}", style.value(record.args()))
});
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pub fn set_bold(&mut self, yes: bool) -> &mut Style

Set the text weight.

If yes is true then text will be written in bold. If yes is false then text will be written in the default weight.

Examples

Create a style with bold text:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_bold(true);

    writeln!(buf, "{}", style.value(record.args()))
});
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pub fn set_intense(&mut self, yes: bool) -> &mut Style

Set the text intensity.

If yes is true then text will be written in a brighter color. If yes is false then text will be written in the default color.

Examples

Create a style with intense text:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_intense(true);

    writeln!(buf, "{}", style.value(record.args()))
});
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pub fn set_dimmed(&mut self, yes: bool) -> &mut Style

Set whether the text is dimmed.

If yes is true then text will be written in a dimmer color. If yes is false then text will be written in the default color.

Examples

Create a style with dimmed text:

use std::io::Write;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_dimmed(true);

    writeln!(buf, "{}", style.value(record.args()))
});
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pub fn set_bg(&mut self, color: Color) -> &mut Style

Set the background color.

Examples

Create a style with a yellow background:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_bg(Color::Yellow);

    writeln!(buf, "{}", style.value(record.args()))
});
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pub fn value<T>(&self, value: T) -> StyledValue<'_, T>

Wrap a value in the style.

The same Style can be used to print multiple different values.

Examples

Create a bold, red colored style and use it to print the log level:

use std::io::Write;
use env_logger::fmt::Color;

let mut builder = env_logger::Builder::new();

builder.format(|buf, record| {
    let mut style = buf.style();

    style.set_color(Color::Red).set_bold(true);

    writeln!(buf, "{}: {}",
        style.value(record.level()),
        record.args())
});

Trait Implementations§

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impl Clone for Style

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fn clone(&self) -> Style

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Style

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more

Auto Trait Implementations§

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impl !RefUnwindSafe for Style

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impl !Send for Style

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impl !Sync for Style

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impl Unpin for Style

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impl !UnwindSafe for Style

Blanket Implementations§

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impl<T> Any for Twhere T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.