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

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()))
});

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()))
});

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()))
});

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()))
});

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

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

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Convert &Trait (where Trait: Downcast) to &Any. This is needed since Rust cannot generate &Any’s vtable from &Trait’s. Read more

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Use this to cast from one trait object type to another. Read more

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Use this to cast from one trait object type to another. This method is more customizable than the dyn_cast method. Here you can also specify the “source” trait from which the cast is defined. This can for example allow using casts from a supertrait of the current trait object. Read more

Use this to cast from one trait object type to another. With this method the type parameter is a config type that uniquely specifies which cast should be preformed. Read more

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Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

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Calls U::from(self).

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

Should always be Self

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Creates owned data from borrowed data, usually by cloning. Read more

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The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

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