View Source IO.ANSI (Elixir v1.13.0)

Functionality to render ANSI escape sequences.

ANSI escape sequences are characters embedded in text used to control formatting, color, and other output options on video text terminals.

ANSI escapes are typically enabled on all Unix terminals. They are also available on Windows consoles from Windows 10, although it must be explicitly enabled for the current user in the registry by running the following command:

reg add HKCU\Console /v VirtualTerminalLevel /t REG_DWORD /d 1

After running the command above, you must restart your current console.

Examples

Because the ANSI escape sequences are embedded in text, the normal usage of these functions is to concatenate their output with text.

formatted_text = IO.ANSI.blue_background() <> "Example" <> IO.ANSI.reset()
IO.puts(formatted_text)

A higher level and more convenient API is also available via IO.ANSI.format/1, where you use atoms to represent each ANSI escape sequence and by default checks if ANSI is enabled:

IO.puts(IO.ANSI.format([:blue_background, "Example"]))

In case ANSI is disabled, the ANSI escape sequences are simply discarded.

Link to this section Summary

Functions

Sets foreground color to black.

Sets background color to black.

Blink: off.

Blink: rapid. MS-DOS ANSI.SYS; 150 per minute or more; not widely supported.

Blink: slow. Less than 150 per minute.

Sets foreground color to blue.

Sets background color to blue.

Bright (increased intensity) or bold.

Clears screen.

Clears line.

Sets foreground color.

Sets the foreground color from individual RGB values.

Sets background color.

Sets the background color from individual RGB values.

Conceal. Not widely supported.

Crossed-out. Characters legible, but marked for deletion. Not widely supported.

Sends cursor to the absolute position specified by line and column.

Sends cursor lines down.

Sends cursor columns to the left.

Sends cursor columns to the right.

Sends cursor lines up.

Sets foreground color to cyan.

Sets background color to cyan.

Default background color.

Default text color.

Checks if ANSI coloring is supported and enabled on this machine.

Encircled.

Faint (decreased intensity). Not widely supported.

Sets alternative font 1.

Sets alternative font 2.

Sets alternative font 3.

Sets alternative font 4.

Sets alternative font 5.

Sets alternative font 6.

Sets alternative font 7.

Sets alternative font 8.

Sets alternative font 9.

Formats a chardata-like argument by converting named ANSI sequences into actual ANSI codes.

Formats a chardata-like argument by converting named ANSI sequences into actual ANSI codes.

Framed.

Sets foreground color to green.

Sets background color to green.

Sends cursor home.

Image: negative. Swap foreground and background.

Image: positive. Normal foreground and background.

Italic: on. Not widely supported. Sometimes treated as inverse.

Sets foreground color to light black.

Sets background color to light black.

Sets foreground color to light blue.

Sets background color to light blue.

Sets foreground color to light cyan.

Sets background color to light cyan.

Sets foreground color to light green.

Sets background color to light green.

Sets foreground color to light magenta.

Sets background color to light magenta.

Sets foreground color to light red.

Sets background color to light red.

Sets foreground color to light white.

Sets background color to light white.

Sets foreground color to light yellow.

Sets background color to light yellow.

Sets foreground color to magenta.

Sets background color to magenta.

Underline: none.

Normal color or intensity.

Not framed or encircled.

Not italic.

Not overlined.

Overlined.

Sets primary (default) font.

Sets foreground color to red.

Sets background color to red.

Resets all attributes.

Image: negative. Swap foreground and background.

Image: positive. Normal foreground and background.

Underline: single.

Sets foreground color to white.

Sets background color to white.

Sets foreground color to yellow.

Sets background color to yellow.

Link to this section Types

@type ansicode() :: atom()
@type ansidata() :: ansilist() | ansicode() | binary()
@type ansilist() ::
  maybe_improper_list(
    char() | ansicode() | binary() | ansilist(),
    binary() | ansicode() | []
  )

Link to this section Functions

Sets foreground color to black.

Sets background color to black.

Sets foreground color to blue.

Sets background color to blue.

Bright (increased intensity) or bold.

Clears screen.

Clears line.

@spec color(0..255) :: String.t()

Sets foreground color.

@spec color(0..5, 0..5, 0..5) :: String.t()

Sets the foreground color from individual RGB values.

Valid values for each color are in the range 0 to 5.

@spec color_background(0..255) :: String.t()

Sets background color.

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color_background(r, g, b)

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@spec color_background(0..5, 0..5, 0..5) :: String.t()

Sets the background color from individual RGB values.

Valid values for each color are in the range 0 to 5.

Conceal. Not widely supported.

Crossed-out. Characters legible, but marked for deletion. Not widely supported.

@spec cursor(non_neg_integer(), non_neg_integer()) :: String.t()

Sends cursor to the absolute position specified by line and column.

Line 0 and column 0 would mean the top left corner.

@spec cursor_down(pos_integer()) :: String.t()

Sends cursor lines down.

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cursor_left(columns \\ 1)

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@spec cursor_left(pos_integer()) :: String.t()

Sends cursor columns to the left.

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cursor_right(columns \\ 1)

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@spec cursor_right(pos_integer()) :: String.t()

Sends cursor columns to the right.

@spec cursor_up(pos_integer()) :: String.t()

Sends cursor lines up.

Sets foreground color to cyan.

Sets background color to cyan.

Default background color.

Default text color.

@spec enabled?() :: boolean()

Checks if ANSI coloring is supported and enabled on this machine.

This function simply reads the configuration value for :ansi_enabled in the :elixir application. The value is by default false unless Elixir can detect during startup that both stdout and stderr are terminals.

Encircled.

Faint (decreased intensity). Not widely supported.

Sets alternative font 1.

Sets alternative font 2.

Sets alternative font 3.

Sets alternative font 4.

Sets alternative font 5.

Sets alternative font 6.

Sets alternative font 7.

Sets alternative font 8.

Sets alternative font 9.

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format(chardata, emit? \\ enabled?())

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Formats a chardata-like argument by converting named ANSI sequences into actual ANSI codes.

The named sequences are represented by atoms.

It will also append an IO.ANSI.reset/0 to the chardata when a conversion is performed. If you don't want this behaviour, use format_fragment/2.

An optional boolean parameter can be passed to enable or disable emitting actual ANSI codes. When false, no ANSI codes will be emitted. By default checks if ANSI is enabled using the enabled?/0 function.

Examples

iex> IO.ANSI.format(["Hello, ", :red, :bright, "world!"], true)
[[[[[[], "Hello, "] | "\e[31m"] | "\e[1m"], "world!"] | "\e[0m"]
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format_fragment(chardata, emit? \\ enabled?())

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Formats a chardata-like argument by converting named ANSI sequences into actual ANSI codes.

The named sequences are represented by atoms.

An optional boolean parameter can be passed to enable or disable emitting actual ANSI codes. When false, no ANSI codes will be emitted. By default checks if ANSI is enabled using the enabled?/0 function.

Examples

iex> IO.ANSI.format_fragment([:bright, 'Word'], true)
[[[[[[] | "\e[1m"], 87], 111], 114], 100]

Framed.

Sets foreground color to green.

Sets background color to green.

Sends cursor home.

Image: negative. Swap foreground and background.

Image: positive. Normal foreground and background.

Italic: on. Not widely supported. Sometimes treated as inverse.

Sets foreground color to light black.

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light_black_background()

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Sets background color to light black.

Sets foreground color to light blue.

Sets background color to light blue.

Sets foreground color to light cyan.

Sets background color to light cyan.

Sets foreground color to light green.

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light_green_background()

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Sets background color to light green.

Sets foreground color to light magenta.

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light_magenta_background()

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Sets background color to light magenta.

Sets foreground color to light red.

Sets background color to light red.

Sets foreground color to light white.

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light_white_background()

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Sets background color to light white.

Sets foreground color to light yellow.

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light_yellow_background()

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Sets background color to light yellow.

Sets foreground color to magenta.

Sets background color to magenta.

Underline: none.

Normal color or intensity.

Not framed or encircled.

Not italic.

Not overlined.

Overlined.

Sets primary (default) font.

Sets foreground color to red.

Sets background color to red.

Resets all attributes.

Image: negative. Swap foreground and background.

Image: positive. Normal foreground and background.

Underline: single.

Sets foreground color to white.

Sets background color to white.

Sets foreground color to yellow.

Sets background color to yellow.