@thi.ng/text-format

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About

Customizable color text formatting with presets for ANSI & HTML.

This package provides a number of color and other styling format constants, as well as formatting functions to interpret and apply these abstract format identifiers for different output formats.

The format constants provided by this package are primarily (not exclusively) aimed at being used with the @thi.ng/text-canvas package. The text canvas stores all characters in a Uint32Array with the lower 16 bits used for the UTF-16 code and the upper 16 bits for abitrary formatting data.

The format IDs provided here are tailored for some of the included ANSI & HTML formatters, but users are free to choose use any other interpretation (but then will also need to implement a custom string formatter impl).

Colors

These color IDs MUST be prefixed with either FG_ (foreground) or BG_ (background):

BLACK
RED
GREEN
YELLOW
BLUE
MAGENTA
CYAN
GRAY
WHITE
LIGHT_GRAY
LIGHT_RED
LIGHT_GREEN
LIGHT_YELLOW
LIGHT_BLUE
LIGHT_MAGENTA
LIGHT_CYAN

Stylistic variations

BOLD
DIM
UNDERLINE

Combined formats

Format IDs can be combined via the binary OR operator, e.g.:

FG_BLACK | BG_LIGHT_CYAN | BOLD | UNDERLINE

Compatibility

These above listed built-in format IDs are only compatible with these bundled formatters (described below):

FMT_ANSI16
FMT_HTML_INLINE_CSS
FMT_HTML_TACHYONS

String conversion format presets

String formatting is completely customizable via the StringFormat interface. Currently the following presets are supplied:

FMT_ANSI16 - translate built-in format IDs to 4-bit ANSI escape sequences
FMT_ANSI256 - uses all 16 format bits for fg & bg colors (ANSI esc sequences)
FMT_ANSI565 - uses all 16 format bits for RGB565 fg colors (ANSI esc sequences)
FMT_ANSI_RAW - verbatim use of format IDs to ANSI sequences
FMT_HTML_INLINE_CSS - HTML <span> elements with inline CSS
FMT_HTML_TACHYONS - HTML <span> elements with Tachyons CSS class names
FMT_HTML565 - HTML <span> elements with RGB565 color coding
FMT_NONE - dummy formatter outputting plain text only (all format information discarded, e.g. for NO_COLOR support)

256 color ANSI format

If targeting this output format, all 16 bits available for formatting information are used to encode 2x 8bit foreground/background colors. Therefore, none of the above mentioned preset color names and/or any additional formatting flags (e.g. bold, underline etc.) cannot be used. Instead, use the format256() function to create a format ID based on given FG, BG colors.

ANSI256 color pallette

Source: Wikipedia

16bit color ANSI & HTML formats

Similar to the above custom ANSI format, here all available 16 bits are used to store color information, but here in the standard RGB565 format (5bits red, 6bits green, 5bits blue). This too means, only either the text or background color⁽¹⁾ can be controlled and no other formatting flags (bold, underline etc.) are available.

⁽¹⁾ In the ANSI version it's always only the text color.

These formats are primarily intended for image display, see the @thi.ng/text-canvas readme for usage examples...

Ad-hoc formatting of strings

String formatters can also be used in an ad-hoc manner, without requiring any of the other text canvas functionality.

import { defFormat, FMT_HTML_INLINE_CSS, FG_LIGHT_RED, BG_GRAY } from "@thi.ng/text-format";

// create & use a HTML formatter
defFormat(FMT_HTML_INLINE_CSS, FG_LIGHT_RED | BG_GRAY)("hello")
// "<span style="color:#f55;background:#555;">hello</span>"

import { defFormat, FMT_ANSI16, FG_LIGHT_RED, BG_GRAY } from "@thi.ng/text-format";

// create & use an ANSI formatter
defFormat(FMT_ANSI16, FG_LIGHT_RED | BG_GRAY)("hello")
// "\x1B[91;100mhello\x1B[0m"

import { defAnsi16, FG_LIGHT_RED, BG_GRAY } from "@thi.ng/text-format";

// ANSI syntax sugar (same result as above)
defAnsi16(FG_LIGHT_RED | BG_GRAY)("hello")
// "\x1B[91;100mhello\x1B[0m"

Furthermore, defFormatPresets() can be used to create formatting functions for all 16 preset foreground color IDs for a given string format strategy:

import { defFormatPresets, FMT_ANSI16, FMT_HTML_TACHYONS } from "@thi.ng/text-format";

// since v1.3.0 also available as PRESET_ANSI16
const ansi = defFormatPresets(FMT_ANSI16);

`${ansi.green("hello")} ${ansi.lightRed("world")}!`;
// '\x1B[32mhello\x1B[0m \x1B[91mworld\x1B[0m!'

const html = defFormatPresets(FMT_HTML_TACHYONS);

`${html.green("hello")} ${html.lightRed("world")}!`;
// '<span class="dark-green ">hello</span> <span class="red ">world</span>!'

Status

STABLE - used in production

Search or submit any issues for this package

Related packages

@thi.ng/text-canvas - Text based canvas, drawing, plotting, tables with arbitrary formatting (incl. ANSI/HTML)

Installation

yarn add @thi.ng/text-format

ES module import:

<script type="module" src="https://cdn.skypack.dev/@thi.ng/text-format"></script>

Skypack documentation

For Node.js REPL:

const textFormat = await import("@thi.ng/text-format");

Package sizes (brotli'd, pre-treeshake): ESM: 1.87 KB

Dependencies

Usage examples

Several projects in this repo's /examples directory are using this package:

Description	Live demo	Source
ASCII art raymarching with thi.ng/shader-ast & thi.ng/text-canvas	Demo	Source
3D wireframe textmode demo	Demo	Source
Textmode image warping w/ 16bit color output	Demo	Source

API

Generated API docs

TODO

Authors

Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

@misc{thing-text-format,
  title = "@thi.ng/text-format",
  author = "Karsten Schmidt",
  note = "https://thi.ng/text-format",
  year = 2020
}