QRTOOL-ENCODE(1)

General Commands Manual

QRTOOL-ENCODE(1)

NAME

qrtool-encode - encode input data in a QR code

SYNOPSIS

qrtool encode [OPTION]... [STRING]

DESCRIPTION

This command encodes input data in a QR code https://www.qrcode.com/ and outputs it as a PNG image, SVG image or string. By default, the result will be output to standard output.

This command will read up to the first 7,090 bytes of the input data. The amount of data that can be represented by a QR code depends on the mode, version and error correction level. The storage capacity is maximized for version 40 and error correction level L (40-L).

Table 1. Maximum character storage capacity (40-L)

Input mode	Max. characters	Possible characters
Numeric	7,089	0–9
Alphanumeric	4,296	0–9, A–Z (uppercase only), and few symbols (space, $, %, *, +, -, ., /, :)
Byte	2,953	Arbitrary binary data
Kanji	1,817	Any double-byte JIS X 0208 character

By default, this command encodes the input data in a QR code with a black
foreground and white background, but this can be changed by specifying --foreground and/or --background. The CSS color string https://www.w3.org/TR/css-color-4/ can be specified as a value for these options.

Table 2. List of methods to specify a color

Format	Examples
Named colors	brown, lightslategray
Hexadecimal notations	#111, #eee8, #a52a2a, #7788997f
RGB functions	rgb(165 42 42), rgb(119 136 153 / 49.8%)
HSL functions	hsl(248 39% 39.2%), hsl(0 0% 66.3% / 49.8%)
HWB function	hwb(50.6 0% 0%), hwb(0 66.3% 33.7% / 49.8%)
Oklab function	oklab(50.4% -0.0906 0.0069), oklab(61.9% -0.0120 -0.0302 / 0.5)
Oklch function	oklch(59.41% 0.16 301.29), oklch(61.9% 0.032 248.35 / 49.8%)

This command can also encode the input data in a Micro QR code. This can embed
data in a smaller area than with QR code, but the storage capacity is strongly limited.

qrtool enc and qrtool e are aliases for this command.

POSITIONAL ARGUMENTS

STRING

Input data. If STRING is not specified, data will be read from standard input. STRING must be a valid UTF-8 string. Use --read-from or read from standard input if taking other than a valid UTF-8 string. This positional argument conflicts with --read-from.

OPTIONS

-o, --output FILE

Output the result to a file.

-r, --read-from FILE

Read input data from a file. This option conflicts with STRING.

-s, --size NUMBER

The module size in pixels. If this option is not specified, the module size is 8 when the output format is PNG or SVG, and 1 otherwise.

-l, --error-correction-level LEVEL

Error correction level.

The possible values are:

Level L. 7% of codewords can be restored.

Level M. 15% of codewords can be restored. This is the default value.

Level Q. 25% of codewords can be restored.

Level H. 30% of codewords can be restored.

--level LEVEL

Alias for -l, --error-correction-level.

-v, --symbol-version NUMBER

The version of the symbol. If this option is not specified, the minimum version required to store the data will be automatically chosen. For normal QR code, NUMBER should be between 1 and 40. For Micro QR code, NUMBER should be between 1 and 4.

--symversion NUMBER

Alias for -v, --symbol-version.

-m, --margin NUMBER

The width of margin. If this option is not specified, the margin will be 4 for normal QR code and 2 for Micro QR code.

-t, --type FORMAT

The format of the output.

The possible values are:

png

Portable Network Graphics. This outputs 32-bit RGBA PNG image. This is the default value.

svg

Scalable Vector Graphics.

pic

PIC markup language.

ascii

To the terminal as ASCII string.

ascii-invert

To the terminal as ASCII string. This value inverts foreground and background colors of ascii and outputs the inverted string. ASCIIi is an alias for this value.

unicode

To the terminal as UTF-8 string. terminal and UTF8 are aliases for this value.

unicode-invert

To the terminal as UTF-8 string. This value inverts foreground and background colors of unicode and outputs the inverted string. UTF8i is an alias for this value.

--mode MODE

The mode of the output. If this option is not specified, use the optimal encoding. This option requires --symbol-version.

The possible values are:

numeric

All digits.

alphanumeric

Alphanumerics and few symbols.

byte

Arbitrary binary data.

kanji

Shift JIS text.

--variant TYPE

The type of QR code. This option requires --symbol-version.

The possible values are:

normal

Normal QR code. This is the default value.

micro

Micro QR code.

--foreground COLOR

Foreground color. COLOR takes a CSS color string. Colored output is only available when the output format is PNG, SVG or any ANSI escape sequences. Note that lossy conversion may be performed depending on the color space supported by the method to specify a color, the color depth supported by the output format, etc. Default is black.

--background COLOR

Background color. COLOR takes a CSS color string. Colored output is only available when the output format is PNG, SVG or any ANSI escape sequences. Note that lossy conversion may be performed depending on the color space supported by the method to specify a color, the color depth supported by the output format, etc. Default is white.

--verbose

Also print the metadata. It is output to stderr.

-h, --help

Print help message. The short flag (-h) will print a condensed help message while the long flag (--help) will print a detailed help message.

-V, --version

Print version number. The long flag (--version) will also print the copyright notice, the license notice and where to report bugs.