ITF-14

Added in version 0.16: ITF-14 and Interleaved 2 of 5 support were added in this release.

ITF-14 is the GS1 barcode for a GTIN-14 – the 14-digit identifier printed on shipping cartons and cases rather than on the retail item inside. It is an application of Interleaved 2 of 5 (ITF), which packs pairs of digits into alternating bars and spaces, wrapped in a bearer bar that frames the symbol. Pass either 13 digits (the check digit is computed and appended) or 14 digits (the final digit is treated as a check digit and recomputed).

See also

Interleaved 2 of 5 on Wikipedia for background on the symbology.

Interleaved 2 of 5 barcodes are defined in ISO/IEC 16390.

Warning

Real-world GTIN-14 codes are derived from a GS1-allocated GTIN; you cannot simply invent one.

Input must be exactly 13 or 14 digits, ASCII 0-9. Anything else raises PyStrichInvalidInput. The 14-digit human-readable label below the bars is rendered by default (see Label to suppress it).

The check digit is always computed by pyStrich; pass either 13 digits (it is appended) or 14 digits (the supplied final digit is discarded and recomputed):

>>> from pystrich.itf import ITF14Encoder
>>> ITF14Encoder("1505007000766").full_code
'15050070007661'
>>> ITF14Encoder("15050070007660").full_code
'15050070007661'

Example

from pystrich.itf import ITF14Encoder

encoder = ITF14Encoder("1505007000766")
encoder.save_svg("itf14-example.svg")
ITF-14 barcode encoding "15050070007661".

Bearer bar

ITF-14 is drawn with a full-frame bearer bar – the heavy border enclosing the symbol. It reduces the chance of a partial scan being misread as a short, valid code. Its thickness defaults to 4 narrow-bar widths; adjust it with the bearer_width key of ITFRenderOptions (set it to 0 to omit the bearer):

ITF14Encoder("1505007000766", options={"bearer_width": 6}).save("itf14.png")

Label

The human-readable label is rendered by default. To lay out your own instead, suppress it with show_label:

ITF14Encoder("1505007000766", options={"show_label": False}).save("itf14.png")

Interleaved 2 of 5

For a plain Interleaved 2 of 5 symbol – any even number of digits – use ITFEncoder directly. It has no bearer bar by default, but accepts the same bearer_width option.

from pystrich.itf import ITFEncoder

ITFEncoder("1234567890").save_svg("itf-example.svg")
Interleaved 2 of 5 barcode encoding "1234567890".

Output formats

Like the other 1D symbologies, ITF-14 renders to SVG (save_svg()), PNG (save()) and EPS (save_eps()). The bar_width argument sets the width of the narrowest bar.

See also

Printing barcodes for guidance on selecting bar_width for printed output.

API

class ITF14Encoder(code: str, options: ITFRenderOptions | None = None)[source]

Bases: ITFEncoder

Encode a 13- or 14-digit code as an ITF-14 (GTIN-14) barcode.

The check digit is computed for you. If a 14-digit code is supplied, its final digit is discarded and recomputed. The symbol is framed by a bearer bar unless bearer_width is overridden in options.

Typical use:

encoder = ITF14Encoder("1540141453698")
encoder.save("itf14.png")
Variables:

  • check_digit – The computed mod-10 check digit.

  • full_code – The 14-digit code including check digit (== digits).

get_eps(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return EPS markup.

Parameters:

  • bar_width – Width in PostScript points of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA, opaque. Defaults to white.

Return type:

str

get_imagedata(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → bytes

Render the barcode and return PNG bytes.

Parameters:

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Returns:

PNG-encoded image data.

Return type:

bytes

get_pilimage(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → PILImage

Render the barcode and return a Pillow image.

Parameters:

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Returns:

The rendered barcode.

Return type:

PIL.Image.Image

get_svg(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return SVG markup.

Parameters:

  • bar_width – Width in user units of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Return type:

str

png_dataurl(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return a PNG data: URL string.

Parameters:

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Return type:

str

save(filename: str | os.PathLike[str], bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → None

Render the barcode to a PNG file.

Parameters:

  • filename – Path to write the PNG to.

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

save_eps(filename: str | os.PathLike[str], bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → None

Save the barcode as an EPS file. Pass an .eps filename.

Parameters:

  • filename – EPS output path.

  • bar_width – Width in PostScript points of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA, opaque. Defaults to white.

save_svg(filename: str | os.PathLike[str], bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → None

Save the barcode as an SVG file. Pass a .svg filename.

Parameters:

  • filename – SVG output path.

  • bar_width – Width in user units of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

svg_dataurl(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return an SVG data: URL string.

Parameters:

  • bar_width – Width in user units of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Return type:

str

static calculate_check_digit(code: str) → int[source]

Compute the GTIN-14 mod-10 check digit for the 13 data digits.

Working right-to-left, the digits are weighted 3, 1, 3, 1, …; the check digit brings the weighted sum up to a multiple of 10.

init_renderer() → ITFRenderer[source]

Construct an ITFRenderer, defaulting the bearer bar on.

class ITFEncoder(digits: str, options: ITFRenderOptions | None = None)[source]

Bases: Bar1DEncoder

Encode an even-length string of digits as an Interleaved 2 of 5 barcode.

Typical use:

encoder = ITFEncoder("1234567890")
encoder.save("itf.png")
Variables:

  • digits – The digits being encoded.

  • bars – The bar/space pattern as a string of "1" and "0".

  • options – Render-time options dict (empty if none were supplied).

  • width – Pixel width of the most recently rendered image.

  • height – Pixel height of the most recently rendered image.

init_renderer() → ITFRenderer[source]

Construct an ITFRenderer for the encoded bars.

get_eps(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return EPS markup.

Parameters:

  • bar_width – Width in PostScript points of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA, opaque. Defaults to white.

Return type:

str

get_imagedata(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → bytes

Render the barcode and return PNG bytes.

Parameters:

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Returns:

PNG-encoded image data.

Return type:

bytes

get_pilimage(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → PILImage

Render the barcode and return a Pillow image.

Parameters:

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Returns:

The rendered barcode.

Return type:

PIL.Image.Image

get_svg(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return SVG markup.

Parameters:

  • bar_width – Width in user units of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Return type:

str

png_dataurl(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return a PNG data: URL string.

Parameters:

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Return type:

str

save(filename: str | os.PathLike[str], bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → None

Render the barcode to a PNG file.

Parameters:

  • filename – Path to write the PNG to.

  • bar_width – Width in pixels of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

save_eps(filename: str | os.PathLike[str], bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → None

Save the barcode as an EPS file. Pass an .eps filename.

Parameters:

  • filename – EPS output path.

  • bar_width – Width in PostScript points of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA, opaque. Defaults to white.

save_svg(filename: str | os.PathLike[str], bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → None

Save the barcode as an SVG file. Pass a .svg filename.

Parameters:

  • filename – SVG output path.

  • bar_width – Width in user units of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

svg_dataurl(bar_width: int = 3, *, dark_hex: str | RGBA | None = None, light_hex: str | RGBA | None = None) → str

Render the barcode and return an SVG data: URL string.

Parameters:

  • bar_width – Width in user units of the narrowest bar.

  • dark_hex – Bar and text colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to black.

  • light_hex – Background colour as a 3-, 6- or 8-digit hex string or an RGBA. Defaults to white.

Return type:

str

class ITFRenderOptions

Bases: BarcodeRenderOptions

Optional render-time tweaks for Interleaved 2 of 5 / ITF-14 barcodes.

Extends pystrich.types.BarcodeRenderOptions. All keys are optional; omitted keys fall back to library defaults.

bearer_width: int

Thickness of the bearer bar’s rules, in narrow-bar widths. 0 draws no bearer. Defaults to 0 for plain Interleaved 2 of 5 and to 4 for ITF-14.