Code 39
*******

Code 39 is a 1D symbology widely used for industrial labelling. The
default character set is uppercase letters, digits, space and
"-.$/+%"; pass "full_ascii=True" to encode any 7-bit character as a
pair of symbols.

   Code39Encoder("17 E North 32 St", full_ascii=True).save("code39-address.png")

See also: Code 39 on Wikipedia for background on the symbology itself.


Example
=======

   from pystrich.code39 import Code39Encoder

   encoder = Code39Encoder("64755")
   encoder.save_svg("code39-example.svg")

[image: Code 39 barcode encoding "64755".][image]


Sizing, label, font and layout
==============================

The "bar_width" argument to "save()" and "get_imagedata()" sets the
pixel width of the narrowest bar (default "3").

The "options" dict passed to "Code39Encoder" controls the human-
readable label and the surrounding layout. All keys are optional.

"show_label"
   Whether to render the human-readable label underneath the bars.
   Defaults to "True"; set to "False" to suppress it.

"ttf_font"
   Absolute path to a TrueType font file used for the label. Defaults
   to a bundled bitmap font if unset.

"ttf_fontsize"
   Font size in points.

"height"
   Total image height in pixels. Defaults to "120".

"label_border"
   Pixels of vertical space between the bars and the label.

"bottom_border"
   Pixels of vertical space between the label and the bottom edge.

See also:

  Printing barcodes for guidance on selecting "bar_width" for printed
  output.

   options = {
       "height": 200,
       "label_border": 10,
       "bottom_border": 10,
       "ttf_fontsize": 24,
       # "ttf_font": "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
   }
   encoder = Code39Encoder("64755", options=options)
   encoder.save("code39-custom.png", bar_width=4)

[image: Code 39 barcode encoding "64755" with a taller image and
larger label.][image]


Output formats
==============


SVG output
----------

For embedding in web pages or any workflow that benefits from
resolution-independent output, use "save_svg()" (or "get_svg()" to
receive the SVG as a string).

   Code39Encoder("64755").save_svg("code39.svg")

[image: SVG Code 39 barcode encoding "64755".][image]

The SVG's "viewBox" is in module units (one narrow bar = one unit),
while "width" and "height" scale by "bar_width". The 10-module quiet
zones mandated by the standard are applied automatically on each side.

Added in version 0.12.


PNG output
----------

For raster output, use "save()" to write a PNG file or
"get_imagedata()" to receive the raw PNG bytes.

   Code39Encoder("64755").save("code39.png")


EPS output
----------

For embedding in LaTeX ("\includegraphics") or other vector print
workflows, use "save_eps()" (or "get_eps()" to receive the EPS as a
string).

   Code39Encoder("64755").save_eps("code39.eps")

The "bar_width" argument is the width of the narrowest bar in
PostScript points (1 point = 1/72 inch). The 10-module quiet zones are
applied automatically.

Added in version 0.12.


API
===

class Code39Encoder(text: str, full_ascii: bool = False, options: BarcodeRenderOptions | None = None)

   Bases: "Bar1DEncoder"

   Encode a string as a Code 39 1D barcode.

   By default only the standard Code 39 character set is accepted
   ("0-9", "A-Z", space, and "-.$/+%"). Pass "full_ascii=True" to use
   the Full ASCII extension, which encodes any 7-bit character via
   paired symbols.

   Typical use:

      encoder = Code39Encoder("ABC-123")
      encoder.save("barcode.png")

   Variables:
      * **text** -- The original input text.

      * **encoded_text** -- List of code values produced by the text
        encoder.

      * **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.

   get_eps(bar_width: int = 3) -> str

      Render the barcode and return EPS markup.

      Parameters:
         **bar_width** -- Width in PostScript points of the narrowest
         bar.

      Return type:
         str

      Added in version 0.12.

   get_imagedata(bar_width: int = 3) -> bytes

      Render the barcode and return PNG bytes.

      Parameters:
         **bar_width** -- Width in pixels of the narrowest bar.

      Returns:
         PNG-encoded image data.

      Return type:
         bytes

   get_pilimage(bar_width: int = 3) -> PIL.Image.Image

      Render the barcode and return a Pillow image.

      Parameters:
         **bar_width** -- Width in pixels of the narrowest bar.

      Returns:
         The rendered barcode.

      Return type:
         PIL.Image.Image

      Added in version 0.11.

   get_svg(bar_width: int = 3) -> str

      Render the barcode and return SVG markup.

      Parameters:
         **bar_width** -- Width in user units of the narrowest bar.

      Return type:
         str

      Added in version 0.12.

   save(filename: str | PathLike[str], bar_width: int = 3) -> 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.

   save_eps(filename: str | PathLike[str], bar_width: int = 3) -> 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.

      Added in version 0.12.

   save_svg(filename: str | PathLike[str], bar_width: int = 3) -> 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.

      Added in version 0.12.

   init_renderer() -> Code39Renderer

      Construct a "Code39Renderer" for the encoded bars.

      Return type:
         "Code39Renderer"