Skip to content

writers.rst

Latest commit

 

History

History
134 lines (97 loc) · 3.51 KB

writers.rst

File metadata and controls

134 lines (97 loc) · 3.51 KB

Writers

Common Writer Options

All writer take the following options (specified as keyword arguments to Barcode.save(filename, options) or set via Writer.set_options(options), where options is a dictionary where keys are option names and values are option values to be set).

Note

See the documentation of the specific writer for special options, only available for this writer.

module_width:

The width of one barcode module in mm as float. Defaults to 0.2.
module_height:

The height of the barcode modules in mm as float. Defaults to 15.0.
quiet_zone:

Distance on the left and on the right from the border to the first (last) barcode module in mm as float. Defaults to 6.5.
font_path:

Path to the font file to be used. Defaults to DejaVuSansMono (which is bundled with this package).
font_size:

Font size of the text under the barcode in pt as integer. Font size zero suppresses text. Defaults to 10.
text_distance:

Distance between the barcode and the text under it in mm as float. Defaults to 5.0.
background:

The background color of the created barcode as string. Defaults to white.
foreground:

The foreground and text color of the created barcode as string. Defaults to black.
center_text:

If true (the default) the text is centered under the barcode else left aligned.

.. versionadded:: 0.6

Note

Some barcode classes change the above defaults to fit in some kind of specification.

BaseWriter

Both ImageWriter and SVGWriter are subclasses of BaseWriter:

.. autoclass:: barcode.writer.BaseWriter
   :members:

SVGWriter

Renders barcodes as [optionally, compressed] SVG objects.

In addition to the common writer options you can give the following special option.

compress:Boolean value to output a compressed SVG object (.svgz). Defaults to False

ImageWriter

.. versionadded:: 0.4b1

Renders barcodes as image. Supports all the image formats supported by Pillow.

In addition to the common writer options you can give the following special options:

format:The image file format as str. All formats supported by Pillow are valid (e.g. PNG, JPEG, BMP, ...). Defaults to PNG.
dpi:DPI as int to calculate the image size in pixel. This value is used for all mm to px calculations. Defaults to 300

Custom writers

It's possible to create your own writer by inheriting from barcode.writer.BaseWriter.

In your __init__ method call BaseWriter's __init__ and give your callbacks for:

  • initialize(raw_code)
  • paint_module(xpos, ypos, width, color)
  • paint_text(xpos, ypos)
  • finish()

Now instantiate a new barcode and give an instance of your new writer as argument. If you now call render on the barcode instance your callbacks get called.

Creating compressed SVGs

Saving a compressed SVG (SVGZ):

>>> import barcode
>>> ean = barcode.get('ean13', '123456789102')
# Now we look if the checksum was added
>>> ean.get_fullcode()
'1234567891026'
>>> filename = ean.save('ean13')
>>> filename
'ean13.svg'
>>> options = dict(compress=True)
>>> filename = ean.save('ean13', options)
>>> filename
'ean13.svgz'

Now you have ean13.svg and the compressed ean13.svgz in your current working directory. Open it and see the result.