161 lines
6.1 KiB
Python
161 lines
6.1 KiB
Python
"""Utilities for label generation.
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stolen from: https://github.com/Edinburgh-Genome-Foundry/blabel
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"""
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import base64
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from io import BytesIO
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import datetime
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import textwrap
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from math import floor
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import PIL.Image
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import barcode as python_barcode
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from PIL import Image, ImageDraw, ImageFont
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import labelprinter
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def now(fmt="%Y-%m-%d %H:%M"):
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"""Display the current time.
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Default format is "year-month-day hour:minute" but another format can be
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provided (see ``datetime`` docs for date formatting).
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"""
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now = datetime.datetime.now()
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if fmt is not None:
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now = now.strftime(fmt)
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return now
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def pil_to_html_imgdata(img, fmt='PNG'):
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"""Convert a PIL image into HTML-displayable data.
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The result is a string ``data:image/FMT;base64,xxxxxxxxx`` which you
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can provide as a "src" parameter to a ``<img/>`` tag.
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Examples:
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---------
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>>> data = pil_to_html_imgdata(my_pil_img)
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>>> html_data = '<img src="%s"/>' % data
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"""
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buffered = BytesIO()
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img.save(buffered, format=fmt)
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img_str = base64.b64encode(buffered.getvalue())
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prefix = 'data:image/%s;charset=utf-8;base64,' % fmt.lower()
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return prefix + img_str.decode()
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def wrap(text, col_width):
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"""Breaks the text into lines with at maximum 'col_width' characters."""
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return "\n".join(textwrap.wrap(text, col_width))
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def container_label(data, barcode_class='code128', fmt='png', logo_file='./static/images/djlogo256.png',
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owner_name='Dirk Jahnke', description='', description_line2='', **options):
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"""Return a barcode's image data.
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Powered by the Python library ``python-barcode``. See this library's
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documentation for more details.
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Parameters
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----------
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data
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Data to be encoded in the datamatrix.
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barcode_class
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Class/standard to use to encode the data. Different standards have
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different constraints.
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fmt
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The format to be used when rendering the resulting image
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png -> png image
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svg -> embeddable code for html img tag
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logo_file
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File path to logo file to be included
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owner_name
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Name of owner printed underneath the logo
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description
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Text to be printed on bottom of the label
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writer_options
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Various options for the writer to tune the appearance of the barcode
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(see python-barcode documentation).
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Returns
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-------
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image_base64_data
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A string ``data:image/png;base64,xxxxxxxxx`` which you can provide as a
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"src" parameter to a ``<img/>`` tag.
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Examples:
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---------
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>>> data = barcode('EGF12134', barcode_class='code128')
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>>> html_data = '<img src="%s"/>' % data
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Examples of writer options:
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>>> { 'background': 'white',
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>>> 'font_size': 10,
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>>> 'foreground': 'black',
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>>> 'module_height': 15.0,
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>>> 'module_width': 0.2,
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>>> 'quiet_zone': 6.5,
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>>> 'text': '',
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>>> 'text_distance': 5.0,
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>>> 'write_text': True
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>>> }
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"""
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with Image.open(logo_file) as logo_img:
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font_size = 22
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font_size_small = 16
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owner_name_font_size = 26
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logo_img = logo_img.resize((128, 128))
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logo_img = logo_img.convert('L')
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threshold = 20
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logo_img = logo_img.point(lambda p: 255 if p < threshold else 0)
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logo_img = logo_img.convert('1')
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constructor = python_barcode.get_barcode_class(barcode_class)
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data = str(data).zfill(constructor.digits)
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writer = {
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'svg': python_barcode.writer.ImageWriter,
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'png': python_barcode.writer.ImageWriter,
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'image': python_barcode.writer.ImageWriter
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}[fmt]
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barcode_img = constructor(data, writer=writer())
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writer_options = {
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'font_size': 24,
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'module_width': 0.25,
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'module_height': 10,
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'quiet_zone': 3,
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'text_distance': 1.0
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}
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writer_options.update(options['writer_options'])
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img = barcode_img.render(writer_options=writer_options)
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barcode_xsize, barcode_ysize = img.size
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logo_xsize, logo_ysize = logo_img.size
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label_xsize = 696
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label_ysize = barcode_ysize + font_size if description_line2 == '' else barcode_ysize + 2 * font_size
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result_img = Image.new('1', (label_xsize, label_ysize), 1)
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result_img.paste(logo_img, (owner_name_font_size + 10, floor(barcode_ysize / 2) - 20 - floor(logo_ysize / 2)))
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start_x_for_barcode = logo_xsize + 10
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max_x_for_barcode = 696 - start_x_for_barcode
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result_img.paste(img, (start_x_for_barcode + floor((max_x_for_barcode - barcode_xsize) / 2), 5))
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fnt = ImageFont.truetype("./static/fonts/DejaVuSerif.ttf", font_size)
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owner_name_fnt = ImageFont.truetype("./static/fonts/DejaVuSerif.ttf", owner_name_font_size)
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owner_text_img = Image.new('1', (floor(owner_name_fnt.getlength(owner_name)+1), owner_name_font_size+5), 1)
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d = ImageDraw.Draw(owner_text_img)
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d.text((0,0), owner_name, font=owner_name_fnt)
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owner_text_img = owner_text_img.transpose(PIL.Image.ROTATE_90)
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result_img.paste(owner_text_img, (0, 10))
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d = ImageDraw.Draw(result_img)
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#d.text((20, logo_ysize), owner_name, font=fnt)
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if fnt.getlength(description) > 660:
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fnt_small = ImageFont.truetype("./static/fonts/DejaVuSerif.ttf", font_size_small)
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d.text((0, barcode_ysize), description, font=fnt_small)
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if description_line2 != '':
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d.text((0, barcode_ysize + font_size), description_line2, font=fnt_small)
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else:
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#d.text((30 + floor((660 - fnt.getlength(description)) / 2), barcode_ysize), description, font=fnt)
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d.text((0, barcode_ysize), description, font=fnt)
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if description_line2 != '':
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d.text((0, barcode_ysize + font_size), description_line2, font=fnt)
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if fmt == 'image':
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return result_img
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elif fmt == 'png':
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return pil_to_html_imgdata(result_img, fmt='PNG')
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else:
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prefix = "data:image/svg+xml;charset=utf-8;base64,"
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return prefix + base64.b64encode(result_img).decode()
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