ZPL Utils

[agritheory]

This PR provides a couple of ZPL related utilities and POC for BEAM.

A print preview using a jinja method and the free Labelary API

A POC for click-to-print

This utilizes a CUPS instance that is on the same network or localhost to the ERPNext instance. Authentication if required would be a stretch goal.

A ZPL and jinja mixed environment

This allows the use of the helpers from the py-zebra-zpl library for object-orient label composition.

{% set hu = get_handling_unit(doc.name) %}
{% set label = zebra_zpl_label(width=6*203, length=4*203, dpi=203, orientation="R") -%}

{{ label.add(zebra_zpl_barcode(hu.handling_unit, width=4, height=260, position=(120, 40), justification="C", ratio=1, human_readable='N', orientation="N")) -}}
{{ label.add(zebra_zpl_text(hu.handling_unit, position=(40, 320), width=(4*203-80), font_size=40, justification="R", orientation="N")) }}
{{ label.add(zebra_zpl_text(frappe.utils.cstr(hu.qty) + " " + hu.uom, position=(120, 400), width=(4*203-80), font_size=40, orientation="N")) }}
{{ label.add(zebra_zpl_text(hu.item_code, position=(120, 480), width=(4*203-80), font_size=40, orientation="N")) }}
{{ label.add(zebra_zpl_text(hu.warehouse, position=(120, 560), width=(4*203-80), font_size=40, orientation="N")) }}
{{ label.add(zebra_zpl_text(frappe.utils.format_datetime(hu.posting_datetime), position=(120, 640), width=(4*203-80), font_size=40, orientation="N")) }}

{{ label.dump_contents() }}

It almost works, I am having an issue getting the orientation correct.

[Alchez]

@agritheory

• I couldn't find the dependency on PyPI, so I've added it as a Github URL in pyproject.toml.
• As for the incorrect orientation, I think the ZPL part of the code is correct and the issue might be coming from printing the generated PNG? Is there a printer-specific orientation setting as well?