mirror of
https://github.com/inventree/InvenTree.git
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Add SVG support to datamatrix (#12875)
* Extract Data Matrix rendering helpers * Add SVG Data Matrix output * Verify vector Data Matrix output in PDFs --------- Co-authored-by: Oliver <oliver.henry.walters@gmail.com>
This commit is contained in:
Petr Ledvina
Oliver
@@ -129,7 +129,12 @@ which produces the following output:
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!!! info "ppf.datamatrix"
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Data Matrix codes are generated using the [ppf.datamatrix](https://pypi.org/project/ppf-datamatrix/) library.
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[Data Matrix Codes](https://en.wikipedia.org/wiki/Data_Matrix) provide an alternative to QR codes for encoding data in a two-dimensional matrix. To render a Data Matrix code, use the `datamatrix` template tag:
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[Data Matrix Codes](https://en.wikipedia.org/wiki/Data_Matrix) provide an alternative to QR codes for encoding data in a two-dimensional matrix. To render a Data Matrix code, use the `datamatrix` template tag.
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Data Matrix codes are rendered as PNG images by default. Use `fmt="SVG"` to
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generate a vector image, avoiding intermediate raster scaling when a report
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is resized or converted to printer output. Final module alignment still depends
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on the printed dimensions and the printer's rasterization.
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::: report.templatetags.barcode.datamatrix
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options:
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@@ -161,7 +166,7 @@ which produces the following output:
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{% block content %}
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<img class='qr' src='{% datamatrix "Foo Bar" back_color="yellow" %}'>
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<img class='qr' src='{% datamatrix "Foo Bar" back_color="yellow" fmt="SVG" %}'>
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{% endblock content %}
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{% endraw %}
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@@ -1,5 +1,8 @@
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"""Template tags for rendering various barcodes."""
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import base64
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from collections.abc import Sequence
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from django import template
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from django.core.exceptions import ValidationError
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from django.utils.safestring import mark_safe
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@@ -30,6 +33,104 @@ def image_data(img, fmt='PNG') -> str:
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return report.helpers.encode_image_base64(img, fmt)
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def _render_2d_barcode_svg(
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matrix: Sequence[Sequence[bool]],
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foreground: tuple[int, int, int],
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background: tuple[int, int, int],
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width: int,
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height: int,
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scale: float,
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border: int,
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) -> str:
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"""Render a two-dimensional barcode matrix as SVG image data."""
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foreground_hex = '#{:02x}{:02x}{:02x}'.format(*foreground)
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background_hex = '#{:02x}{:02x}{:02x}'.format(*background)
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path = ' '.join(
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f'M{x + border} {y + border}h1v1h-1z'
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for y, row in enumerate(matrix)
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for x, value in enumerate(row)
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if value
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)
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svg = (
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f'<svg xmlns="http://www.w3.org/2000/svg" '
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f'width="{int(width * scale)}" height="{int(height * scale)}" '
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f'viewBox="0 0 {width} {height}" shape-rendering="crispEdges">'
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f'<rect width="{width}" height="{height}" fill="{background_hex}"/>'
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f'<path d="{path}" fill="{foreground_hex}"/>'
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'</svg>'
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)
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data = base64.b64encode(svg.encode()).decode()
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return f'data:image/svg+xml;charset=utf-8;base64,{data}'
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def _render_2d_barcode_raster(
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matrix: Sequence[Sequence[bool]],
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foreground: tuple[int, int, int],
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background: tuple[int, int, int],
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width: int,
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height: int,
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scale: float,
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border: int,
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fmt: str,
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) -> str:
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"""Render a two-dimensional barcode matrix as raster image data."""
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img = Image.new('RGB', (width, height), color=background)
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for y, row in enumerate(matrix):
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for x, value in enumerate(row):
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if value:
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img.putpixel((x + border, y + border), foreground)
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img = img.resize(
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(int(width * scale), int(height * scale)), Image.Resampling.NEAREST
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)
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return image_data(img, fmt=fmt)
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def _render_2d_barcode(
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matrix: Sequence[Sequence[bool]],
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fill_color: str = 'black',
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back_color: str = 'white',
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scale: float = 1.0,
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border: int = 1,
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fmt: str = 'PNG',
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) -> str:
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"""Render a two-dimensional barcode matrix in the requested format."""
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try:
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border = int(border)
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except Exception:
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border = 1
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border = max(0, border)
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try:
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foreground = ImageColor.getcolor(fill_color, 'RGB')
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except Exception:
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foreground = ImageColor.getcolor('black', 'RGB')
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try:
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background = ImageColor.getcolor(back_color, 'RGB')
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except Exception:
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background = ImageColor.getcolor('white', 'RGB')
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height = len(matrix) + 2 * border
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width = len(matrix[0]) + 2 * border
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if str(fmt).upper() == 'SVG':
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return _render_2d_barcode_svg(
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matrix, foreground, background, width, height, scale, border
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)
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return _render_2d_barcode_raster(
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matrix, foreground, background, width, height, scale, border, fmt
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)
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@register.simple_tag()
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def clean_barcode(data):
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"""Return a 'cleaned' string for encoding into a barcode / qrcode.
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@@ -154,7 +255,7 @@ def datamatrix(
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back_color: Background color (default = 'white')
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scale: Scaling factor (default = 1)
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border: Border width (default = 1)
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fmt: Generated image format (default = 'PNG')
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fmt: Generated image format (default = 'PNG'; use 'SVG' for vector output)
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Returns:
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image (str): base64 encoded image data
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@@ -170,36 +271,11 @@ def datamatrix(
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dm = DataMatrix(data, rect=rectangular)
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try:
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border = int(border)
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except Exception:
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border = 1
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border = max(0, border)
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try:
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fg = ImageColor.getcolor(fill_color, 'RGB')
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except Exception:
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fg = ImageColor.getcolor('black', 'RGB')
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try:
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bg = ImageColor.getcolor(back_color, 'RGB')
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except Exception:
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bg = ImageColor.getcolor('white', 'RGB')
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height = len(dm.matrix) + 2 * border
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width = len(dm.matrix[0]) + 2 * border
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# Generate raw image from the matrix
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img = Image.new('RGB', (width, height), color=bg)
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for y, row in enumerate(dm.matrix):
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for x, value in enumerate(row):
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if value:
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img.putpixel((x + border, y + border), fg)
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img = img.resize(
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(int(width * scale), int(height * scale)), Image.Resampling.NEAREST
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return _render_2d_barcode(
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dm.matrix,
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fill_color=fill_color,
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back_color=back_color,
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scale=scale,
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border=border,
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fmt=fmt,
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)
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return image_data(img, fmt=fmt)
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@@ -1,11 +1,17 @@
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"""Test for custom report tags."""
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import base64
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import hashlib
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import io
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import re
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from decimal import Decimal
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from xml.etree import ElementTree
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from zoneinfo import ZoneInfo
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from django.conf import settings
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from django.contrib.contenttypes.models import ContentType
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from django.core.exceptions import ValidationError
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from django.template import Context, Template
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from django.test import TestCase, override_settings
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from django.utils import timezone
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from django.utils.safestring import SafeString
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@@ -861,6 +867,65 @@ class ReportTagTest(PartImageTestMixin, InvenTreeTestCase):
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class BarcodeTagTest(TestCase):
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"""Unit tests for the barcode template tags."""
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def test_datamatrix_raster_geometry(self):
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"""Raster output preserves modules, borders, colors, and scaling."""
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# Pixel digests captured before extracting the raster renderer.
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for rectangular, border, scale, fmt, size, digest in [
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(
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False,
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0,
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1,
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'PNG',
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(16, 16),
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'df39de36e5926c66d156d7984876a5c6a1493211b2cc324548317da363589da2',
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),
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(
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True,
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3,
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2,
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'PNG',
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(76, 28),
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'ae64b12a2a1e30aa886aeb5abfd61eec9499da6101eee9b8a0476de98cfd551c',
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),
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(
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False,
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-2,
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1,
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'BMP',
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(16, 16),
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'df39de36e5926c66d156d7984876a5c6a1493211b2cc324548317da363589da2',
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),
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(
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True,
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'abc',
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2.5,
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'PNG',
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(85, 25),
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'58006f73ca9b70eec4ed7090ed0f28455a5bb93507fdf60320d1e62a7f1e259b',
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),
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]:
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with self.subTest(
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rectangular=rectangular, border=border, scale=scale, fmt=fmt
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):
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data = barcode_tags.datamatrix(
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'hello world',
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rectangular=rectangular,
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border=border,
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scale=scale,
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fill_color='red',
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back_color='blue',
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fmt=fmt,
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)
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prefix, payload = data.split(',', 1)
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self.assertEqual(
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prefix, f'data:image/{fmt.lower()};charset=utf-8;base64'
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)
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with Image.open(io.BytesIO(base64.b64decode(payload))) as image:
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self.assertEqual(image.size, size)
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self.assertEqual(
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hashlib.sha256(image.tobytes()).hexdigest(), digest
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)
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def test_barcode(self):
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"""Test the barcode generation tag."""
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barcode = barcode_tags.barcode('12345')
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@@ -936,3 +1001,157 @@ class BarcodeTagTest(TestCase):
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datamatrix,
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'data:image/png;charset=utf-8;base64,iVBORw0KGgoAAAANSUhEUgAAABIAAAASCAIAAADZrBkAAAAAlElEQVR4nJ1TQQ7AIAgri///cncw6wroEseBgEFbCgZJnNsFICKOPAAIjeSM5T11IznK5f5WRMgnkhP9JfCcTC/MxFZ5hxLOgqrn3o/z/OqtsNpdSL31Iu9W4Dq8Sulu+q5Nuqa3XYOdnuidlICPpXhZVBruyzAKSZehT+yNlzvZQcq6JiW7Ni592swf/43kdlDfdgMk1eOtR7kWpAAAAABJRU5ErkJggg==',
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)
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def test_2d_barcode_svg_renderer(self):
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"""Test vector rendering of a two-dimensional barcode matrix."""
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svg_data = barcode_tags._render_2d_barcode(
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[[True, False], [False, True]],
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fill_color='red',
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back_color='blue',
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scale=2,
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border=1,
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fmt='SVG',
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)
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prefix, payload = svg_data.split(',', 1)
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self.assertEqual(prefix, 'data:image/svg+xml;charset=utf-8;base64')
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root = ElementTree.fromstring(base64.b64decode(payload))
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namespace = '{http://www.w3.org/2000/svg}'
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self.assertEqual(root.attrib['width'], '8')
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self.assertEqual(root.attrib['height'], '8')
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self.assertEqual(root.attrib['viewBox'], '0 0 4 4')
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self.assertEqual(root.attrib['shape-rendering'], 'crispEdges')
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background = root.find(f'{namespace}rect')
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path = root.find(f'{namespace}path')
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self.assertIsNotNone(background)
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self.assertIsNotNone(path)
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self.assertEqual(background.attrib['fill'], '#0000ff')
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self.assertEqual(path.attrib['fill'], '#ff0000')
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self.assertEqual(path.attrib['d'], 'M1 1h1v1h-1z M2 2h1v1h-1z')
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def test_datamatrix_svg(self):
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"""Test SVG output from the Data Matrix template tag."""
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datamatrix = barcode_tags.datamatrix(
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'hello world',
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rectangular=True,
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border='abc',
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fill_color='aaaaaaa',
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back_color='aaaaaaa',
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fmt='svg',
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)
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prefix, payload = datamatrix.split(',', 1)
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self.assertEqual(prefix, 'data:image/svg+xml;charset=utf-8;base64')
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root = ElementTree.fromstring(base64.b64decode(payload))
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namespace = '{http://www.w3.org/2000/svg}'
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_, _, width, height = root.attrib['viewBox'].split()
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self.assertNotEqual(width, height)
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background = root.find(f'{namespace}rect')
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path = root.find(f'{namespace}path')
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self.assertIsNotNone(background)
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self.assertIsNotNone(path)
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self.assertEqual(background.attrib['fill'], '#ffffff')
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self.assertEqual(path.attrib['fill'], '#000000')
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def test_datamatrix_svg_geometry(self):
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"""SVG modules retain the encoded matrix geometry at different scales."""
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from ppf.datamatrix.datamatrix import DataMatrix
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namespace = '{http://www.w3.org/2000/svg}'
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for rectangular, border, scale in [
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(False, 0, 1),
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(True, 3, 2.5),
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(False, -2, 2),
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]:
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with self.subTest(rectangular=rectangular, border=border, scale=scale):
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matrix = DataMatrix('hello world', rect=rectangular).matrix
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padding = max(0, border)
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width = len(matrix[0]) + 2 * padding
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height = len(matrix) + 2 * padding
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data = barcode_tags.datamatrix(
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'hello world',
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rectangular=rectangular,
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border=border,
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scale=scale,
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fmt='SVG',
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)
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root = ElementTree.fromstring(base64.b64decode(data.split(',', 1)[1]))
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self.assertEqual(root.attrib['viewBox'], f'0 0 {width} {height}')
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self.assertEqual(root.attrib['width'], str(int(width * scale)))
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self.assertEqual(root.attrib['height'], str(int(height * scale)))
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background = root.find(f'{namespace}rect')
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self.assertEqual(background.attrib['width'], str(width))
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self.assertEqual(background.attrib['height'], str(height))
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path = root.find(f'{namespace}path').attrib['d']
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modules = re.findall(r'M(\d+) (\d+)h1v1h-1z', path)
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self.assertEqual(len(modules), sum(map(sum, matrix)))
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self.assertEqual(
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{(int(x), int(y)) for x, y in modules},
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{
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(x + padding, y + padding)
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for y, row in enumerate(matrix)
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for x, dark in enumerate(row)
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if dark
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},
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)
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def test_datamatrix_svg_template(self):
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"""The template tag produces embeddable SVG and rejects empty data."""
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template = Template(
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'{% load barcode %}<img src="{% datamatrix data fmt="SVG" %}"/>'
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)
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html = template.render(Context({'data': 'hello world'}))
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image = ElementTree.fromstring(html)
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self.assertEqual(
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image.attrib['src'], barcode_tags.datamatrix('hello world', fmt='SVG')
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)
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for data in ['', ' ']:
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with self.subTest(data=data), self.assertRaises(ValidationError):
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template.render(Context({'data': data}))
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def test_datamatrix_svg_pdf(self):
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"""PDF output contains painted vector modules, not a missing image."""
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from ppf.datamatrix.datamatrix import DataMatrix
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from pypdf import PdfReader
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from weasyprint import HTML
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template = Template(
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'{% load barcode %}'
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'<img src="{% datamatrix data fmt="SVG" fill_color="red" %}">'
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)
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html = template.render(Context({'data': 'hello world'}))
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with self.assertNoLogs('weasyprint', level='WARNING'):
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pdf = HTML(string=html).write_pdf()
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reader = PdfReader(io.BytesIO(pdf))
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self.assertEqual(len(reader.pages), 1)
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page = reader.pages[0]
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self.assertEqual(len(page.images), 0)
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# Count closed module outlines painted in the selected foreground color.
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# A valid PDF header also occurs when WeasyPrint omits a broken image.
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color = None
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closed_paths = 0
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painted_modules = 0
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for operands, operator in page.get_contents().operations:
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if operator == b'rg':
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color = tuple(operands)
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elif operator == b'h':
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closed_paths += 1
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elif operator in (b'f', b'f*'):
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if color == (1, 0, 0):
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painted_modules += closed_paths
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closed_paths = 0
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elif operator == b'n':
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closed_paths = 0
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matrix = DataMatrix('hello world').matrix
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self.assertEqual(painted_modules, sum(map(sum, matrix)))
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