Add --mask-pattern option to the qr command line script

CHANGES.rst

@@ -42,6 +42,7 @@ WIP 8.x
 
 - **Added** ``GappedCircleModuleDrawer`` (PIL) to render QR code modules as non-contiguous circles. (BenwestGate in `#373`_)
 - **Added** ability to execute as a Python module: ``python -m qrcode --output qrcode.png "hello world"`` (stefansjs in `#400`_)
+- **Added** ``--mask-pattern`` option to the ``qr`` command line script to select a specific mask pattern instead of the automatically chosen one. (ChrisJr404 in `#433`_)
 - **Removed** the hardcoded 'id' argument from SVG elements. The fixed element ID caused conflicts when embedding multiple QR codes in a single document. (m000 in `#385`_)
 - **Fixed** typos in code that used ``embeded`` instead of ``embedded``. For backwards compatibility, the misspelled parameter names are still accepted but now emit deprecation warnings. These deprecated parameter names will be removed in v9.0. (benjnicholls in `#349`_)
 - **Fixed** an issue where an ``<svg:`` prefix in the SVG output caused invalid markup when inlined within HTML documents. (bartTC in `#412`_)
@@ -63,6 +64,7 @@ WIP 8.x
 .. _#397: https://github.com/lincolnloop/python-qrcode/pull/397
 .. _#399: https://github.com/lincolnloop/python-qrcode/pull/399
 .. _#400: https://github.com/lincolnloop/python-qrcode/pull/400
+.. _#433: https://github.com/lincolnloop/python-qrcode/pull/433
 .. _#408: https://github.com/lincolnloop/python-qrcode/pull/408
 .. _#411: https://github.com/lincolnloop/python-qrcode/pull/411
 .. _#412: https://github.com/lincolnloop/python-qrcode/pull/412

doc/qr.1

@@ -3,7 +3,7 @@
 .SH NAME
 qr \- script to create QR codes at the command line
 .SH SYNOPSIS
-qr [\-\-help] [\-\-factory=FACTORY] [\-\-optimize=OPTIMIZE] [\-\-error\-correction=LEVEL] [data]
+qr [\-\-help] [\-\-factory=FACTORY] [\-\-optimize=OPTIMIZE] [\-\-error\-correction=LEVEL] [\-\-mask\-pattern=PATTERN] [data]
 .SH DESCRIPTION
 This script uses the python qrcode module. It can take data from stdin or from the commandline and generate a QR code.
 Normally it will output the QR code as ascii art to the terminal. If the output is piped to a file, it will output the image (default type of PNG).
@@ -39,6 +39,14 @@ The error correction level to use. Choices are L (7%),
 M (15%, default), Q (25%), and H (30%).
 .RE
 
+.PP
+\fB\ \-\-mask\-pattern=PATTERN\fR
+.RS 4
+The mask pattern (0-7) to use. By default the pattern that
+scores best under the standard penalty rules is chosen
+automatically.
+.RE
+
 .PP
 \fB\ data\fR
 .RS 4

qrcode/console_scripts.py

@@ -83,6 +83,12 @@ def raise_error(msg: str) -> NoReturn:
         help="The error correction level to use. Choices are L (7%), "
         "M (15%, default), Q (25%), and H (30%).",
     )
+    parser.add_option(
+        "--mask-pattern",
+        type=int,
+        help="The mask pattern (0-7) to use. By default the pattern that "
+        "scores best under the standard penalty rules is chosen automatically.",
+    )
     parser.add_option(
         "--ascii", help="Print as ascii even if stdout is piped.", action="store_true"
     )
@@ -103,10 +109,14 @@ def raise_error(msg: str) -> NoReturn:
     else:
         image_factory = None
 
-    qr = qrcode.QRCode(
-        error_correction=error_correction[opts.error_correction],
-        image_factory=image_factory,
-    )
+    try:
+        qr = qrcode.QRCode(
+            error_correction=error_correction[opts.error_correction],
+            mask_pattern=opts.mask_pattern,
+            image_factory=image_factory,
+        )
+    except (TypeError, ValueError) as e:
+        raise_error(str(e))
 
     if args:
         data = args[0]

qrcode/tests/test_script.py

@@ -57,6 +57,26 @@ def test_optimize():
     main(["testtext", "--optimize", "0"])
 
 
+@mock.patch("os.isatty", return_value=True)
+@mock.patch("qrcode.QRCode")
+def test_mask_pattern(mock_qrcode, mock_isatty):
+    main(["testtext", "--mask-pattern", "1"])
+    assert mock_qrcode.call_args.kwargs["mask_pattern"] == 1
+
+
+@mock.patch("os.isatty", return_value=True)
+@mock.patch("qrcode.QRCode")
+def test_mask_pattern_default(mock_qrcode, mock_isatty):
+    main(["testtext"])
+    assert mock_qrcode.call_args.kwargs["mask_pattern"] is None
+
+
+def test_mask_pattern_out_of_range(capsys):
+    with pytest.raises(SystemExit):
+        main(["testtext", "--mask-pattern", "8"])
+    assert "Mask pattern should be in range(8)" in capsys.readouterr()[1]
+
+
 def test_factory():
     main(["testtext", "--factory", "svg"])