prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Escape unicode characters when producing latex
  Currently, the qcircuit to latex code passes through unicode characters like ↺ ↻. LaTeX may not be happy about this. We should replace the unicode characters with some that LaTeX is happy with. Or perhaps throw an error?
  
  </issue>
  <code>
  [start of cirq/contrib/qcircuit/qcircuit_pdf.py]
  1 # Copyright 2018 The Cirq Developers
  2 #
  3 # Licensed under the Apache License, Version 2.0 (the "License");
  4 # you may not use this file except in compliance with the License.
  5 # You may obtain a copy of the License at
  6 #
  7 #     https://www.apache.org/licenses/LICENSE-2.0
  8 #
  9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14 
  15 # coverage: ignore
  16 
  17 import errno
  18 import os
  19 
  20 from pylatex import Document, NoEscape, Package
  21 
  22 from cirq import circuits
  23 from cirq.contrib.qcircuit.qcircuit_diagram import (
  24         circuit_to_latex_using_qcircuit)
  25 
  26 
  27 def circuit_to_pdf_using_qcircuit_via_tex(circuit: circuits.Circuit,
  28                                           filepath: str,
  29                                           pdf_kwargs=None,
  30                                           qcircuit_kwargs=None,
  31                                           clean_ext=('dvi', 'ps'),
  32                                           documentclass='article'):
  33     """Compiles the QCircuit-based latex diagram of the given circuit.
  34 
  35     Args:
  36         circuit: The circuit to produce a pdf of.
  37         filepath: Where to output the pdf.
  38         pdf_kwargs: The arguments to pass to generate_pdf.
  39         qcircuit_kwargs: The arguments to pass to
  40             circuit_to_latex_using_qcircuit.
  41         clean_ext: The file extensions to clean up after compilation. By
  42             default, latexmk is used with the '-pdfps' flag, which produces
  43             intermediary dvi and ps files.
  44         documentclass: The documentclass of the latex file.
  45     """
  46     pdf_kwargs = {'compiler': 'latexmk', 'compiler_args': ['-pdfps'],
  47                   **({} if pdf_kwargs is None else pdf_kwargs)}
  48     qcircuit_kwargs = {} if qcircuit_kwargs is None else qcircuit_kwargs
  49     tex = circuit_to_latex_using_qcircuit(circuit, **qcircuit_kwargs)
  50     doc = Document(documentclass=documentclass, document_options='dvips')
  51     doc.packages.append(Package('amsmath'))
  52     doc.packages.append(Package('qcircuit'))
  53     doc.append(NoEscape(tex))
  54     doc.generate_pdf(filepath, **pdf_kwargs)
  55     for ext in clean_ext:
  56         try:
  57             os.remove(filepath + '.' + ext)
  58         except (OSError, IOError) as e:
  59             if e.errno != errno.ENOENT:
  60                 raise
  61
  [end of cirq/contrib/qcircuit/qcircuit_pdf.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/cirq/contrib/qcircuit/qcircuit_pdf.py b/cirq/contrib/qcircuit/qcircuit_pdf.py
  --- a/cirq/contrib/qcircuit/qcircuit_pdf.py
  +++ b/cirq/contrib/qcircuit/qcircuit_pdf.py
  @@ -50,6 +50,7 @@
       doc = Document(documentclass=documentclass, document_options='dvips')
       doc.packages.append(Package('amsmath'))
       doc.packages.append(Package('qcircuit'))
  +    doc.preamble.append(Package('inputenc', options=['utf8']))
       doc.append(NoEscape(tex))
       doc.generate_pdf(filepath, **pdf_kwargs)
       for ext in clean_ext:
  
verification_info: {"golden_diff": "diff --git a/cirq/contrib/qcircuit/qcircuit_pdf.py b/cirq/contrib/qcircuit/qcircuit_pdf.py\n--- a/cirq/contrib/qcircuit/qcircuit_pdf.py\n+++ b/cirq/contrib/qcircuit/qcircuit_pdf.py\n@@ -50,6 +50,7 @@\n     doc = Document(documentclass=documentclass, document_options='dvips')\n     doc.packages.append(Package('amsmath'))\n     doc.packages.append(Package('qcircuit'))\n+    doc.preamble.append(Package('inputenc', options=['utf8']))\n     doc.append(NoEscape(tex))\n     doc.generate_pdf(filepath, **pdf_kwargs)\n     for ext in clean_ext:\n", "issue": "Escape unicode characters when producing latex\nCurrently, the qcircuit to latex code passes through unicode characters like \u21ba \u21bb. LaTeX may not be happy about this. We should replace the unicode characters with some that LaTeX is happy with. Or perhaps throw an error?\n", "before_files": [{"content": "# Copyright 2018 The Cirq Developers\n#\n# Licensed under the Apache License, Version 2.0 (the \"License\");\n# you may not use this file except in compliance with the License.\n# You may obtain a copy of the License at\n#\n#     https://www.apache.org/licenses/LICENSE-2.0\n#\n# Unless required by applicable law or agreed to in writing, software\n# distributed under the License is distributed on an \"AS IS\" BASIS,\n# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n# See the License for the specific language governing permissions and\n# limitations under the License.\n\n# coverage: ignore\n\nimport errno\nimport os\n\nfrom pylatex import Document, NoEscape, Package\n\nfrom cirq import circuits\nfrom cirq.contrib.qcircuit.qcircuit_diagram import (\n        circuit_to_latex_using_qcircuit)\n\n\ndef circuit_to_pdf_using_qcircuit_via_tex(circuit: circuits.Circuit,\n                                          filepath: str,\n                                          pdf_kwargs=None,\n                                          qcircuit_kwargs=None,\n                                          clean_ext=('dvi', 'ps'),\n                                          documentclass='article'):\n    \"\"\"Compiles the QCircuit-based latex diagram of the given circuit.\n\n    Args:\n        circuit: The circuit to produce a pdf of.\n        filepath: Where to output the pdf.\n        pdf_kwargs: The arguments to pass to generate_pdf.\n        qcircuit_kwargs: The arguments to pass to\n            circuit_to_latex_using_qcircuit.\n        clean_ext: The file extensions to clean up after compilation. By\n            default, latexmk is used with the '-pdfps' flag, which produces\n            intermediary dvi and ps files.\n        documentclass: The documentclass of the latex file.\n    \"\"\"\n    pdf_kwargs = {'compiler': 'latexmk', 'compiler_args': ['-pdfps'],\n                  **({} if pdf_kwargs is None else pdf_kwargs)}\n    qcircuit_kwargs = {} if qcircuit_kwargs is None else qcircuit_kwargs\n    tex = circuit_to_latex_using_qcircuit(circuit, **qcircuit_kwargs)\n    doc = Document(documentclass=documentclass, document_options='dvips')\n    doc.packages.append(Package('amsmath'))\n    doc.packages.append(Package('qcircuit'))\n    doc.append(NoEscape(tex))\n    doc.generate_pdf(filepath, **pdf_kwargs)\n    for ext in clean_ext:\n        try:\n            os.remove(filepath + '.' + ext)\n        except (OSError, IOError) as e:\n            if e.errno != errno.ENOENT:\n                raise\n", "path": "cirq/contrib/qcircuit/qcircuit_pdf.py"}]}