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1 | 1 | # -*- coding: utf-8 -*- |
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2 | 2 | """Tools for handling LaTeX. |
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3 | 3 | |
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4 | 4 | Authors: |
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5 | 5 | |
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6 | 6 | * Brian Granger |
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7 | 7 | """ |
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8 | 8 | #----------------------------------------------------------------------------- |
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9 | 9 | # Copyright (C) 2010 IPython Development Team. |
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10 | 10 | # |
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11 | 11 | # Distributed under the terms of the Modified BSD License. |
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12 | 12 | # |
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13 | 13 | # The full license is in the file COPYING.txt, distributed with this software. |
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14 | 14 | #----------------------------------------------------------------------------- |
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15 | 15 | |
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16 | 16 | #----------------------------------------------------------------------------- |
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17 | 17 | # Imports |
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18 | 18 | #----------------------------------------------------------------------------- |
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19 | 19 | |
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20 | 20 | from io import BytesIO |
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21 | 21 | from base64 import encodestring |
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22 | 22 | import os |
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23 | 23 | import tempfile |
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24 | 24 | import shutil |
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25 | 25 | import subprocess |
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26 | 26 | |
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27 | 27 | from IPython.utils.process import find_cmd, FindCmdError |
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28 | 28 | from IPython.config.configurable import SingletonConfigurable |
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29 | 29 | from IPython.utils.traitlets import List, CBool, CUnicode |
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30 | 30 | from IPython.utils.py3compat import bytes_to_str |
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31 | 31 | |
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32 | 32 | #----------------------------------------------------------------------------- |
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33 | 33 | # Tools |
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34 | 34 | #----------------------------------------------------------------------------- |
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35 | 35 | |
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36 | 36 | |
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37 | 37 | class LaTeXTool(SingletonConfigurable): |
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38 | 38 | """An object to store configuration of the LaTeX tool.""" |
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39 | 39 | |
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40 | 40 | backends = List( |
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41 | 41 | CUnicode, ["matplotlib", "dvipng"], |
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42 | 42 | help="Preferred backend to draw LaTeX math equations. " |
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43 | 43 | "Backends in the list are checked one by one and the first " |
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44 | 44 | "usable one is used. Note that `matplotlib` backend " |
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45 | 45 | "is usable only for inline style equations. To draw " |
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46 | 46 | "display style equations, `dvipng` backend must be specified. ", |
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47 | 47 | # It is a List instead of Enum, to make configuration more |
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48 | 48 | # flexible. For example, to use matplotlib mainly but dvipng |
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49 | 49 | # for display style, the default ["matplotlib", "dvipng"] can |
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50 | 50 | # be used. To NOT use dvipng so that other repr such as |
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51 | 51 | # unicode pretty printing is used, you can use ["matplotlib"]. |
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52 | 52 | config=True) |
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53 | 53 | |
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54 | 54 | use_breqn = CBool( |
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55 | 55 | True, |
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56 | 56 | help="Use breqn.sty to automatically break long equations. " |
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57 | 57 | "This configuration takes effect only for dvipng backend.", |
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58 | 58 | config=True) |
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59 | 59 | |
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60 | 60 | packages = List( |
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61 | 61 | ['amsmath', 'amsthm', 'amssymb', 'bm'], |
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62 | 62 | help="A list of packages to use for dvipng backend. " |
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63 | 63 | "'breqn' will be automatically appended when use_breqn=True.", |
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64 | 64 | config=True) |
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65 | 65 | |
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66 | 66 | preamble = CUnicode( |
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67 | 67 | help="Additional preamble to use when generating LaTeX source " |
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68 | 68 | "for dvipng backend.", |
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69 | 69 | config=True) |
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70 | 70 | |
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71 | 71 | |
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72 | 72 | def latex_to_png(s, encode=False, backend=None, wrap=False): |
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73 | 73 | """Render a LaTeX string to PNG. |
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74 | 74 | |
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75 | 75 | Parameters |
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76 | 76 | ---------- |
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77 | 77 | s : str |
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78 | 78 | The raw string containing valid inline LaTeX. |
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79 | 79 | encode : bool, optional |
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80 | 80 | Should the PNG data bebase64 encoded to make it JSON'able. |
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81 | 81 | backend : {matplotlib, dvipng} |
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82 | 82 | Backend for producing PNG data. |
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83 | 83 | wrap : bool |
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84 | 84 | If true, Automatically wrap `s` as a LaTeX equation. |
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85 | 85 | |
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86 | 86 | None is returned when the backend cannot be used. |
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87 | 87 | |
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88 | 88 | """ |
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89 | 89 | allowed_backends = LaTeXTool.instance().backends |
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90 | 90 | if backend is None: |
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91 | 91 | backend = allowed_backends[0] |
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92 | 92 | if backend not in allowed_backends: |
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93 | 93 | return None |
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94 | 94 | if backend == 'matplotlib': |
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95 | 95 | f = latex_to_png_mpl |
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96 | 96 | elif backend == 'dvipng': |
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97 | 97 | f = latex_to_png_dvipng |
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98 | 98 | else: |
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99 | 99 | raise ValueError('No such backend {0}'.format(backend)) |
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100 | 100 | bin_data = f(s, wrap) |
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101 | 101 | if encode and bin_data: |
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102 | 102 | bin_data = encodestring(bin_data) |
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103 | 103 | return bin_data |
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104 | 104 | |
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105 | 105 | |
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106 | 106 | def latex_to_png_mpl(s, wrap): |
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107 | 107 | try: |
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108 | 108 | from matplotlib import mathtext |
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109 | 109 | except ImportError: |
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110 | 110 | return None |
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111 | 111 | |
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112 | 112 | if wrap: |
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113 | 113 | s = '${0}$'.format(s) |
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114 | 114 | mt = mathtext.MathTextParser('bitmap') |
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115 | 115 | f = BytesIO() |
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116 | 116 | mt.to_png(f, s, fontsize=12) |
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117 | 117 | return f.getvalue() |
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118 | 118 | |
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119 | 119 | |
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120 | 120 | def latex_to_png_dvipng(s, wrap): |
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121 | 121 | try: |
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122 | 122 | find_cmd('latex') |
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123 | 123 | find_cmd('dvipng') |
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124 | 124 | except FindCmdError: |
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125 | 125 | return None |
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126 | 126 | try: |
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127 | 127 | workdir = tempfile.mkdtemp() |
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128 | 128 | tmpfile = os.path.join(workdir, "tmp.tex") |
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129 | 129 | dvifile = os.path.join(workdir, "tmp.dvi") |
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130 | 130 | outfile = os.path.join(workdir, "tmp.png") |
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131 | 131 | |
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132 | 132 | with open(tmpfile, "w") as f: |
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133 | 133 | f.writelines(genelatex(s, wrap)) |
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134 | 134 | |
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135 | 135 | with open(os.devnull, 'w') as devnull: |
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136 | 136 | subprocess.check_call( |
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137 |
["latex", "-halt-on-error", tmpfile], |
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138 | stdout=devnull, stderr=devnull) | |
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137 | ["latex", "-halt-on-error", "-interaction", "batchmode", tmpfile], | |
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138 | cwd=workdir, stdout=devnull, stderr=devnull) | |
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139 | 139 | |
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140 | 140 | subprocess.check_call( |
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141 | 141 | ["dvipng", "-T", "tight", "-x", "1500", "-z", "9", |
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142 | 142 | "-bg", "transparent", "-o", outfile, dvifile], cwd=workdir, |
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143 | 143 | stdout=devnull, stderr=devnull) |
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144 | 144 | |
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145 | 145 | with open(outfile, "rb") as f: |
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146 | 146 | return f.read() |
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147 | 147 | finally: |
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148 | 148 | shutil.rmtree(workdir) |
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149 | 149 | |
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150 | 150 | |
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151 | 151 | def kpsewhich(filename): |
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152 | 152 | """Invoke kpsewhich command with an argument `filename`.""" |
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153 | 153 | try: |
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154 | 154 | find_cmd("kpsewhich") |
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155 | 155 | proc = subprocess.Popen( |
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156 | 156 | ["kpsewhich", filename], |
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157 | 157 | stdout=subprocess.PIPE, stderr=subprocess.PIPE) |
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158 | 158 | (stdout, stderr) = proc.communicate() |
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159 | 159 | return stdout.strip() |
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160 | 160 | except FindCmdError: |
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161 | 161 | pass |
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162 | 162 | |
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163 | 163 | |
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164 | 164 | def genelatex(body, wrap): |
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165 | 165 | """Generate LaTeX document for dvipng backend.""" |
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166 | 166 | lt = LaTeXTool.instance() |
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167 | 167 | breqn = wrap and lt.use_breqn and kpsewhich("breqn.sty") |
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168 | 168 | yield r'\documentclass{article}' |
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169 | 169 | packages = lt.packages |
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170 | 170 | if breqn: |
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171 | 171 | packages = packages + ['breqn'] |
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172 | 172 | for pack in packages: |
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173 | 173 | yield r'\usepackage{{{0}}}'.format(pack) |
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174 | 174 | yield r'\pagestyle{empty}' |
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175 | 175 | if lt.preamble: |
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176 | 176 | yield lt.preamble |
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177 | 177 | yield r'\begin{document}' |
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178 | 178 | if breqn: |
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179 | 179 | yield r'\begin{dmath*}' |
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180 | 180 | yield body |
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181 | 181 | yield r'\end{dmath*}' |
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182 | 182 | elif wrap: |
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183 | 183 | yield '$${0}$$'.format(body) |
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184 | 184 | else: |
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185 | 185 | yield body |
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186 | 186 | yield r'\end{document}' |
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187 | 187 | |
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188 | 188 | |
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189 | 189 | _data_uri_template_png = """<img src="data:image/png;base64,%s" alt=%s />""" |
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190 | 190 | |
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191 | 191 | def latex_to_html(s, alt='image'): |
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192 | 192 | """Render LaTeX to HTML with embedded PNG data using data URIs. |
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193 | 193 | |
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194 | 194 | Parameters |
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195 | 195 | ---------- |
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196 | 196 | s : str |
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197 | 197 | The raw string containing valid inline LateX. |
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198 | 198 | alt : str |
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199 | 199 | The alt text to use for the HTML. |
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200 | 200 | """ |
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201 | 201 | base64_data = bytes_to_str(latex_to_png(s, encode=True), 'ascii') |
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202 | 202 | if base64_data: |
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203 | 203 | return _data_uri_template_png % (base64_data, alt) |
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204 | 204 | |
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205 | 205 | |
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206 | 206 | # From matplotlib, thanks to mdboom. Once this is in matplotlib releases, we |
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207 | 207 | # will remove. |
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208 | 208 | def math_to_image(s, filename_or_obj, prop=None, dpi=None, format=None): |
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209 | 209 | """ |
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210 | 210 | Given a math expression, renders it in a closely-clipped bounding |
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211 | 211 | box to an image file. |
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212 | 212 | |
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213 | 213 | *s* |
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214 | 214 | A math expression. The math portion should be enclosed in |
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215 | 215 | dollar signs. |
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216 | 216 | |
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217 | 217 | *filename_or_obj* |
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218 | 218 | A filepath or writable file-like object to write the image data |
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219 | 219 | to. |
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220 | 220 | |
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221 | 221 | *prop* |
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222 | 222 | If provided, a FontProperties() object describing the size and |
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223 | 223 | style of the text. |
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224 | 224 | |
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225 | 225 | *dpi* |
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226 | 226 | Override the output dpi, otherwise use the default associated |
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227 | 227 | with the output format. |
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228 | 228 | |
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229 | 229 | *format* |
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230 | 230 | The output format, eg. 'svg', 'pdf', 'ps' or 'png'. If not |
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231 | 231 | provided, will be deduced from the filename. |
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232 | 232 | """ |
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233 | 233 | from matplotlib import figure |
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234 | 234 | # backend_agg supports all of the core output formats |
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235 | 235 | from matplotlib.backends import backend_agg |
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236 | 236 | from matplotlib.font_manager import FontProperties |
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237 | 237 | from matplotlib.mathtext import MathTextParser |
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238 | 238 | |
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239 | 239 | if prop is None: |
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240 | 240 | prop = FontProperties() |
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241 | 241 | |
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242 | 242 | parser = MathTextParser('path') |
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243 | 243 | width, height, depth, _, _ = parser.parse(s, dpi=72, prop=prop) |
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244 | 244 | |
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245 | 245 | fig = figure.Figure(figsize=(width / 72.0, height / 72.0)) |
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246 | 246 | fig.text(0, depth/height, s, fontproperties=prop) |
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247 | 247 | backend_agg.FigureCanvasAgg(fig) |
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248 | 248 | fig.savefig(filename_or_obj, dpi=dpi, format=format) |
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249 | 249 | |
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250 | 250 | return depth |
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251 | 251 |
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