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  22 <div class="chapter">
  23 <div class="titlepage"><div><div><h2 class="title">
  24 <a name="utilities"></a>Utilities</h2></div></div></div>
  25 <div class="toc"><dl class="toc">
  26 <dt><span class="section"><a href="utilities.html#utilities-command-line-tools">Command-line tools</a></span></dt>
  27 <dd><dl>
  28 <dt><span class="section"><a href="utilities.html#utilities-command-line-hbshape">hb-shape</a></span></dt>
  29 <dt><span class="section"><a href="utilities.html#utilities-command-line-hbview">hb-view</a></span></dt>
  30 <dt><span class="section"><a href="utilities.html#utilities-command-line-hbsubset">hb-subset</a></span></dt>
  31 </dl></dd>
  32 <dt><span class="section"><a href="utilities-common-types-apis.html">Common data types and APIs</a></span></dt>
  33 </dl></div>
  34 <p>
  35     HarfBuzz includes several auxiliary components in addition to the
  36     main APIs. These include a set of command-line tools, a set of
  37     lower-level APIs for common data types that may be of interest to
  38     client programs.
  39   </p>
  40 <div class="section">
  41 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  42 <a name="utilities-command-line-tools"></a>Command-line tools</h2></div></div></div>
  43 <p>
  44       HarfBuzz include three command-line tools:
  45       <span class="command"><strong>hb-shape</strong></span>, <span class="command"><strong>hb-view</strong></span>, and
  46       <span class="command"><strong>hb-subset</strong></span>. They can be used to examine
  47       HarfBuzz's functionality, debug font binaries, or explore the
  48       various shaping models and features from a terminal.
  49     </p>
  50 <div class="section">
  51 <div class="titlepage"><div><div><h3 class="title">
  52 <a name="utilities-command-line-hbshape"></a>hb-shape</h3></div></div></div>
  53 <p>
  54         <span class="emphasis"><em><span class="command"><strong>hb-shape</strong></span></em></span> allows you to run HarfBuzz's
  55         <code class="function">hb_shape()</code> function on an input string and
  56         to examine the outcome, in human-readable form, as terminal
  57         output. <span class="command"><strong>hb-shape</strong></span> does
  58         <span class="emphasis"><em>not</em></span> render the results of the shaping call
  59         into rendered text (you can use <span class="command"><strong>hb-view</strong></span>, below, for
  60         that). Instead, it prints out the final glyph indices and
  61         positions, taking all shaping operations into account, as if the
  62         input string were a HarfBuzz input buffer.
  63       </p>
  64 <p>
  65         You can specify the font to be used for shaping and, with
  66         command-line options, you can add various aspects of the
  67         internal state to the output that is sent to the terminal. The
  68         general format is
  69       </p>
  70 <pre class="programlisting">
  71         <span class="command"><strong>hb-shape</strong></span> [<span class="optional">[OPTIONS]</span>]
  72       <em class="parameter"><code>path/to/font/file.ttf</code></em>
  73       <em class="parameter"><code>yourinputtext</code></em>
  74       </pre>
  75 <p>
  76         The default output format is plain text (although JSON output
  77         can be selected instead by specifying the option
  78         [<span class="optional">--output-format=json</span>]). The default output
  79         syntax reports each glyph name (or glyph index if there is no
  80         name) followed by its cluster value, its horizontal and vertical
  81         position displacement, and its horizontal and vertical advances.
  82       </p>
  83 <p>
  84         Output options exist to skip any of these elements in the
  85         output, and to include additional data, such as Unicode
  86         code-point values, glyph extents, glyph flags, or interim
  87         shaping results.
  88       </p>
  89 <p>
  90         Output can also be redirected to a file, or input read from a
  91         file. Additional options enable you to enable or disable
  92         specific font features, to set variation-font axis values, to
  93         alter the language, script, direction, and clustering settings
  94         used, to enable sanity checks, or to change which shaping engine is used.
  95       </p>
  96 <p>
  97         For a complete explanation of the options available, run
  98       </p>
  99 <pre class="programlisting">
 100         <span class="command"><strong>hb-shape</strong></span> <em class="parameter"><code>--help</code></em>
 101       </pre>
 102 </div>
 103 <div class="section">
 104 <div class="titlepage"><div><div><h3 class="title">
 105 <a name="utilities-command-line-hbview"></a>hb-view</h3></div></div></div>
 106 <p>
 107         <span class="emphasis"><em><span class="command"><strong>hb-view</strong></span></em></span> allows you to
 108         see the shaped output of an input string in rendered
 109         form. Like <span class="command"><strong>hb-shape</strong></span>,
 110         <span class="command"><strong>hb-view</strong></span> takes a font file and a text string
 111         as its arguments:
 112       </p>
 113 <pre class="programlisting">
 114         <span class="command"><strong>hb-view</strong></span> [<span class="optional">[OPTIONS]</span>]
 115         <em class="parameter"><code>path/to/font/file.ttf</code></em>
 116         <em class="parameter"><code>yourinputtext</code></em>
 117       </pre>
 118 <p>
 119         By default, <span class="command"><strong>hb-view</strong></span> renders the shaped
 120         text in ASCII block-character images as terminal output. By
 121         appending the
 122         <span class="command"><strong>--output-file=[<span class="optional">filename</span>]</strong></span>
 123         switch, you can write the output to a PNG, SVG, or PDF file
 124         (among other formats).
 125       </p>
 126 <p>
 127         As with <span class="command"><strong>hb-shape</strong></span>, a lengthy set of options
 128         is available, with which you can  enable or disable
 129         specific font features, set variation-font axis values,
 130         alter the language, script, direction, and clustering settings
 131         used, enable sanity checks, or change which shaping engine is
 132         used.
 133       </p>
 134 <p>
 135         You can also set the foreground and background colors used for
 136         the output, independently control the width of all four
 137         margins, alter the line spacing, and annotate the output image
 138         with
 139       </p>
 140 <p>
 141         In general, <span class="command"><strong>hb-view</strong></span> is a quick way to
 142         verify that the output of HarfBuzz's shaping operation looks
 143         correct for a given text-and-font combination, but you may
 144         want to use <span class="command"><strong>hb-shape</strong></span> to figure out exactly
 145         why something does not appear as expected.
 146       </p>
 147 </div>
 148 <div class="section">
 149 <div class="titlepage"><div><div><h3 class="title">
 150 <a name="utilities-command-line-hbsubset"></a>hb-subset</h3></div></div></div>
 151 <p>
 152         <span class="emphasis"><em><span class="command"><strong>hb-subset</strong></span></em></span> allows you
 153         to generate a subset of a given font, with a limited set of
 154         supported characters, features, and variation settings.
 155       </p>
 156 <p>
 157         By default, you provide an input font and an input text string
 158         as the arguments to <span class="command"><strong>hb-subset</strong></span>, and it will
 159         generate a font that covers the input text exactly like the
 160         input font does, but includes no other characters or features.
 161       </p>
 162 <pre class="programlisting">
 163         <span class="command"><strong>hb-subset</strong></span> [<span class="optional">[OPTIONS]</span>]
 164         <em class="parameter"><code>path/to/font/file.ttf</code></em>
 165         <em class="parameter"><code>yourinputtext</code></em>
 166       </pre>
 167 <p>
 168         For example, to create a subset of Noto Serif that just includes the
 169         numerals and the lowercase Latin alphabet, you could run
 170       </p>
 171 <pre class="programlisting">
 172         <span class="command"><strong>hb-subset</strong></span> [<span class="optional">[OPTIONS]</span>]
 173         <em class="parameter"><code>NotoSerif-Regular.ttf</code></em>
 174         <em class="parameter"><code>0123456789abcdefghijklmnopqrstuvwxyz</code></em>
 175       </pre>
 176 <p>
 177         There are options available to remove hinting from the
 178         subsetted font and to specify a list of variation-axis settings.
 179       </p>
 180 </div>
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