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<h1>Up and Running With Collagen</h1>
<div id="toc" class="toc2">
<div id="toctitle">Contents</div>
<ul class="sectlevel1">
<li><a href="#_introduction">Introduction</a></li>
<li><a href="#_using_collagen">Using Collagen</a>
<ul class="sectlevel2">
<li><a href="#_a_basic_example">A Basic Example</a></li>
<li><a href="#_a_more_complicated_example">A More Complicated Example</a></li>
<li><a href="#_memes">Memes</a></li>
</ul>
</li>
</ul>
</div>
</div>
<div id="content">
<div class="sect1">
<h2 id="_introduction">Introduction</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Collagen is a program that takes as input a folder containing zero or more image files
(<code>.jpeg</code>, <code>.png</code>, etc.) and a JSON or <a href="https://jsonnet.org">Jsonnet</a> manifest file describing the layout of these images
along with SVG components such as shapes and text, and produces as output a single SVG
file with all assets embedded.</p>
</div>
<div class="paragraph">
<p>This allows a user to combine several graphics into a single file that can be displayed as an image without compromising on visual quality or file size.<sup class="footnote">[<a id="_footnoteref_1" class="footnote" href="#_footnotedef_1" title="View footnote.">1</a>]</sup></p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_using_collagen">Using Collagen</h2>
<div class="sectionbody">
<div class="paragraph">
<p>The input to Collagen is a folder containing at the very least a <code>collagen.json</code> or <code>collagen.jsonnet</code> manifest file describing the layout of the resulting SVG.
If the manifest specifies any image files (by their path relative to the folder), then those image files must also be present at the expected path in the folder.
An input folder satisfying these criteria will be referred to as a <em>skeleton</em>.</p>
</div>
<div class="paragraph">
<p>If <code>collagen.jsonnet</code> is provided, it is first expanded into JSON, then evaluated as if it were a <code>collagen.json</code> file.
While <code>collagen.json</code> is supported, even the least bit of complexity will quickly become overwhelming, in which case you should switch from JSON to Jsonnet.
Jsonnet was designed to look like JSON (and, when evaluated, produces JSON) while supporting common programmatic features such as variables, functions, string interpolation, and array concatenation and object merging.
These features make building the desired SVG a breeze.</p>
</div>
<div class="sect2">
<h3 id="_a_basic_example">A Basic Example</h3>
<div class="paragraph">
<p>An example of a simple input-output pair is below.
Suppose you have the following simple skeleton at directory <code>example-01</code>:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="text"><span></span>example-01
├── collagen.jsonnet
└── images
└── smiley.jpg</code></pre>
</div>
</div>
<div class="paragraph">
<p>Where <a href="tests/examples/kitty-nesting-smiley/skeleton/smiley/skeleton/images/smiley.jpg" target="_blank" rel="noopener"><code>images/smiley.jpg</code></a> is the following image (whose native size is 380×380 pixels):</p>
</div>
<div class="imageblock">
<div class="content">
<img src="tests/examples/kitty-nesting-smiley/skeleton/smiley/skeleton/images/smiley.jpg" alt="smiley" width="200px">
</div>
</div>
<div class="paragraph">
<p>And where <a href="tests/examples/kitty-nesting-smiley/skeleton/smiley/skeleton/collagen.jsonnet" target="_blank" rel="noopener"><code>collagen.jsonnet</code></a> contains the following:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="jsonnet"><span></span><span class="tok-k">local</span><span class="tok-w"> </span><span class="tok-nv">bubble_text</span><span class="tok-w"> </span><span class="tok-o">=</span><span class="tok-w"> </span><span class="tok-s">'Collagen!!'</span><span class="tok-p">;</span><span class="tok-w"> </span><i class="conum" data-value="1"></i><b>(1)</b>
<span class="tok-k">local</span><span class="tok-w"> </span><span class="tok-nv">nose_color</span><span class="tok-w"> </span><span class="tok-o">=</span><span class="tok-w"> </span><span class="tok-s">'#f00'</span><span class="tok-p">;</span>
<span class="tok-k">local</span><span class="tok-w"> </span><span class="tok-nv">text_color</span><span class="tok-w"> </span><span class="tok-o">=</span><span class="tok-w"> </span><span class="tok-s">'#000'</span><span class="tok-p">;</span>
<span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span><span class="tok-w"> </span><span class="tok-nv">viewBox</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'0 0 500 400'</span><span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">image_path</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'images/smiley.jpg'</span><span class="tok-p">,</span><span class="tok-w"> </span><i class="conum" data-value="2"></i><b>(2)</b>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span><span class="tok-w"> </span><span class="tok-nv">transform</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'translate(0 100) scale(1.3)'</span><span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'circle'</span><span class="tok-p">,</span><span class="tok-w"> </span><i class="conum" data-value="3"></i><b>(3)</b>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">cx</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">123</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">cy</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">240</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">r</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">15</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">fill</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-nv">nose_color</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">stroke</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'#000'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'stroke-width'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">3</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'path'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">d</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'M 230 140 L 265 120 A 100 40 0 1 0 235 110 Z'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">stroke</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'#000'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'stroke-width'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">3</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">fill</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'#fff'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'text'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">250</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">y</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">97</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'text-anchor'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'start'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'dominant-baseline'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'top'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'font-family'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'Impact'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'font-size'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">30</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">fill</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-nv">text_color</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span><span class="tok-nv">bubble_text</span><span class="tok-p">],</span><span class="tok-w"> </span><i class="conum" data-value="4"></i><b>(4)</b>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">],</span>
<span class="tok-p">}</span></code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" data-value="1"></i><b>1</b></td>
<td>Some variable declarations we’ll make use of later.</td>
</tr>
<tr>
<td><i class="conum" data-value="2"></i><b>2</b></td>
<td>To include an image, just give its relative path.</td>
</tr>
<tr>
<td><i class="conum" data-value="3"></i><b>3</b></td>
<td>Most other tags are specified with the <code>tag</code> field, which contains the name of the SVG tag to use.</td>
</tr>
<tr>
<td><i class="conum" data-value="4"></i><b>4</b></td>
<td>A string like <code>'Collagen!!'</code> gets turned into a text node: in SVG, <code><text>Collagen!!</text></code>.</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>Then, running the following command:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="bash"><span></span>clgn<span class="tok-w"> </span>-i<span class="tok-w"> </span>example-01<span class="tok-w"> </span>-o<span class="tok-w"> </span>example-01.svg</code></pre>
</div>
</div>
<div class="paragraph">
<p>Will produce the following file, <a href="tests/examples/kitty-nesting-smiley/skeleton/smiley/out.svg" target="_blank" rel="noopener"><code>examples-01.svg</code></a>:</p>
</div>
<div class="imageblock">
<div class="content">
<img src="tests/examples/kitty-nesting-smiley/skeleton/smiley/out.svg" alt="out" width="500">
</div>
</div>
<div class="paragraph">
<p>If you zoom in, you’ll see the smiley face’s pixels — this is unavoidable, as the original smiley was just a jpeg.
But because the nose and speech bubble are SVG elements (i.e. vector graphics, not raster) they look nice and smooth and crisp even when zoomed in.
That’s the whole point!
Perfectly precise vector graphics can coexist alongside raster graphics.</p>
</div>
</div>
<div class="sect2">
<h3 id="_a_more_complicated_example">A More Complicated Example</h3>
<div class="paragraph">
<p>As we’ve seen, we can include raster images in skeletons; it would be silly if we couldn’t also include other skeletons.
Nested skeletons can be included by adding a child of the form <code>{"clgn_path": <path>}</code>.
(Whereas a standalone skeleton gets turned into a <code><svg></code> tag, a nested skeleton will reside in a <code><g></code> tag.)
Let’s include the above skeleton in another (and just for fun, let’s add a photo of a kitten (<a href="https://commons.wikimedia.org/w/index.php?title=File:Cute_grey_kitten.jpg&oldid=479136954" target="_blank" rel="noopener">source</a>) too, because why not):</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="text"><span></span>example-02
├── collagen.jsonnet
├── example-01
│ ├── collagen.jsonnet
│ └── images
│ └── smiley.jpg
└── kitty.jpg</code></pre>
</div>
</div>
<div class="paragraph">
<p>Where <a href="tests/examples/kitty-nesting-smiley/skeleton/collagen.jsonnet" target="_blank" rel="noopener"><code>example-02/collagen.jsonnet</code></a> is below:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="jsonnet"><span></span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span><span class="tok-w"> </span><span class="tok-nv">viewBox</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'0 0 300 250'</span><span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'rect'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'10'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">y</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'10'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">width</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'275'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">height</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'225'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">fill</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'#ddd'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">stroke</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'#00f'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'stroke-width'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'10'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">'stroke-dasharray'</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'10 10'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'g'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span><span class="tok-w"> </span><span class="tok-nv">transform</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'translate(50 25) scale(.5)'</span><span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">clgn_path</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'./smiley/skeleton'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">],</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">image_path</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'./kitty.jpg'</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span><span class="tok-w"> </span><span class="tok-nv">transform</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">'translate(180 150) scale(.15)'</span><span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">],</span>
<span class="tok-p">}</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>Here’s <a href="tests/examples/kitty-nesting-smiley/out.svg" target="_blank" rel="noopener">the result</a> when you run <code>clgn -i example-02 -o example-02.svg</code>:</p>
</div>
<div class="imageblock">
<div class="content">
<img src="tests/examples/kitty-nesting-smiley/out.svg" alt="out" width="600">
</div>
</div>
<div class="paragraph">
<p>So, as far as Collagen is concerned, skeletons act more or less the same as raster images, in the sense that the path is sufficient to include them.
The only difference is that the path to a skeleton child is given by the key <code>clgn_path</code> instead of <code>image_path</code>.</p>
</div>
</div>
<div class="sect2">
<h3 id="_memes">Memes</h3>
<div class="paragraph">
<p>A format that makes it easy to place text on images?
Sounds like it would be perfect for memes.
But it’s not a meme unless it uses the “Impact” font.</p>
</div>
<div class="listingblock">
<div class="title"><a href="tests/examples/drake-user-specified-font-loop/skeleton/collagen.jsonnet" target="_blank" rel="noopener"><code>example-03/collagen.jsonnet</code></a></div>
<div class="content">
<pre class="pygments highlight"><code data-lang="jsonnet"><span></span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">viewBox</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"0 0 800 650"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">fonts</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">name</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"Impact"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">path</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"./impact.woff2"</span><span class="tok-p">,</span><span class="tok-w"> </span><i class="conum" data-value="1"></i><b>(1)</b>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">],</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">image_path</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"./drake-small.jpg"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">width</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">800</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-k">local</span><span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-w"> </span><span class="tok-o">=</span><span class="tok-w"> </span><span class="tok-mf">550</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-k">local</span><span class="tok-w"> </span><span class="tok-nv">dy</span><span class="tok-w"> </span><span class="tok-o">=</span><span class="tok-w"> </span><span class="tok-mf">50</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"text"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">"font-family"</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"Impact"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">"font-size"</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">50</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">color</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"black"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">"text-anchor"</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"middle"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">"vertical-align"</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"top"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">y</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-mf">420</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span>
<span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">tag</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-s">"tspan"</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">attrs</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">{</span>
<span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-nv">x</span><span class="tok-p">,</span>
<span class="tok-w"> </span><span class="tok-nv">dy</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-k">if</span><span class="tok-w"> </span><span class="tok-nv">i</span><span class="tok-w"> </span><span class="tok-o">==</span><span class="tok-w"> </span><span class="tok-mf">0</span><span class="tok-w"> </span><span class="tok-k">then</span><span class="tok-w"> </span><span class="tok-mf">0</span><span class="tok-w"> </span><span class="tok-k">else</span><span class="tok-w"> </span><span class="tok-nv">dy</span><span class="tok-p">,</span><span class="tok-w"> </span><i class="conum" data-value="3"></i><b>(3)</b>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-nv">children</span><span class="tok-p">:</span><span class="tok-w"> </span><span class="tok-p">[</span><span class="tok-s">"Using SVG-based text,"</span><span class="tok-p">,</span><span class="tok-w"> </span><span class="tok-s">"which is infinitely"</span><span class="tok-p">,</span><span class="tok-w"> </span><span class="tok-s">"zoomable and has"</span><span class="tok-p">,</span><span class="tok-w"> </span><span class="tok-s">"no artifacts"</span><span class="tok-p">][</span><span class="tok-nv">i</span><span class="tok-p">],</span><span class="tok-w"> </span><i class="conum" data-value="4"></i><b>(4)</b>
<span class="tok-w"> </span><span class="tok-p">}</span>
<span class="tok-w"> </span><span class="tok-k">for</span><span class="tok-w"> </span><span class="tok-nv">i</span><span class="tok-w"> </span><span class="tok-k">in</span><span class="tok-w"> </span><span class="tok-nb">std.range</span><span class="tok-p">(</span><span class="tok-mf">0</span><span class="tok-p">,</span><span class="tok-w"> </span><span class="tok-mf">3</span><span class="tok-p">)</span><span class="tok-w"> </span><i class="conum" data-value="2"></i><b>(2)</b>
<span class="tok-w"> </span><span class="tok-p">],</span>
<span class="tok-w"> </span><span class="tok-p">},</span>
<span class="tok-w"> </span><span class="tok-p">],</span>
<span class="tok-p">}</span></code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" data-value="1"></i><b>1</b></td>
<td>We can include a path to the font file to embed it directly in the SVG.</td>
</tr>
<tr>
<td><i class="conum" data-value="2"></i><b>2</b></td>
<td>We can use list comprehensions…​</td>
</tr>
<tr>
<td><i class="conum" data-value="3"></i><b>3</b></td>
<td>And use the variable in conditional statements…​</td>
</tr>
<tr>
<td><i class="conum" data-value="4"></i><b>4</b></td>
<td>And as a list index (0-indexed).</td>
</tr>
</table>
</div>
</div>
</div>
</div>
</div>
<div id="footnotes">
<hr>
<div class="footnote" id="_footnotedef_1">
<a href="#_footnoteref_1">1</a>. Technically base64 encoding data does increase its size by about a third. However, you don’t need to pay this cost when transmitting the file; you can transmit the raw components and then use Collagen to encode them into an SVG on the receiving end. In other words, Collagen is akin to compression such as gunzip: it allows a smaller payload to be transmitted as long as the receiving end can turn it back into something useful.
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