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A place to cache linked articles (think custom and personal wayback machine)
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  12. <title>Representing SHA-256 Hashes As Avatars (archive) — David Larlet</title>

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  61. <article>

  62.   <header>

  63.     <h1>Representing SHA-256 Hashes As Avatars</h1>

  64.   </header>

  65.   <nav>

  66.     <p class="center">

  67.       <a href="/david/" title="Aller à l’accueil"><svg class="icon icon-home">

  68.         <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-home"></use>

  69.       </svg> Accueil</a> •

  70.       <a href="https://francoisbest.com/posts/2021/hashvatars" title="Lien vers le contenu original">Source originale</a>

  71.     </p>

  72.   </nav>

  73.   <hr>

  74.   <p class="chakra-text css-8fkoyy">If you <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://twitter.com/fortysevenfx">follow me on Twitter</a>, you may be aware

  75. of my weird <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://twitter.com/search?q=%40fortysevenfx%20%22weekend%20project%22">weekend projects</a>.</p>

  76. <p class="chakra-text css-8fkoyy">They are little challenges I give myself, usually without too many stakes

  77. involved, and with small enough a scope so that I can ship it in a day or two,

  78. while keeping spare family time.</p>

  79. <p class="chakra-text css-8fkoyy">This weekend's project is to build a transaction explorer for the <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://centralized-coin.com">Centralized Coin</a>

  80. experiment. Something like a blockchain explorer, but without the crypto overhead.</p>

  81. <p class="chakra-text css-8fkoyy">Each node in the system is represented by a hash. Because humans are

  82. terrible at reading and quickly identifying large numbers (other than by their

  83. first or last few digits), a visual representation is needed.</p>

  84. <p class="chakra-text css-8fkoyy">There are <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://barro.github.io/2018/02/avatars-identicons-and-hash-visualization/">many solutions</a>

  85. out there: WordPress and GitHub identicons, <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://robohash.org/">robohash</a>, monsterID etc..</p>

  86. <p class="chakra-text css-8fkoyy">I wanted one that still looks abstract (not as opinionated as monsters or robots),

  87. and that plays nice in a rounded avatar UI component.</p>

  88. <p class="chakra-text css-8fkoyy">This is what I ended up with:<br><small class="chakra-text css-1lrujbg">Change the input below to see how the SHA-256 hash changes the render</small></p>

  89. <p class="chakra-text css-8fkoyy">If you are allergic to maths and trigonometry, feel free to play with the more

  90. detailed <a class="chakra-link css-y3jojq" href="/hashvatar">interactive example here</a>. Otherwise, let's dive into

  91. how it's done.</p>

  92. <h2 class="chakra-heading css-1rjvsw4" id="space-partitioning">Space Partitioning<a class="chakra-link css-jchjfc" aria-label="anchor" href="#space-partitioning">#</a></h2>

  93. <p class="chakra-text css-8fkoyy">Many of the existing solutions produce square images, yet avatars are often

  94. displayed as circles. They would lose information on the corners when rounded,

  95. so instead of a cartesian (x-y) approach, we're going to use polar (angle-radius)

  96. coordinates instead.</p>

  97. <p class="chakra-text css-8fkoyy">A grid in cartesian space maps to concentric circles and pie-like cuts in

  98. polar space.</p>

  99. <p class="chakra-text css-8fkoyy">SHA-256 hashes have 256 bits of information that we need to represent. Dividing

  100. a circle into 256 sections would make each section too small to be visually useful,

  101. and would only leave 1 bit of "value" to represent in each section

  102. (0 or 1, black or white).</p>

  103. <p class="chakra-text css-8fkoyy">Instead, we're going to divide the circle into 32 sections:</p>

  104. <ul role="list" class="css-80rt2u"><li class="css-77vupy">4 concentric rings</li><li class="css-77vupy">8 pie-like cuts</li></ul>

  105. <p class="chakra-text css-8fkoyy">The resulting SVG code for such a grid looks like this (in a React component):</p>

  106. <pre class="language-tsx"><code class="language-tsx"><span class="token keyword">export</span> <span class="token keyword">const</span> <span class="token function-variable function"><span class="token maybe-class-name">SHA256Avatar</span></span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token arrow operator">=&gt;</span> <span class="token punctuation">{</span>

  107. 

  108.   <span class="token keyword">const</span> r1 <span class="token operator">=</span> <span class="token number">1</span>

  109.   <span class="token keyword">const</span> r2 <span class="token operator">=</span> r1 <span class="token operator">*</span> <span class="token number">0.75</span>

  110.   <span class="token keyword">const</span> r3 <span class="token operator">=</span> r1 <span class="token operator">*</span> <span class="token number">0.5</span>

  111.   <span class="token keyword">const</span> r4 <span class="token operator">=</span> r1 <span class="token operator">*</span> <span class="token number">0.25</span>

  112.   <span class="token keyword">return</span> <span class="token punctuation">(</span>

  113.     <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>svg</span> <span class="token attr-name">viewBox</span><span class="token attr-value"><span class="token punctuation">=</span><span class="token punctuation">"</span>-1 -1 2 2<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span><span class="token plain-text">

  114.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>circle</span> <span class="token attr-name">cx</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">cy</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">r</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1<span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  115.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>circle</span> <span class="token attr-name">cx</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">cy</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">r</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r2<span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  116.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>circle</span> <span class="token attr-name">cx</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">cy</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">r</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r3<span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  117.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>circle</span> <span class="token attr-name">cx</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">cy</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">r</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r4<span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  118.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>line</span> <span class="token attr-name">x1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token operator">-</span>r1<span class="token punctuation">}</span></span> <span class="token attr-name">x2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1<span class="token punctuation">}</span></span> <span class="token attr-name">y1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">y2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  119.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>line</span> <span class="token attr-name">y1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token operator">-</span>r1<span class="token punctuation">}</span></span> <span class="token attr-name">y2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1<span class="token punctuation">}</span></span> <span class="token attr-name">x1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token attr-name">x2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token number">0</span><span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  120.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>line</span>

  121.         <span class="token attr-name">x1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token operator">-</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  122.         <span class="token attr-name">x2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  123.         <span class="token attr-name">y1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token operator">-</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  124.         <span class="token attr-name">y2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  125.       <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  126.       </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>line</span>

  127.         <span class="token attr-name">x1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  128.         <span class="token attr-name">x2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token operator">-</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  129.         <span class="token attr-name">y1</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span><span class="token operator">-</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  130.         <span class="token attr-name">y2</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>r1 <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">SQRT1_2</span><span class="token punctuation">}</span></span>

  131.       <span class="token punctuation">/&gt;</span></span><span class="token plain-text">

  132.     </span><span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>svg</span><span class="token punctuation">&gt;</span></span>

  133.   <span class="token punctuation">)</span>

  134. <span class="token punctuation">}</span>

  135. </code></pre>

  136. <p class="chakra-text css-8fkoyy">Doing this naively, with each concentric ring's radius being 1/4th of the

  137. outermost/largest one gives us this:</p>

  138. <p><svg xmlns="http://www.w3.org/2000/svg" role="img" viewbox="-1 -1 2 2" class="css-q1xci"><g><path d="M 0 0 L 6.123233995736766e-17 -1 A 1 1 0 0 1 0.7071067811865476 -0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 -0.7071067811865475 A 1 1 0 0 1 1 0 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 1 0 A 1 1 0 0 1 0.7071067811865476 0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 0.7071067811865475 A 1 1 0 0 1 6.123233995736766e-17 1 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 6.123233995736766e-17 1 A 1 1 0 0 1 -0.7071067811865475 0.7071067811865476 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865475 0.7071067811865476 A 1 1 0 0 1 -1 1.2246467991473532e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1 1.2246467991473532e-16 A 1 1 0 0 1 -0.7071067811865477 -0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865477 -0.7071067811865475 A 1 1 0 0 1 -1.8369701987210297e-16 -1 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1.3777276490407724e-16 -0.75 A 0.75 0.75 0 0 1 0.5303300858899105 -0.5303300858899107 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5303300858899105 -0.5303300858899107 A 0.75 0.75 0 0 1 0.75 -1.8369701987210297e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.75 -1.8369701987210297e-16 A 0.75 0.75 0 0 1 0.5303300858899113 0.53033008588991 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5303300858899113 0.53033008588991 A 0.75 0.75 0 0 1 2.2962127484012875e-16 0.75 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 2.2962127484012875e-16 0.75 A 0.75 0.75 0 0 1 -0.5303300858899109 0.5303300858899104 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5303300858899109 0.5303300858899104 A 0.75 0.75 0 0 1 -0.75 2.755455298081545e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.75 2.755455298081545e-16 A 0.75 0.75 0 0 1 -0.5303300858899114 -0.5303300858899099 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5303300858899114 -0.5303300858899099 A 0.75 0.75 0 0 1 -3.214697847761802e-16 -0.75 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -2.143131898507868e-16 -0.5 A 0.5 0.5 0 0 1 0.3535533905932739 -0.3535533905932736 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.3535533905932739 -0.3535533905932736 A 0.5 0.5 0 0 1 0.5 -2.4492935982947064e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5 -2.4492935982947064e-16 A 0.5 0.5 0 0 1 0.3535533905932743 0.3535533905932733 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.3535533905932743 0.3535533905932733 A 0.5 0.5 0 0 1 2.755455298081545e-16 0.5 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 2.755455298081545e-16 0.5 A 0.5 0.5 0 0 1 -0.35355339059327384 0.3535533905932737 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.35355339059327384 0.3535533905932737 A 0.5 0.5 0 0 1 -0.5 1.1943401194869635e-15 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5 1.1943401194869635e-15 A 0.5 0.5 0 0 1 -0.3535533905932737 -0.35355339059327384 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.3535533905932737 -0.35355339059327384 A 0.5 0.5 0 0 1 -1.2249562894656473e-15 -0.5 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -6.124781447328236e-16 -0.25 A 0.25 0.25 0 0 1 0.17677669529663723 -0.17677669529663653 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.17677669529663723 -0.17677669529663653 A 0.25 0.25 0 0 1 0.25 -1.8369701987210297e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.25 -1.8369701987210297e-16 A 0.25 0.25 0 0 1 0.17677669529663748 0.17677669529663628 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.17677669529663748 0.17677669529663628 A 0.25 0.25 0 0 1 -2.450841049886177e-16 0.25 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -2.450841049886177e-16 0.25 A 0.25 0.25 0 0 1 -0.1767766952966366 0.1767766952966372 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.1767766952966366 0.1767766952966372 A 0.25 0.25 0 0 1 -0.25 1.1024916095509121e-15 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.25 1.1024916095509121e-15 A 0.25 0.25 0 0 1 -0.1767766952966369 -0.1767766952966369 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.1767766952966369 -0.1767766952966369 A 0.25 0.25 0 0 1 -6.737104846901913e-16 -0.25 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path></g></svg>

  139. <p class="chakra-text css-8fkoyy">There are some issues: the innermost ring sections are tiny compared to the outermost.</p></p>

  140. <p class="chakra-text css-8fkoyy">If we calculate the radii so that each section has an equal area, we get

  141. the following result:</p>

  142. <p><svg xmlns="http://www.w3.org/2000/svg" role="img" viewbox="-1 -1 2 2" class="css-q1xci"><g><path d="M 0 0 L 6.123233995736766e-17 -1 A 1 1 0 0 1 0.7071067811865476 -0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 -0.7071067811865475 A 1 1 0 0 1 1 0 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 1 0 A 1 1 0 0 1 0.7071067811865476 0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 0.7071067811865475 A 1 1 0 0 1 6.123233995736766e-17 1 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 6.123233995736766e-17 1 A 1 1 0 0 1 -0.7071067811865475 0.7071067811865476 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865475 0.7071067811865476 A 1 1 0 0 1 -1 1.2246467991473532e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1 1.2246467991473532e-16 A 1 1 0 0 1 -0.7071067811865477 -0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865477 -0.7071067811865475 A 1 1 0 0 1 -1.8369701987210297e-16 -1 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1.5908628580873602e-16 -0.8660254037844386 A 0.8660254037844386 0.8660254037844386 0 0 1 0.6123724356957944 -0.6123724356957946 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.6123724356957944 -0.6123724356957946 A 0.8660254037844386 0.8660254037844386 0 0 1 0.8660254037844386 -2.1211504774498136e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.8660254037844386 -2.1211504774498136e-16 A 0.8660254037844386 0.8660254037844386 0 0 1 0.6123724356957952 0.6123724356957938 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.6123724356957952 0.6123724356957938 A 0.8660254037844386 0.8660254037844386 0 0 1 2.6514380968122674e-16 0.8660254037844386 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 2.6514380968122674e-16 0.8660254037844386 A 0.8660254037844386 0.8660254037844386 0 0 1 -0.6123724356957948 0.6123724356957941 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.6123724356957948 0.6123724356957941 A 0.8660254037844386 0.8660254037844386 0 0 1 -0.8660254037844386 3.1817257161747205e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.8660254037844386 3.1817257161747205e-16 A 0.8660254037844386 0.8660254037844386 0 0 1 -0.6123724356957952 -0.6123724356957937 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.6123724356957952 -0.6123724356957937 A 0.8660254037844386 0.8660254037844386 0 0 1 -3.7120133355371736e-16 -0.8660254037844386 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -3.030846196824227e-16 -0.7071067811865476 A 0.7071067811865476 0.7071067811865476 0 0 1 0.5000000000000002 -0.49999999999999983 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5000000000000002 -0.49999999999999983 A 0.7071067811865476 0.7071067811865476 0 0 1 0.7071067811865476 -3.4638242249419736e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 -3.4638242249419736e-16 A 0.7071067811865476 0.7071067811865476 0 0 1 0.5000000000000008 0.4999999999999994 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5000000000000008 0.4999999999999994 A 0.7071067811865476 0.7071067811865476 0 0 1 3.8968022530597204e-16 0.7071067811865476 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 3.8968022530597204e-16 0.7071067811865476 A 0.7071067811865476 0.7071067811865476 0 0 1 -0.5000000000000001 0.4999999999999999 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5000000000000001 0.4999999999999999 A 0.7071067811865476 0.7071067811865476 0 0 1 -0.7071067811865476 1.6890519950647668e-15 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865476 1.6890519950647668e-15 A 0.7071067811865476 0.7071067811865476 0 0 1 -0.4999999999999999 -0.5000000000000001 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.4999999999999999 -0.5000000000000001 A 0.7071067811865476 0.7071067811865476 0 0 1 -1.7323497978765413e-15 -0.7071067811865476 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1.2249562894656473e-15 -0.5 A 0.5 0.5 0 0 1 0.35355339059327445 -0.35355339059327306 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.35355339059327445 -0.35355339059327306 A 0.5 0.5 0 0 1 0.5 -3.6739403974420594e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5 -3.6739403974420594e-16 A 0.5 0.5 0 0 1 0.35355339059327495 0.35355339059327257 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.35355339059327495 0.35355339059327257 A 0.5 0.5 0 0 1 -4.901682099772354e-16 0.5 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -4.901682099772354e-16 0.5 A 0.5 0.5 0 0 1 -0.3535533905932732 0.3535533905932744 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.3535533905932732 0.3535533905932744 A 0.5 0.5 0 0 1 -0.5 2.2049832191018243e-15 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5 2.2049832191018243e-15 A 0.5 0.5 0 0 1 -0.3535533905932738 -0.3535533905932738 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.3535533905932738 -0.3535533905932738 A 0.5 0.5 0 0 1 -1.3474209693803826e-15 -0.5 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path></g></svg></p>

  143. <div role="alert" class="chakra-alert css-7l7mra"><div class="chakra-alert__desc css-12db8z9"><p>Equal areas are calculated by solving a system of equations.</p><ol role="list" class="css-138fnjp"><li class="css-77vupy">Each section area is 1/32nd of the area of the whole circle. Assuming the outer circle has a radius of 1, that's an area of <code>π/32</code>.</li><li class="css-77vupy">To compute the associated radius for a ring, we express the pie slice area with the outer radius R and subtract the pie slice area with the inner radius r: <code>Pi R^2 - Pi r^2</code>, then we iterate from the outside in.</li></ol><a target="_blank" rel="noopener noreferrer" class="chakra-link css-zqkdi0" href="https://www.desmos.com/calculator/cenpmgvqdy">More details</a></div></div>

  144. <p class="chakra-text css-8fkoyy">Not very pleasing either. How about a mix of both ?<br><small class="chakra-text css-0">(Play with the slider to blend between equal radii and equal areas)</small></p>

  145. <p class="chakra-text css-8fkoyy">I don't know about you, but <code class="chakra-code css-1uwjdr8">0.42</code> hits the ballpark both in aesthetics and

  146. <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://xkcd.com/356/">nerd-sniping satisfaction</a>, so let's go for that.</p>

  147. <h2 class="chakra-heading css-1rjvsw4" id="section-mapping">Section Mapping<a class="chakra-link css-jchjfc" aria-label="anchor" href="#section-mapping">#</a></h2>

  148. <p class="chakra-text css-8fkoyy">Now that we have 32 nice looking sections on our circle, we can map each section

  149. to an 8-bit value in the hash.</p>

  150. <p class="chakra-text css-8fkoyy">As an example, let's take the following hash, the output of <code class="chakra-code css-1uwjdr8">sha256("Hello, world!")</code>:</p>

  151. <pre><code>315f5bdb76d078c43b8ac0064e4a0164612b1fce77c869345bfc94c75894edd3

  152. </code></pre>

  153. <p class="chakra-text css-8fkoyy">We can split it in 32 blocks of 8 bits (2 hexadecimal digits), and organise them by

  154. 4 blocks of 8 to map to the rings:</p>

  155. <pre><code>12 o'clock -&gt; clockwise

  156. 31 5f 5b db 76 d0 78 c4  Outer ring

  157. 3b 8a c0 06 4e 4a 01 64  Middle-outer ring

  158. 61 2b 1f ce 77 c8 69 34  Middle-inner ring

  159. 5b fc 94 c7 58 94 ed d3  Inner ring

  160. </code></pre>

  161. <p><svg xmlns="http://www.w3.org/2000/svg" role="img" viewbox="-1 -1 2 2" class="css-q1xci"><g><path d="M 0 0 L 6.123233995736766e-17 -1 A 1 1 0 0 1 0.7071067811865476 -0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 -0.7071067811865475 A 1 1 0 0 1 1 0 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 1 0 A 1 1 0 0 1 0.7071067811865476 0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 0.7071067811865475 A 1 1 0 0 1 6.123233995736766e-17 1 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 6.123233995736766e-17 1 A 1 1 0 0 1 -0.7071067811865475 0.7071067811865476 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865475 0.7071067811865476 A 1 1 0 0 1 -1 1.2246467991473532e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1 1.2246467991473532e-16 A 1 1 0 0 1 -0.7071067811865477 -0.7071067811865475 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865477 -0.7071067811865475 A 1 1 0 0 1 -1.8369701987210297e-16 -1 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1.4672444368403393e-16 -0.7987306695894643 A 0.7987306695894643 0.7987306695894643 0 0 1 0.5647878728083817 -0.564787872808382 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5647878728083817 -0.564787872808382 A 0.7987306695894643 0.7987306695894643 0 0 1 0.7987306695894643 -1.9563259157871192e-16 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7987306695894643 -1.9563259157871192e-16 A 0.7987306695894643 0.7987306695894643 0 0 1 0.5647878728083826 0.5647878728083813 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5647878728083826 0.5647878728083813 A 0.7987306695894643 0.7987306695894643 0 0 1 2.4454073947338993e-16 0.7987306695894643 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 2.4454073947338993e-16 0.7987306695894643 A 0.7987306695894643 0.7987306695894643 0 0 1 -0.5647878728083822 0.5647878728083816 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5647878728083822 0.5647878728083816 A 0.7987306695894643 0.7987306695894643 0 0 1 -0.7987306695894643 2.9344888736806786e-16 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stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5869848480983499 -2.8753964614865583e-16 A 0.5869848480983499 0.5869848480983499 0 0 1 0.4150609665440994 0.4150609665440982 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.4150609665440994 0.4150609665440982 A 0.5869848480983499 0.5869848480983499 0 0 1 3.2348210191723783e-16 0.5869848480983499 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 3.2348210191723783e-16 0.5869848480983499 A 0.5869848480983499 0.5869848480983499 0 0 1 -0.41506096654409885 0.4150609665440987 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.41506096654409885 0.4150609665440987 A 0.5869848480983499 0.5869848480983499 0 0 1 -0.5869848480983499 1.4021191072296408e-15 Z" fill="none" 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d="M 0 0 L 0.355 -2.608497682183862e-16 A 0.355 0.355 0 0 1 0.25102290732122523 0.2510229073212235 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.25102290732122523 0.2510229073212235 A 0.355 0.355 0 0 1 -3.4801942908383715e-16 0.355 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -3.4801942908383715e-16 0.355 A 0.355 0.355 0 0 1 -0.25102290732122395 0.2510229073212248 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.25102290732122395 0.2510229073212248 A 0.355 0.355 0 0 1 -0.355 1.565538085562295e-15 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.355 1.565538085562295e-15 A 0.355 0.355 0 0 1 -0.2510229073212244 -0.2510229073212244 Z" fill="none" stroke="var(--colors-accent-500)" stroke-width="0.02" 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text-anchor="middle" font-size="0.1" fill="currentColor">01</text><text x="-0.26514518529517056" y="-0.6101171023375265" text-anchor="middle" font-size="0.1" fill="currentColor">64</text><text x="0.18024099745309213" y="-0.40514026054690944" text-anchor="middle" font-size="0.1" fill="currentColor">61</text><text x="0.43514026054690935" y="-0.15024099745309252" text-anchor="middle" font-size="0.1" fill="currentColor">2b</text><text x="0.43514026054690946" y="0.2102409974530921" text-anchor="middle" font-size="0.1" fill="currentColor">1f</text><text x="0.18024099745309255" y="0.4651402605469094" text-anchor="middle" font-size="0.1" fill="currentColor">ce</text><text x="-0.1802409974530913" y="0.4651402605469098" text-anchor="middle" font-size="0.1" fill="currentColor">77</text><text x="-0.43514026054690935" y="0.21024099745309258" text-anchor="middle" font-size="0.1" fill="currentColor">c8</text><text x="-0.43514026054690924" y="-0.1502409974530928" text-anchor="middle" font-size="0.1" fill="currentColor">69</text><text x="-0.1802409974530926" y="-0.4051402605469093" text-anchor="middle" font-size="0.1" fill="currentColor">34</text><text x="0.08966272820313972" y="-0.18646497446739482" text-anchor="middle" font-size="0.1" fill="currentColor">5b</text><text x="0.21646497446739454" y="-0.059662728203140405" text-anchor="middle" font-size="0.1" fill="currentColor">fc</text><text x="0.21646497446739468" y="0.11966272820314008" text-anchor="middle" font-size="0.1" fill="currentColor">94</text><text x="0.08966272820314003" y="0.2464649744673947" text-anchor="middle" font-size="0.1" fill="currentColor">c7</text><text x="-0.08966272820314046" y="0.24646497446739454" text-anchor="middle" font-size="0.1" fill="currentColor">58</text><text x="-0.21646497446739424" y="0.11966272820314121" text-anchor="middle" font-size="0.1" fill="currentColor">94</text><text x="-0.21646497446739438" y="-0.05966272820314082" text-anchor="middle" font-size="0.1" fill="currentColor">ed</text><text x="-0.08966272820314082" y="-0.18646497446739438" text-anchor="middle" font-size="0.1" fill="currentColor">d3</text></g></svg>

  162. <p class="chakra-text css-8fkoyy">In order to fill each section with a different colour, we generate an SVG <code class="chakra-code css-1uwjdr8">&lt;path&gt;</code> polygon.

  163. Each section resembles a pie/pizza slice, going from the center

  164. of the circle to a given radius, and covering 1/8th of the circle.</p></p>

  165. <div role="alert" class="chakra-alert css-xjse24"><p class="chakra-alert__desc css-12db8z9">The reason we can get away with all sections going to the center is because of our mapping order: by laying out from the outside in, the inner sections will be overlaid on top of the outer ones in z-index.</p></div>

  166. <p class="chakra-text css-8fkoyy">Since SVG uses cartesian coordinates, we'll have to convert our polar logic

  167. into cartesian SVG path commands:</p>

  168. <pre class="language-tsx"><code class="language-tsx{31,32,33,34,35,36}"><span class="token keyword">interface</span> <span class="token class-name">Point</span> <span class="token punctuation">{</span>

  169.   x<span class="token punctuation">:</span> <span class="token builtin">number</span>

  170.   y<span class="token punctuation">:</span> <span class="token builtin">number</span>

  171. <span class="token punctuation">}</span>

  172. 

  173. <span class="token keyword">function</span> <span class="token function">polarPoint</span><span class="token punctuation">(</span><span class="token parameter">radius<span class="token punctuation">:</span> <span class="token builtin">number</span><span class="token punctuation">,</span> angle<span class="token punctuation">:</span> <span class="token builtin">number</span></span><span class="token punctuation">)</span><span class="token punctuation">:</span> <span class="token maybe-class-name">Point</span> <span class="token punctuation">{</span>

  174. 

  175. 

  176. 

  177.   <span class="token keyword">return</span> <span class="token punctuation">{</span>

  178.     x<span class="token punctuation">:</span> radius <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token method function property-access">cos</span><span class="token punctuation">(</span><span class="token number">2</span> <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">PI</span> <span class="token operator">*</span> angle <span class="token operator">-</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">PI</span> <span class="token operator">/</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">,</span>

  179.     y<span class="token punctuation">:</span> radius <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token method function property-access">sin</span><span class="token punctuation">(</span><span class="token number">2</span> <span class="token operator">*</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">PI</span> <span class="token operator">*</span> angle <span class="token operator">-</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token constant">PI</span> <span class="token operator">/</span> <span class="token number">2</span><span class="token punctuation">)</span>

  180.   <span class="token punctuation">}</span>

  181. <span class="token punctuation">}</span>

  182. 

  183. <span class="token keyword">function</span> <span class="token function">moveTo</span><span class="token punctuation">(</span><span class="token parameter"><span class="token punctuation">{</span> x<span class="token punctuation">,</span> y <span class="token punctuation">}</span><span class="token punctuation">:</span> <span class="token maybe-class-name">Point</span></span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

  184.   <span class="token keyword">return</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">M </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>x<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>y<span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span>

  185. <span class="token punctuation">}</span>

  186. 

  187. <span class="token keyword">function</span> <span class="token function">lineTo</span><span class="token punctuation">(</span><span class="token parameter"><span class="token punctuation">{</span> x<span class="token punctuation">,</span> y <span class="token punctuation">}</span><span class="token punctuation">:</span> <span class="token maybe-class-name">Point</span></span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

  188.   <span class="token keyword">return</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">L </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>x<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>y<span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span>

  189. <span class="token punctuation">}</span>

  190. 

  191. <span class="token keyword">function</span> <span class="token function">arcTo</span><span class="token punctuation">(</span><span class="token parameter"><span class="token punctuation">{</span> x<span class="token punctuation">,</span> y <span class="token punctuation">}</span><span class="token punctuation">:</span> <span class="token maybe-class-name">Point</span><span class="token punctuation">,</span> radius<span class="token punctuation">:</span> <span class="token builtin">number</span></span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

  192.   <span class="token keyword">return</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">A </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>radius<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>radius<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> 0 0 0 </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>x<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string"> </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>y<span class="token interpolation-punctuation punctuation">}</span></span><span class="token template-punctuation string">`</span></span>

  193. <span class="token punctuation">}</span>

  194. 

  195. <span class="token keyword">const</span> <span class="token function-variable function"><span class="token maybe-class-name">Section</span></span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token parameter"><span class="token punctuation">{</span> index<span class="token punctuation">,</span> radius <span class="token punctuation">}</span></span><span class="token punctuation">)</span> <span class="token arrow operator">=&gt;</span> <span class="token punctuation">{</span>

  196.   <span class="token keyword">const</span> angleA <span class="token operator">=</span> index <span class="token operator">/</span> <span class="token number">8</span>

  197.   <span class="token keyword">const</span> angleB <span class="token operator">=</span> <span class="token punctuation">(</span>index <span class="token operator">+</span> <span class="token number">1</span><span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">8</span>

  198. <p class="mdx-marker">  <span class="token keyword">const</span> path <span class="token operator">=</span> <span class="token punctuation">[</span>

  199. </p><p class="mdx-marker">    <span class="token function">moveTo</span><span class="token punctuation">(</span><span class="token punctuation">{</span> x<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span> y<span class="token punctuation">:</span> <span class="token number">0</span> <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">,</span>

  200. </p><p class="mdx-marker">    <span class="token function">lineTo</span><span class="token punctuation">(</span><span class="token function">polarPoint</span><span class="token punctuation">(</span>radius<span class="token punctuation">,</span> angleA<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>

  201. </p><p class="mdx-marker">    <span class="token function">arcTo</span><span class="token punctuation">(</span><span class="token function">polarPoint</span><span class="token punctuation">(</span>radius<span class="token punctuation">,</span> angleB<span class="token punctuation">)</span><span class="token punctuation">,</span> radius<span class="token punctuation">)</span><span class="token punctuation">,</span>

  202. </p><p class="mdx-marker">    <span class="token string">'Z'</span> 

  203. </p><p class="mdx-marker">  <span class="token punctuation">]</span><span class="token punctuation">.</span><span class="token method function property-access">join</span><span class="token punctuation">(</span><span class="token string">' '</span><span class="token punctuation">)</span>

  204. </p>  <span class="token keyword">return</span> <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>path</span> <span class="token attr-name">d</span><span class="token script language-javascript"><span class="token script-punctuation punctuation">=</span><span class="token punctuation">{</span>path<span class="token punctuation">}</span></span> <span class="token punctuation">/&gt;</span></span>

  205. <span class="token punctuation">}</span>

  206. </code></pre>

  207. <h2 class="chakra-heading css-1rjvsw4" id="colour-mapping">Colour Mapping<a class="chakra-link css-jchjfc" aria-label="anchor" href="#colour-mapping">#</a></h2>

  208. <p class="chakra-text css-8fkoyy">Now we can turn each section's byte value into a colour.</p>

  209. <p class="chakra-text css-8fkoyy">For that, we have many options. 8 bits could map directly to 256 colours like the

  210. old Windows systems, but that would require a lookup table. Instead, we can

  211. generate colours using the <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/hsl()"><code class="chakra-code css-1uwjdr8">hsl()</code></a> CSS function.</p>

  212. <p class="chakra-text css-8fkoyy">Hue is the component that has the most visual impact, while Saturation and

  213. Lightness can be used to add little variants to each section.</p>

  214. <p class="chakra-text css-8fkoyy">To map our 8 bit value to 3 components, we can divide the byte into:</p>

  215. <ul role="list" class="css-80rt2u"><li class="css-77vupy">4 bits for the Hue (16 values)</li><li class="css-77vupy">2 bits for the Saturation (4 values)</li><li class="css-77vupy">2 bits for the Lightness (4 values)</li></ul>

  216. <pre class="language-ts"><code class="language-ts"><span class="token keyword">function</span> <span class="token function">mapValueToColor</span><span class="token punctuation">(</span><span class="token parameter">value</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

  217.   <span class="token keyword">const</span> colorH <span class="token operator">=</span> value <span class="token operator">&gt;&gt;</span> <span class="token number">4</span>

  218.   <span class="token keyword">const</span> colorS <span class="token operator">=</span> <span class="token punctuation">(</span>value <span class="token operator">&gt;&gt;</span> <span class="token number">2</span><span class="token punctuation">)</span> <span class="token operator">&amp;</span> <span class="token number">0x03</span>

  219.   <span class="token keyword">const</span> colorL <span class="token operator">=</span> value <span class="token operator">&amp;</span> <span class="token number">0x03</span>

  220.   <span class="token keyword">const</span> normalizedH <span class="token operator">=</span> colorH <span class="token operator">/</span> <span class="token number">16</span>

  221.   <span class="token keyword">const</span> normalizedS <span class="token operator">=</span> colorS <span class="token operator">/</span> <span class="token number">4</span>

  222.   <span class="token keyword">const</span> normalizedL <span class="token operator">=</span> colorL <span class="token operator">/</span> <span class="token number">4</span>

  223.   <span class="token keyword">const</span> h <span class="token operator">=</span> <span class="token number">360</span> <span class="token operator">*</span> normalizedH

  224.   <span class="token keyword">const</span> s <span class="token operator">=</span> <span class="token number">50</span> <span class="token operator">+</span> <span class="token number">50</span> <span class="token operator">*</span> normalizedS 

  225.   <span class="token keyword">const</span> l <span class="token operator">=</span> <span class="token number">40</span> <span class="token operator">+</span> <span class="token number">30</span> <span class="token operator">*</span> normalizedL 

  226.   <span class="token keyword">return</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">hsl(</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>h<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">, </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>s<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">%, </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>l<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">%)</span><span class="token template-punctuation string">`</span></span>

  227. <span class="token punctuation">}</span>

  228. </code></pre>

  229. <p class="chakra-text css-8fkoyy">We can adjust the range for each component to get nice results:</p>

  230. <p><svg xmlns="http://www.w3.org/2000/svg" role="img" viewbox="-1 -1 2 2" class="css-q1xci"><g><path d="M 0 0 L 6.123233995736766e-17 -1 A 1 1 0 0 1 0.7071067811865476 -0.7071067811865475 Z" fill="hsl(67.5, 50%, 47.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 -0.7071067811865475 A 1 1 0 0 1 1 0 Z" fill="hsl(112.5, 87.5%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 1 0 A 1 1 0 0 1 0.7071067811865476 0.7071067811865475 Z" fill="hsl(112.5, 75%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7071067811865476 0.7071067811865475 A 1 1 0 0 1 6.123233995736766e-17 1 Z" fill="hsl(292.5, 75%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 6.123233995736766e-17 1 A 1 1 0 0 1 -0.7071067811865475 0.7071067811865476 Z" fill="hsl(157.5, 62.5%, 55%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865475 0.7071067811865476 A 1 1 0 0 1 -1 1.2246467991473532e-16 Z" fill="hsl(292.5, 50%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1 1.2246467991473532e-16 A 1 1 0 0 1 -0.7071067811865477 -0.7071067811865475 Z" fill="hsl(157.5, 75%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7071067811865477 -0.7071067811865475 A 1 1 0 0 1 -1.8369701987210297e-16 -1 Z" fill="hsl(270, 62.5%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -1.4672444368403393e-16 -0.7987306695894643 A 0.7987306695894643 0.7987306695894643 0 0 1 0.5647878728083817 -0.564787872808382 Z" fill="hsl(67.5, 75%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5647878728083817 -0.564787872808382 A 0.7987306695894643 0.7987306695894643 0 0 1 0.7987306695894643 -1.9563259157871192e-16 Z" fill="hsl(180, 75%, 55%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.7987306695894643 -1.9563259157871192e-16 A 0.7987306695894643 0.7987306695894643 0 0 1 0.5647878728083826 0.5647878728083813 Z" fill="hsl(270, 50%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5647878728083826 0.5647878728083813 A 0.7987306695894643 0.7987306695894643 0 0 1 2.4454073947338993e-16 0.7987306695894643 Z" fill="hsl(0, 62.5%, 55%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 2.4454073947338993e-16 0.7987306695894643 A 0.7987306695894643 0.7987306695894643 0 0 1 -0.5647878728083822 0.5647878728083816 Z" fill="hsl(90, 87.5%, 55%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5647878728083822 0.5647878728083816 A 0.7987306695894643 0.7987306695894643 0 0 1 -0.7987306695894643 2.9344888736806786e-16 Z" fill="hsl(90, 75%, 55%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.7987306695894643 2.9344888736806786e-16 A 0.7987306695894643 0.7987306695894643 0 0 1 -0.5647878728083826 -0.5647878728083812 Z" fill="hsl(0, 50%, 47.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5647878728083826 -0.5647878728083812 A 0.7987306695894643 0.7987306695894643 0 0 1 -3.4235703526274585e-16 -0.7987306695894643 Z" fill="hsl(135, 62.5%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -2.5159719038007387e-16 -0.5869848480983499 A 0.5869848480983499 0.5869848480983499 0 0 1 0.4150609665440989 -0.4150609665440986 Z" fill="hsl(135, 50%, 47.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.4150609665440989 -0.4150609665440986 A 0.5869848480983499 0.5869848480983499 0 0 1 0.5869848480983499 -2.8753964614865583e-16 Z" fill="hsl(45, 75%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.5869848480983499 -2.8753964614865583e-16 A 0.5869848480983499 0.5869848480983499 0 0 1 0.4150609665440994 0.4150609665440982 Z" fill="hsl(22.5, 87.5%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.4150609665440994 0.4150609665440982 A 0.5869848480983499 0.5869848480983499 0 0 1 3.2348210191723783e-16 0.5869848480983499 Z" fill="hsl(270, 87.5%, 55%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 3.2348210191723783e-16 0.5869848480983499 A 0.5869848480983499 0.5869848480983499 0 0 1 -0.41506096654409885 0.4150609665440987 Z" fill="hsl(157.5, 62.5%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.41506096654409885 0.4150609665440987 A 0.5869848480983499 0.5869848480983499 0 0 1 -0.5869848480983499 1.4021191072296408e-15 Z" fill="hsl(270, 75%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.5869848480983499 1.4021191072296408e-15 A 0.5869848480983499 0.5869848480983499 0 0 1 -0.4150609665440987 -0.41506096654409885 Z" fill="hsl(135, 75%, 47.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.4150609665440987 -0.41506096654409885 A 0.5869848480983499 0.5869848480983499 0 0 1 -1.4380615629982227e-15 -0.5869848480983499 Z" fill="hsl(67.5, 62.5%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -8.697189655206095e-16 -0.355 A 0.355 0.355 0 0 1 0.25102290732122484 -0.25102290732122384 Z" fill="hsl(112.5, 75%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.25102290732122484 -0.25102290732122384 A 0.355 0.355 0 0 1 0.355 -2.608497682183862e-16 Z" fill="hsl(337.5, 87.5%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.355 -2.608497682183862e-16 A 0.355 0.355 0 0 1 0.25102290732122523 0.2510229073212235 Z" fill="hsl(202.5, 62.5%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L 0.25102290732122523 0.2510229073212235 A 0.355 0.355 0 0 1 -3.4801942908383715e-16 0.355 Z" fill="hsl(270, 62.5%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -3.4801942908383715e-16 0.355 A 0.355 0.355 0 0 1 -0.25102290732122395 0.2510229073212248 Z" fill="hsl(112.5, 75%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.25102290732122395 0.2510229073212248 A 0.355 0.355 0 0 1 -0.355 1.565538085562295e-15 Z" fill="hsl(202.5, 62.5%, 40%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.355 1.565538085562295e-15 A 0.355 0.355 0 0 1 -0.2510229073212244 -0.2510229073212244 Z" fill="hsl(315, 87.5%, 47.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path><path d="M 0 0 L -0.2510229073212244 -0.2510229073212244 A 0.355 0.355 0 0 1 -9.566688882600716e-16 -0.355 Z" fill="hsl(292.5, 50%, 62.5%)" stroke="white" stroke-width="0.02" stroke-linejoin="round"></path></g></svg></p>

  231. <div role="alert" class="chakra-alert css-7l7mra"><p class="chakra-alert__desc css-12db8z9">The colour mapping function could use a high-contrast version that focuses on the Luminosity channel rather than the Hue.</p></div>

  232. <h3 class="chakra-heading css-106yvz" id="order-chaos--soul">Order, Chaos &amp; Soul<a class="chakra-link css-jchjfc" aria-label="anchor" href="#order-chaos--soul">#</a></h3>

  233. <p class="chakra-text css-8fkoyy">Our colour encoding suffers from a flaw: two hashes can look very similar, but

  234. have a few bits of difference here and there. They can go unnoticed especially

  235. if differences occur in the LSBs of hue/saturation/lightness components.</p>

  236. <p class="chakra-text css-8fkoyy">Also, the sections look random in colour, and the whole avatar lacks coherence.</p>

  237. <p class="chakra-text css-8fkoyy">It would be nice if there was some pattern to a hash that makes it

  238. random enough to be distinguished yet coherent enough within itself.

  239. A balance between order and chaos.</p>

  240. <p class="chakra-text css-8fkoyy">In order to fix that, we compute the <strong class="chakra-text css-35ezg3">soul</strong> of the hash, using XOR operations.</p>

  241. <ol role="list" class="css-h1hn4m"><li class="css-77vupy">We XOR all the bytes of the hash together to compute the <strong class="chakra-text css-35ezg3">hash soul</strong></li><li class="css-77vupy">For each ring, we XOR the bytes that form this ring's section to compute the <strong class="chakra-text css-35ezg3">ring's soul</strong>. <em><a class="chakra-link css-y3jojq" href="/horcrux">(horcruxes?)</a></em></li></ol>

  242. <pre class="language-ts"><code class="language-ts">

  243. <span class="token keyword">function</span> <span class="token function">computeSouls</span><span class="token punctuation">(</span><span class="token parameter">bytes<span class="token punctuation">:</span> <span class="token builtin">string</span><span class="token punctuation">[</span><span class="token punctuation">]</span></span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

  244.   <span class="token keyword">const</span> ringLength <span class="token operator">=</span> <span class="token known-class-name class-name">Math</span><span class="token punctuation">.</span><span class="token method function property-access">round</span><span class="token punctuation">(</span>bytes<span class="token punctuation">.</span><span class="token property-access">length</span> <span class="token operator">/</span> <span class="token number">4</span><span class="token punctuation">)</span>

  245.   <span class="token keyword">const</span> rings <span class="token operator">=</span> <span class="token punctuation">[</span>

  246.     bytes<span class="token punctuation">.</span><span class="token method function property-access">slice</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> ringLength<span class="token punctuation">)</span><span class="token punctuation">,</span>

  247.     bytes<span class="token punctuation">.</span><span class="token method function property-access">slice</span><span class="token punctuation">(</span><span class="token number">1</span> <span class="token operator">*</span> ringLength<span class="token punctuation">,</span> <span class="token number">2</span> <span class="token operator">*</span> ringLength<span class="token punctuation">)</span><span class="token punctuation">,</span>

  248.     bytes<span class="token punctuation">.</span><span class="token method function property-access">slice</span><span class="token punctuation">(</span><span class="token number">2</span> <span class="token operator">*</span> ringLength<span class="token punctuation">,</span> <span class="token number">3</span> <span class="token operator">*</span> ringLength<span class="token punctuation">)</span><span class="token punctuation">,</span>

  249.     bytes<span class="token punctuation">.</span><span class="token method function property-access">slice</span><span class="token punctuation">(</span><span class="token number">3</span> <span class="token operator">*</span> ringLength<span class="token punctuation">,</span> <span class="token number">4</span> <span class="token operator">*</span> ringLength<span class="token punctuation">)</span>

  250.   <span class="token punctuation">]</span>

  251.   <span class="token keyword">const</span> <span class="token function-variable function">xorReducer</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token parameter">xor<span class="token punctuation">:</span> <span class="token builtin">number</span><span class="token punctuation">,</span> byte<span class="token punctuation">:</span> <span class="token builtin">string</span></span><span class="token punctuation">)</span> <span class="token arrow operator">=&gt;</span> xor <span class="token operator">^</span> <span class="token function">parseInt</span><span class="token punctuation">(</span>byte<span class="token punctuation">,</span> <span class="token number">16</span><span class="token punctuation">)</span>

  252.   <span class="token keyword">return</span> <span class="token punctuation">{</span>

  253.     hashSoul<span class="token punctuation">:</span> <span class="token punctuation">(</span>bytes<span class="token punctuation">.</span><span class="token method function property-access">reduce</span><span class="token punctuation">(</span>xorReducer<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">0xff</span><span class="token punctuation">)</span> <span class="token operator">*</span> <span class="token number">2</span> <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">,</span>

  254.     ringSouls<span class="token punctuation">:</span> rings<span class="token punctuation">.</span><span class="token method function property-access">map</span><span class="token punctuation">(</span><span class="token parameter">ring</span> <span class="token arrow operator">=&gt;</span> <span class="token punctuation">(</span>ring<span class="token punctuation">.</span><span class="token method function property-access">reduce</span><span class="token punctuation">(</span>xorReducer<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span> <span class="token operator">/</span> <span class="token number">0xff</span><span class="token punctuation">)</span> <span class="token operator">*</span> <span class="token number">2</span> <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">)</span>

  255.   <span class="token punctuation">}</span>

  256. <span class="token punctuation">}</span>

  257. 

  258. 

  259. 

  260. 

  261. 

  262. 

  263. 

  264. </code></pre>

  265. <p class="chakra-text css-8fkoyy">These values give us additional parameters to play with in the colour calculation.</p>

  266. <p class="chakra-text css-8fkoyy">Notably, we can <em>"seed"</em> the Hue with the hash soul, and introduce hue varitions

  267. per-ring with each ring soul, and with the value itself.</p>

  268. <pre class="language-ts"><code class="language-ts{8,9,10}"><span class="token keyword">export</span> <span class="token keyword">function</span> <span class="token function">mapValueToColor</span><span class="token punctuation">(</span><span class="token parameter"><span class="token punctuation">{</span> value<span class="token punctuation">,</span> hashSoul<span class="token punctuation">,</span> ringSoul <span class="token punctuation">}</span></span><span class="token punctuation">)</span> <span class="token punctuation">{</span>

  269.   <span class="token keyword">const</span> colorH <span class="token operator">=</span> value <span class="token operator">&gt;&gt;</span> <span class="token number">4</span>

  270.   <span class="token keyword">const</span> colorS <span class="token operator">=</span> <span class="token punctuation">(</span>value <span class="token operator">&gt;&gt;</span> <span class="token number">2</span><span class="token punctuation">)</span> <span class="token operator">&amp;</span> <span class="token number">0x03</span>

  271.   <span class="token keyword">const</span> colorL <span class="token operator">=</span> value <span class="token operator">&amp;</span> <span class="token number">0x03</span>

  272.   <span class="token keyword">const</span> normalizedH <span class="token operator">=</span> colorH <span class="token operator">/</span> <span class="token number">16</span>

  273.   <span class="token keyword">const</span> normalizedS <span class="token operator">=</span> colorS <span class="token operator">/</span> <span class="token number">4</span>

  274.   <span class="token keyword">const</span> normalizedL <span class="token operator">=</span> colorL <span class="token operator">/</span> <span class="token number">4</span>

  275. <p class="mdx-marker">  <span class="token keyword">const</span> h <span class="token operator">=</span> <span class="token number">360</span> <span class="token operator">*</span> hashSoul

  276. </p><p class="mdx-marker">          <span class="token operator">+</span> <span class="token number">120</span> <span class="token operator">*</span> ringSoul

  277. </p><p class="mdx-marker">          <span class="token operator">+</span>  <span class="token number">30</span> <span class="token operator">*</span> normalizedH

  278. </p>  <span class="token keyword">const</span> s <span class="token operator">=</span> <span class="token number">50</span> <span class="token operator">+</span> <span class="token number">50</span> <span class="token operator">*</span> normalizedS

  279.   <span class="token keyword">const</span> l <span class="token operator">=</span> <span class="token number">40</span> <span class="token operator">+</span> <span class="token number">30</span> <span class="token operator">*</span> normalizedL

  280.   <span class="token keyword">return</span> <span class="token template-string"><span class="token template-punctuation string">`</span><span class="token string">hsl(</span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>h<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">, </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>s<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">%, </span><span class="token interpolation"><span class="token interpolation-punctuation punctuation">${</span>l<span class="token interpolation-punctuation punctuation">}</span></span><span class="token string">%)</span><span class="token template-punctuation string">`</span></span>

  281. <span class="token punctuation">}</span>

  282. </code></pre>

  283. <p class="chakra-text css-8fkoyy">We can also introduce structural variations by changing each ring's starting

  284. angle based on the ring soul, to create a staggering effect:</p>

  285. <div class="css-8fkoyy"><div class="css-1u4m77"><p class="chakra-text css-1fz97de">Without souls</p><p class="chakra-text css-1fz97de">With souls</p><p class="chakra-text css-1fz97de">With souls &amp; staggering</p></div></div>

  286. <p class="chakra-text css-8fkoyy">Not only does this help give a bit more uniqueness to the avatar, it also helps

  287. with accessibility for colour-blind people</p>

  288. <h2 class="chakra-heading css-1rjvsw4" id="a-bit-of-fun">A Bit Of Fun<a class="chakra-link css-jchjfc" aria-label="anchor" href="#a-bit-of-fun">#</a></h2>

  289. <p class="chakra-text css-8fkoyy">If we change the radius and flags for the arc part of the section paths and

  290. play with each ring's starting angle, we can obtain interesting variations:</p>

  291. <h2 class="chakra-heading css-1rjvsw4" id="going-further">Going Further<a class="chakra-link css-jchjfc" aria-label="anchor" href="#going-further">#</a></h2>

  292. <p class="chakra-text css-8fkoyy">With a bit of tweaking in the colour mapping value, we can easily extend this

  293. technique to arbitrary hash lengths (as long as said length is divisible by 32).</p>

  294. <p class="chakra-text css-8fkoyy">It so happens that when I started this project, Centralized Coin was using SHA-256,

  295. but later on switched to SHA-384, which gives 12 bits per section.</p>

  296. <h2 class="chakra-heading css-1rjvsw4" id="conclusion">Conclusion<a class="chakra-link css-jchjfc" aria-label="anchor" href="#conclusion">#</a></h2>

  297. <p class="chakra-text css-8fkoyy">You can see the hashvatars <em>(thanks to <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://twitter.com/wzulfikar">@wzulfikar</a> for the name)</em>

  298. in action in the

  299. <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://centralized-coin-explorer.vercel.app">Centralized Coin Explorer</a>,

  300. or play with the variants yourself <a class="chakra-link css-y3jojq" href="/hashvatar">on the playground</a>.</p>

  301. <p class="chakra-text css-8fkoyy">I will publish the code as an NPM package later, in the mean time the source

  302. <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://github.com/franky47/francoisbest.com/blob/next/src/pages/posts/2021/hashvatars.mdx">code for this article</a>

  303. is on GitHub, as well as the

  304. <a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://github.com/franky47/francoisbest.com/blob/next/src/components/SHA256Avatar.tsx">component itself</a>.</p>

  305. <p class="chakra-text css-8fkoyy"><a target="_blank" rel="noopener noreferrer" class="chakra-link css-y3jojq" href="https://twitter.com/fortysevenfx">Follow me on Twitter</a> for updates and more weekend projects.</p>

  306. </article>

  307. 

  308. 

  309. <hr>

  310. 

  311. <footer>

  312.   <p>

  313.     <a href="/david/" title="Aller à l’accueil"><svg class="icon icon-home">

  314.         <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-home"></use>

  315.       </svg> Accueil</a> •

  316.     <a href="/david/log/" title="Accès au flux RSS"><svg class="icon icon-rss2">

  317.         <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-rss2"></use>

  318.       </svg> Suivre</a> •

  319.     <a href="http://larlet.com" title="Go to my English profile" data-instant><svg class="icon icon-user-tie">

  320.         <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-user-tie"></use>

  321.       </svg> Pro</a> •

  322.     <a href="mailto:david%40larlet.fr" title="Envoyer un courriel"><svg class="icon icon-mail">

  323.         <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-mail"></use>

  324.       </svg> Email</a> •

  325.     <abbr class="nowrap" title="Hébergeur : Alwaysdata, 62 rue Tiquetonne 75002 Paris, +33184162340"><svg class="icon icon-hammer2">

  326.         <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-hammer2"></use>

  327.       </svg> Légal</abbr>

  328.   </p>

  329.   <template id="theme-selector">

  330.       <form>

  331.           <fieldset>

  332.               <legend><svg class="icon icon-brightness-contrast">

  333.                 <use xlink:href="/static/david/icons2/symbol-defs.svg#icon-brightness-contrast"></use>

  334.               </svg> Thème</legend>

  335.               <label>

  336.                   <input type="radio" value="auto" name="chosen-color-scheme" checked> Auto

  337.               </label>

  338.               <label>

  339.                   <input type="radio" value="dark" name="chosen-color-scheme"> Foncé

  340.               </label>

  341.               <label>

  342.                   <input type="radio" value="light" name="chosen-color-scheme"> Clair

  343.               </label>

  344.           </fieldset>

  345.       </form>

  346.   </template>

  347. </footer>

  348. <script src="/static/david/js/instantpage-5.1.0.min.js" type="module"></script>

  349. <script>

  350.     function loadThemeForm(templateName) {

  351.         const themeSelectorTemplate = document.querySelector(templateName)

  352.         const form = themeSelectorTemplate.content.firstElementChild

  353.         themeSelectorTemplate.replaceWith(form)

  354. 

  355.         form.addEventListener('change', (e) => {

  356.             const chosenColorScheme = e.target.value

  357.             localStorage.setItem('theme', chosenColorScheme)

  358.             toggleTheme(chosenColorScheme)

  359.         })

  360. 

  361.         const selectedTheme = localStorage.getItem('theme')

  362.         if (selectedTheme && selectedTheme !== 'undefined') {

  363.             form.querySelector(`[value="${selectedTheme}"]`).checked = true

  364.         }

  365.     }

  366. 

  367.     const prefersColorSchemeDark = '(prefers-color-scheme: dark)'

  368.     window.addEventListener('load', () => {

  369.         let hasDarkRules = false

  370.         for (const styleSheet of Array.from(document.styleSheets)) {

  371.             let mediaRules = []

  372.             for (const cssRule of styleSheet.cssRules) {

  373.                 if (cssRule.type !== CSSRule.MEDIA_RULE) {

  374.                     continue

  375.                 }

  376.                 // WARNING: Safari does not have/supports `conditionText`.

  377.                 if (cssRule.conditionText) {

  378.                     if (cssRule.conditionText !== prefersColorSchemeDark) {

  379.                         continue

  380.                     }

  381.                 } else {

  382.                     if (cssRule.cssText.startsWith(prefersColorSchemeDark)) {

  383.                         continue

  384.                     }

  385.                 }

  386.                 mediaRules = mediaRules.concat(Array.from(cssRule.cssRules))

  387.             }

  388. 

  389.             // WARNING: do not try to insert a Rule to a styleSheet you are

  390.             // currently iterating on, otherwise the browser will be stuck

  391.             // in a infinite loop…

  392.             for (const mediaRule of mediaRules) {

  393.                 styleSheet.insertRule(mediaRule.cssText)

  394.                 hasDarkRules = true

  395.             }

  396.         }

  397.         if (hasDarkRules) {

  398.             loadThemeForm('#theme-selector')

  399.         }

  400.     })

  401. </script>

  402. </body>

  403. </html>