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    <title>DEV Community: spinwheelplus</title>
    <description>The latest articles on DEV Community by spinwheelplus (@spinwheelplus).</description>
    <link>https://dev.to/spinwheelplus</link>
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    <item>
      <title>How to Build a Spin Wheel with HTML, CSS, and JavaScript</title>
      <dc:creator>spinwheelplus</dc:creator>
      <pubDate>Thu, 13 Aug 2026 13:29:52 +0000</pubDate>
      <link>https://dev.to/spinwheelplus/how-to-build-a-spin-wheel-with-html-css-and-javascript-k12</link>
      <guid>https://dev.to/spinwheelplus/how-to-build-a-spin-wheel-with-html-css-and-javascript-k12</guid>
      <description>&lt;p&gt;A spin wheel is a simple but useful interactive component for random selection. You can use one to pick a name, choose a classroom activity, select a prize, make a decision, or add a game-like interaction to a website.&lt;/p&gt;

&lt;p&gt;In this tutorial, we'll build a simple &lt;strong&gt;spin wheel with HTML, CSS, and JavaScript&lt;/strong&gt; from scratch.&lt;/p&gt;

&lt;p&gt;The final version will:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Display a circular wheel with multiple options&lt;/li&gt;
&lt;li&gt;Draw the wheel using HTML Canvas&lt;/li&gt;
&lt;li&gt;Select a random winner&lt;/li&gt;
&lt;li&gt;Animate the wheel with JavaScript&lt;/li&gt;
&lt;li&gt;Slow the wheel down smoothly&lt;/li&gt;
&lt;li&gt;Display the selected result&lt;/li&gt;
&lt;li&gt;Work on desktop and mobile screens&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;The goal is not to build a production-ready wheel with every possible feature, but to understand the basic mechanics behind a JavaScript spin wheel.&lt;/p&gt;

&lt;p&gt;&lt;a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fsjf15s04zcvltskf247b.png" class="article-body-image-wrapper"&gt;&lt;img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fsjf15s04zcvltskf247b.png" alt=" " width="800" height="362"&gt;&lt;/a&gt;&lt;/p&gt;

&lt;h2&gt;
  
  
  What We're Building
&lt;/h2&gt;

&lt;p&gt;Our wheel will contain several options such as:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Pizza&lt;/li&gt;
&lt;li&gt;Burger&lt;/li&gt;
&lt;li&gt;Sushi&lt;/li&gt;
&lt;li&gt;Tacos&lt;/li&gt;
&lt;li&gt;Pasta&lt;/li&gt;
&lt;li&gt;Salad&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;When the user clicks &lt;strong&gt;Spin&lt;/strong&gt;, the wheel will rotate several times and gradually slow down until one segment reaches the pointer.&lt;/p&gt;

&lt;p&gt;The important part is that the random result is selected by JavaScript before the animation finishes. The animation then makes the wheel visually land on that result.&lt;/p&gt;

&lt;h2&gt;
  
  
  1. Create the HTML Structure
&lt;/h2&gt;

&lt;p&gt;Start with a simple HTML page containing a canvas and a button.&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight html"&gt;&lt;code&gt;&lt;span class="cp"&gt;&amp;lt;!DOCTYPE html&amp;gt;&lt;/span&gt;
&lt;span class="nt"&gt;&amp;lt;html&lt;/span&gt; &lt;span class="na"&gt;lang=&lt;/span&gt;&lt;span class="s"&gt;"en"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&lt;/span&gt;
&lt;span class="nt"&gt;&amp;lt;head&amp;gt;&lt;/span&gt;
    &lt;span class="nt"&gt;&amp;lt;meta&lt;/span&gt; &lt;span class="na"&gt;charset=&lt;/span&gt;&lt;span class="s"&gt;"UTF-8"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&lt;/span&gt;
    &lt;span class="nt"&gt;&amp;lt;meta&lt;/span&gt; &lt;span class="na"&gt;name=&lt;/span&gt;&lt;span class="s"&gt;"viewport"&lt;/span&gt; &lt;span class="na"&gt;content=&lt;/span&gt;&lt;span class="s"&gt;"width=device-width, initial-scale=1.0"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&lt;/span&gt;
    &lt;span class="nt"&gt;&amp;lt;title&amp;gt;&lt;/span&gt;JavaScript Spin Wheel&lt;span class="nt"&gt;&amp;lt;/title&amp;gt;&lt;/span&gt;

    &lt;span class="nt"&gt;&amp;lt;style&amp;gt;&lt;/span&gt;
        &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;box-sizing&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;border-box&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nt"&gt;body&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;margin&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;0&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;min-height&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;100vh&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;display&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;flex&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;align-items&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;center&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;justify-content&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;center&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;flex-direction&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;column&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="py"&gt;gap&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;24px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;font-family&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;Arial&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nb"&gt;sans-serif&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;background&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;#f5f5f5&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nc"&gt;.wheel-container&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;position&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;relative&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;width&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;min&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;90vw&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="m"&gt;500px&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
            &lt;span class="py"&gt;aspect-ratio&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;1&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nt"&gt;canvas&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;width&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;100%&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;height&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;100%&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;display&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;block&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nc"&gt;.pointer&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;position&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;absolute&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;top&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;-5px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;left&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;50%&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;transform&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;translateX&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;-50%&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
            &lt;span class="nl"&gt;width&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;0&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;height&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;0&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;border-left&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;18px&lt;/span&gt; &lt;span class="nb"&gt;solid&lt;/span&gt; &lt;span class="nb"&gt;transparent&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;border-right&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;18px&lt;/span&gt; &lt;span class="nb"&gt;solid&lt;/span&gt; &lt;span class="nb"&gt;transparent&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;border-top&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;32px&lt;/span&gt; &lt;span class="nb"&gt;solid&lt;/span&gt; &lt;span class="m"&gt;#222&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;z-index&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nt"&gt;button&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;border&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;0&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;padding&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;12px&lt;/span&gt; &lt;span class="m"&gt;28px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;border-radius&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;8px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;background&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;#222&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;color&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="no"&gt;white&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;font-size&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;16px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;cursor&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nb"&gt;pointer&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nt"&gt;button&lt;/span&gt;&lt;span class="nd"&gt;:disabled&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;opacity&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;0.5&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;cursor&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;not-allowed&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;

        &lt;span class="nf"&gt;#result&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nl"&gt;min-height&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;24px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;font-size&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;20px&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nl"&gt;font-weight&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;700&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;
    &lt;span class="nt"&gt;&amp;lt;/style&amp;gt;&lt;/span&gt;
&lt;span class="nt"&gt;&amp;lt;/head&amp;gt;&lt;/span&gt;

&lt;span class="nt"&gt;&amp;lt;body&amp;gt;&lt;/span&gt;

    &lt;span class="nt"&gt;&amp;lt;div&lt;/span&gt; &lt;span class="na"&gt;class=&lt;/span&gt;&lt;span class="s"&gt;"wheel-container"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&lt;/span&gt;
        &lt;span class="nt"&gt;&amp;lt;div&lt;/span&gt; &lt;span class="na"&gt;class=&lt;/span&gt;&lt;span class="s"&gt;"pointer"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&amp;lt;/div&amp;gt;&lt;/span&gt;
        &lt;span class="nt"&gt;&amp;lt;canvas&lt;/span&gt; &lt;span class="na"&gt;id=&lt;/span&gt;&lt;span class="s"&gt;"wheel"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&amp;lt;/canvas&amp;gt;&lt;/span&gt;
    &lt;span class="nt"&gt;&amp;lt;/div&amp;gt;&lt;/span&gt;

    &lt;span class="nt"&gt;&amp;lt;button&lt;/span&gt; &lt;span class="na"&gt;id=&lt;/span&gt;&lt;span class="s"&gt;"spinButton"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&lt;/span&gt;Spin&lt;span class="nt"&gt;&amp;lt;/button&amp;gt;&lt;/span&gt;

    &lt;span class="nt"&gt;&amp;lt;div&lt;/span&gt; &lt;span class="na"&gt;id=&lt;/span&gt;&lt;span class="s"&gt;"result"&lt;/span&gt;&lt;span class="nt"&gt;&amp;gt;&amp;lt;/div&amp;gt;&lt;/span&gt;

&lt;span class="nt"&gt;&amp;lt;/body&amp;gt;&lt;/span&gt;
&lt;span class="nt"&gt;&amp;lt;/html&amp;gt;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The canvas is responsible for rendering the wheel, while the pointer remains fixed at the top.&lt;/p&gt;

&lt;p&gt;Using a responsive container also allows the wheel to scale down on smaller screens.&lt;/p&gt;

&lt;h2&gt;
  
  
  2. Draw the Wheel with Canvas
&lt;/h2&gt;

&lt;p&gt;Now we can use the Canvas API to draw the wheel.&lt;/p&gt;

&lt;p&gt;First, define the options:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;items&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Pizza&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Burger&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Sushi&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Tacos&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Pasta&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;Salad&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
&lt;span class="p"&gt;];&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Each option will occupy one segment of the wheel.&lt;/p&gt;

&lt;p&gt;If there are six items, each segment takes up:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;360 / 6 = 60 degrees
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;In radians, we can calculate the angle like this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;segmentAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;PI&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="nx"&gt;items&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;length&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Now create the canvas setup:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;canvas&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nb"&gt;document&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getElementById&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;wheel&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;ctx&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getContext&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;2d&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;500&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;width&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;height&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;center&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;radius&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="mi"&gt;10&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Then draw each segment:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;colors&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;[&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#ff6b6b&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#ffd93d&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#6bcB77&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#4d96ff&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#845ec2&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#ff9671&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;
&lt;span class="p"&gt;];&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;drawWheel&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;rotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;clearRect&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

    &lt;span class="k"&gt;for &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kd"&gt;let&lt;/span&gt; &lt;span class="nx"&gt;i&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="nx"&gt;i&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="nx"&gt;items&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;length&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="nx"&gt;i&lt;/span&gt;&lt;span class="o"&gt;++&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;startAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;rotation&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;i&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;segmentAngle&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;endAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;startAngle&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;segmentAngle&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;beginPath&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;moveTo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;center&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;center&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;arc&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
            &lt;span class="nx"&gt;center&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
            &lt;span class="nx"&gt;center&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
            &lt;span class="nx"&gt;radius&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
            &lt;span class="nx"&gt;startAngle&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
            &lt;span class="nx"&gt;endAngle&lt;/span&gt;
        &lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;closePath&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;fillStyle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;colors&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;i&lt;/span&gt; &lt;span class="o"&gt;%&lt;/span&gt; &lt;span class="nx"&gt;colors&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;length&lt;/span&gt;&lt;span class="p"&gt;];&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;fill&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;strokeStyle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#ffffff&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;lineWidth&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;3&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;stroke&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

        &lt;span class="c1"&gt;// Draw text&lt;/span&gt;
        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;textAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;startAngle&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;segmentAngle&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;textRadius&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;radius&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.65&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;textX&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;center&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;cos&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;textAngle&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;textRadius&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;textY&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;center&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;sin&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;textAngle&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;textRadius&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;save&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;translate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;textX&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;textY&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;rotate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;textAngle&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;fillStyle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;#222&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;font&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;bold 18px Arial&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;textAlign&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;center&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;textBaseline&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;middle&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;fillText&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;items&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;i&lt;/span&gt;&lt;span class="p"&gt;],&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;restore&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Finally, draw the initial wheel:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="nf"&gt;drawWheel&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;At this point, we already have a functional visual wheel.&lt;/p&gt;

&lt;h2&gt;
  
  
  3. Choose a Random Winner
&lt;/h2&gt;

&lt;p&gt;The next step is selecting the winning segment.&lt;/p&gt;

&lt;p&gt;A simple approach is to generate a random integer between &lt;code&gt;0&lt;/code&gt; and the last item index:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;getRandomIndex&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;floor&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;random&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;items&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;length&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;For a six-item wheel, this produces a number from &lt;code&gt;0&lt;/code&gt; to &lt;code&gt;5&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;For example:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;winnerIndex&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;getRandomIndex&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

&lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;items&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;winnerIndex&lt;/span&gt;&lt;span class="p"&gt;]);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This is enough for a normal interactive website where the wheel is being used for casual random selection.&lt;/p&gt;

&lt;p&gt;If you were building a security-sensitive or high-stakes randomization system, you would want a stronger source of randomness instead of relying on &lt;code&gt;Math.random()&lt;/code&gt;.&lt;/p&gt;

&lt;h2&gt;
  
  
  4. Calculate the Target Rotation
&lt;/h2&gt;

&lt;p&gt;Selecting a winner is only half of the problem.&lt;/p&gt;

&lt;p&gt;We also need to make the wheel visually stop with that segment underneath the pointer.&lt;/p&gt;

&lt;p&gt;The center of the winning segment is:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;winnerAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
    &lt;span class="nx"&gt;winnerIndex&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;segmentAngle&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt;
    &lt;span class="nx"&gt;segmentAngle&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Because our pointer is at the top of the wheel, we need to rotate the wheel so the winning segment reaches the top position.&lt;/p&gt;

&lt;p&gt;We can calculate a target angle like this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;pointerAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt;&lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;PI&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;targetRotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
    &lt;span class="nx"&gt;pointerAngle&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt;
    &lt;span class="nx"&gt;winnerAngle&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Then add several complete rotations:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;fullSpins&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;5&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;finalRotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
    &lt;span class="nx"&gt;targetRotation&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt;
    &lt;span class="nx"&gt;fullSpins&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;PI&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Adding several full rotations makes the animation look much more natural than simply rotating directly to the winner.&lt;/p&gt;

&lt;h2&gt;
  
  
  5. Add Smooth Deceleration
&lt;/h2&gt;

&lt;p&gt;A common mistake when creating a spin wheel is using a constant rotation speed.&lt;/p&gt;

&lt;p&gt;A real-looking wheel should accelerate quickly and then gradually slow down.&lt;/p&gt;

&lt;p&gt;We can use an easing function:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;easeOutCubic&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;t&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;pow&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;1&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;t&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;3&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The function receives a value between &lt;code&gt;0&lt;/code&gt; and &lt;code&gt;1&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;At the beginning:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;t = 0
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;At the end:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;t = 1
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The easing function makes the rotation move quickly at first and slow down near the end.&lt;/p&gt;

&lt;p&gt;Now create the animation:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;let&lt;/span&gt; &lt;span class="nx"&gt;rotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="kd"&gt;let&lt;/span&gt; &lt;span class="nx"&gt;spinning&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;spin&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;if &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;spinning&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="k"&gt;return&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;

    &lt;span class="nx"&gt;spinning&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;spinButton&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="nb"&gt;document&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getElementById&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;spinButton&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

    &lt;span class="nx"&gt;spinButton&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;disabled&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;result&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="nb"&gt;document&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getElementById&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;result&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

    &lt;span class="nx"&gt;result&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;textContent&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;""&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;winnerIndex&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="nf"&gt;getRandomIndex&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;winnerAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="nx"&gt;winnerIndex&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;segmentAngle&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt;
        &lt;span class="nx"&gt;segmentAngle&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;pointerAngle&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="o"&gt;-&lt;/span&gt;&lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;PI&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;fullSpins&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;5&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;targetRotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="nx"&gt;pointerAngle&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt;
        &lt;span class="nx"&gt;winnerAngle&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt;
        &lt;span class="nx"&gt;fullSpins&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;PI&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mi"&gt;2&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;startRotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;rotation&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;totalRotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
        &lt;span class="nx"&gt;targetRotation&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;startRotation&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;duration&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;4000&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;startTime&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;performance&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;now&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

    &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;animate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;currentTime&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;elapsed&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;currentTime&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;startTime&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;progress&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nb"&gt;Math&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;min&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;elapsed&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="nx"&gt;duration&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;eased&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nf"&gt;easeOutCubic&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;progress&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="nx"&gt;rotation&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
            &lt;span class="nx"&gt;startRotation&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt;
            &lt;span class="nx"&gt;totalRotation&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;eased&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

        &lt;span class="nf"&gt;drawWheel&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;rotation&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

        &lt;span class="k"&gt;if &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;progress&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nf"&gt;requestAnimationFrame&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;animate&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="k"&gt;else&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
            &lt;span class="nx"&gt;spinning&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
            &lt;span class="nx"&gt;spinButton&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;disabled&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

            &lt;span class="nx"&gt;result&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;textContent&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt;
                &lt;span class="s2"&gt;`Winner: &lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;items&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;winnerIndex&lt;/span&gt;&lt;span class="p"&gt;]}&lt;/span&gt;&lt;span class="s2"&gt;`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
        &lt;span class="p"&gt;}&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;

    &lt;span class="nf"&gt;requestAnimationFrame&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;animate&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Connect the function to the button:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="nb"&gt;document&lt;/span&gt;
    &lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;getElementById&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;spinButton&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
    &lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;addEventListener&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;click&lt;/span&gt;&lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;spin&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Now the wheel can spin, slow down, and announce the winner.&lt;/p&gt;

&lt;h2&gt;
  
  
  6. Why Use requestAnimationFrame?
&lt;/h2&gt;

&lt;p&gt;For browser animations, &lt;code&gt;requestAnimationFrame()&lt;/code&gt; is generally a better choice than repeatedly calling a function with &lt;code&gt;setInterval()&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;The browser can synchronize the animation with its rendering cycle.&lt;/p&gt;

&lt;p&gt;That makes it useful for things such as:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Canvas animations&lt;/li&gt;
&lt;li&gt;Game interfaces&lt;/li&gt;
&lt;li&gt;Interactive visualizations&lt;/li&gt;
&lt;li&gt;Progress animations&lt;/li&gt;
&lt;li&gt;Spinning wheels&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;It also gives us a timestamp that we can use to calculate animation progress.&lt;/p&gt;

&lt;h2&gt;
  
  
  7. Make the Wheel Responsive
&lt;/h2&gt;

&lt;p&gt;The canvas itself is 500 × 500 pixels, but CSS allows it to scale with the container:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight css"&gt;&lt;code&gt;&lt;span class="nc"&gt;.wheel-container&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nl"&gt;width&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="n"&gt;min&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="m"&gt;90vw&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="m"&gt;500px&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
    &lt;span class="py"&gt;aspect-ratio&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="m"&gt;1&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This means the wheel can shrink on a mobile screen while maintaining its square shape.&lt;/p&gt;

&lt;p&gt;For more advanced implementations, you can also account for device pixel ratio so the canvas remains sharp on high-density displays.&lt;/p&gt;

&lt;p&gt;For example:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight javascript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;dpr&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nb"&gt;window&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;devicePixelRatio&lt;/span&gt; &lt;span class="o"&gt;||&lt;/span&gt; &lt;span class="mi"&gt;1&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;width&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;dpr&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;height&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;size&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;dpr&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;style&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;width&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="s2"&gt;`&lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;size&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt;px`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="nx"&gt;canvas&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;style&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;height&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="s2"&gt;`&lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;size&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt;px`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

&lt;span class="nx"&gt;ctx&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;scale&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;dpr&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;dpr&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This becomes especially useful when building a polished production-quality wheel.&lt;/p&gt;

&lt;h2&gt;
  
  
  Complete Example
&lt;/h2&gt;

&lt;p&gt;The main concepts are now in place:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Create a canvas.&lt;/li&gt;
&lt;li&gt;Divide the circle into equal segments.&lt;/li&gt;
&lt;li&gt;Draw each segment.&lt;/li&gt;
&lt;li&gt;Select a random winner.&lt;/li&gt;
&lt;li&gt;Calculate the target rotation.&lt;/li&gt;
&lt;li&gt;Add several full rotations.&lt;/li&gt;
&lt;li&gt;Animate using &lt;code&gt;requestAnimationFrame()&lt;/code&gt;.&lt;/li&gt;
&lt;li&gt;Apply easing so the wheel slows down naturally.&lt;/li&gt;
&lt;li&gt;Display the selected item.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;From here, you can add many other features.&lt;/p&gt;

&lt;p&gt;For example:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Sound effects&lt;/li&gt;
&lt;li&gt;Confetti&lt;/li&gt;
&lt;li&gt;Custom colors&lt;/li&gt;
&lt;li&gt;Images inside segments&lt;/li&gt;
&lt;li&gt;Remove-winner mode&lt;/li&gt;
&lt;li&gt;Spin history&lt;/li&gt;
&lt;li&gt;Custom fonts&lt;/li&gt;
&lt;li&gt;Weighted probabilities&lt;/li&gt;
&lt;li&gt;Saved wheels&lt;/li&gt;
&lt;li&gt;Shareable wheel URLs&lt;/li&gt;
&lt;li&gt;Embedding the wheel into another website&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  Building a Production-Ready Spin Wheel
&lt;/h2&gt;

&lt;p&gt;A basic JavaScript spin wheel is relatively easy to create, but a production-ready version requires more attention to user experience.&lt;/p&gt;

&lt;p&gt;You need to think about how the wheel behaves when someone clicks Spin repeatedly, how long the animation should last, how text fits into small segments, how the wheel performs on mobile devices, and how the final result stays synchronized with the visual animation.&lt;/p&gt;

&lt;p&gt;You also need to consider accessibility, responsive layouts, touch interaction, audio controls, and state management.&lt;/p&gt;

&lt;p&gt;That's where a simple Canvas experiment starts turning into a complete interactive product.&lt;/p&gt;

&lt;p&gt;If you want to try a ready-to-use version instead of building everything from scratch, you can explore &lt;a href="https://spinwheelplus.com/" rel="noopener noreferrer"&gt;SpinWheelPlus&lt;/a&gt;, an online toolkit for customizable spin wheels and random selection tools.&lt;/p&gt;

&lt;h2&gt;
  
  
  Conclusion
&lt;/h2&gt;

&lt;p&gt;Building a spin wheel with HTML, CSS, and JavaScript is a great small project for learning browser animation.&lt;/p&gt;

&lt;p&gt;The most important concept is separating the &lt;strong&gt;random result&lt;/strong&gt; from the &lt;strong&gt;visual animation&lt;/strong&gt;.&lt;/p&gt;

&lt;p&gt;JavaScript first determines which item should win. The animation then rotates the wheel until that item reaches the pointer.&lt;/p&gt;

&lt;p&gt;Once you understand that relationship, you can build much more advanced versions with custom themes, sounds, effects, saved configurations, and interactive controls.&lt;/p&gt;

&lt;p&gt;A spin wheel may look simple, but it combines several useful web development concepts: Canvas drawing, trigonometry, random selection, animation timing, easing functions, responsive design, and user interaction.&lt;/p&gt;

&lt;p&gt;That's what makes it a fun project to build — and a useful component to reuse in many different types of websites.&lt;/p&gt;

</description>
      <category>tutorial</category>
      <category>webdev</category>
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