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    <title>DEV Community: Cliff</title>
    <description>The latest articles on DEV Community by Cliff (@cliffwang).</description>
    <link>https://dev.to/cliffwang</link>
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      <title>DEV Community: Cliff</title>
      <link>https://dev.to/cliffwang</link>
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    <item>
      <title>How to Build a Browser-Based Jigsaw Puzzle Game with JavaScript and HTML5 Canvas</title>
      <dc:creator>Cliff</dc:creator>
      <pubDate>Fri, 06 Nov 2026 01:47:01 +0000</pubDate>
      <link>https://dev.to/cliffwang/how-to-build-a-browser-based-jigsaw-puzzle-game-with-javascript-and-html5-canvas-33gm</link>
      <guid>https://dev.to/cliffwang/how-to-build-a-browser-based-jigsaw-puzzle-game-with-javascript-and-html5-canvas-33gm</guid>
      <description>&lt;p&gt;Building a jigsaw puzzle game for the browser is an interesting combination of geometry, graphics programming, and interactive game development.&lt;/p&gt;

&lt;p&gt;Unlike a traditional grid-based puzzle, a jigsaw puzzle requires irregular piece shapes, matching edges, image clipping, and precise drag-and-drop interactions. Players should be able to move individual pieces, connect matching pieces, and gradually reconstruct the original image.&lt;/p&gt;

&lt;p&gt;In this tutorial, we'll explore how to build a browser-based jigsaw puzzle game using JavaScript and HTML5 Canvas, starting with the basic game architecture and moving through piece generation, rendering, interaction, and performance optimization.&lt;/p&gt;

&lt;p&gt;The goal is to create a fully playable game that runs directly in a web browser without requiring downloads or additional software.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Planning the Game Architecture&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Before implementing the puzzle mechanics, it's useful to break the game into smaller components.&lt;/p&gt;

&lt;p&gt;A browser-based jigsaw puzzle game typically needs several systems:&lt;/p&gt;

&lt;p&gt;Component&lt;/p&gt;

&lt;p&gt;Responsibility&lt;/p&gt;

&lt;p&gt;Game Manager&lt;/p&gt;

&lt;p&gt;Controls the overall game state&lt;/p&gt;

&lt;p&gt;Puzzle Generator&lt;/p&gt;

&lt;p&gt;Divides the original image into pieces&lt;/p&gt;

&lt;p&gt;Shape Generator&lt;/p&gt;

&lt;p&gt;Creates realistic jigsaw piece boundaries&lt;/p&gt;

&lt;p&gt;Canvas Renderer&lt;/p&gt;

&lt;p&gt;Draws pieces and the game board&lt;/p&gt;

&lt;p&gt;Input Manager&lt;/p&gt;

&lt;p&gt;Handles mouse and touch interactions&lt;/p&gt;

&lt;p&gt;Snap Manager&lt;/p&gt;

&lt;p&gt;Detects matching pieces and connections&lt;/p&gt;

&lt;p&gt;Progress Tracker&lt;/p&gt;

&lt;p&gt;Tracks completed pieces and game progress&lt;/p&gt;

&lt;p&gt;Keeping these systems separate makes the game easier to maintain and extend.&lt;/p&gt;

&lt;p&gt;For example, changing the puzzle difficulty from 16 pieces to 100 pieces should not require rewriting the rendering or interaction logic.&lt;/p&gt;

&lt;p&gt;A basic game state might look like this:&lt;/p&gt;

&lt;p&gt;`const gameState = {&lt;br&gt;
  status: "playing",&lt;/p&gt;

&lt;p&gt;rows: 4,&lt;br&gt;
  cols: 4,&lt;/p&gt;

&lt;p&gt;pieces: [],&lt;/p&gt;

&lt;p&gt;selectedPiece: null,&lt;/p&gt;

&lt;p&gt;placedCount: 0,&lt;/p&gt;

&lt;p&gt;startTime: Date.now()&lt;br&gt;
};`&lt;/p&gt;

&lt;p&gt;Possible game states include:&lt;/p&gt;

&lt;p&gt;loading: Preparing the puzzle image and geometry.&lt;/p&gt;

&lt;p&gt;playing: The player is assembling the puzzle.&lt;/p&gt;

&lt;p&gt;paused: Gameplay is temporarily suspended.&lt;/p&gt;

&lt;p&gt;completed: All pieces have been correctly assembled.&lt;/p&gt;

&lt;p&gt;This simple structure provides a foundation for implementing the rest of the game.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Creating the Puzzle Grid&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;The first step is dividing the original image into a rectangular grid.&lt;/p&gt;

&lt;p&gt;Suppose the source image has a width of 1200 pixels and a height of 800 pixels.&lt;/p&gt;

&lt;p&gt;For a 4 × 4 puzzle:&lt;/p&gt;

&lt;p&gt;const rows = 4;&lt;br&gt;
const cols = 4;&lt;/p&gt;

&lt;p&gt;const pieceWidth = image.width / cols;&lt;br&gt;
const pieceHeight = image.height / rows;&lt;/p&gt;

&lt;p&gt;Each piece has a logical position in the completed image.&lt;/p&gt;

&lt;p&gt;We can calculate its original coordinates using its row and column:&lt;/p&gt;

&lt;p&gt;function getPiecePosition(row, col, width, height) {&lt;br&gt;
  return {&lt;br&gt;
    x: col * width,&lt;br&gt;
    y: row * height&lt;br&gt;
  };&lt;br&gt;
}&lt;/p&gt;

&lt;p&gt;However, these rectangular regions are only the starting point.&lt;/p&gt;

&lt;p&gt;A realistic jigsaw puzzle requires each piece to have a unique outline, with tabs and blanks that fit neighboring pieces.&lt;/p&gt;

&lt;p&gt;This brings us to the most important part of the geometry system.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Generating Matching Jigsaw Piece Edges&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;A common mistake when implementing jigsaw puzzles is generating every piece independently.&lt;/p&gt;

&lt;p&gt;This can lead to small differences between neighboring edges, creating visible gaps or overlaps.&lt;/p&gt;

&lt;p&gt;A better approach is to generate shared boundaries first.&lt;/p&gt;

&lt;p&gt;Each internal boundary is created once and reused by the two adjacent pieces.&lt;/p&gt;

&lt;p&gt;For a grid of rows and columns, we need two sets of boundaries:&lt;/p&gt;

&lt;p&gt;Horizontal boundaries between rows.&lt;/p&gt;

&lt;p&gt;Vertical boundaries between columns.&lt;/p&gt;

&lt;p&gt;Each boundary contains a geometric description and a polarity.&lt;/p&gt;

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

&lt;p&gt;Positive polarity: A protruding tab.&lt;/p&gt;

&lt;p&gt;Negative polarity: A recessed blank.&lt;/p&gt;

&lt;p&gt;A simplified edge map can be generated as follows:&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;randomPolarity&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;random&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="o"&gt;&amp;gt;&lt;/span&gt; &lt;span class="mf"&gt;0.5&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="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="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;createEdgeMap&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;rows&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;cols&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;horizontal&lt;/span&gt; &lt;span class="o"&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;vertical&lt;/span&gt; &lt;span class="o"&gt;=&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;r&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;r&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="nx"&gt;rows&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="nx"&gt;r&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="nx"&gt;horizontal&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;r&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&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;c&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;c&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="nx"&gt;cols&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="nx"&gt;c&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="nx"&gt;horizontal&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;r&lt;/span&gt;&lt;span class="p"&gt;][&lt;/span&gt;&lt;span class="nx"&gt;c&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;randomPolarity&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="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;r&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;r&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="nx"&gt;rows&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="nx"&gt;r&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="nx"&gt;vertical&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;r&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&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;c&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;c&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="nx"&gt;cols&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="nx"&gt;c&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="nx"&gt;vertical&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;r&lt;/span&gt;&lt;span class="p"&gt;][&lt;/span&gt;&lt;span class="nx"&gt;c&lt;/span&gt;&lt;span class="p"&gt;]&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;randomPolarity&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="k"&gt;return&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;horizontal&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;vertical&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;In a complete implementation, each entry should store the full edge geometry rather than just its polarity.&lt;/p&gt;

&lt;p&gt;The neighboring pieces then reuse the same geometry in opposite directions.&lt;/p&gt;

&lt;p&gt;This ensures that their boundaries match exactly.&lt;/p&gt;

&lt;p&gt;Outer puzzle boundaries are treated differently: they remain straight rather than receiving tabs or blanks.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Creating Realistic Piece Shapes with Bézier Curves&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Jigsaw puzzle pieces are recognizable because of their characteristic tabs and recessed edges.&lt;/p&gt;

&lt;p&gt;We can approximate these shapes using cubic Bézier curves.&lt;/p&gt;

&lt;p&gt;A cubic Bézier curve is defined by four control points:&lt;/p&gt;

&lt;p&gt;P0: Starting point.&lt;/p&gt;

&lt;p&gt;P1: First control point.&lt;/p&gt;

&lt;p&gt;P2: Second control point.&lt;/p&gt;

&lt;p&gt;P3: Ending point.&lt;/p&gt;

&lt;p&gt;Its mathematical representation is:&lt;/p&gt;

&lt;p&gt;B(t) = (1-t)³P0&lt;br&gt;
     + 3(1-t)²tP1&lt;br&gt;
     + 3(1-t)t²P2&lt;br&gt;
     + t³P3&lt;/p&gt;

&lt;p&gt;where t ranges from 0 to 1.&lt;/p&gt;

&lt;p&gt;By adjusting the control points, we can create the rounded head and narrow neck of a traditional jigsaw tab.&lt;/p&gt;

&lt;p&gt;For example, Canvas provides a convenient method:&lt;/p&gt;

&lt;p&gt;&lt;code&gt;ctx.bezierCurveTo(&lt;br&gt;
  controlX1,&lt;br&gt;
  controlY1,&lt;br&gt;
  controlX2,&lt;br&gt;
  controlY2,&lt;br&gt;
  endX,&lt;br&gt;
  endY&lt;br&gt;
);&lt;/code&gt;&lt;/p&gt;

&lt;p&gt;A simplified edge renderer might look 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;function&lt;/span&gt; &lt;span class="nf"&gt;drawTab&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;x&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;width&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;depth&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;direction&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;w&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;width&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;d&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;depth&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;direction&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;lineTo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.25&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&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;bezierCurveTo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.25&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.15&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.28&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.55&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.40&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.55&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;bezierCurveTo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.45&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.95&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.55&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.95&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.60&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.55&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;bezierCurveTo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.72&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.55&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.75&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;d&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.15&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.75&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&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;lineTo&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;x&lt;/span&gt; &lt;span class="o"&gt;+&lt;/span&gt; &lt;span class="nx"&gt;w&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&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 direction determines whether the tab protrudes or curves inward.&lt;/p&gt;

&lt;p&gt;For a production-quality game, the geometry should also account for:&lt;/p&gt;

&lt;p&gt;Consistent endpoints and tangent directions.&lt;/p&gt;

&lt;p&gt;Variable tab widths and depths.&lt;/p&gt;

&lt;p&gt;Different shapes for horizontal and vertical edges.&lt;/p&gt;

&lt;p&gt;Reversed traversal when rendering neighboring pieces.&lt;/p&gt;

&lt;p&gt;Shared control points to prevent mismatched boundaries.&lt;/p&gt;

&lt;p&gt;The objective is to generate varied-looking pieces while maintaining mathematically consistent connections.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Constructing the Complete Puzzle Piece&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Once all four edges are available, we can construct the outline of each piece.&lt;/p&gt;

&lt;p&gt;A convenient strategy is to trace the shape clockwise:&lt;/p&gt;

&lt;p&gt;Start at the top-left corner.&lt;/p&gt;

&lt;p&gt;Draw the top edge from left to right.&lt;/p&gt;

&lt;p&gt;Draw the right edge from top to bottom.&lt;/p&gt;

&lt;p&gt;Draw the bottom edge from right to left.&lt;/p&gt;

&lt;p&gt;Draw the left edge from bottom to top.&lt;/p&gt;

&lt;p&gt;Close the path.&lt;/p&gt;

&lt;p&gt;A simplified structure looks 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;function&lt;/span&gt; &lt;span class="nf"&gt;createPiecePath&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;piece&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="p"&gt;{&lt;/span&gt; &lt;span class="nx"&gt;x&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;edges&lt;/span&gt; &lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;piece&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;x&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;y&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;

  &lt;span class="nf"&gt;drawEdge&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;edges&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;top&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="nf"&gt;drawEdge&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;edges&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;right&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="nf"&gt;drawEdge&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;edges&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;bottom&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="kc"&gt;true&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="nf"&gt;drawEdge&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;edges&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;left&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="kc"&gt;true&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="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Here, drawEdge() is a reusable function that renders the corresponding edge geometry.&lt;/p&gt;

&lt;p&gt;For a clean implementation, it is helpful to define each edge in local coordinates and apply transformations when placing it on different sides of the piece.&lt;/p&gt;

&lt;p&gt;This avoids duplicating the same Bézier geometry for horizontal and vertical boundaries.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Rendering Puzzle Pieces with HTML5 Canvas&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;With the geometry generated, we can start rendering the actual puzzle.&lt;/p&gt;

&lt;p&gt;The key technique is Canvas clipping.&lt;/p&gt;

&lt;p&gt;Instead of creating a separate cropped image for every piece, we draw the original image through each piece's irregular clipping path.&lt;/p&gt;

&lt;p&gt;This preserves image alignment across the entire puzzle.&lt;/p&gt;

&lt;p&gt;The basic process is:&lt;/p&gt;

&lt;p&gt;Save the current Canvas state.&lt;/p&gt;

&lt;p&gt;Translate to the piece's position.&lt;/p&gt;

&lt;p&gt;Define its clipping path.&lt;/p&gt;

&lt;p&gt;Draw the original image.&lt;/p&gt;

&lt;p&gt;Restore the Canvas state.&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;function&lt;/span&gt; &lt;span class="nf"&gt;renderPiece&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;image&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;piece&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;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;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentX&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentY&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;path&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;createLocalPiecePath&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;piece&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;clip&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;path&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;drawImage&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
    &lt;span class="nx"&gt;image&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="o"&gt;-&lt;/span&gt;&lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;sourceX&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
    &lt;span class="o"&gt;-&lt;/span&gt;&lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;sourceY&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;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The important detail is that every piece uses the same original image coordinate system.&lt;/p&gt;

&lt;p&gt;This means that when all pieces are placed correctly, the image lines up seamlessly.&lt;/p&gt;

&lt;p&gt;We can also draw a border around each piece:&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="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;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentX&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentY&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;path&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;createLocalPiecePath&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;piece&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;rgba(0, 0, 0, 0.25)&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="mf"&gt;1.5&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="nx"&gt;path&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;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Additional visual effects such as shadows, hover highlights, and selection outlines can make the game feel much more responsive.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Implementing Drag-and-Drop Interaction&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;A jigsaw puzzle would not be playable without intuitive piece movement.&lt;/p&gt;

&lt;p&gt;Each piece needs to track two different positions:&lt;/p&gt;

&lt;p&gt;Its original position in the completed puzzle.&lt;/p&gt;

&lt;p&gt;Its current position on the game board.&lt;/p&gt;

&lt;p&gt;A simple piece object might look like this:&lt;/p&gt;

&lt;p&gt;`const piece = {&lt;br&gt;
  id: 0,&lt;/p&gt;

&lt;p&gt;correctX: 120,&lt;br&gt;
  correctY: 80,&lt;/p&gt;

&lt;p&gt;currentX: 350,&lt;br&gt;
  currentY: 220,&lt;/p&gt;

&lt;p&gt;isDragging: false,&lt;br&gt;
  isPlaced: false&lt;br&gt;
};`&lt;/p&gt;

&lt;p&gt;When the player selects a piece, we record the pointer offset:&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;startDrag&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;pointerX&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;pointerY&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;isDragging&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="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;dragOffsetX&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;pointerX&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentX&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;dragOffsetY&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;pointerY&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentY&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="nx"&gt;While&lt;/span&gt; &lt;span class="nx"&gt;dragging&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;movePiece&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;pointerX&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;pointerY&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="o"&gt;!&lt;/span&gt;&lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;isDragging&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="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentX&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;pointerX&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;dragOffsetX&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentY&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;pointerY&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;dragOffsetY&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;When the pointer is released, the game can check whether the piece is close enough to its correct position.&lt;/p&gt;

&lt;p&gt;For browser games, the Pointer Events API is particularly useful because it supports mouse, touch, and pen input through a unified event model.&lt;/p&gt;

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

&lt;p&gt;canvas.addEventListener("pointerdown", handlePointerDown);&lt;br&gt;
canvas.addEventListener("pointermove", handlePointerMove);&lt;br&gt;
canvas.addEventListener("pointerup", handlePointerUp);&lt;/p&gt;

&lt;p&gt;canvas.addEventListener("pointercancel", handlePointerUp);&lt;/p&gt;

&lt;p&gt;For mobile browsers, setting an appropriate touch-action CSS property on the game interaction surface also helps prevent unwanted browser gestures while dragging.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Detecting Correct Placement and Snapping Pieces&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;A simple snapping system compares the current position of a piece with its original position.&lt;/p&gt;

&lt;p&gt;We can use Euclidean distance:&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;checkSnap&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;threshold&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="mi"&gt;20&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;dx&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentX&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;correctX&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;dy&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentY&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;correctY&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;distance&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;hypot&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;dx&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;dy&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;distance&lt;/span&gt; &lt;span class="o"&gt;&amp;lt;&lt;/span&gt; &lt;span class="nx"&gt;threshold&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentX&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;correctX&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;currentY&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;correctY&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

    &lt;span class="nx"&gt;piece&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;isPlaced&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="k"&gt;return&lt;/span&gt; &lt;span class="kc"&gt;true&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="kc"&gt;false&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 works well for a basic puzzle where pieces are placed directly into their final positions.&lt;/p&gt;

&lt;p&gt;However, more advanced games can support connections between neighboring pieces before they reach the correct location.&lt;/p&gt;

&lt;p&gt;For example, when two pieces are close enough and their corresponding edges match, they can snap together and form a larger group.&lt;/p&gt;

&lt;p&gt;This introduces the concept of connected piece clusters.&lt;/p&gt;

&lt;p&gt;A cluster can be represented as a collection of pieces that share a common movement offset.&lt;/p&gt;

&lt;p&gt;When the player drags one piece in a connected cluster, all the other pieces move with it.&lt;/p&gt;

&lt;p&gt;This creates a more natural puzzle-solving experience, especially for larger puzzles.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Adding Difficulty Levels and Game Progress&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;A complete browser-based jigsaw puzzle game should offer more than just a fixed grid.&lt;/p&gt;

&lt;p&gt;Different piece counts can provide different difficulty levels.&lt;/p&gt;

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

&lt;p&gt;Difficulty&lt;/p&gt;

&lt;p&gt;Grid&lt;/p&gt;

&lt;p&gt;Total Pieces&lt;/p&gt;

&lt;p&gt;Easy&lt;/p&gt;

&lt;p&gt;3 × 3&lt;/p&gt;

&lt;p&gt;9&lt;/p&gt;

&lt;p&gt;Medium&lt;/p&gt;

&lt;p&gt;5 × 5&lt;/p&gt;

&lt;p&gt;25&lt;/p&gt;

&lt;p&gt;Hard&lt;/p&gt;

&lt;p&gt;8 × 8&lt;/p&gt;

&lt;p&gt;64&lt;/p&gt;

&lt;p&gt;Expert&lt;/p&gt;

&lt;p&gt;10 × 10&lt;/p&gt;

&lt;p&gt;100&lt;/p&gt;

&lt;p&gt;The actual difficulty also depends on the image itself, the shape variation, and whether players can use a reference image.&lt;/p&gt;

&lt;p&gt;A progress tracker can be implemented with a simple counter:&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;updateProgress&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;gameState&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;total&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;gameState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;rows&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="nx"&gt;gameState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;cols&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="nx"&gt;gameState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;placedCount&lt;/span&gt; &lt;span class="o"&gt;/&lt;/span&gt; &lt;span class="nx"&gt;total&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;gt;=&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="nx"&gt;gameState&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;status&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="dl"&gt;"&lt;/span&gt;&lt;span class="s2"&gt;completed&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="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;progress&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;Other useful gameplay features include:&lt;/p&gt;

&lt;p&gt;A timer to track completion time.&lt;/p&gt;

&lt;p&gt;A preview of the completed image.&lt;/p&gt;

&lt;p&gt;A shuffle function.&lt;/p&gt;

&lt;p&gt;A restart option.&lt;/p&gt;

&lt;p&gt;A completion animation.&lt;/p&gt;

&lt;p&gt;A responsive puzzle board for smaller screens.&lt;/p&gt;

&lt;p&gt;These features turn the underlying rendering engine into a more complete game experience.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Optimizing Performance for Desktop and Mobile Browsers&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;Performance becomes increasingly important as the number of pieces grows.&lt;/p&gt;

&lt;p&gt;A 3 × 3 puzzle is relatively easy to render. A 100-piece puzzle requires more careful management.&lt;/p&gt;

&lt;p&gt;Several techniques can help.&lt;/p&gt;

&lt;p&gt;Separate rendering layers&lt;/p&gt;

&lt;p&gt;Instead of redrawing everything unnecessarily, divide the game into layers:&lt;/p&gt;

&lt;p&gt;Background and board.&lt;/p&gt;

&lt;p&gt;Static completed pieces.&lt;/p&gt;

&lt;p&gt;Loose puzzle pieces.&lt;/p&gt;

&lt;p&gt;Active dragging and interaction effects.&lt;/p&gt;

&lt;p&gt;Use offscreen rendering&lt;/p&gt;

&lt;p&gt;Static piece images can be rendered into offscreen canvases and reused.&lt;/p&gt;

&lt;p&gt;This reduces repeated clipping and drawing operations.&lt;/p&gt;

&lt;p&gt;Optimize hit testing&lt;/p&gt;

&lt;p&gt;Checking every pixel of every piece is expensive.&lt;/p&gt;

&lt;p&gt;Start with bounding-box checks to eliminate pieces that are clearly not under the pointer. More precise path-based checks can then be performed on the remaining candidates.&lt;/p&gt;

&lt;p&gt;Avoid unnecessary redraws&lt;/p&gt;

&lt;p&gt;A requestAnimationFrame-based rendering loop can be used to update the game smoothly, but static scenes do not need to be redrawn continuously.&lt;/p&gt;

&lt;p&gt;Consider device pixel ratio&lt;/p&gt;

&lt;p&gt;High-density mobile screens require careful Canvas scaling to keep puzzle edges sharp without creating excessively large rendering surfaces.&lt;/p&gt;

&lt;p&gt;The best optimization strategy depends on the puzzle size, device capabilities, and rendering architecture.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Putting Everything Together&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;At this point, we have the major building blocks of a browser-based jigsaw puzzle game:&lt;/p&gt;

&lt;p&gt;Grid generation determines the number and dimensions of pieces.&lt;/p&gt;

&lt;p&gt;Edge generation creates matching boundaries.&lt;/p&gt;

&lt;p&gt;Bézier curves define realistic tabs and blanks.&lt;/p&gt;

&lt;p&gt;Canvas clipping maps the original image onto each piece.&lt;/p&gt;

&lt;p&gt;Pointer events enable interactive dragging.&lt;/p&gt;

&lt;p&gt;Snap detection handles correct placement.&lt;/p&gt;

&lt;p&gt;Game state management tracks progress and completion.&lt;/p&gt;

&lt;p&gt;The complete gameplay flow can be summarized as:&lt;/p&gt;

&lt;p&gt;Load Puzzle Image&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Generate Puzzle Grid&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Create Shared Edge Geometry&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Generate Individual Pieces&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Shuffle Pieces on the Board&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Player Drags and Connects Pieces&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Check Placement and Connections&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Update Game Progress&lt;br&gt;
       |&lt;br&gt;
       v&lt;br&gt;
Complete the Puzzle&lt;/p&gt;

&lt;p&gt;The most important architectural decision is keeping geometry, rendering, interaction, and game state independent.&lt;/p&gt;

&lt;p&gt;This makes it easier to add new features without introducing unnecessary complexity into the core puzzle engine.&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Try a Browser-Based Jigsaw Puzzle Game&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;The techniques discussed in this tutorial are the foundation of an interactive jigsaw puzzle experience.&lt;/p&gt;

&lt;p&gt;If you want to explore how a browser-based jigsaw puzzle game works in practice, you can try &lt;a href="https://jigsawpuzzlespot.com/" rel="noopener noreferrer"&gt;Jigsaw Puzzle Spot&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;It offers free online jigsaw puzzles that can be played directly in the browser, providing a practical example of image-based puzzle gameplay without requiring a separate application or installation.&lt;/p&gt;

&lt;p&gt;Conclusion&lt;/p&gt;

&lt;p&gt;Building a browser-based jigsaw puzzle game with JavaScript and HTML5 Canvas involves several interesting engineering challenges.&lt;/p&gt;

&lt;p&gt;The most important ones are generating matching piece geometry, rendering irregular shapes, maintaining image alignment, and implementing intuitive drag-and-drop interactions.&lt;/p&gt;

&lt;p&gt;By separating these systems into reusable components, it is possible to build a flexible puzzle engine that supports different image sizes, difficulty levels, and gameplay mechanics.&lt;/p&gt;

&lt;p&gt;What starts as a simple image-splitting exercise can become a surprisingly rich browser game development project.&lt;/p&gt;

&lt;p&gt;And the best part is that the entire experience can run directly in a modern web browser.&lt;/p&gt;

</description>
      <category>frontend</category>
      <category>gamedev</category>
      <category>javascript</category>
      <category>tutorial</category>
    </item>
    <item>
      <title>Building a Browser-Based Boggle Game with Astro and Vue 3</title>
      <dc:creator>Cliff</dc:creator>
      <pubDate>Sat, 26 Sep 2026 23:29:23 +0000</pubDate>
      <link>https://dev.to/cliffwang/building-a-browser-based-boggle-game-with-astro-and-vue-3-1m6l</link>
      <guid>https://dev.to/cliffwang/building-a-browser-based-boggle-game-with-astro-and-vue-3-1m6l</guid>
      <description>&lt;p&gt;Building a word game looks simple at first.&lt;/p&gt;

&lt;p&gt;A Boggle-style game seems to need only a letter grid, a word list, some input handling, and a score counter. But once the game needs to work well on both desktop and mobile, the implementation becomes a combination of UI state management, graph traversal, word validation, touch interaction, and performance optimization.&lt;/p&gt;

&lt;p&gt;I recently built a browser-based Boggle game using &lt;strong&gt;Astro and Vue 3&lt;/strong&gt;, and this article explains some of the engineering decisions behind it.&lt;/p&gt;

&lt;p&gt;The goal was not to build a large game engine. Instead, I wanted a lightweight architecture where Astro handles the website and content-oriented pages, while Vue manages the interactive game itself.&lt;/p&gt;

&lt;p&gt;The resulting project is &lt;a href="https://puzzle-boggle.com/" rel="noopener noreferrer"&gt;Puzzle Boggle&lt;/a&gt;.&lt;/p&gt;

&lt;h2&gt;
  
  
  Why Astro + Vue 3?
&lt;/h2&gt;

&lt;p&gt;Astro is particularly interesting for projects that contain both static content and interactive applications.&lt;/p&gt;

&lt;p&gt;A word game website usually has two very different types of pages:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Content and informational pages&lt;/li&gt;
&lt;li&gt;Highly interactive game pages&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;A traditional SPA can handle the second problem well, but it can be unnecessarily heavy for the first one.&lt;/p&gt;

&lt;p&gt;Astro provides a useful separation between the two.&lt;/p&gt;

&lt;p&gt;The static parts of the site can be rendered by Astro, while Vue components can be introduced where interactive behavior is required.&lt;/p&gt;

&lt;p&gt;The basic architecture looks roughly like this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;Astro
│
├── Layout
├── SEO / Metadata
├── Content Pages
├── Game Pages
│
└── Vue
    ├── GameBoard
    ├── LetterTile
    ├── WordInput
    ├── ScorePanel
    └── GameResult
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The important idea is that &lt;strong&gt;not everything needs to become a Vue application&lt;/strong&gt;.&lt;/p&gt;

&lt;p&gt;Only the parts that actually need client-side state need to be hydrated.&lt;/p&gt;

&lt;h2&gt;
  
  
  Separating the Game UI From the Website
&lt;/h2&gt;

&lt;p&gt;One of the first architectural decisions was separating the website layer from the game layer.&lt;/p&gt;

&lt;p&gt;The Astro side is responsible for things such as:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;page structure&lt;/li&gt;
&lt;li&gt;navigation&lt;/li&gt;
&lt;li&gt;metadata&lt;/li&gt;
&lt;li&gt;informational content&lt;/li&gt;
&lt;li&gt;SEO&lt;/li&gt;
&lt;li&gt;static layouts&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;Vue is responsible for:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;current game state&lt;/li&gt;
&lt;li&gt;selected letters&lt;/li&gt;
&lt;li&gt;user input&lt;/li&gt;
&lt;li&gt;word validation&lt;/li&gt;
&lt;li&gt;scoring&lt;/li&gt;
&lt;li&gt;timers&lt;/li&gt;
&lt;li&gt;animations&lt;/li&gt;
&lt;li&gt;game completion&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;This separation makes the project easier to reason about.&lt;/p&gt;

&lt;p&gt;The game can behave like a small application inside a larger content-oriented website.&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 plaintext"&gt;&lt;code&gt;src/
├── components/
│   ├── GameBoard.vue
│   ├── LetterTile.vue
│   ├── ScorePanel.vue
│   └── GameResult.vue
│
├── composables/
│   ├── useGame.ts
│   ├── useBoard.ts
│   └── useTimer.ts
│
├── data/
│   ├── dictionaries/
│   └── puzzles/
│
├── pages/
│   ├── index.astro
│   ├── daily-challenge/
│   └── boggle/
│
└── layouts/
    └── Layout.astro
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This is not the only valid structure, but separating UI components, game logic, and data early makes the project much easier to maintain.&lt;/p&gt;

&lt;h2&gt;
  
  
  Modeling the Boggle Board
&lt;/h2&gt;

&lt;p&gt;The board can be represented as a two-dimensional array.&lt;/p&gt;

&lt;p&gt;For example, a 4 × 4 board can be represented as:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;board&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="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;T&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="s1"&gt;R&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="s1"&gt;A&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="s1"&gt;P&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="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;E&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="s1"&gt;S&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="s1"&gt;I&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="s1"&gt;N&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="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;L&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="s1"&gt;O&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="s1"&gt;G&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="s1"&gt;D&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="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;M&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="s1"&gt;E&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="s1"&gt;T&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="s1"&gt;A&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;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Each cell needs to contain more than just a letter during gameplay.&lt;/p&gt;

&lt;p&gt;A useful internal representation is:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kr"&gt;interface&lt;/span&gt; &lt;span class="nx"&gt;Cell&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nl"&gt;row&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;
  &lt;span class="nx"&gt;col&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;
  &lt;span class="nx"&gt;letter&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The row and column coordinates are important because Boggle is fundamentally a path-search problem.&lt;/p&gt;

&lt;p&gt;A player is not simply selecting letters.&lt;/p&gt;

&lt;p&gt;They are creating a path through adjacent cells.&lt;/p&gt;

&lt;h2&gt;
  
  
  The Core Gameplay Problem Is a Graph Traversal
&lt;/h2&gt;

&lt;p&gt;This is probably the most interesting part of implementing Boggle.&lt;/p&gt;

&lt;p&gt;Each letter tile can be considered a node in a graph.&lt;/p&gt;

&lt;p&gt;A tile can connect to its neighboring tiles:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;A B C
D E F
G H I
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;From &lt;code&gt;E&lt;/code&gt;, the player can potentially move to:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;A B C
D   F
G H I
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;That means the game board can be treated as a graph where each tile has up to eight neighbors.&lt;/p&gt;

&lt;p&gt;The eight possible directions are:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;directions&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="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="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="p"&gt;[&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="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="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="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="mi"&gt;0&lt;/span&gt;&lt;span class="p"&gt;,&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="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;1&lt;/span&gt;&lt;span class="p"&gt;],&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="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="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="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="mi"&gt;1&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="p"&gt;]&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;When a player selects a tile, the game needs to determine whether the next tile is adjacent to the previous tile.&lt;/p&gt;

&lt;p&gt;A simple helper function can handle this:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;isAdjacent&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;
  &lt;span class="nx"&gt;a&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;Cell&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt;
  &lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;Cell&lt;/span&gt;
&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="nx"&gt;boolean&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;rowDistance&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;abs&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;a&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;row&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;row&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;colDistance&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;abs&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;a&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;col&lt;/span&gt; &lt;span class="o"&gt;-&lt;/span&gt; &lt;span class="nx"&gt;b&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;col&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="nx"&gt;rowDistance&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="o"&gt;&amp;amp;&amp;amp;&lt;/span&gt;
    &lt;span class="nx"&gt;colDistance&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="o"&gt;&amp;amp;&amp;amp;&lt;/span&gt;
    &lt;span class="o"&gt;!&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;rowDistance&lt;/span&gt; &lt;span class="o"&gt;===&lt;/span&gt; &lt;span class="mi"&gt;0&lt;/span&gt; &lt;span class="o"&gt;&amp;amp;&amp;amp;&lt;/span&gt; &lt;span class="nx"&gt;colDistance&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="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The next important rule is that the same tile cannot normally be used twice in the same word.&lt;/p&gt;

&lt;p&gt;So the game state needs to maintain the path:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;selectedCells&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;ref&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Cell&lt;/span&gt;&lt;span class="p"&gt;[]&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;&lt;span class="p"&gt;([])&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;When the player selects a new tile, the game checks:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Is this tile adjacent to the previous tile?&lt;/li&gt;
&lt;li&gt;Has this tile already been selected?&lt;/li&gt;
&lt;li&gt;If valid, add it to the current path.&lt;/li&gt;
&lt;li&gt;Otherwise reject the selection.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;These rules become especially important on mobile devices where users interact with the board using touch rather than a mouse.&lt;/p&gt;

&lt;h2&gt;
  
  
  Using Vue 3 Composition API
&lt;/h2&gt;

&lt;p&gt;Vue 3's Composition API is a good fit for this type of game because game logic can be separated into reusable composables.&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 typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;score&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;ref&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="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;currentWord&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;ref&lt;/span&gt;&lt;span class="p"&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;selectedCells&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;ref&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="nx"&gt;Cell&lt;/span&gt;&lt;span class="p"&gt;[]&lt;/span&gt;&lt;span class="o"&gt;&amp;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;foundWords&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;ref&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;[]&lt;/span&gt;&lt;span class="o"&gt;&amp;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;gameOver&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;ref&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="kc"&gt;false&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Then the logic can be organized into functions:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;selectCell&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;cell&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;Cell&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="o"&gt;!&lt;/span&gt;&lt;span class="nf"&gt;canSelect&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;cell&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="nx"&gt;selectedCells&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;push&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;cell&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
  &lt;span class="nx"&gt;currentWord&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt; &lt;span class="o"&gt;+=&lt;/span&gt; &lt;span class="nx"&gt;cell&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;letter&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;And:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;submitWord&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;word&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;currentWord&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;toLowerCase&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="o"&gt;!&lt;/span&gt;&lt;span class="nf"&gt;isValidWord&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;word&lt;/span&gt;&lt;span class="p"&gt;))&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nf"&gt;resetSelection&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="k"&gt;if &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;foundWords&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;includes&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;word&lt;/span&gt;&lt;span class="p"&gt;))&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="nf"&gt;resetSelection&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="nx"&gt;foundWords&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;push&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;word&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
  &lt;span class="nx"&gt;score&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;value&lt;/span&gt; &lt;span class="o"&gt;+=&lt;/span&gt; &lt;span class="nf"&gt;calculateScore&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;word&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;

  &lt;span class="nf"&gt;resetSelection&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 is one of the reasons I prefer Composition API for interactive game components.&lt;/p&gt;

&lt;p&gt;The state and behavior can stay close together without forcing the entire game into one huge component.&lt;/p&gt;

&lt;h2&gt;
  
  
  Word Validation Is a Separate Problem
&lt;/h2&gt;

&lt;p&gt;The board traversal algorithm and the dictionary system should not be tightly coupled.&lt;/p&gt;

&lt;p&gt;These are two different problems:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;Can the player create this sequence of letters?
                    ↓
              currentWord

                    ↓

Is this sequence a valid word?
                    ↓
               dictionary
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;Keeping them separate makes the game easier to modify.&lt;/p&gt;

&lt;p&gt;For example, the dictionary can be loaded into a &lt;code&gt;Set&lt;/code&gt;:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;dictionary&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;Set&lt;/span&gt;&lt;span class="p"&gt;([&lt;/span&gt;
  &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;apple&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="s1"&gt;orange&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="s1"&gt;stone&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="s1"&gt;game&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;Then validation becomes very fast:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;isValidWord&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;word&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&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="nx"&gt;dictionary&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;has&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;word&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;In a real game, the dictionary is obviously much larger.&lt;/p&gt;

&lt;p&gt;One of the interesting engineering challenges is therefore not simply "finding words", but deciding how much dictionary data should be loaded into the browser.&lt;/p&gt;

&lt;h2&gt;
  
  
  Client-Side vs Server-Side Validation
&lt;/h2&gt;

&lt;p&gt;For a casual browser word game, client-side validation can be extremely fast.&lt;/p&gt;

&lt;p&gt;The flow can be:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;Player
  ↓
Select tiles
  ↓
Build word
  ↓
Check dictionary
  ↓
Calculate score
  ↓
Update UI
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This avoids sending a network request every time the player submits a word.&lt;/p&gt;

&lt;p&gt;For a competitive game, however, there is another consideration.&lt;/p&gt;

&lt;p&gt;If the client is responsible for everything, a technically sophisticated player can potentially manipulate the game state.&lt;/p&gt;

&lt;p&gt;For a casual game this may be acceptable.&lt;/p&gt;

&lt;p&gt;For competitive scoring or leaderboards, important results should be verified on a server.&lt;/p&gt;

&lt;p&gt;That leads to a useful distinction:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;Local gameplay
    ↓
Fast client-side validation

Competitive result
    ↓
Server-side verification
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This architecture also makes it easier to introduce daily challenges or leaderboards later.&lt;/p&gt;

&lt;h2&gt;
  
  
  Generating Interesting Boards
&lt;/h2&gt;

&lt;p&gt;Random letters do not necessarily produce an interesting Boggle board.&lt;/p&gt;

&lt;p&gt;A completely random board can generate too many impossible combinations or produce boards with very few playable words.&lt;/p&gt;

&lt;p&gt;A better approach is to treat board generation as a constrained problem.&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 plaintext"&gt;&lt;code&gt;Random letters
      ↓
Generate candidate board
      ↓
Evaluate board
      ↓
Check word count
      ↓
Check difficulty
      ↓
Accept / regenerate
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The board generator can evaluate a candidate board using a dictionary and estimate how many valid words are available.&lt;/p&gt;

&lt;p&gt;This creates an interesting separation between:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Board generation&lt;/li&gt;
&lt;li&gt;Word discovery&lt;/li&gt;
&lt;li&gt;Difficulty evaluation&lt;/li&gt;
&lt;li&gt;Gameplay&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;A deterministic seed can also be useful.&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 typescript"&gt;&lt;code&gt;&lt;span class="nf"&gt;generateBoard&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;seed&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;If the same seed produces the same board, a daily puzzle can be reproduced consistently.&lt;/p&gt;

&lt;p&gt;This is useful for a daily challenge system because every player can receive the same puzzle.&lt;/p&gt;

&lt;h2&gt;
  
  
  Designing a Daily Challenge
&lt;/h2&gt;

&lt;p&gt;A daily puzzle introduces another interesting engineering problem.&lt;/p&gt;

&lt;p&gt;The simplest model is:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;date
  ↓
deterministic seed
  ↓
board generator
  ↓
daily board
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



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

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;seed&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;createDailySeed&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;2026-09-26&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;board&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nf"&gt;generateBoard&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;seed&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The server does not necessarily need to store every generated board if the generation algorithm is deterministic.&lt;/p&gt;

&lt;p&gt;Instead, the date can act as the source of the seed.&lt;/p&gt;

&lt;p&gt;This can significantly simplify the data model.&lt;/p&gt;

&lt;p&gt;The same concept can also be used for:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;daily Sudoku&lt;/li&gt;
&lt;li&gt;daily Wordle-style games&lt;/li&gt;
&lt;li&gt;daily crossword puzzles&lt;/li&gt;
&lt;li&gt;daily logic puzzles&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  Mobile Interaction Is Harder Than Desktop Interaction
&lt;/h2&gt;

&lt;p&gt;A desktop implementation can start with:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;mousedown
mousemove
mouseup
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;But mobile users interact with their fingers.&lt;/p&gt;

&lt;p&gt;That introduces several issues:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;Finger size is much larger than a mouse cursor.&lt;/li&gt;
&lt;li&gt;The finger can obscure the selected tile.&lt;/li&gt;
&lt;li&gt;Touch movement can accidentally trigger page scrolling.&lt;/li&gt;
&lt;li&gt;Rapid movement between tiles needs to feel responsive.&lt;/li&gt;
&lt;li&gt;The selection path needs clear visual feedback.&lt;/li&gt;
&lt;/ul&gt;

&lt;p&gt;The interaction therefore needs to be designed around touch from the beginning rather than treating mobile as an afterthought.&lt;/p&gt;

&lt;p&gt;A good Boggle interface should make the current path visually obvious.&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 plaintext"&gt;&lt;code&gt;[ T ][ R ][ A ][ P ]
       \   \
        [ E ][ S ]
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The exact visual design can vary, but the user should immediately understand:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;which tiles are selected&lt;/li&gt;
&lt;li&gt;what word is being formed&lt;/li&gt;
&lt;li&gt;where the path started&lt;/li&gt;
&lt;li&gt;what happens when the finger moves&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  Keeping the Vue Component Manageable
&lt;/h2&gt;

&lt;p&gt;One mistake I wanted to avoid was putting everything inside &lt;code&gt;GameBoard.vue&lt;/code&gt;.&lt;/p&gt;

&lt;p&gt;A game board can quickly become responsible for:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;Board rendering
Touch events
Mouse events
Word validation
Scoring
Timer
Animations
Game state
Statistics
API calls
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;That becomes difficult to maintain.&lt;/p&gt;

&lt;p&gt;Instead, I prefer smaller responsibilities.&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 plaintext"&gt;&lt;code&gt;GameBoard.vue
    ↓
useGame()
    ↓
useBoard()
    ↓
useWordValidation()
    ↓
useScore()
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;The components handle presentation while composables handle stateful behavior.&lt;/p&gt;

&lt;p&gt;This is especially useful when the same game logic needs to be reused by different interfaces.&lt;/p&gt;

&lt;h2&gt;
  
  
  Astro Handles the Site, Vue Handles the Game
&lt;/h2&gt;

&lt;p&gt;The final architecture can be summarized as:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight plaintext"&gt;&lt;code&gt;                    Astro
                      │
          ┌───────────┼───────────┐
          │           │           │
       Content      SEO        Routing
          │                       │
          └───────────┬───────────┘
                      │
                  Vue Island
                      │
              ┌───────┴────────┐
              │                │
          Game Board        Game State
              │                │
        Touch / Mouse       Composables
              │                │
              └───────┬────────┘
                      │
                 Word Engine
                      │
              ┌───────┴────────┐
              │                │
          Dictionary       Board Logic
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;p&gt;This architecture keeps the interactive portion focused while allowing the rest of the website to remain lightweight.&lt;/p&gt;

&lt;p&gt;It also leaves room for future features without turning the entire website into a monolithic JavaScript application.&lt;/p&gt;

&lt;h2&gt;
  
  
  What I Learned From Building It
&lt;/h2&gt;

&lt;p&gt;The biggest lesson is that a simple word game is actually several different engineering problems combined together.&lt;/p&gt;

&lt;p&gt;The core gameplay requires:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Grid modeling&lt;/li&gt;
&lt;li&gt;Graph traversal&lt;/li&gt;
&lt;li&gt;Path validation&lt;/li&gt;
&lt;li&gt;Dictionary lookup&lt;/li&gt;
&lt;li&gt;Scoring&lt;/li&gt;
&lt;li&gt;State management&lt;/li&gt;
&lt;li&gt;Touch interaction&lt;/li&gt;
&lt;li&gt;Board generation&lt;/li&gt;
&lt;li&gt;Difficulty balancing&lt;/li&gt;
&lt;li&gt;Performance considerations&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;The technology stack is only part of the problem.&lt;/p&gt;

&lt;p&gt;The more interesting challenge is finding clean boundaries between these systems.&lt;/p&gt;

&lt;p&gt;Astro works well for the website layer because it allows the application to contain static and interactive parts without forcing everything to become a client-side application.&lt;/p&gt;

&lt;p&gt;Vue 3 works well for the game layer because reactive state and composable logic map naturally to gameplay.&lt;/p&gt;

&lt;p&gt;And the Boggle rules themselves provide a surprisingly interesting algorithmic problem.&lt;/p&gt;

&lt;h2&gt;
  
  
  A Small Game Is a Good Engineering Exercise
&lt;/h2&gt;

&lt;p&gt;One reason I enjoy building browser games is that they force you to think about both software architecture and user experience.&lt;/p&gt;

&lt;p&gt;A Boggle board is small.&lt;/p&gt;

&lt;p&gt;The number of rules is small.&lt;/p&gt;

&lt;p&gt;The interface is small.&lt;/p&gt;

&lt;p&gt;But implementing it well requires thinking about algorithms, state, input devices, performance, accessibility, and product design at the same time.&lt;/p&gt;

&lt;p&gt;That's what makes these projects useful engineering exercises.&lt;/p&gt;

&lt;p&gt;If you'd like to see the result, I've published the browser version as &lt;a href="https://puzzle-boggle.com/" rel="noopener noreferrer"&gt;Puzzle Boggle&lt;/a&gt;.&lt;/p&gt;

&lt;p&gt;The project is still evolving, but building it has been a useful way to explore how Astro and Vue 3 can work together for a small, interactive web application.&lt;/p&gt;

&lt;p&gt;I hope some of these architectural ideas are useful for anyone building a browser game or another interactive application with Astro and Vue.&lt;/p&gt;

</description>
      <category>astro</category>
      <category>vue</category>
      <category>javascript</category>
      <category>webdev</category>
    </item>
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