Orchestrating Imperative Canvas Rendering via $effect

Snippet

Orchestrating Imperative Canvas Rendering via $effect

When dealing with imperative APIs like HTML5 Canvas, $effect serves as the bridge. Any change to 'color' or 'position' (if they are reactive runes) will trigger the effect, allowing for high-performance visual synchronization between state and pixels.

snippet.js
javascript
$effect(() => {
  const ctx = canvasElement.getContext('2d');
  ctx.clearRect(0, 0, 500, 500);
  ctx.fillStyle = color;
  ctx.fillRect(position.x, position.y, 50, 50);
});

svelte

Breakdown

canvasElement.getContext('2d');

Obtains the drawing context for the imperative API.

ctx.clearRect(0, 0, 500, 500);

Resets the frame before the next reactive draw cycle.

ctx.fillRect(position.x, position.y, 50, 50);

Draws the element using the current values of reactive state.

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Orchestrating Imperative Canvas Rendering via $effect

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