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svelte/site/content/tutorial/06-bindings/12-bind-this/app-b/App.svelte

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<script>
import { onMount } from 'svelte';
let canvas;
onMount(() => {
const ctx = canvas.getContext('2d');
let frame = requestAnimationFrame(loop);
function loop(t) {
frame = requestAnimationFrame(loop);
const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
for (let p = 0; p < imageData.data.length; p += 4) {
const i = p / 4;
const x = i % canvas.width;
const y = i / canvas.width >>> 0;
const r = 64 + (128 * x / canvas.width) + (64 * Math.sin(t / 1000));
const g = 64 + (128 * y / canvas.height) + (64 * Math.cos(t / 1000));
const b = 128;
imageData.data[p + 0] = r;
imageData.data[p + 1] = g;
imageData.data[p + 2] = b;
imageData.data[p + 3] = 255;
}
ctx.putImageData(imageData, 0, 0);
}
return () => {
cancelAnimationFrame(frame);
};
});
</script>
<canvas
bind:this={canvas}
width={32}
height={32}
></canvas>
<style>
canvas {
width: 100%;
height: 100%;
background-color: #666;
-webkit-mask: url(svelte-logo-mask.svg) 50% 50% no-repeat;
mask: url(svelte-logo-mask.svg) 50% 50% no-repeat;
}
</style>