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Boof 2023-05-30 12:10:08 +02:00 committed by GitHub
parent 88993eb955
commit fdb1cd849c
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@ -1,8 +1,12 @@
<html>
<body>
<div>
<input type="file" id="image-input" accept="image/*">
<img id="preview"></img>
<button onclick="const img = document.getElementById('preview');
const blackAndWhiteImg = convertToBlackAndWhite(img);
">Black and white</button>
</div>
<script>
let imgInput = document.getElementById('image-input');
@ -25,5 +29,27 @@
}
});
</script>
<script>
function convertToBlackAndWhite(img) {
const canvas = document.createElement('canvas');
const ctx = canvas.getContext('2d');
const imgData = ctx.getImageData(0, 0, img.width, img.height);
for (let i = 0; i < imgData.data.length; i += 4) {
let count = imgData.data[i] + imgData.data[i + 1] + imgData.data[i + 2];
let colour = 0;
if (count > 383) colour = 255;
imgData.data[i] = colour;
imgData.data[i + 1] = colour;
imgData.data[i + 2] = colour;
imgData.data[i + 3] = 255;
}
ctx.putImageData(imgData, 0, 0);
return canvas.toDataURL('image/png');
}
</script>
</body>
</html>
</html>