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@fujidig
Created August 12, 2017 13:57
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<!-- 白黒画像を透過画像に変換する -->
<body bgcolor="blue">
<script>
let img=new Image;
img.src="hierarchy-000001.png";
img.onload=()=>{
let canvas=document.createElement("canvas");
canvas.width=img.width;
canvas.height=img.height;
let ctx=canvas.getContext("2d");
ctx.drawImage(img, 0, 0);
var imageData = ctx.getImageData(0,0,canvas.width, canvas.height);
var data = imageData.data;
for (var i = 0; i < data.length; i += 4) {
let c = data[i];
data[i] = data[i + 1] = data[i + 2] = 0;
data[i + 3] = 255 - c;
}
ctx.putImageData(imageData, 0, 0);
document.body.appendChild(canvas);
}
</script>
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