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Add support for pasting an image in the page, and a grayscale button #2

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Add support for pasting an image in the page, and a grayscale button #2

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da38789
Add a button to view the image as grayscale
AmineI Jun 15, 2020
633d04e
Add support for pasting an image to the page
AmineI Jun 15, 2020
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27 changes: 23 additions & 4 deletions iview.html
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,10 @@

<body>

<p>Open image: <input type="file" id="inputImage"/></p>
<p>
Open image: <input type="file" id="inputImage"/>
<button onclick="grayscale()">Grayscale</button>
</p>

<canvas id="canvas" style="margin:12px;"></canvas>

Expand All @@ -38,6 +41,10 @@
window.onload = function() {
var inputImage = document.getElementById('inputImage');
inputImage.addEventListener('change', handleImageFiles, false);
window.addEventListener('paste', e => {
inputImage.files = e.clipboardData.files
handleImageFiles()
},false)
}

function copyMousePos(evt) {
Expand All @@ -63,9 +70,21 @@
+ p[2] + '</td><td>Alpha: ' + p[3]+"</td></table>";
return {x, y};
}

function handleImageFiles(e) {
var url = URL.createObjectURL(e.target.files[0]);

var grayscale = function() {
var imageData= ctx.getImageData(0, 0, cvs.width, cvs.height)
var data= imageData.data
for (var i = 0; i < data.length; i += 4) {
var avg = (data[i] + data[i + 1] + data[i + 2]) / 3;
data[i] = avg; // red
data[i + 1] = avg; // green
data[i + 2] = avg; // blue
}
ctx.putImageData(imageData, 0, 0);
};

function handleImageFiles() {
var url = URL.createObjectURL(inputImage.files[0]);
var img = new Image();
img.onload = function() {
cvs.width = img.width;
Expand Down