Created
October 18, 2020 22:47
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Save drofp/c327ec11f168457fd4042b93ba9a658c to your computer and use it in GitHub Desktop.
show pixels values where mouse is hovering: https://yangcha.github.io/ImageViewer/
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<!DOCTYPE HTML> | |
<!-- Display image, show mouse position and pixel values | |
Author: Changjiang Yang | |
Date: 08/14/2016 | |
TODO: Add drag and drop | |
source: https://yangcha.github.io/ImageViewer/ | |
--> | |
<html> | |
<head> | |
<style> | |
div.footer { | |
position: fixed; | |
bottom: 0; | |
left: 0; | |
margin: 0 auto; | |
background: #0072BB; | |
color:#fff; | |
} | |
</style> | |
</head> | |
<body> | |
<p>Open image: <input type="file" id="inputImage"/></p> | |
<canvas id="canvas" style="margin:12px;"></canvas> | |
<div class="footer" id="results">Move mouse over image to show mouse location and pixel value and alpha</div> | |
<script> | |
var URL = window.URL; | |
var cvs = document.getElementById('canvas'); | |
var ctx = cvs.getContext('2d'); | |
var res = document.getElementById('results'); | |
cvs.addEventListener('mousemove', mousePos, false); | |
window.onload = function() { | |
var inputImage = document.getElementById('inputImage'); | |
inputImage.addEventListener('change', handleImageFiles, false); | |
} | |
function mousePos(evt) { | |
var rect = cvs.getBoundingClientRect(); | |
var x = parseInt(evt.clientX - rect.left); | |
var y = parseInt(evt.clientY - rect.top); | |
var p = ctx.getImageData(x, y, 1, 1).data; | |
results.innerHTML = '<table style="width:100%;table-layout:fixed"><td>X: ' | |
+ x + '</td><td>Y: ' + y + '</td><td>Red: ' | |
+ p[0] + '</td><td>Green: ' + p[1] + '</td><td>Blue: ' | |
+ p[2] + '</td><td>Alpha: ' + p[3]+"</td></table>"; | |
return {x, y}; | |
} | |
function handleImageFiles(e) { | |
var url = URL.createObjectURL(e.target.files[0]); | |
var img = new Image(); | |
img.onload = function() { | |
cvs.width = img.width; | |
cvs.height = img.height; | |
ctx.drawImage(img, 0, 0); | |
} | |
img.src = url; | |
} | |
</script> | |
</body> | |
</html> |
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