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harunpehlivan/how-to-resize-and-compress-images.markdown

Created January 10, 2023 20:11
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How to Resize and Compress Images
Raw
index.html
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<link rel="stylesheet" href="style.css">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="script.js" defer></script>
</head>
<body>
<div class="wrapper">
<div class="upload-box">
<input type="file" accept="image/*" hidden>
<img src="http://bit.ly/3ATfPAV" alt="">
<p>Browse File to Upload</p>
</div>
<div class="content">
<div class="row sizes">
<div class="column width">
<label>Width</label>
<input type="number">
</div>
<div class="column height">
<label>Height</label>
<input type="number">
</div>
</div>
<div class="row checkboxes">
<div class="column ratio">
<input type="checkbox" id="ratio" checked>
<label for="ratio">Lock aspect ratio</label>
</div>
<div class="column quality">
<input type="checkbox" id="quality">
<label for="quality">Reduce quality</label>
</div>
</div>
<button class="download-btn">Download Image</button>
</div>
</div>
</body>
</html>
Raw
script.js
const uploadBox = document.querySelector(".upload-box"),
previewImg = uploadBox.querySelector("img"),
fileInput = uploadBox.querySelector("input"),
widthInput = document.querySelector(".width input"),
heightInput = document.querySelector(".height input"),
ratioInput = document.querySelector(".ratio input"),
qualityInput = document.querySelector(".quality input"),
downloadBtn = document.querySelector(".download-btn");
let ogImageRatio;
const loadFile = (e) => {
const file = e.target.files[0]; // getting first user selected file
if (!file) return; // return if user hasn't selected any file
previewImg.src = URL.createObjectURL(file); // passing selected file url to preview img src
previewImg.addEventListener("load", () => { // once img loaded
widthInput.value = previewImg.naturalWidth;
heightInput.value = previewImg.naturalHeight;
ogImageRatio = previewImg.naturalWidth / previewImg.naturalHeight;
document.querySelector(".wrapper").classList.add("active");
});
}
widthInput.addEventListener("keyup", () => {
// getting height according to the ratio checkbox status
const height = ratioInput.checked ? widthInput.value / ogImageRatio : heightInput.value;
heightInput.value = Math.floor(height);
});
heightInput.addEventListener("keyup", () => {
// getting width according to the ratio checkbox status
const width = ratioInput.checked ? heightInput.value * ogImageRatio : widthInput.value;
widthInput.value = Math.floor(width);
});
const resizeAndDownload = () => {
const canvas = document.createElement("canvas");
const a = document.createElement("a");
const ctx = canvas.getContext("2d");
// if quality checkbox is checked, pass 0.5 to imgQuality else pass 1.0
// 1.0 is 100% quality where 0.5 is 50% of total. you can pass from 0.1 - 1.0
const imgQuality = qualityInput.checked ? 0.5 : 1.0;
// setting canvas height & width according to the input values
canvas.width = widthInput.value;
canvas.height = heightInput.value;
// drawing user selected image onto the canvas
ctx.drawImage(previewImg, 0, 0, canvas.width, canvas.height);
// passing canvas data url as href value of <a> element
a.href = canvas.toDataURL("image/jpeg", imgQuality);
a.download = new Date().getTime(); // passing current time as download value
a.click(); // clicking <a> element so the file download
}
downloadBtn.addEventListener("click", resizeAndDownload);
fileInput.addEventListener("change", loadFile);
uploadBox.addEventListener("click", () => fileInput.click());
Raw
style.css
/* Import Google font - Poppins */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600&display=swap');
*{
margin: 0;
padding: 0;
box-sizing: border-box;
font-family: 'Poppins', sans-serif;
}
body{
display: flex;
align-items: center;
justify-content: center;
min-height: 100vh;
background: #e4702d;
}
.wrapper{
width: 450px;
height: 288px;
padding: 30px;
background: #fff;
border-radius: 9px;
transition: height 0.2s ease;
}
.wrapper.active{
height: 537px;
}
.wrapper .upload-box{
height: 225px;
display: flex;
cursor: pointer;
align-items: center;
justify-content: center;
flex-direction: column;
border-radius: 5px;
border: 2px dashed #afafaf;
}
.wrapper.active .upload-box{
border: none;
}
.upload-box p{
font-size: 1.06rem;
margin-top: 20px;
}
.wrapper.active .upload-box p{
display: none;
}
.wrapper.active .upload-box img{
width: 100%;
height: 100%;
object-fit: cover;
border-radius: 5px;
}
.wrapper .content{
opacity: 0;
margin-top: 28px;
pointer-events: none;
}
.wrapper.active .content{
opacity: 1;
pointer-events: auto;
transition: opacity 0.5s 0.05s ease;
}
.content .row{
display: flex;
justify-content: space-between;
}
.content .row .column{
width: calc(100% / 2 - 15px);
}
.row .column label{
font-size: 1.06rem;
}
.sizes .column input{
width: 100%;
height: 49px;
outline: none;
margin-top: 7px;
padding: 0 15px;
font-size: 1.06rem;
border-radius: 4px;
border: 1px solid #aaa;
}
.sizes .column input:focus{
padding: 0 14px;
border: 2px solid #927DFC;
}
.content .checkboxes{
margin-top: 20px;
}
.checkboxes .column{
display: flex;
align-items: center;
}
.checkboxes .column input{
width: 17px;
height: 17px;
margin-right: 9px;
accent-color: #927DFC;
}
.content .download-btn{
width: 100%;
color: #fff;
outline: none;
border: none;
cursor: pointer;
font-size: 1.06rem;
border-radius: 5px;
padding: 15px 0;
margin: 30px 0 10px;
background: #927DFC;
text-transform: uppercase;
}
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