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How to read an image from the localhost url and get its width and height in javascript

Hey guys I am new to javascript and react, I want to get the image's width and height when its loaded from the image url. How to do it? Help would be much appreciated.
I know it starts with this but doesn't really understand how to continue..
const imageDimension = (img) => {
let reader = new FileReader();
}
Thanks

You can use the load event:
const image = new Image();
image.addEventListener('load', () => {
console.log('image height', image.height);
console.log('image width', image.width);
})
image.src = 'http://localhost/image.png'

The "load" event listener works if the image is going to be loaded in the browser.
However, if that is not the case, and you really don't want the image to be visible then you could do this.
const getImageDimension = (imgUrl) => {
const img = new Image();
// set some styles to hide the img
img.src = imgUrl;
img.style.left = -9999;
img.style.position = 'absolute';
img.style.visibility = 'hidden';
// inject it into the page
document.body.appendChild(img);
// resolve when image has been injected and
// img.height and width is available
return new Promise((resolve) => {
const interval = setInterval(() => {
const height = img.naturalHeight;
const width = img.naturalWidth;
if (height && width) {
clearInterval(interval);
document.body.removeChild(img);
resolve({
height,
width,
})
}
})
})
}
const SAMPLE_IMAGE = "https://asia.olympus-imaging.com/content/000107507.jpg";
getImageDimension(SAMPLE_IMAGE)
.then((dimension) => console.log(dimension))

How to wait for image to load before setting scope in AngularJS?

I'm using AngularJS and TypeScript. I am using the cytoscape library with the extension cytoscape-edgehandles and the wrapper ngCytoscape for AngularJS. I am trying to add an image to the hover handle of the nodes, however the implementation of the drawImage method in cytoscape-edgehandles 2.7.1 does not wait for the image to load before drawing, therefore a range error occurs.
I have tried to give the cytoscape graph the options after the image is loaded, however the cytoscape graph expects the options to immediately be available for use. So somehow I need to load the image before passing it to the graph.
In the constructor of the controller:
this.$scope.ehOptions = this.GetEhOptions();
The get EhOptions method:
protected GetEhOptions(): GraphModels.EhOptions {
var options = new GraphModels.EhOptions;
var img = new Image();
img.width = 25;
img.height = 25
img.src = "../../Content/icons/ic_circle_add_24px.svg";
options.handleImage = img;
img.addEventListener('load', e => {
return options;
});
}
This results in the options never being loaded by the graph. If I do this in stead, I get all the options, except the image:
var options = new GraphModels.EhOptions;
var img = new Image();
img.width = 25;
img.height = 25
img.src = "../../Content/icons/ic_circle_add_24px.svg";
img.addEventListener('load', e => {
options.handleImage = img;
});
return options;
The code of cytoscape-edgehandles concerning the handleIcon:
if(options().handleIcon){
var icon = options().handleIcon;
var width = icon.width*cy.zoom(), height = icon.height*cy.zoom();
ctx.drawImage(icon, hx-(width/2), hy-(height/2), width, height);
}
If it is changed to this, then it works:
if (true) {
var img = new Image();
var width = 25 * cy.zoom();
var height = 25 * cy.zoom();
img.width = width;
img.height = height
img.src = "../../Content/icons/ic_circle_add_24px.svg";
img.addEventListener('load', e => {
ctx.drawImage(img, hx - (width/2), hy - (height/2), width, height)
})
}
However, I cannot change the library code.
Hope you have any ideas. Thanks!

Create an AngularJS promise:
protected GetEhOptions(): GraphModels.EhOptions {
var deferred = $q.defer();
var options = new GraphModels.EhOptions;
var img = new Image();
img.width = 25;
img.height = 25
img.src = "../../Content/icons/ic_circle_add_24px.svg";
options.handleImage = img;
img.addEventListener('load', e => {
̶r̶e̶t̶u̶r̶n̶ ̶o̶p̶t̶i̶o̶n̶s̶;̶
deferred.resolve(options);
});
img.addEventListener('error', e => {
deferred.reject(e);
});
return deferred.promise;
}
Then extract the options from the returned promise:
this.GetEhOptions().then(options => {
this.$scope.ehOptions = options;
});
For more information, see
AngularJS $q Service API Reference - The Deferred API

I don't have any idea about cytoscape, but try this,
options:any = new GraphModels.EhOptions;
let globleThis = this;
var img = new Image();
img.width = 25;
img.height = 25
img.src = "../../Content/icons/ic_circle_add_24px.svg";
this.options.handleImage = img;
img.addEventListener('load', e => {
this.GetEhOptions(globleThis.options);
});
protected GetEhOptions(options): GraphModels.EhOptions {
return options;
}
or
var options = new GraphModels.EhOptions;
var img = new Image();
img.width = 25;
img.height = 25
img.src = "../../Content/icons/ic_circle_add_24px.svg";
img.addEventListener('load', e => {
return options.handleImage = img;
});

No experiance with a specific library but I worked with similar ones. In those cases I wrapped it into my own directive and then controlled the creation from there directly. In that case you have access to the $element and you can create it on the fly.

getting image width and height from input:files multiple [duplicate]

I have a Base64 image encoded that you can find here. How can I get the height and the width of it?

var i = new Image();
i.onload = function(){
alert(i.width + ", " + i.height);
};
i.src = imageData;

For synchronous use just wrap it into a promise like this:
function getImageDimensions(file) {
return new Promise (function (resolved, rejected) {
var i = new Image()
i.onload = function(){
resolved({w: i.width, h: i.height})
};
i.src = file
})
}
then you can use await to get the data in synchronous coding style:
var dimensions = await getImageDimensions(file)

I found that using .naturalWidth and .naturalHeight had the best results.
const img = new Image();
img.src = 'https://via.placeholder.com/350x150';
img.onload = function() {
const imgWidth = img.naturalWidth;
const imgHeight = img.naturalHeight;
console.log('imgWidth: ', imgWidth);
console.log('imgHeight: ', imgHeight);
};
Documentation:
HTMLImageElement.naturalWidth
HTMLImageElement.naturalHeight
This is only supported in modern browsers. NaturalWidth and NaturalHeight in IE

A more modern solution is to use HTMLImageElement.decode() instead of the onload event. decode() returns a promise and thus can be used synchronously with await.
Asynchronous use:
let img = new Image();
img.src = "myImage.png";
img.decode().then(() => {
let width = img.width;
let height = img.height;
// Do something with dimensions
});
Synchronous use (inside an async function):
let img = new Image();
img.src = "myImage.png";
await img.decode();
let width = img.width;
let height = img.height;
// Do something with dimensions

Create a hidden <img> with that image and then use jQuery's .width() and . height()
$("body").append("<img id='hiddenImage' src='" + imageData + "' />");
var width = $('#hiddenImage').width();
var height = $('#hiddenImage').height();
$('#hiddenImage').remove();
alert("width:" + width + " height:" + height);
Test here: JSFiddle
The image is not initially created hidden. It gets created, and then you get width and height and then remove it. This may cause a very short visibility in large images. In this case, you have to wrap the image in another container and make that container hidden, not the image itself.
Another Fiddle that does not add to the DOM as per gp.'s answer:
here

Get image width and height from the Base64 code in JavaScript

I have a Base64 image encoded that you can find here. How can I get the height and the width of it?

var i = new Image();
i.onload = function(){
alert(i.width + ", " + i.height);
};
i.src = imageData;

For synchronous use just wrap it into a promise like this:
function getImageDimensions(file) {
return new Promise (function (resolved, rejected) {
var i = new Image()
i.onload = function(){
resolved({w: i.width, h: i.height})
};
i.src = file
})
}
then you can use await to get the data in synchronous coding style:
var dimensions = await getImageDimensions(file)

I found that using .naturalWidth and .naturalHeight had the best results.
const img = new Image();
img.src = 'https://via.placeholder.com/350x150';
img.onload = function() {
const imgWidth = img.naturalWidth;
const imgHeight = img.naturalHeight;
console.log('imgWidth: ', imgWidth);
console.log('imgHeight: ', imgHeight);
};
Documentation:
HTMLImageElement.naturalWidth
HTMLImageElement.naturalHeight
This is only supported in modern browsers. NaturalWidth and NaturalHeight in IE

A more modern solution is to use HTMLImageElement.decode() instead of the onload event. decode() returns a promise and thus can be used synchronously with await.
Asynchronous use:
let img = new Image();
img.src = "myImage.png";
img.decode().then(() => {
let width = img.width;
let height = img.height;
// Do something with dimensions
});
Synchronous use (inside an async function):
let img = new Image();
img.src = "myImage.png";
await img.decode();
let width = img.width;
let height = img.height;
// Do something with dimensions

Create a hidden <img> with that image and then use jQuery's .width() and . height()
$("body").append("<img id='hiddenImage' src='" + imageData + "' />");
var width = $('#hiddenImage').width();
var height = $('#hiddenImage').height();
$('#hiddenImage').remove();
alert("width:" + width + " height:" + height);
Test here: JSFiddle
The image is not initially created hidden. It gets created, and then you get width and height and then remove it. This may cause a very short visibility in large images. In this case, you have to wrap the image in another container and make that container hidden, not the image itself.
Another Fiddle that does not add to the DOM as per gp.'s answer:
here

Check image width and height before upload with Javascript

I have a JPS with a form in which a user can put an image:
<div class="photo">
<div>Photo (max 240x240 and 100 kb):</div>
<input type="file" name="photo" id="photoInput" onchange="checkPhoto(this)"/>
</div>
I have written this js:
function checkPhoto(target) {
if(target.files[0].type.indexOf("image") == -1) {
document.getElementById("photoLabel").innerHTML = "File not supported";
return false;
}
if(target.files[0].size > 102400) {
document.getElementById("photoLabel").innerHTML = "Image too big (max 100kb)";
return false;
}
document.getElementById("photoLabel").innerHTML = "";
return true;
}
which works fine to check file type and size. Now I want to check image width and height but I cannot do it.
I have tried with target.files[0].width but I get undefined. With other ways I get 0.
Any suggestions?

The file is just a file, you need to create an image like so:
var _URL = window.URL || window.webkitURL;
$("#file").change(function (e) {
var file, img;
if ((file = this.files[0])) {
img = new Image();
var objectUrl = _URL.createObjectURL(file);
img.onload = function () {
alert(this.width + " " + this.height);
_URL.revokeObjectURL(objectUrl);
};
img.src = objectUrl;
}
});
Demo: http://jsfiddle.net/4N6D9/1/
I take it you realize this is only supported in a few browsers. Mostly firefox and chrome, could be opera as well by now.
P.S. The URL.createObjectURL() method has been removed from the MediaStream interface. This method has been deprecated in 2013 and superseded by assigning streams to HTMLMediaElement.srcObject. The old method was removed because it is less safe, requiring a call to URL.revokeOjbectURL() to end the stream. Other user agents have either deprecated (Firefox) or removed (Safari) this feature feature.
For more information, please refer here.

In my view the perfect answer you must required is
var reader = new FileReader();
//Read the contents of Image File.
reader.readAsDataURL(fileUpload.files[0]);
reader.onload = function (e) {
//Initiate the JavaScript Image object.
var image = new Image();
//Set the Base64 string return from FileReader as source.
image.src = e.target.result;
//Validate the File Height and Width.
image.onload = function () {
var height = this.height;
var width = this.width;
if (height > 100 || width > 100) {
alert("Height and Width must not exceed 100px.");
return false;
}
alert("Uploaded image has valid Height and Width.");
return true;
};
};

I agree. Once it is uploaded to somewhere the user's browser can access then it is pretty easy to get the size. As you need to wait for the image to load you'll want to hook into the onload event for img.
Updated example:
// async/promise function for retrieving image dimensions for a URL
function imageSize(url) {
const img = document.createElement("img");
const promise = new Promise((resolve, reject) => {
img.onload = () => {
// Natural size is the actual image size regardless of rendering.
// The 'normal' `width`/`height` are for the **rendered** size.
const width = img.naturalWidth;
const height = img.naturalHeight;
// Resolve promise with the width and height
resolve({width, height});
};
// Reject promise on error
img.onerror = reject;
});
// Setting the source makes it start downloading and eventually call `onload`
img.src = url;
return promise;
}
// How to use in an async function
(async() => {
const imageUrl = 'http://your.website.com/userUploadedImage.jpg';
const imageDimensions = await imageSize(imageUrl);
console.info(imageDimensions); // {width: 1337, height: 42}
})();
Older example:
var width, height;
var img = document.createElement("img");
img.onload = function() {
// `naturalWidth`/`naturalHeight` aren't supported on <IE9. Fallback to normal width/height
// The natural size is the actual image size regardless of rendering.
// The 'normal' width/height are for the **rendered** size.
width = img.naturalWidth || img.width;
height = img.naturalHeight || img.height;
// Do something with the width and height
}
// Setting the source makes it start downloading and eventually call `onload`
img.src = "http://your.website.com/userUploadedImage.jpg";

This is the easiest way to check the size
let img = new Image()
img.src = window.URL.createObjectURL(event.target.files[0])
img.onload = () => {
alert(img.width + " " + img.height);
}
Check for specific size. Using 100 x 100 as example
let img = new Image()
img.src = window.URL.createObjectURL(event.target.files[0])
img.onload = () => {
if(img.width === 100 && img.height === 100){
alert(`Nice, image is the right size. It can be uploaded`)
// upload logic here
} else {
alert(`Sorry, this image doesn't look like the size we wanted. It's
${img.width} x ${img.height} but we require 100 x 100 size image.`);
}
}

Attach the function to the onchange method of the input type file /onchange="validateimg(this)"/
function validateimg(ctrl) {
var fileUpload = ctrl;
var regex = new RegExp("([a-zA-Z0-9\s_\\.\-:])+(.jpg|.png|.gif)$");
if (regex.test(fileUpload.value.toLowerCase())) {
if (typeof (fileUpload.files) != "undefined") {
var reader = new FileReader();
reader.readAsDataURL(fileUpload.files[0]);
reader.onload = function (e) {
var image = new Image();
image.src = e.target.result;
image.onload = function () {
var height = this.height;
var width = this.width;
if (height < 1100 || width < 750) {
alert("At least you can upload a 1100*750 photo size.");
return false;
}else{
alert("Uploaded image has valid Height and Width.");
return true;
}
};
}
} else {
alert("This browser does not support HTML5.");
return false;
}
} else {
alert("Please select a valid Image file.");
return false;
}
}

const ValidateImg = (file) =>{
let img = new Image()
img.src = window.URL.createObjectURL(file)
img.onload = () => {
if(img.width === 100 && img.height ===100){
alert("Correct size");
return true;
}
alert("Incorrect size");
return true;
}
}

I think this may be the simplest for uploads if you want to use it other functions.
async function getImageDimensions(file) {
let img = new Image();
img.src = URL.createObjectURL(file);
await img.decode();
let width = img.width;
let height = img.height;
return {
width,
height,
}
}
Use like
const {width, height } = await getImageDimensions(file)
Suppose you were storing an image for Tiger taken in Kenya. So you could use it like to upload to cloud storage and then store photo information.
const addImage = async (file, title, location) => {
const { width, height } = await getImageDimensions(file)
const url = await uploadToCloudStorage(file) // returns storage url
await addToDatabase(url, width, height, title, location)
}

function validateimg(ctrl) {
var fileUpload = $("#txtPostImg")[0];
var regex = new RegExp("([a-zA-Z0-9\s_\\.\-:])+(.jpg|.png|.gif)$");
if (regex.test(fileUpload.value.toLowerCase())) {
if (typeof (fileUpload.files) != "undefined") {
var reader = new FileReader();
reader.readAsDataURL(fileUpload.files[0]);
reader.onload = function (e) {
var image = new Image();
image.src = e.target.result;
image.onload = function () {
var height = this.height;
var width = this.width;
console.log(this);
if ((height >= 1024 || height <= 1100) && (width >= 750 || width <= 800)) {
alert("Height and Width must not exceed 1100*800.");
return false;
}
alert("Uploaded image has valid Height and Width.");
return true;
};
}
} else {
alert("This browser does not support HTML5.");
return false;
}
} else {
alert("Please select a valid Image file.");
return false;
}
}

You can do the steps for previewing the image without showing it which is supported on all browsers. Following js code shows you how to check the width and height :
var file = e.target.files[0];
if (/\.(jpe?g|png|gif)$/i.test(file.name)) {
var reader = new FileReader();
reader.addEventListener("load", function () {
var image = new Image();
image.src = this.result as string;
image.addEventListener('load', function () {
console.log(`height: ${this.height}, width: ${this.width}`);
});
}, false);
reader.readAsDataURL(file);
}
Based on Mozilla docs:
The readAsDataURL method is used to read the contents of the specified
Blob or File. When the read operation is finished, the readyState
becomes DONE, and the loadend is triggered. At that time, the result
attribute contains the data as a data: URL representing the file's
data as a base64 encoded string.
And the browser compatibility is listed too.

In my case, I needed to also prevent the form from being submited, so here is the solution that worked for me.
The preventDefault will stop the form action, then we check the size and dimensions of the image in the onload function.
If all good, we allow the submit.
As the submit button gets disabled if a user still tries to submit the form with an invalid image, I also had to re-able the submit button once a valid image is inputted.
const validateMaxImageFileSize = (e) => {
e.preventDefault();
const el = $("input[type='file']")[0];
if (el.files && el.files[0]) {
const file = el.files[0];
const maxFileSize = 5242880; // 5 MB
const maxWidth = 1920;
const maxHeight = 1080;
const img = new Image();
img.src = window.URL.createObjectURL(file);
img.onload = () => {
if (file.type.match('image.*') && file.size > maxFileSize) {
alert('The selected image file is too big. Please choose one that is smaller than 5 MB.');
} else if (file.type.match('image.*') && (img.width > maxWidth || img.height > maxHeight)) {
alert(`The selected image is too big. Please choose one with maximum dimensions of ${maxWidth}x${maxHeight}.`);
} else {
e.target.nodeName === 'INPUT'
? (e.target.form.querySelector("input[type='submit']").disabled = false)
: e.target.submit();
}
};
}
};
$('form.validate-image-size').on('submit', validateMaxImageFileSize);
$("form.validate-image-size input[type='file']").on('change', validateMaxImageFileSize);

function uploadfile(ctrl) {
var validate = validateimg(ctrl);
if (validate) {
if (window.FormData !== undefined) {
ShowLoading();
var fileUpload = $(ctrl).get(0);
var files = fileUpload.files;
var fileData = new FormData();
for (var i = 0; i < files.length; i++) {
fileData.append(files[i].name, files[i]);
}
fileData.append('username', 'Wishes');
$.ajax({
url: 'UploadWishesFiles',
type: "POST",
contentType: false,
processData: false,
data: fileData,
success: function(result) {
var id = $(ctrl).attr('id');
$('#' + id.replace('txt', 'hdn')).val(result);
$('#imgPictureEn').attr('src', '../Data/Wishes/' + result).show();
HideLoading();
},
error: function(err) {
alert(err.statusText);
HideLoading();
}
});
} else {
alert("FormData is not supported.");
}
}