jQuery - How do I get the image width of an online image?
Question
I have a project which consists of a HTML, JS and CSS file. When I open the project in my browser I have an input field (url input), a button and a canvas. After I insert the URL of an image in the input field and click the button, I want the canvas to resize according to the width and height of the image. Of course, I also want the image to be displayed in the canvas. Note: Later I want to add a functionality where someone can resize the image with a slider. This means that I really have to save the width of the image in a variable.
So, my main problem is that I don't know how to get the width of that image.
The last thing I tried is the following:
$('#btn_load').click(function () {
input_url = $('#input_url');
var url = input_url.val();
var img_width = url.width;
...
});
Would be glad about some help here, since I tried a lot of stuff in the last hours:)
EDIT:
I now also tried the following:
var inputURL, imgWidth;
inputURL = $('#input_url');
$('#btn_load').click(function () {
var url = inputURL.val();
var img = new Image();
img.src = url;
img.onload = function () {
imgWidth = img.width;
};
canvas.css({
'background-image': 'url(' + url + ')',
//'background-size': 'cover',
});
//This is just to check the width value
inputURL.val(imgWidth + url);
});
But still doesn't work.
3 answers
solution1
1 ACCPTED 2020-05-11 14:13:58
This will get the img width and height in the global variables 'imgHeight' and 'imgWidth' It will also display the image on the screen, width a slider to make it bigger or smaller, the min and max value of the input type range are dynamically set to the original width and height divider by 2 or for the maximum multiplied by 2.
Javascript:
var imgHeight;
var imgWidth;
var img = new Image();
function LoadImage() {
input_url = $('#input_url');
img.src = input_url.val();
//img.src = 'http://www.google.com/intl/en_ALL/images/logo.gif';
img.onload = function() {
imgHeight = this.height;
imgWidth = this.width;
//alert(imgHeight + " : " + imgWidth);
//Now set the image to html
document.getElementById("imgID").src=img.src;
//Now set the dimensions.
$("#imgID").css({'height' : imgHeight+'px', 'width' : imgWidth+'px'});
//Now set the range min to imgwidth / 2. and the max to imgwidth * 2
document.getElementById("range").min = imgWidth / 2;
document.getElementById("range").max = imgWidth * 2;
document.getElementById("range").value = imgWidth;
}
}
function ChangeImageSize(value) {
//Calculate new height so the image doesn't get stretched.
newHeight = value / imgWidth * imgHeight;
//Set the new width and height
$("#imgID").css({'height' : newHeight+'px', 'width' : value+'px'});
}
HTML
<button onclick="LoadImage()">click me</button>
<input type="range" id="range" oninput="ChangeImageSize(this.value)">
<input type="text" id="input_url">
<img id="imgID">
solution2
0 2020-05-11 13:52:23
You should load the imag to get its natural width and height:
var img = new Image();
img.src = $('#input_url').val();
img.onload = function () {
imageWidth= img.naturalWidth;
imageHeight = img.naturalHeight;
...
}
solution3
0 2020-05-11 14:07:16
<html>
<head>
<script src="https://code.jquery.com/jquery-3.5.1.js" > </script>
<script>
function loadUrl() {
//You can get the value of your url_input and use it instead.
var url = "https://cdn.sstatic.net/Sites/stackoverflow/Img/apple-touch-icon.png?v=c78bd457575a"; //You can take it from your input_url
$("#img-size").attr("src", url);
};
function imageLoaded(sender){
alert($(sender).width() + 'x' + $(sender).height());
}
</script>
</head>
<body>
<img src="" id="img-size" onload="imageLoaded(this);">
<input type="button" onclick="loadUrl();" id="btn_load" value="Load" />
</body>
</html>
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