How to get the true image height using JQuery? - javascript

I want to load html , and then get the true image height.
$("#cover").html(stuff); //this has the image inside it
$(function(){
console.log($("#cover img").height()); //sometimes it's 0
});
For some reason, height is sometimes 0. Could it be because the image hasn't been fully loaded yet, and JQuery sees it as 0? If so, how do I overcome this? Is there a callback or something when the image is loaded?

You can use the .load() method of jQuery
$('#cover').html(stuff);
$('#cover img').load(function () {
console.log($(this).height());
};

Why do the console.log inside an anonymous function? Have you tried this?
$("#cover").html(stuff); //this has the image inside it
console.log($("#cover img").height());

//locate the image(s)
$("#cover img").each(function(){
//Build a new Image Object outside the DOM
//that way, CSS won't affect it
var img = new Image();
//add a callback when loaded
img.onload = function(){
//your width and height
//img.width
//img.height
}
//use the image src to load
//use attr() to resolve path issues across browsers
img.src = $(this).attr('src');
});

try to using load method method that we can take advantage of to make this work the way we want it too.
The problem we have right now is that, in the Webkit browsers, the jQuery code runs when the DOM is ready and the DOM is ready before the image has been loaded. So the code runs but since there’s no image to get a width of, we get 0 for the image’s width. We can use the load method to make the code wait until the window has loaded entirely before it runs.
$(window).load(function() {
console.log($("#cover img").height());
});

try using attr() to get the height:-
$("#yourElemengtID").attr('height')

Here is a piece of small code i used before hope this will help you
On my displayed image when mouse is in call this function
function MouseIn()
{
var src;
//to get original image size
var img =$(this);// displayed image
var theImage = new Image();// create a cache image
var imgsource =img.attr("src");// take the src of displayed image
theImage.src = imgsource;// give cached image the source of displayed image
var original_height = theImage.height// take height of image from the source
var original_width = theImage.width;//take width of image from the source
// to get the displayed image size
var Image_displaysize_width= img.width();
var Image_displaysize_height= img.height();
}

Don't you mean to do something like this?
jQuery("#myImg")[0].naturalHeight
better still don't use overhead of jQuery when possible.
document.getElementById('myImg').naturalHeight

Related

Determine when an image has loaded in svg with RaphaelJS

I'm trying to work out how to determine when an svg image has loaded in the browser. I'm using Raphael JS and I've tried:
var image = paper.image(path, 0,0,10,10);
image.node.addEventListener('load', function(){alert("test");});
and:
$('image').on('load')
all to no avail. I've also used "onload" and "onsvgload" none of which work.
Is there away to determine if an svg image has actually loaded?
I even tried loading the image using an Image() object and then calling paper.image() - but I get two calls to the image (instead of using the preloaded image);
ie:
var preload = new Image();
preload.src = imgPath;
preload.addEventListener('load', function () {
image.path = preload.src;
//Now load image in raphael - except this still forces the browser to make another call for the image
});
Any ideas?
Using the onLoad event handler works, with one additional line of code:
var image = paper.image(path, 0,0,10,10);
var image_node = image.node;
image_node.setAttribute('externalResourcesRequired','true');
image_node.addEventListener("load", function() {
console.log("image is loaded!");
})
You need to set the externalResourcesRequired attribute to true. You may read more about it here: http://www.w3.org/TR/SVG/struct.html#ExternalResourcesRequired

Javascript slowly "flush" DOM Tree

I have really strange problem. I'm trying to get width and height of an image using following way:
Create a image tag and add .src to it.
add this image tag to document.body.
making this image tag visible (display:inline).
getting .offsetWidth and .offsetHeight of element.
hidding image tag(display:none);
all this is done using JS and it all work really well on my localhost, but when I uploaded a site to my client hosting provider I was amazed. offsetWidth and .offsetHeight was 0 in step 4. Why do that happen? I think that I need some kind of "flush" after step 3 before step 4, but I'm not exactly sure. Any suggestions ? Thank you.
You have to wait for the image to actually load over the network. You don't need to add the thing to the DOM either:
var img = new Image();
img.onload = function() {
handleImageSize(this.width, this.height);
};
img.src = "http://whatever.com/your/img.jpg";
Here, "handleImageSize" would be a function you write to do whatever it is you need to do with the image dimensions.
This was probably caused by the image not being loaded yet. Try something like this:
img.onload = function() {
// get the offsetWidth and offsetHeight
}
As other answers suggest, is due to the image not being fully loaded by the DOM. This was working fine on your local server as I suspect you were loading images locally, meaning they were almost instantaneous; however after moving them to the server there is a slight delay. It's an easily overlooked problem, that is easily fixed.
Other answers will do the trick; but here's the jQuery version for sake of argument
var img = $('<img>', {
src: 'http://dummyimage.com/150/000/fff.gif'
}).one('load', function() {
var offsets = $(this).offset();
});
$('body').append(img);
jsFiddle

Image width traces zero with onload when cached

I'm building a Javascript lightbox and I'm trying to adjust the size once the image has loaded. I'm using the code below, which works fine - it outputs the correct width once loaded.
My problem:
When I refresh, it will load the image instantly from the cache, and it seems to bypass the load. I get an instant zero for the width. Why does this happen?
My code:
var oImage = new Image();
oImage.src = 'http://mydomain.com/image.png';
container.html(oImage);
oImage.onload = function(){
alert(this.width);
}
** Update **
#Alex: This is the code I've tried with your plugin, I assume I'm probably doing something wrong. I'd be eager to get this working because your plugin looks quite good.
container.waitForImages(function() {
var cWidth = $(this).width();
alert("width: "+cWidth); // returns 0 - works first time but not cached
});
// Adding the image to the container for preload
container.html('<img src="mygraphic.png" />');
You need to do a few things...
Check the complete property of the img element.
Attach the load event before setting the src property.
Also, I found creating a new Image and assigning the src there is the best way to determine if the image has loaded or not.
You may want to switch the .html() and the .onload() calls.
If the image is loading from cache, I'm imagining that the .html() call completes before the script has had a chance to attach a function handler to the image's onload event. Therefore, effectively bypassing the load event itself (as the image has already loaded).
If it's still downloading the image (i.e. not cached), there will be more than enough time to call the .onload attach before the image completely finishes rendering.
While you're at it, you may want to do this the jQuery way, just so you're attaching events more similarly to DOM2 than DOM0.
var image = $('<img/>', {
src : 'http://mydomain.com/image.png'
}).load(function () {
alert(this.width);
})
// maybe clear container before if you want
.appendTo(container);
If we're going to have to set the src after the onload, we might as well do this instead:
var image = $('<img/>')
.load(function () {
alert(this.width);
})
.attr('src','http://mydomain.com/image.png')
.appendTo(container)
;
Hopefully that works cleanly.
This answer JavaScript: Know when an image is fully loaded suggests that you should set onload before setting src

Get image size when it loads from an extern URL in Javascript

I need to know the image size when it loads from an extern URL because the project needs to resize the image div.
I need to do something like this:
<img id="imglegend'+layername+'" src="url_to_an_extern_host" />
And, using Javascript and JQuery:
$('#imglegend'+layername).ready(function(){
var h = $('#imglegend'+layername);
// Resize image div container
});
But this didn't work. Is it possible to do?
Thanks in advance!
$('#imglegend').load(function(){
var w = $(this).width();
var h = $(this).height();
alert(w); alert(h);
}).error(function (){
$(this).remove();//remove image if it fails to load// or what ever u want
})
Images don't have a ready event. They do however have a load event:
$('#imglegend'+layername).load(function(){
alert(this.width);
});
EDIT: BTW, you need to make sure that the image isn't loaded before you attach the event handler. You'll wither need to assign the src in your script after assigning the handler instead of in your HTML, or assign the handler in the onload HTML instead.

Get the real width and height of an image with JavaScript? (in Safari/Chrome)

I am creating a jQuery plugin.
How do I get the real image width and height with Javascript in Safari?
The following works with Firefox 3, IE7 and Opera 9:
var pic = $("img")
// need to remove these in of case img-element has set width and height
pic.removeAttr("width");
pic.removeAttr("height");
var pic_real_width = pic.width();
var pic_real_height = pic.height();
But in Webkit browsers like Safari and Google Chrome values are 0.
Webkit browsers set the height and width property after the image is loaded. Instead of using timeouts, I'd recommend using an image's onload event. Here's a quick example:
var img = $("img")[0]; // Get my img elem
var pic_real_width, pic_real_height;
$("<img/>") // Make in memory copy of image to avoid css issues
.attr("src", $(img).attr("src"))
.load(function() {
pic_real_width = this.width; // Note: $(this).width() will not
pic_real_height = this.height; // work for in memory images.
});
To avoid any of the effects CSS might have on the image's dimensions, the code above makes an in memory copy of the image. This is a very clever solution suggested by FDisk.
You can also use the naturalHeight and naturalWidth HTML5 attributes.
Use the naturalHeight and naturalWidth attributes from HTML5.
For example:
var h = document.querySelector('img').naturalHeight;
Works in IE9+, Chrome, Firefox, Safari and Opera (stats).
function getOriginalWidthOfImg(img_element) {
var t = new Image();
t.src = (img_element.getAttribute ? img_element.getAttribute("src") : false) || img_element.src;
return t.width;
}
You don't need to remove style from the image or image dimensions attributes. Just create an element with javascript and get the created object width.
There's a lot of discussion in the accepted answer about a problem where the onload event doesn't fire if an image is loaded from the WebKit cache.
In my case, onload fires for cached images, but the height and width are still 0. A simple setTimeout resolved the issue for me:
$("img").one("load", function(){
var img = this;
setTimeout(function(){
// do something based on img.width and/or img.height
}, 0);
});
I can't speak as to why the onload event is firing even when the image is loaded from the cache (improvement of jQuery 1.4/1.5?) — but if you are still experiencing this problem, maybe a combination of my answer and the var src = img.src; img.src = ""; img.src = src; technique will work.
(Note that for my purposes, I'm not concerned about pre-defined dimensions, either in the image's attributes or CSS styles — but you might want to remove those, as per Xavi's answer. Or clone the image.)
The root problem is that WebKit browsers (Safari and Chrome) load JavaScript and CSS information in parallel. Thus, JavaScript may execute before the styling effects of CSS have been computed, returning the wrong answer. In jQuery, I've found that the solution is to wait until document.readyState == 'complete', .e.g.,
jQuery(document).ready(function(){
if (jQuery.browser.safari && document.readyState != "complete"){
//console.info('ready...');
setTimeout( arguments.callee, 100 );
return;
}
... (rest of function)
As far as width and height goes... depending on what you are doing you may want offsetWidth and offsetHeight, which include things like borders and padding.
this works for me (safari 3.2), by firing from within the window.onload event:
$(window).load(function() {
var pic = $('img');
pic.removeAttr("width");
pic.removeAttr("height");
alert( pic.width() );
alert( pic.height() );
});
You can programmatically get the image and check the dimensions using Javascript without having to mess with the DOM at all.
var img = new Image();
img.onload = function() {
console.log(this.width + 'x' + this.height);
}
img.src = 'http://www.google.com/intl/en_ALL/images/logo.gif';
What about image.naturalHeight and image.naturalWidth properties?
Seems to work fine back quite a few versions in Chrome, Safari and Firefox, but not at all in IE8 or even IE9.
Jquery has two properties called naturalWidth and naturalHeight, you can use in this way.
$('.my-img')[0].naturalWidth
$('.my-img')[0].naturalHeight
Where my-img is a class name used to select my image.
How we get right real dimensions without a blink real image:
(function( $ ){
$.fn.getDimensions=function(){
alert("First example:This works only for HTML code without CSS width/height definition.");
w=$(this, 'img')[0].width;
h=$(this, 'img')[0].height;
alert("This is a width/height on your monitor: " + $(this, 'img')[0].width+"/"+$(this, 'img')[0].height);
//This is bad practice - it shows on your monitor
$(this, 'img')[0].removeAttribute( "width" );
$(this, 'img')[0].removeAttribute( "height" );
alert("This is a bad effect of view after attributes removing, but we get right dimensions: "+ $(this, 'img')[0].width+"/"+$(this, 'img')[0].height);
//I'am going to repare it
$(this, 'img')[0].width=w;
$(this, 'img')[0].height=h;
//This is a good practice - it doesn't show on your monitor
ku=$(this, 'img').clone(); //We will work with a clone
ku.attr( "id","mnbv1lk87jhy0utrd" );//Markup clone for a final removing
ku[0].removeAttribute( "width" );
ku[0].removeAttribute( "height" );
//Now we still get 0
alert("There are still 0 before a clone appending to document: "+ $(ku)[0].width+"/"+$(ku)[0].height);
//Hide a clone
ku.css({"visibility" : "hidden",'position':'absolute','left':'-9999px'});
//A clone appending
$(document.body).append (ku[0]);
alert("We get right dimensions: "+ $(ku)[0].width+"/"+$(ku)[0].height);
//Remove a clone
$("#mnbv1lk87jhy0utrd").remove();
//But a next resolution is the best of all. It works in case of CSS definition of dimensions as well.
alert("But if you want to read real dimensions for image with CSS class definition outside of img element, you can't do it with a clone of image. Clone method is working with CSS dimensions, a clone has dimensions as well as in CSS class. That's why you have to work with a new img element.");
imgcopy=$('<img src="'+ $(this, 'img').attr('src') +'" />');//new object
imgcopy.attr( "id","mnbv1lk87jhy0aaa" );//Markup for a final removing
imgcopy.css({"visibility" : "hidden",'position':'absolute','left':'-9999px'});//hide copy
$(document.body).append (imgcopy);//append to document
alert("We get right dimensions: "+ imgcopy.width()+"/"+imgcopy.height());
$("#mnbv1lk87jhy0aaa").remove();
}
})( jQuery );
$(document).ready(function(){
$("img.toreaddimensions").click(function(){$(this).getDimensions();});
});
It works with <img class="toreaddimensions"...
As stated before, Xavi answer won't work if images are in the cache. The issue responds to webkit not firing the load event on cached images, so if the width/height attrs are no explicitly set in the img tag, the only reliable way to get the images is to wait for the window.load event to be fired.
The window.load event will fire always, so it's safe to access the width/height of and img after that without any trick.
$(window).load(function(){
//these all work
$('img#someId').css('width');
$('img#someId').width();
$('img#someId').get(0).style.width;
$('img#someId').get(0).width;
});
If you need to get the size of dynamically loaded images that might get cached (previously loaded), you can use Xavi method plus a query string to trigger a cache refresh. The downside is that it will cause another request to the server, for an img that is already cached and should be already available. Stupid Webkit.
var pic_real_width = 0,
img_src_no_cache = $('img#someId').attr('src') + '?cache=' + Date.now();
$('<img/>').attr('src', img_src_no_cache).load(function(){
pic_real_width = this.width;
});
ps: if you have a QueryString in the img.src already, you will have to parse it and add the extra param to clear the cache.
As Luke Smith says, image load is a mess. It's not reliable on all browsers. This fact has given me great pain. A cached image will not fire the event at all in some browsers, so those who said "image load is better than setTimeout" are wrong.
Luke Smith's solution is here.
And there is an interesting discussion about how this mess might be handled in jQuery 1.4.
I have found that it's pretty reliable to set the width to 0, then wait for the "complete" property to go true and the width property to come in greater than zero. You should watch for errors, too.
$("#myImg").one("load",function(){
//do something, like getting image width/height
}).each(function(){
if(this.complete) $(this).trigger("load");
});
From Chris' comment: http://api.jquery.com/load-event/
My situation is probably a little different. I am dynamically changing the src of an image via javascript and needed to ensure that the new image is sized proportionally to fit a fixed container (in a photo gallery). I initially just removed the width and height attributes of the image after it is loaded (via the image's load event) and reset these after calculating the preferred dimensions. However, that does not work in Safari and possibly IE (I have not tested it in IE thoroughly, but the image doesn't even show, so...).
Anyway, Safari keeps the dimensions of the previous image so the dimensions are always one image behind. I assume that this has something to do with cache. So the simplest solution is to just clone the image and add it to the DOM (it is important that it be added to the DOM the get the with and height). Give the image a visibility value of hidden (do not use display none because it will not work). After you get the dimensions remove the clone.
Here is my code using jQuery:
// Hack for Safari and others
// clone the image and add it to the DOM
// to get the actual width and height
// of the newly loaded image
var cloned,
o_width,
o_height,
src = 'my_image.jpg',
img = [some existing image object];
$(img)
.load(function()
{
$(this).removeAttr('height').removeAttr('width');
cloned = $(this).clone().css({visibility:'hidden'});
$('body').append(cloned);
o_width = cloned.get(0).width; // I prefer to use native javascript for this
o_height = cloned.get(0).height; // I prefer to use native javascript for this
cloned.remove();
$(this).attr({width:o_width, height:o_height});
})
.attr(src:src);
This solution works in any case.
There is now a jQuery plugin, event.special.load, to deal with cases where the load event on a cached image doesn't fire: http://github.com/peol/jquery.imgloaded/raw/master/ahpi.imgload.js
Recently I needed to find width and height for setting default size of .dialog representing graph. Solution I use was :
graph= $('<img/>', {"src":'mySRC', id:'graph-img'});
graph.bind('load', function (){
wid = graph.attr('width');
hei = graph.attr('height');
graph.dialog({ autoOpen: false, title: 'MyGraphTitle', height:hei, width:wid })
})
For me this works in FF3, Opera 10, IE 8,7,6
P.S. You may be find some more solutions looking inside some plugins like LightBox or ColorBox
To add to Xavi's answer, Paul Irish's github David Desandro's gitgub offers a function called imagesLoaded() that works on the same principles, and gets around the problem of some browser's cached images not firing the .load() event (with clever original_src -> data_uri -> original_src switching).
It's is widely used and updated regularly, which contributes to it being the most robust solution to the problem, IMO.
This works for both cached and dynamically loaded images.
function LoadImage(imgSrc, callback){
var image = new Image();
image.src = imgSrc;
if (image.complete) {
callback(image);
image.onload=function(){};
} else {
image.onload = function() {
callback(image);
// clear onLoad, IE behaves erratically with animated gifs otherwise
image.onload=function(){};
}
image.onerror = function() {
alert("Could not load image.");
}
}
}
To use this script:
function AlertImageSize(image) {
alert("Image size: " + image.width + "x" + image.height);
}
LoadImage("http://example.org/image.png", AlertImageSize);
Demo: http://jsfiddle.net/9543z/2/
I've done some workaround utility function, using imagesLoaded jquery plugin:
https://github.com/desandro/imagesloaded
function waitForImageSize(src, func, ctx){
if(!ctx)ctx = window;
var img = new Image();
img.src = src;
$(img).imagesLoaded($.proxy(function(){
var w = this.img.innerWidth||this.img.naturalWidth;
var h = this.img.innerHeight||this.img.naturalHeight;
this.func.call(this.ctx, w, h, this.img);
},{img: img, func: func, ctx: ctx}));
},
You can use this by passing url, function and its context. Function is performed after image is loaded and return created image, its width and height.
waitForImageSize("image.png", function(w,h){alert(w+","+h)},this)
If the image is already used, you sholud:
set image simensions to initial
image.css('width', 'initial');
image.css('height', 'initial');
get dimensions
var originalWidth = $(this).width();
var originalHeight = $(this).height();
You can use the naturalWidth and naturalHeight properties of the HTML image element. (Here's more info).
You would use it like this:
//you need a reference to the DOM element, not a jQuery object. It would be better if you can use document.getElementByTagsName or ID or any other native method
var pic = $("img")[0];
var pic_real_width = pic.naturalWidth;
var pic_real_height = pic.naturalHeight;
It seems like this works in all browsers except on IE from version 8 and below.
I checked out the answer of Dio and it works great for me.
$('#image').fadeIn(10,function () {var tmpW = $(this).width(); var tmpH = $(this).height(); });
Make sure that you call all your functions aso. that handle with the image size in the recaller function of fadeIn().
Thanks for this.
I use different approach, simply make Ajax call to server to get image size when image object is in use.
//make json call to server to get image size
$.getJSON("http://server/getimagesize.php",
{"src":url},
SetImageWidth
);
//callback function
function SetImageWidth(data) {
var wrap = $("div#image_gallery #image_wrap");
//remove height
wrap.find("img").removeAttr('height');
//remove height
wrap.find("img").removeAttr('width');
//set image width
if (data.width > 635) {
wrap.find("img").width(635);
}
else {
wrap.find("img").width(data.width);
}
}
and of course server side code:
<?php
$image_width = 0;
$image_height = 0;
if (isset ($_REQUEST['src']) && is_file($_SERVER['DOCUMENT_ROOT'] . $_REQUEST['src'])) {
$imageinfo = getimagesize($_SERVER['DOCUMENT_ROOT'].$_REQUEST['src']);
if ($imageinfo) {
$image_width= $imageinfo[0];
$image_height= $imageinfo[1];
}
}
$arr = array ('width'=>$image_width,'height'=>$image_height);
echo json_encode($arr);
?>
This works cross browser
var img = new Image();
$(img).bind('load error', function(e)
{
$.data(img, 'dimensions', { 'width': img.width, 'height': img.height });
});
img.src = imgs[i];
get the dimensions by using
$(this).data('dimensions').width;
$(this).data('dimensions').height;
Cheers!
Another suggestion is to use imagesLoaded plugin.
$("img").imagesLoaded(function(){
alert( $(this).width() );
alert( $(this).height() );
});
$(document).ready(function(){
var image = $("#fix_img");
var w = image.width();
var h = image.height();
var mr = 274/200;
var ir = w/h
if(ir > mr){
image.height(200);
image.width(200*ir);
} else{
image.width(274);
image.height(274/ir);
}
});
// This code helps to show image with 200*274 dimention
Here's a cross browser solution that triggers an event when your selected images are loaded: http://desandro.github.io/imagesloaded/ you can look up the height and width within the imagesLoaded() function.
Stumbled upon this thread trying to find an answer for my own question. I was trying to get an image's width/height in a function AFTER the loader, and kept coming up with 0. I feel like this might be what you're looking for, though, as it works for me:
tempObject.image = $('<img />').attr({ 'src':"images/prod-" + tempObject.id + ".png", load:preloader });
xmlProjectInfo.push(tempObject);
function preloader() {
imagesLoaded++;
if (imagesLoaded >= itemsToLoad) { //itemsToLoad gets set elsewhere in code
DetachEvent(this, 'load', preloader); //function that removes event listener
drawItems();
}
}
function drawItems() {
for(var i = 1; i <= xmlProjectInfo.length; i++)
alert(xmlProjectInfo[i - 1].image[0].width);
}
Check out this repository in github!
Great Example to check the Width and Height using Javascript
https://github.com/AzizAK/ImageRealSize
---Edited is requested from some comments ..
Javascript code:
function CheckImageSize(){
var image = document.getElementById("Image").files[0];
createReader(image, function (w, h) {
alert("Width is: " + w + " And Height is: "+h);
});
}
function createReader(file, whenReady) {
var reader = new FileReader;
reader.onload = function (evt) {
var image = new Image();
image.onload = function (evt) {
var width = this.width;
var height = this.height;
if (whenReady) whenReady(width, height);
};
image.src = evt.target.result;
};
reader.readAsDataURL(file);
}
and HTML code :
<html>
<head>
<title>Image Real Size</title>
<script src="ImageSize.js"></script>
</head>
<body>
<input type="file" id="Image"/>
<input type="button" value="Find the dimensions" onclick="CheckImageSize()"/>
</body>
<html>
For functions where you do not want to alter the original placement or image.
$(this).clone().removeAttr("width").attr("width");
$(this).clone().removeAttr("height").attr("height);

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