jQueryjavascript - Get Image size before load - Stack Overflow

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I have a list of images that is rendered as thumbnails after upload. The issue that I have is I need the dimensions of the fully uploaded images, so that I can run a resize function if sized incorrectly.

Function that builds the image list

function buildEditList(json, galleryID)
{
    //Hide the list
    $sortable = $('#sortable');
    $sortable.hide();

    for(i = 0, j = json.revision_images.length; i < j; i++) {
        $sortable.append(
            "<li id='image_" + json.revision_images[i].id + "'><a class=\"ui-lightbox\" href=\"../data/gallery/"
            + galleryID
            + "/images/album/"
            + json.revision_images[i].OrgImageName
            + "\"><img id=\""
            + json.revision_images[i].id
            + "\" alt=\"\" src=\"../data/gallery/"
            + galleryID 
            + "/images/album/" 
            + json.revision_images[i].OrgImageName 
            + "\"/></a></li>"
        ).hide();
    }
    //Set first and last li to 50% so that it fits the format
    $('#sortable li img').first().css('width','50%');
    $('#sortable li img').last().css('width', '50%');

    //Fade images back in 
    $sortable.fadeIn("fast",function(){
        var img = $("#703504"); // Get my img elem -- hard coded at the moment
        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.
        });
        alert(pic_real_height);
    });

}

I have been trying to use the solution from this stackoverflow post, but have yet to get it to work, or it may just be my code. if you have any ideas on this I could use the help. Currently the alert is ing back undefined.

I have a list of images that is rendered as thumbnails after upload. The issue that I have is I need the dimensions of the fully uploaded images, so that I can run a resize function if sized incorrectly.

Function that builds the image list

function buildEditList(json, galleryID)
{
    //Hide the list
    $sortable = $('#sortable');
    $sortable.hide();

    for(i = 0, j = json.revision_images.length; i < j; i++) {
        $sortable.append(
            "<li id='image_" + json.revision_images[i].id + "'><a class=\"ui-lightbox\" href=\"../data/gallery/"
            + galleryID
            + "/images/album/"
            + json.revision_images[i].OrgImageName
            + "\"><img id=\""
            + json.revision_images[i].id
            + "\" alt=\"\" src=\"../data/gallery/"
            + galleryID 
            + "/images/album/" 
            + json.revision_images[i].OrgImageName 
            + "\"/></a></li>"
        ).hide();
    }
    //Set first and last li to 50% so that it fits the format
    $('#sortable li img').first().css('width','50%');
    $('#sortable li img').last().css('width', '50%');

    //Fade images back in 
    $sortable.fadeIn("fast",function(){
        var img = $("#703504"); // Get my img elem -- hard coded at the moment
        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.
        });
        alert(pic_real_height);
    });

}

I have been trying to use the solution from this stackoverflow post, but have yet to get it to work, or it may just be my code. if you have any ideas on this I could use the help. Currently the alert is ing back undefined.

• javascript
• jquery

Share Improve this question Follow edited Jan 14, 2018 at 19:26 BenMorel 36.7k5252 gold badges206206 silver badges337337 bronze badges asked Dec 13, 2012 at 0:05 SuperNinjaSuperNinja 1,61677 gold badges2323 silver badges4545 bronze badges 4

• Sounds like something i'd do server side. – Jeroen Commented Dec 13, 2012 at 0:08
• Please be more specific as to what is going wrong. – Mark Commented Dec 13, 2012 at 0:09
• @Mark - currently my alert(pic_real_width) is ing back undefined. – SuperNinja Commented Dec 13, 2012 at 0:11
• @Jeroen - I thought about handling this with PHP on the upload with getimagesize(); but that drastically slowed down the upload process. – SuperNinja Commented Dec 13, 2012 at 0:12

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1 Answer 1

Sorted by: Reset to default 2

There's a newer js method called naturalHeight or naturalWidth that will return the information you're looking for. Unfortunately it wont work in older IE versions. Here's a function I created a few months back that may work for you. I added a bit of your code below it for an example:

function getNatural($mainImage) {
    var mainImage = $mainImage[0],
        d = {};

    if (mainImage.naturalWidth === undefined) {
        var i = new Image();
        i.src = mainImage.src;
        d.oWidth = i.width;
        d.oHeight = i.height;
    } else {
        d.oWidth = mainImage.naturalWidth;
        d.oHeight = mainImage.naturalHeight;
    }
    return d;
}

var img = $("#703504");
var naturalDimension = getNatural(img);
alert(naturalDimension.oWidth, naturalDimension.oHeight)​

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