Position the center of an image using css - html

Question

let's say I have to place an image RIGHT in a proper spot, but I need its CENTER to be in that spot. I wanted to place an image in the top-left corner of a div, so I placed the image in the div, gave position: relative to the div and position: absolute to the image then set its top and left values to 0. It quite worked but I'd need the CENTER of that image to be right over the top left corner. I'd do it manually setting top: -xpx, left: -ypx BUT I don't have any specific value for the image size (which could vary a lot).
So is there any way to say something like: position: absolute-but-i'm-talking-about-the-center; top: 0px; left: 0px;?
Thank you very much indeed!
Matteo

Answer 1

You could use javascript yo get the size of the image and then set the css left value needed.
Be mindful of the way images are loaded though as they are asynchronous so will not necesserily be available when the document is ready. This means that unless you handle the images correctly you will end up with width and height dimensions of 0.

Answer 2

You should wrap the image in another block element and put a negative left position to the image.
Something like this:
<div id="something">
<div class="imagewrap">
<img>
</div>
</div>
Then give #something a relative position, .imagewrap an absolute, etc... And img should have a relative position with left:-50%. Same for the top.

Answer 3

have you tried;
name_of_div_with_image {
display: block;
margin-left: auto;
margin-right: auto }
give that a go.

Answer 4

No need to use Javascript, this can be done in CSS.
The required HTML: (you must change the div to an img obviously)
<div id="container">
<div id="imgwrapper">
<div id="img">Change this div-tag to an img-tag</div>
</div>
</div>
The required CSS:
#container
{
position: absolute;
left: 200px;
top: 100px;
height: auto;
overflow: visible;
border: 2px dashed green;
}
#imgwrapper
{
position: relative;
margin-left: -50%;
margin-top: -50%;
padding-top: 25%;
border: 2px dashed blue;
}
#img
{
display: block;
width: 200px;
height: 100px;
border: 2px solid red;
}
Click here for a jsFiddle link
The margin-left: 50%; obviously works when using the container div, because the width of the container will be exactly that of the content. (You might need to add width: auto;)
But margin-top: -50%; will not work because the height of the container div will change with it, thus you need yet another wrapper div in which you use this margin-top: -50%; and then you need to fix this error it makes by using a positive percentage based padding. Obviously there may be other solutions to fix this, but the solution should be something like this.

Answer 5

Probably one of the simplest solutions is to place the image in the upper left corner at position
left: 0px; top: 0px; and then use translate to move its center to this position. Here's a working snippet for that:
#theDiv {
position: absolute;
left: 100px;
top: 100px;
background: yellow;
width: 200px;
height: 200px;
}
#theImage {
background: green;
position: absolute;
left: 0px;
top: 0px;
transform: translate(-50%, -50%);
}
<div id="theDiv">
<image width=31.41 height=41.31 id="theImage"></image>
</div>