Scale all images to fit container proportionally

问题

I am building a customization script where a user can upload an image and drag it around a template image to get a desired result. The problem is the template image is over 1000px tall and wide, so I put it inside a container limiting it's height/width.

How do I make it so the uploaded image is scaled exactly the same so when I create the image via PHP I can take the left: and top: CSS values and apply them to the much larger template image and uploaded image?

Current CSS:

#template {
    position: relative;
    padding: 0;
    width: 500px;
    height: 500px;
    z-index: 1;
}
#uploaded {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 2;
}

回答1:

I'm not quite sure if that is what you are asking for … anyway:

The CSS3 property background-size: 100% lets you specify that the background image of should fill out the container's size and stretch proportionally. Together with background-repeat: no-repeat it might be what you are looking for:

#uploaded {
    height: 500px;
    width: 500px;

    background-image: url(...);
    background-size: 100%;
    background-repeat: no-repeat;
}

Demo: http://jsfiddle.net/pu76s/3/

来源：https://stackoverflow.com/questions/11622403/scale-all-images-to-fit-container-proportionally