Scale and reposition iframe like background-size: cover

Answer 1

Ok. The merit is NOT mine as I got the jquery here

I remembered that question as I used it on one of my old projects and I wanted to check if it would work the same with an iframe. It does.

basically with this css:

.container {
    position: absolute;
    top: 0;
    overflow: hidden;
}

and this jquery:

var min_w = 300; // minimum video width allowed
var vid_w_orig;  // original video dimensions
var vid_h_orig;

jQuery(function() { // runs after DOM has loaded

    vid_w_orig = parseInt(jQuery('iframe').attr('width'));
    vid_h_orig = parseInt(jQuery('iframe').attr('height'));

    jQuery(window).resize(function () { resizeToCover(); });
    jQuery(window).trigger('resize');
});

function resizeToCover() {

    // set the video viewport to the window size
    jQuery('.container').width(jQuery(window).width());
    jQuery('.container').height(jQuery(window).height());

    // use largest scale factor of horizontal/vertical
    var scale_h = jQuery(window).width() / vid_w_orig;
    var scale_v = jQuery(window).height() / vid_h_orig;
    var scale = scale_h > scale_v ? scale_h : scale_v;

    // don't allow scaled width < minimum video width
    if (scale * vid_w_orig < min_w) {scale = min_w / vid_w_orig;};

    // now scale the video
    jQuery('iframe').width(scale * vid_w_orig);
    jQuery('iframe').height(scale * vid_h_orig);
    // and center it by scrolling the video viewport
    jQuery('.container').scrollLeft((jQuery('iframe').width() - jQuery(window).width()) / 2);
    jQuery('.container').scrollTop((jQuery('iframe').height() - jQuery(window).height()) / 2);
};

You get this: JSFIDDLE

(I know you were looking for a pure css solution, which I don't think it's possible but I can be wrong, but I have posted this answer because it could help other people with same issue)