Pinch and Zoom Using Javascript/Jquery without plugin

Tried to implement the pinch and zoom without using plugin, but I am able to zoom it but unable to zoom out.

It should support both desktop and tablets. This is what have tried.

JS:

 image = $('#image')
    wrap = $('#wrap')

    width = image.width()
    height = image.height()

    offset = wrap.offset()        

    newX = 0
    newY = 0

    testScale = 1

    image.click (event) ->
        testScale = if event.ctrlKey then (testScale - 0.4) else (testScale + 0.4) 
        pinch event.clientX, event.clientY, testScale

    window.pinch = (x, y, scale) ->

        newWidth = image.width() * scale
        newHeight = image.height() * scale

        # Convert from screen to image coordinates
        x -= offset.left + newX
        y -= offset.top + newY

        newX += -x * (newWidth - width) / newWidth
        newY += -y * (newHeight - height) / newHeight

        image.css '-webkit-transform', "scale3d(#{scale}, #{scale}, 1)"         
        wrap.css '-webkit-transform', "translate3d(#{newX}px, #{newY}px, 0)"

        width = newWidth
        height = newHeight

Demo

Solution

I Got This

var clicks = 0;
$('#wrap').on("click", function(e){
    clicks++;  //count clicks
        if(clicks === 1) {   
    e.preventDefault();
    $('#wrap img').each(function(index) {
        $(this).animate({
            width: $(this).width() * 1.25,
            height: $(this).height() * 1.25
        });

    });
        }
}).on("dblclick", function(e){
        e.preventDefault();

    $('#wrap img').each(function(index) {
        $(this).animate({
            width: $(this).width() / 1.25,
            height: $(this).height() / 1.25
        });
    });
    });

Pinch and Zoom Using Javascript/Jquery without plugin

DEMO1

DEMO2