图片裁剪

function img_adaption(img) {

    if (!$(img).hasClass('img_adapted')) {

        $(img).css({'display': 'none'});

        var originalWidth = $(img).width();

        var originalHeight = $(img).height();

        var parentWidth = $(img).parent().width();

        var parentHeight = $(img).parent().height();

        var originalScale = originalWidth / originalHeight;

        var parentScal = parentWidth / parentHeight;

        var scaleNum, newImgWidth;

        var newImgHeight = 0;

        var changeNum = 0;

        if ($(img).parent().css('position') == 'static') {

            $(img).parent().css({

                'position': 'relative',

                'overflow': 'hidden'

            })

        }

        if (originalScale > parentScal) {

            scaleNum = originalHeight / parentHeight;

            newImgWidth = originalWidth / scaleNum;

            changeNum = (newImgWidth - parentWidth) / 2;

            $(img).css({

                'width': 'auto',

                'height': parentHeight,

                'margin-left': -changeNum,

                'display': 'block',

                'border-radius': '0'

            });

            $(img).fadeIn();

        } else if (originalScale < parentScal) {

            scaleNum = originalWidth / parentWidth;

            newImgHeight = originalHeight / scaleNum;

            changeNum = (newImgHeight - parentHeight) / 2;

            $(img).css({

                'width': parentWidth,

                'height': 'auto',

                'margin-top': -changeNum,

                'display': 'block',

                'border-radius': '0'

            });

            $(img).fadeIn();

        } else {

            $(img).css({

                'width': '100%',

                'height': '100%',

                'display': 'block'

            });

            $(img).fadeIn();

        }

 

        $(img).addClass('img_adapted');

    } else {

        $(img).css({'display': 'block'})

    }

}