Javascript 如何根据滚动位置缩小图像宽度
我想缩小一个基于卷轴的标志 到目前为止,我有类似的东西Javascript 如何根据滚动位置缩小图像宽度,javascript,jquery,Javascript,Jquery,我想缩小一个基于卷轴的标志 到目前为止,我有类似的东西 logoSize = function(){ var headerOffset = $(window).height() - 650; var maxScrollDistance = 1300; $(window).scroll(function() { var percentage = maxScrollDistance / $(document).scrollTop(); if (
logoSize = function(){
var headerOffset = $(window).height() - 650;
var maxScrollDistance = 1300;
$(window).scroll(function() {
var percentage = maxScrollDistance / $(document).scrollTop();
if (percentage <= headerOffset) {
$('.logo').css('width', percentage * 64);
}
console.log(percentage);
});
}
logoSize();
logoSize=function(){
var headerOffset=$(窗口).height()-650;
var maxScrollDistance=1300;
$(窗口)。滚动(函数(){
var percentage=maxScrollDistance/$(document).scrollTop();
如果(百分比我基于您心中有目标大小的假设重新编写了您的代码,例如,在滚动650px后,您希望您的图像宽度为250px
它在本机大小和目标大小之间平滑滚动,并考虑到窗口高度可能小于最大滚动距离的事实:
logoSize = function () {
// Get the real width of the logo image
var theLogo = $("#thelogo");
var newImage = new Image();
newImage.src = theLogo.attr("src");
var imgWidth = newImage.width;
// distance over which zoom effect takes place
var maxScrollDistance = 650;
// set to window height if that is smaller
maxScrollDistance = Math.min(maxScrollDistance, $(window).height());
// width at maximum zoom out (i.e. when window has scrolled maxScrollDistance)
var widthAtMax = 500;
// calculate diff and how many pixels to zoom per pixel scrolled
var widthDiff = imgWidth - widthAtMax;
var pixelsPerScroll =(widthDiff / maxScrollDistance);
$(window).scroll(function () {
// the currently scrolled-to position - max-out at maxScrollDistance
var scrollTopPos = Math.min($(document).scrollTop(), maxScrollDistance);
// how many pixels to adjust by
var scrollChangePx = Math.floor(scrollTopPos * pixelsPerScroll);
// calculate the new width
var zoomedWidth = imgWidth - scrollChangePx;
// set the width
$('.logo').css('width', zoomedWidth);
});
}
logoSize();
有关工作示例,请参阅。如果发生得太快,请按更改的宽度设置动画…而不仅仅是更改它。