图片渲染要解决的几个主要问题
1、图片默认是水平方向，要设置图片居中
代码语言：javascript复制max-height:100%;max-width:100%;position:absolute;left:50%;top:50%;transform:translate(-50%,-50%)"2、需要旋转的情况是：图片的宽度大于高度，这样旋转后图片显示的就大些
代码语言：javascript复制// 获取图片的实际宽度和高度
var picWidth = $("#showPicContent").width();
var picHeight = $("#showPicContent").height();
if( picWidth > picHeight) {}3、在旋转之前要确认好图片的大小，因为旋转后依然是以旋转前的图片的大小
代码语言：javascript复制var picRate = picWidth / picHeight;
var windowRate = $(window).height() / $(window).width();
console.log(picRate, windowRate)
if (picRate <= windowRate) {
PicMaxWidth = $(window).width() * picRate * 0.95
} else {
PicMaxWidth = $(window).height()
}
$("#showPicContent").css("max-width", PicMaxWidth)4、旋转的代码 要包含样式中设定的 translate(-50%,-50%)，否则会影响居中的效果
代码语言：javascript复制// 旋转的角度 顺时针为正，逆时针为负
$("#showPicContent").css({ "transform": "translate(-50%,-50%) rotate(90deg)" })5、判断手机横屏与竖屏状态
代码语言：javascript复制//判断手机横竖屏状态：
function hengshuping() {
//alert("hii")
// window.orientation 只有在手机上才有，网页测试看不出效果
console.log(window.orientation);
//$("#showPicContent").css({"transform":"translate(-50%,-50%) rotate(0deg)"})
if (window.orientation == 180 || window.orientation == 0) {
//alert("竖屏状态！")
$("#showPicContent").css("max-width", PicMaxWidth)
$("#showPicContent").css({ "transform": "translate(-50%,-50%) rotate(90deg)" })
}
if (window.orientation == 90 || window.orientation == -90) {
//alert("横屏状态！")
$("#showPicContent").css("max-width", "100%")
$("#showPicContent").css({ "transform": "translate(-50%,-50%) rotate(0deg)" })
}
}
window.addEventListener("onorientationchange" in window ? "orientationchange" : "resize", hengshuping, false);完整的代码：实现点击一个图片显示蒙层，蒙层里面有一个图片 与一个关闭按钮
代码语言：javascript复制 <div style="position:fixed;background:rgba(0,0,0,1.0);top:0;right:0;bottom:0;left:0;z-index:1000;font-size:20px;color:#fff;display:none;" class="backdrop">
<div style="position:absolute;right:10px;padding-top:5px;color:#f46608;cursor:pointer;z-index:100;" class="closePic">关闭</div>
<img src="../../dist/img/QQ图片20190604084934.jpg" id="showPicContent" style="max-height:100%;max-width:100%;position:absolute;left:50%;top:50%;transform:translate(-50%,-50%)" />
</div> $("#showPic1").click(function() {
if ($(".backdrop").css("display") == "none") {
$(".backdrop").css("display", "block");
}
var picWidth = $("#showPicContent").width(); // 获取图片的实际宽度和高度
var picHeight = $("#showPicContent").height();
//var picWidth = $("#showPicContent").css("width")// 获取图片样式的宽度与高度
//var picHeight = $("#showPicContent").css("height")
console.log(picWidth, picHeight)
if ($(window).width() < 700) {
if (picWidth > picHeight) {
var PicMaxWidth
var picRate = picWidth / picHeight;
var windowRate = $(window).height() / $(window).width();
console.log(picRate, windowRate)
if (picRate <= windowRate) {
PicMaxWidth = $(window).width() * picRate * 0.95
} else {
PicMaxWidth = $(window).height()
}
$("#showPicContent").css("max-width", PicMaxWidth)
$("#showPicContent").css({ "transform": "translate(-50%,-50%) rotate(90deg)" })
//判断手机横竖屏状态：
function hengshuping() {
//alert("hii")
// window.orientation 只有在手机上才有，网页测试看不出效果
console.log(window.orientation);
//$("#showPicContent").css({"transform":"translate(-50%,-50%) rotate(0deg)"})
if (window.orientation == 180 || window.orientation == 0) {
//alert("竖屏状态！")
$("#showPicContent").css("max-width", PicMaxWidth)
$("#showPicContent").css({ "transform": "translate(-50%,-50%) rotate(90deg)" })
}
if (window.orientation == 90 || window.orientation == -90) {
//alert("横屏状态！")
$("#showPicContent").css("max-width", "100%")
$("#showPicContent").css({ "transform": "translate(-50%,-50%) rotate(0deg)" })
}
}
window.addEventListener("onorientationchange" in window ? "orientationchange" : "resize", hengshuping, false);
}
}
})
$("#showPicContent, .closePic").click(function() {
if ($(".backdrop").css("display") == "block") {
$(".backdrop").css("display", "none");
}
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