前言
移动端1px问题是因为由于不同的手机有不同的像素密度导致的。所谓没有处理的时候1px边框会比平常的粗,对于高分辨率的屏幕不友好,就有了解决1px的方案。
解决方式1
实现原理:伪元素 + transform 缩放
代码落地
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>1px 问题</title>
<style>
body {margin:0;padding:19px}
div { padding:1em;margin:1em;}
.box1{border-top: 1px solid #000;}
.box2{position: relative;border-bottom:1px solid #000;}
.box2::after{
content:'';
position: absolute;
left:0;top:0;width: 100%;
height: 1px;
background-color: #000;
transform: scaleY(0.5);
}
</style>
</head>
<body>
<div class="box1">
1px的上边框
</div>
<div class="box2">
0.5px的上边框
</div>
</body>
</html>
解决方式2
创建公共样式文件:hairline.scss。用它来实现1px效果
参考antd-mobile实现
// src/assets/styles/hairline.scss
@mixin scale-hairline-common($color, $top, $right, $bottom, $left) {
content: '';
position: absolute;
display: block;
z-index: 1;
top: $top;
right: $right;
bottom: $bottom;
left: $left;
background-color: $color;
}
@mixin hairline($direction, $color: #000, $radius: 0) {
@if $direction == top {
border-top: 1px solid $color;
// min-resolution 用来检测设备的最小像素密度
@media (min-resolution: 2dppx) {
border-top: none;
&::before {
@include scale-hairline-common($color, 0, auto, auto, 0);
width: 100%;
height: 1px;
transform-origin: 50% 50%;
transform: scaleY(0.5);
@media (min-resolution: 3dppx) {
transform: scaleY(0.33);
}
}
}
} @else if $direction == right {
border-right: 1px solid $color;
@media (min-resolution: 2dppx) {
border-right: none;
&::after {
@include scale-hairline-common($color, 0, 0, auto, auto);
width: 1px;
height: 100%;
background: $color;
transform-origin: 100% 50%;
transform: scaleX(0.5);
@media (min-resolution: 3dppx) {
transform: scaleX(0.33);
}
}
}
} @else if $direction == bottom {
border-bottom: 1px solid $color;
@media (min-resolution: 2dppx) {
border-bottom: none;
&::after {
@include scale-hairline-common($color, auto, auto, 0, 0);
width: 100%;
height: 1px;
transform-origin: 50% 100%;
transform: scaleY(0.5);
@media (min-resolution: 3dppx) {
transform: scaleY(0.33);
}
}
}
} @else if $direction == left {
border-left: 1px solid $color;
@media (min-resolution: 2dppx) {
border-left: none;
&::before {
@include scale-hairline-common($color, 0, auto, auto, 0);
width: 1px;
height: 100%;
transform-origin: 100% 50%;
transform: scaleX(0.5);
@media (min-resolution: 3dppx) {
transform: scaleX(0.33);
}
}
}
} @else if $direction == all {
border: 1px solid $color;
border-radius: $radius;
@media (min-resolution: 2dppx) {
position: relative;
border: none;
&::before {
content: '';
position: absolute;
left: 0;
top: 0;
width: 200%;
height: 200%;
border: 1px solid $color;
border-radius: $radius * 2;
transform-origin: 0 0;
transform: scale(0.5);
box-sizing: border-box;
pointer-events: none;
}
}
}
}
// 移除边框
@mixin hairline-remove($position: all) {
@if $position == left {
border-left: 0;
&::before {
display: none !important;
}
} @else if $position == right {
border-right: 0;
&::after {
display: none !important;
}
} @else if $position == top {
border-top: 0;
&::before {
display: none !important;
}
} @else if $position == bottom {
border-bottom: 0;
&::after {
display: none !important;
}
} @else if $position == all {
border: 0;
&::before {
display: none !important;
}
&::after {
display: none !important;
}
}
}
用法:
选择器 { @include hairline(参数,xxxx) }
@import '~@scss/hairline.scss';
.box1 {
margin: 10px 0;
position:relative;
@include hairline(bottom, #000); // 添加边框
// 移除边框
// @include hairline-remove(bottom);
}