参考链接
画一条 0.5 px 的边
CSS
.hr {width: 300px;background-color: #000;}.hr.half-px {height: 0.5px;}.hr.one-px {height: 1px;}/* scale */.hr.scale-half {height: 1px;transform: scaleY(0.5);transform-origin: 50% 10%;}/* linear-gradient */.hr.gradient {height: 1px;background: linear-gradient(0deg, #fff, #000);}/* box-shadow */.hr.boxshadow {height: 1px;background: none;box-shadow: 0 0.5px 0 #000;}/* svg */.hr.svg {height: 1px;/*background: url("data:image/svg+xml;utf-8,<svg xmlns='http://www.w3.org/2000/svg' width='100%' height='1px'><line x1='0' y1='0' x2='100%' y2='0' stroke='#000'></line></svg>");*/background: url("data:image/svg+xml;base64,PHN2ZyB4bWxucz0naHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmcnIHdpZHRoPScxMDAlJyBoZWlnaHQ9JzFweCc+PGxpbmUgeDE9JzAnIHkxPScwJyB4Mj0nMTAwJScgeTI9JzAnIHN0cm9rZT0nIzAwMCc+PC9saW5lPjwvc3ZnPg==");}
HTML
<p>svg</p><div class="hr svg"></div><p>box-shadow: 0 0.5px 0 #000</p><div class="hr boxshadow"></div><p>linear-gradient(0deg, #fff, #000)</p><div class="hr gradient"></div><p>1px + scaleY(0.5)</p><div class="hr scale-half"></div><p>0.5px</p><div class="hr half-px"></div><p>1px</p><div class="hr one-px"></div>
window.devicePixelRatio 是设备上物理像素和设备独立像素(device-independent pixels (dips))的比例。
initial-scale 缩放值越大,当前 viewport 的宽度就会越小,反之亦然。实际改变的是 CSS 像素即设备独立像素的大小。
