Question

如果我使用以下CSS：

p {
    font-size: 20.5px;
}

是否所有浏览器都将其绘制为20.5px，或者某些值是否为圆形？

Answer 1

在所有浏览器中，小数都不会一致地舍入。我能找到的最好的帖子是：Browser Rounding

这包含一个显示以下内容的表：

Internet Explorer 7 truncate to 2 decimal places
Internet Explorer 8 truncate to 2 decimal places
Internet Explorer 9 truncate to 2 decimal places
Internet Explorer 10    truncate to 2 decimal places
Internet Explorer 11    truncate to 2 decimal places
Firefox 3.0 truncate to 3 decimal places
Firefox 3.5 truncate to 3 decimal places
Firefox 31  truncate to 3 decimal places
Chrome 20   round to 15 decimal places
Chrome 21   round to 15 decimal places
Chrome 37   round to 13 decimal places
Safari 6 (OSX Lion) round to 15 decimal places
Safari 6.1 (OSX Mountain Lion)  round to 15 decimal places
Safari 7 (OSX Mavericks)    round to 15 decimal places
Mobile Safari 7 (iOS7)  round to 15 decimal places
Mobile Safari 8 (iOS8)  round to 15 decimal places
Chrome 36 (Jelly Bean) [Nexus5] round to 15 decimal places
Chrome 30 (KitKat) [S5] round to 15 decimal places
Android Browser 4 (Jelly Bean) [Nexus7,Nexus4,S4,S3]    round to 15 decimal places
Android Browser 4 (Ice Cream Sandwich) [Nexus,KindleFire2]  round to 15 decimal places
Android Browser 4 (Gingerbread) [S2]    truncate to 3 decimal places
Opera 12    truncate to 2 decimal places
Opera Next 24   round to 13 decimal places

Answer 2

所有最新版本的浏览器允许子像素渲染* 。请参阅research和differences between browser versions的表格。

较旧的浏览器大多将像素向下舍入。最值得注意的例外是IE8和IE9，它们舍入到最接近的整数（IE7也向下舍入，IE10和向上使用子像素渲染）。

_{*如果您以百分比定义大小，则像素值可能会有所不同，就像您以像素直接定义它一样。}

指定所有浏览器都遵守的字体大小时是否为十进制精度？

2 个答案: