如何将绝对定位的元素对齐到中心?

2022-01-17 00:00:00 css html5-canvas

我正在尝试将两个画布堆叠在一起并使其成为双层画布.

I am trying to stack two canvas together and make it a double layers canvas.

我在这里看到了一个例子:

I've saw an example here:

<div style="position: relative;">
 <canvas id="layer1" width="100" height="100" 
   style="position: absolute; left: 0; top: 0; z-index: 0;"></canvas>
 <canvas id="layer2" width="100" height="100" 
   style="position: absolute; left: 0; top: 0; z-index: 1;"></canvas>
</div>

但我想将两个画布都设置在屏幕中心对齐.如果我将 left 的值设置为常量，而我更改屏幕的方向(就像我在 iPad 上做 aps 一样)，画布不会像如何保持在屏幕中间它在

But i would like to set both of the canvas align at the center of the screen. If i set the value of left as a constant, while I change the orientation of the screen (as I'm doing aps on iPad) the canvas won't remain at the middle of the screen like how it act in 

<div align="center">

有人可以帮忙吗?

推荐答案

如果将左右两边都设置为零，左右边距设置为自动，则可以将绝对定位的元素居中.

If you set both left and right to zero, and left and right margins to auto you can center an absolutely positioned element.

position:absolute;
left:0;
right:0;
margin-left:auto;
margin-right:auto;

相关文章