css - "opacity"和 "filter: opacity()"有什么区别

Question

我们大多数人都知道简单的 opacity CSS 规则，但最近我偶然发现了 filter，它可以将 opacity(amount) 作为它的值- 除其他事项外。但这两者到底有什么区别呢？

Answer 1

filter: opacity() is similar to the more established opacity property; the difference is that with filter: opacity(), some browsers provide hardware acceleration for better performance. Negative values are not allowed.

filter: opacity() applies transparency. A value of 0% is completely transparent. A value of 100% leaves the input unchanged. Values between 0% and 100% are linear multipliers on the effect. This is equivalent to multiplying the input image samples by amount. If the “amount” parameter is missing, a value of 100% is used.

来源:https://css-tricks.com/almanac/properties/f/filter/

/*
* -----------
* filter: opacity([ <number> or <percentage> ])
* -----------
*/

.filter-opacity {
  filter: opacity(0.3);
  height: 5rem;
  width: 5rem;
  background-color: mediumvioletred;
}

/*
* -----------
* standard opacity
* -----------
*/

.just-opacity {
  opacity: 0.3;
  height: 5rem;
  width: 5rem;
  background-color: lawngreen;
}

<div class="filter-opacity">
  filter-opacity
</div>

<div class="just-opacity">
  just-opacity
</div>