Why Doesn't This CSS Transition Work On SVG In

问题:

I'm trying to transition the fill and path of an embedded SVG object, however this doesn't seem to work (Code Pen here):

The SVG:

<a class="simple-link svg-link" href="">
  Some Text
  <svg version="1.1" id="next-page-icon" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
      viewBox="0 0 25 25" enable-background="new 0 0 25 25" xml:space="preserve" preserveAspectRatio="xMinYMin meet">
    <circle class="the-background" cx="12.5" cy="12.5" r="12.5"/>
    <g>
      <path class="the-icon"  d="M16.088,11.421l-3.404,3.362l-3.418-3.362v-1.204l3.418,3.444l3.404-3.444V11.421z"/>
     </g>
  </svg>
</a>

The Sass:

a
{
  width:200px;
  height:200px;
  overflow: hidden;

  @include transition(color, 1s);
  @include transition(background, 1s);

  svg
  {
    width:200px;
    height:200px;

    .the-background
    {
      @include transition(fill, 1s);
      fill: grey;
    }

    .the-icon
    {
      @include transition(fill, 2.5s);
    }
  }

  &:hover
  {
    color: red;
    background: black;
    .the-background
    {
      fill: black;
    }

    .the-icon
    {
      fill: red;
    } 

  }
}

Why don't the fills animate on hover?

回答1:

The reason why the transition doesn't work is because it is within a link.

To fix it, put the link inside of the SVG instead like this SO post suggests

OR

Make the SVG a sibling of the link and use the sibling selector

/* This goes within `a { ...` */
&:hover + svg { /* Or use ~ to select all */
  .the-background
  {
    fill: black;
  }

  .the-icon
  {
    fill: red;
  } 
}

回答2:

The way I solved this problem was to place fill="currentColor" on the svg path element that I wanted to transition. Then I added color and transition properties to the surrounding anchor tag and performed the CSS transition on the anchor tag instead of the svg path itself. Below is a very stripped down example:

HTML:

<a>
    <svg>
        <path fill="currentColor" />
    </svg>
</a>

SCSS:

a { color: black; transition: color .2s linear;
    &:hover { color: white; } }

回答3:

I just discovered that in order to transition an svg fill within an anchor element, it only works using rgba color codes. I haven't researched why that is, but it's working on my projects - here's an example: http://rawesome.leveragenewagemedia.com/ (hover the social media icons).

Here's the SASS I'm using:

.icon {
  display: inline-block;
  width: 20px;
  height: 20px;
  fill: rgba(0,0,0,.2);
  -webkit-transition: fill .5s;
  -moz-transition: fill .5s;
  -ms-transition: fill .5s;
  -o-transition: fill .5s;
  transition: fill .5s;

  &:hover {
    fill: rgba(0,0,0,.5);
  }
}