Sass Mixin for animation keyframe which includes multiple stages and transform property

Question

Here is the standard CSS I am trying to produce but want to use a SASS Mixin to do the work.

STANDARD CSS

@-webkit-keyframes crank-up {
  100% { -webkit-transform: rotate(360deg);}
}
@-moz-keyframes crank-up {
  100% { -moz-transform: rotate(360deg);}
}
@-o-keyframes crank-up {
  100% { -o-transform: rotate(360deg);}
}
keyframes crank-up {
  100% { transform: rotate(360deg);}
}

I'm using the same mixin as in the following post SASS keyframes not compiling as wanted which is shown below.

MIXIN

@mixin keyframes($name) {
  @-webkit-keyframes #{$name} {
      @content;
  }
  @-moz-keyframes #{$name} {
      @content;
  }
  @-ms-keyframes #{$name} {
      @content;
  }
  @keyframes #{$name} {
      @content;
  }
}

The above is OK, as long as none of the keyframes include a property that requires a vendor prefix. Like the transform property as all the vendor prefixed keyframes get applied with (in this case) the -webkit- prefix. For example:

SCSS

@include keyframes(crank-up) {
  100% { -webkit-transform: rotate(360deg);}
}

CSS

@-webkit-keyframes crank-up { 100% { -webkit-transform: rotate(360deg); } }
@-moz-keyframes crank-up { 100% { -webkit-transform: rotate(360deg); } }
@-ms-keyframes crank-up { 100% { -webkit-transform: rotate(360deg); } }
@keyframes crank-up { 100% { -webkit-transform: rotate(360deg); } }

Notice the above, -webkit- with a -moz-keyframe. Should be -moz-

So, my first thought was to alter the above mixin to:

ALTERED MIXIN

@mixin keyframes($first-name, $last-name, $argument) {
  @-webkit-keyframes #{$first-name} {
    -webkit-#{$last-name}: #{$argument};
  }
  @-moz-keyframes #{$first-name} {
    -moz-#{$last-name}: #{$argument};
  }
  @-o-keyframes #{$first-name} {
    -o-#{$last-name}: #{$argument};
  }
  @keyframes #{$first-name} {
    #{$last-name}: #{$argument};
  } 
}

With a call to the mixin looking like

SCSS

@include keyframes(crank-up, transform, rotate(360deg)) { }

CSS

@-webkit-keyframes crank-up { -webkit-transform: rotate(360deg); }
@-moz-keyframes crank-up { -moz-transform: rotate(360deg); }
@-o-keyframes crank-up { -o-transform: rotate(360deg); }
@keyframes crank-up { transform: rotate(360deg); }

This works all ok if there is only ONE Keyframe 'stage' (see in original code - top of page, there's only the 100% mark), excuse if my terminology is slightly off in reference to keyframe 'stage'.

PROBLEM

I want a mixin like the above to work with something like.

@-webkit-keyframes crank-up {
  20%,
  40% { -webikit-transform: translateY(34px); }
  80% { opacity: .8; }
  100% { -webkit-transform: rotate(360deg);}
}

I have also looked into the two Compass Animate plugins; compass-animation and the newer compass-animate but not really sure if these can help. I need some way of adding in a variable and testing for this with a mixin but don't know if it's possible to pass variable into mixins.

Any help much appreciated. Thanks

I've been playing around with the following but neither work, just thought I'd add them up to see if anyone knows where I'm going wrong.

EXPERIMENTAL MIXINS:

@mixin vendor-prefix($name, $argument, $webkit: "-webkit-", $moz: "-moz-",$o: "-o-", $stale: ""){
  #{$webkit}: #{$name}: #{$argument};
  #{$moz}: #{$name}: #{$argument};
  #{$o}: #{$name}: #{$argument};
  #{$stale}: #{$name}: #{$argument};
}

@mixin vendor-prefix($last-name, $argument){
  @if $name == webkit { 
    -webkit-#{$name}: #{$argument};
  } @else if $name == moz { 
    -moz-#{$name}: #{$argument};
  } @else if $name == o { 
    -o-#{$name}: #{$argument};
  } @else { 
    #{$name}: #{$argument};
  } 
}

Answer 1

To deal with vendor-prefixers I recommend to use Autoprefixer instead of sass mixins.

Autoprefixer interface is simple: just forget about vendor prefixes and write normal CSS according to latest W3C specs. You don’t need a special language (like Sass) or special mixins.

Because Autoprefixer is a postprocessor for CSS, you can also use it with preprocessors, such as Sass, Stylus or LESS.

So, in your case, you just need to write this:

@keyframes crank-up {
  20%,
  40% { -webkit-transform: translateY(34px); }
  80% { opacity: .8; }
  100% { -webkit-transform: rotate(360deg);}
}

And autoprefixer converts it automatically to:

@-webkit-keyframes crank-up {
  20%, 40% {
    -webkit-transform: translateY(34px);
  }

  80% {
    opacity: .8;
  }

  100% {
    -webkit-transform: rotate(360deg);
  }
}

@keyframes crank-up {
  20%, 40% {
    -webkit-transform: translateY(34px);
  }

  80% {
    opacity: .8;
  }

  100% {
    -webkit-transform: rotate(360deg);
  }
}

Autoprefixer is widely supported, you can process your scss or css styles with this tool through Compass, Grunt, Sublime Text, node.js, Ruby, Ruby on Rails, PHP...

Here is more info about the project

Answer 2

If you are already using Compass and don't want to load whole bounce of extra library and just want to write some mixing then THIS is the best option.

/* animation mixing
keyframe animation
@include animation('animation-name .4s 1')*/

@mixin animation($animate...) {
$max: length($animate);
$animations: '';

@for $i from 1 through $max {
    $animations: #{$animations + nth($animate, $i)};

    @if $i < $max {
        $animations: #{$animations + ", "};
    }
}
-webkit-animation: $animations;
-moz-animation:    $animations;
-o-animation:      $animations;
animation:         $animations;
}

And here is the keyframe Mixing to include CSS3 properties inside particular browser vender prefix, instead of @include translate, we use the full css (Note: if you're using Sass 3.3 or older, you'll need to remove the !global flag):

@mixin keyframes($animationName) {
    @-webkit-keyframes #{$animationName} {
        $browser: '-webkit-' !global;
        @content;
    }
    @-moz-keyframes #{$animationName} {
        $browser: '-moz-' !global;
        @content;
    }
    @-o-keyframes #{$animationName} {
        $browser: '-o-' !global;
        @content;
    }
    @keyframes #{$animationName} {
        $browser: '' !global;
        @content;
    }
} $browser: null;

For your reference here is the SASS example:

@include keyframes(animation-name) {
   0% {
       #{$browser}transform: translate3d(100%, 0, 0);
   }
   100% {
      #{$browser}transform: translate3d(0%, 0, 0);
   }
}

And here how you include your animation to the particular class or ids

.new-class {
@include animation('animation-name 5s linear');
}

That's all.