responsive-sprites.md

Easy responsive sprites using grunt-spritesmith and SCSS

Requires grunt-spritesmith which generates a spritesheet from a bunch of images.

This gist passes a custom template for spritesmith to generate the SCSS file.

Gruntfile.js

sprite: {
  src: "images/*.png",
  dest: "sprites.png",
  destCss: "_sprites.scss",
  padding: 2, // Due to rounding, needs some space between images
  cssTemplate: "sprites.scss.handlebars"
}

index.html

<div class="responsive-sprites">
  <img src="sprites.png" class="icon-github">
</div>

sprites.scss.handlebars

// Handlebars template that generates the scss file

.responsive-sprites {
  height: auto;
  overflow: hidden;

  & > img {
    display: block;
    max-width: none;
  }
}

// explanation:
// width         = 100% * spritesheet width                       / image width
// margin-top    = 100% * distance from top of sprite to image    / image width
// margin-bottom = 100% * distance from bottom of sprite to image / image width
// margin-left   = 100% * distance from left of sprite to image   / image width


// Constants	
{{#spritesheet}}
$total_width: {{width}};
$total_height: {{height}};
{{/spritesheet}}

{{#sprites}}
img.icon-{{name}} {
  width: 100% * $total_width / {{width}};
  margin-top: 100% * {{offset_y}} / {{width}};
  margin-bottom: -100% * ($total_height - ({{y}} + {{height}})) / {{width}};
  margin-left: -100% * {{x}} / {{width}};
}
{{/sprites}}