gabrielcheung128 / sass_logo_sprite_

maintaining logo sprites with SASS mixin

SASS_logo_sprite_

Maintain Logo Sprites with SASS mixins

Background:

Using Logo Sprites can reduce the requests for access, to increase the loading speed. But to maintain it is awful. So I built a strategy to make it easier to maintain with the SASS mixin.

About combining the images into one:

Strongly recommend to use this tool(http://responsive-css.spritegen.com/). It will combine the images into one column with the css classes. It would be like below:

Image:
LOGO-1
LOGO-2
LOGO-3
…

CSS:
.a-logo-1 {
	Background-position: 0 0;
	Width: 100px;
	Height: 100px;
}
...

Why it should be in one column?

Because it won’t bother to worry about the background-position-x, and it will be much easier when you add new images to the exist one, just add them at the end of the existed one.

About the mixin function:

@mixin rqs-logos($index, $heights, $widths){
	width: nth($widths, $index)/2 + 0px;
	height: nth($heights, $index)/2 + 0px;
 	$position : 0;
 	@if $index > 1 {
   		@for $i from 1 through ($index - 1) {
     			$position : $position + nth($heights, $i);
   		}
 	}
 	background-position: 0 -$position + 0px;
	#for Retina screens, you need to -($position/2) instead of -$position
}

With padding between logos:

@mixin rqs-logos($index, $heights, $widths){
	width: nth($widths, $index)/2 + 0px;
	height: nth($heights, $index)/2 + 0px;
	$position : 0;
 	@if $index > 1 {
   		@for $i from 1 through ($index - 1) {
     			$position : $position + nth($heights, $i) + $padding;
   		}
 	}
 	background-position: 0 -$position + 0px;
}

#Usage: Firstly, you need to set up two array of the height and width of all logos:

	$logo-heights: 75, 56, 98, 92, 103, 75, 70, 40, 68, 80, 69, 34, 57, 57;
	$logo-widths: 472, 354, 330, 325, 310, 248, 248, 243, 240, 236, 226, 210, 204, 194;

Secondly, set up a base class: 
	.base {
		background-image: image-url("ofc/[email protected]");
		background-size: 236px auto;
	}

Thirdly, specific class: 
	&.logo-1 {
		@include rqs-logos(3, $logo-heights, $logo-widths );
	}

Notice that the index begins with 1 instead of 0 in SASS.