src/scss/bootstrap-4.0.0-alpha.6/scss/mixins/_breakpoints.scss

   1 // Breakpoint viewport sizes and media queries.
   2 //
   3 // Breakpoints are defined as a map of (name: minimum width), order from small to large:
   4 //
   5 //    (xs: 0, sm: 576px, md: 768px)
   6 //
   7 // The map defined in the `$grid-breakpoints` global variable is used as the `$breakpoints` argument by default.
   8
   9 // Name of the next breakpoint, or null for the last breakpoint.
  10 //
  11 //    >> breakpoint-next(sm)
  12 //    md
  13 //    >> breakpoint-next(sm, (xs: 0, sm: 576px, md: 768px))
  14 //    md
  15 //    >> breakpoint-next(sm, $breakpoint-names: (xs sm md))
  16 //    md
  17 @function breakpoint-next($name, $breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($breakpoints)) {
  18   $n: index($breakpoint-names, $name);
  19   @return if($n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);
  20 }
  21
  22 // Minimum breakpoint width. Null for the smallest (first) breakpoint.
  23 //
  24 //    >> breakpoint-min(sm, (xs: 0, sm: 576px, md: 768px))
  25 //    576px
  26 @function breakpoint-min($name, $breakpoints: $grid-breakpoints) {
  27   $min: map-get($breakpoints, $name);
  28   @return if($min != 0, $min, null);
  29 }
  30
  31 // Maximum breakpoint width. Null for the largest (last) breakpoint.
  32 // The maximum value is calculated as the minimum of the next one less 0.1.
  33 //
  34 //    >> breakpoint-max(sm, (xs: 0, sm: 576px, md: 768px))
  35 //    767px
  36 @function breakpoint-max($name, $breakpoints: $grid-breakpoints) {
  37   $next: breakpoint-next($name, $breakpoints);
  38   @return if($next, breakpoint-min($next, $breakpoints) - 1px, null);
  39 }
  40
  41 // Returns a blank string if smallest breakpoint, otherwise returns the name with a dash infront.
  42 // Useful for making responsive utilities.
  43 //
  44 //    >> breakpoint-infix(xs, (xs: 0, sm: 576px, md: 768px))
  45 //    ""  (Returns a blank string)
  46 //    >> breakpoint-infix(sm, (xs: 0, sm: 576px, md: 768px))
  47 //    "-sm"
  48 @function breakpoint-infix($name, $breakpoints: $grid-breakpoints) {
  49   @return if(breakpoint-min($name, $breakpoints) == null, "", "-#{$name}");
  50 }
  51
  52 // Media of at least the minimum breakpoint width. No query for the smallest breakpoint.
  53 // Makes the @content apply to the given breakpoint and wider.
  54 @mixin media-breakpoint-up($name, $breakpoints: $grid-breakpoints) {
  55   $min: breakpoint-min($name, $breakpoints);
  56   @if $min {
  57     @media (min-width: $min) {
  58       @content;
  59     }
  60   } @else {
  61     @content;
  62   }
  63 }
  64
  65 // Media of at most the maximum breakpoint width. No query for the largest breakpoint.
  66 // Makes the @content apply to the given breakpoint and narrower.
  67 @mixin media-breakpoint-down($name, $breakpoints: $grid-breakpoints) {
  68   $max: breakpoint-max($name, $breakpoints);
  69   @if $max {
  70     @media (max-width: $max) {
  71       @content;
  72     }
  73   } @else {
  74     @content;
  75   }
  76 }
  77
  78 // Media that spans multiple breakpoint widths.
  79 // Makes the @content apply between the min and max breakpoints
  80 @mixin media-breakpoint-between($lower, $upper, $breakpoints: $grid-breakpoints) {
  81   @include media-breakpoint-up($lower, $breakpoints) {
  82     @include media-breakpoint-down($upper, $breakpoints) {
  83       @content;
  84     }
  85   }
  86 }
  87
  88 // Media between the breakpoint's minimum and maximum widths.
  89 // No minimum for the smallest breakpoint, and no maximum for the largest one.
  90 // Makes the @content apply only to the given breakpoint, not viewports any wider or narrower.
  91 @mixin media-breakpoint-only($name, $breakpoints: $grid-breakpoints) {
  92   @include media-breakpoint-between($name, $name, $breakpoints) {
  93     @content;
  94   }
  95 }