gtk2/gtk/theme/HighContrast/_drawing.scss

// Drawing mixins

// generic drawing of more complex things
@function _widget_edge($c:$borders_edge) {
// outer highlight "used" on most widgets
  @return 0 1px $c;
}

@mixin _shadows($shadow1, $shadow2:none, $shadow3:none, $shadow4:none) {
//
// Helper function to stack up to 4 box-shadows;
//
  @if $shadow4!=none { box-shadow: $shadow1, $shadow2, $shadow3, $shadow4; }
  @else if $shadow3!=none { box-shadow: $shadow1, $shadow2, $shadow3; }
  @else if $shadow2!=none { box-shadow: $shadow1, $shadow2; }
  @else { box-shadow: $shadow1; }
}

// entries

@function entry_focus_border($fc) {
  @return $fc;
}

@function entry_focus_glow($fc) {
  $_focus_glow_color: transparentize($fc,0.85);
  @return inset 0 0 0 1px $_focus_glow_color;
}

@function entry_gradient($c) {
  @return linear-gradient(to bottom, darken($c,3%), $c 90%);
}

@mixin entry($t, $fc:$selected_bg_color, $edge: $borders_edge) {
//
// Entries drawing function
//
// $t: entry type
// $fc: focus color
// $edge:none set to true not to draw the bottom edge hilight
//
// possible $t values:
// normal, focus, insensitive, backdrop, backdrop-insensitive;
//
  background-color: transparent;
  border-style: solid;
  background-image: linear-gradient(to bottom,
                                    darken($base_color,3%),
                                    $base_color 90%);
  $_entry_edge: none;
  
  @if $t==normal {
    border-color: $borders_color;
    @include _shadows(inset 0 2px 2px -2px mix(black, $base_color, 50%),
                      $_entry_edge);
  }
  @if $t==focus {
    border-color: $fc;
    @include _shadows(inset 0 2px 2px -2px mix(black, $base_color, 50%),
                      inset 0 0 2px 1px mix($fc,$base_color,20%),
                        $_entry_edge);
  }
  @if $t==insensitive {
    color: $insensitive_fg_color;
    border-color: $borders_color;
    background-image: linear-gradient(to bottom, $insensitive_bg_color);
    @include _shadows($_entry_edge);
  }
  @if $t==backdrop {
    color: $backdrop_fg_color;
    background-image: linear-gradient(to bottom, $backdrop_base_color);
    box-shadow: 0 1px transparentize(white,1);
  }
  @if $t==backdrop-insensitive {
    color: $insensitive_fg_color;
    background-image: linear-gradient(to bottom, $backdrop_bg_color);
    box-shadow: 0 1px transparentize(white,1);
  }
}

// buttons

@mixin _button_border_color ($c) { border-color: darken($c,25%); } // colored buttons want the border form the base color

@mixin _button_text_shadow ($tc:$fg_color, $bg:$bg_color) {
//
// helper function for the text emboss effect
//
// $tc is the optional text color, not the shadow color
//
// TODO: this functions needs a way to deal with special cases
//

  $_dark: black;
  $_bright: white;

  @if lightness($tc) < 50% {
    text-shadow: 0 1px $_bright;
    -gtk-icon-shadow: 0 1px $_bright;
  }
  @else {
    text-shadow: 0 -1px $_dark;
    -gtk-icon-shadow: 0 -1px $_dark;
  }
}

@mixin button($t, $c:$bg_color, $tc:$fg_color, $edge: $borders_color) {
//
// Button drawing function
//
// $t:  button type,
// $c:  base button color for colored* types
// $tc: optional text color for colored* types
// $noedge:none set to true not to draw the bottom edge hilight
//
// possible $t values:
// normal, hover, active, insensitive, insensitive-active,
// backdrop, backdrop-active, backdrop-insensitive, backdrop-insensitive-active
//
  border-width: 2px;
  border-style: solid;

  $_top_hilight: if(lightness($c)> 70%, white, transparentize(white,0.9)); //not just dark/light but colored buttons

  @if $t==normal {
  //
  // normal button
  //
    color: $tc;
    background-image: none;
    background-color: $c;

    @if $c!=$bg_color { @include _button_border_color($c); }
    @else { border-color: $borders_color; }

  }

  @else if $t==hover {
  //
  // hovered button
  //
    color: $tc; //fg_color
    background-color: $c;
    @if $c!=$bg_color { @include _button_border_color($c); }
    @else { border-color: $borders_color; }
    background-image: none;

  }

  @else if $t==active {
  //
  // pushed button
  //
    background-image: none;
    color: invert($tc);
    background-color: invert($c);
    @if $c!=$bg_color { @include _button_border_color($c); }
    @else { border-color: $borders_color; }
  }
  @else if $t==insensitive {
  //
  // insensitive button
  //
    color: $insensitive_fg_color;
    background-color: $insensitive_bg_color;
    border-color: $insensitive_borders_color;
    background-image: none;
    text-shadow: none;
    -gtk-icon-shadow: none;
  }
  @else if $t==insensitive-active {
  //
  // insensitive pushed button
  //
    color: $insensitive_fg_color;
    border-color: $insensitive_borders_color;
    background-image: none;
    background-color: $insensitive_bg_color;
  }

  @else if $t==backdrop {
  //
  // backdrop button
  //
    color: if($c!=$bg_color, $tc, $backdrop_fg_color);
    background-color: if($c!=$bg_color, $c, $backdrop_bg_color);
    border-color: if($c!=$bg_color, $c, $backdrop_borders_color);
    background-image: none;
    text-shadow: none;
    -gtk-icon-shadow: none;
  }

  @else if $t==backdrop-active {
  //
  // backdrop pushed button
  //
    color: invert($backdrop_fg_color);
    background-color: $backdrop_borders_color;
    border-color: $backdrop_borders_color;
    background-image: none;
  }

  @else if $t==backdrop-insensitive {
  //
  // backdrop insensitive button
  //
    color: $insensitive_fg_color;
    background-color: $insensitive_bg_color;
    border-color: $backdrop_borders_color;
    background-image: none;
  }

  @else if $t==backdrop-insensitive-active {
  //
  // backdrop insensitive pushed button
  //
    color: $insensitive_fg_color;
    border-color: $backdrop_borders_color;
    background-image: none;
    background-color: mix($backdrop_borders_color,$backdrop_bg_color, 8%);
  }
  
  @else if $t==osd {
  //
  // normal osd button
  //
    color: $osd_fg_color;
    background-image: none;
    background-color: $osd_bg_color;
    border-color: $osd_borders_color;
    box-shadow: none;
  }
  @else if $t==osd-hover {
  //
  // active osd button
  //
    color: $osd_fg_color;
    background-color: lighten($osd_bg_color,30%);
    border-color: $osd_borders_color;
    box-shadow: none;
  }
  @else if $t==osd-active {
  //
  // active osd button
  //
    color: $osd_bg_color;
    background-color: $osd_fg_color;
    border-color: $osd_borders_color;
    box-shadow: none;
  }
  @else if $t==osd-insensitive {
  //
  // insensitive osd button
  //
    border-color: $osd_borders_color;
    color: $insensitive_fg_color;
  }
  
}

@mixin overshoot($p, $t:normal, $c:$fg_color) {
//
// overshoot
//
// $p: position
// $t: type
// $c: base color
//
// possible $p values:
// top, bottom, right, left
//
// possible $t values:
// normal, backdrop
//

  $_small_gradient_length: 5%;
  $_big_gradient_length: 100%;

  $_position: center top;
  $_small_gradient_size: 100% $_small_gradient_length;
  $_big_gradient_size: 100% $_big_gradient_length;

  @if $p==bottom {
    $_position: center bottom;
    $_linear_gradient_direction: to top; 
  }

  @else if $p==right {
    $_position: right center;
    $_small_gradient_size: $_small_gradient_length 100%;
    $_big_gradient_size: $_big_gradient_length 100%;
  }

  @else if $p==left {
    $_position: left center;
    $_small_gradient_size: $_small_gradient_length 100%;
    $_big_gradient_size: $_big_gradient_length 100%;
  }
  
  $_small_gradient_color: $c;
  $_big_gradient_color: $c;

  @if $c==$fg_color {
    $_small_gradient_color: darken($borders_color, 50%);
    $_big_gradient_color: $fg_color;

    @if $t==backdrop { $_small_gradient_color: $backdrop_borders_color; }
  }

  $_small_gradient: -gtk-gradient(radial,
                                  $_position, 0,
                                  $_position, 0.5,
                                  to($_small_gradient_color),
                                  to(transparentize($_small_gradient_color, 1)));

  $_big_gradient: -gtk-gradient(radial,
                                $_position, 0,
                                $_position, 0.6,
                                from(transparentize($_big_gradient_color, 0.5)),
                                to(transparentize($_big_gradient_color, 1)));

  @if $t==normal {
    background-image: $_small_gradient, $_big_gradient;
    background-size: $_small_gradient_size, $_big_gradient_size;
  }

  @else if $t==backdrop {
    background-image: $_small_gradient;
    background-size: $_small_gradient_size;
  }

  background-repeat: no-repeat;
  background-position: $_position;

  background-color: transparent; // reset some properties to be sure to not inherit them somehow
  border: none;                  //
  box-shadow: none;              //
}

@mixin undershoot($p) {
//
// undershoot
//
// $p: position
//
// possible $p values:
// top, bottom, right, left
//

  $_undershoot_color_dark: transparentize(black, 0.8);
  $_undershoot_color_light: transparentize(white, 0.8);

  $_gradient_dir: left;
  $_dash_bg_size: 10px 1px;
  $_gradient_repeat: repeat-x;
  $_bg_pos: center $p;

  background-color: transparent; // shouldn't be needed, but better to be sure;

  @if ($p == left) or ($p == right) {
    $_gradient_dir: top;
    $_dash_bg_size: 1px 10px;
    $_gradient_repeat: repeat-y;
    $_bg_pos: $p center;
  }

  background-image: linear-gradient(to $_gradient_dir, // this is the dashed line
                                    $_undershoot_color_light 50%,
                                    $_undershoot_color_dark 50%);

  padding-#{$p}: 1px;
  background-size: $_dash_bg_size;
  background-repeat: $_gradient_repeat;
  background-origin: content-box;
  background-position: $_bg_pos;
  border: none;
  box-shadow: none;
}