[gtk/wip/jimmac/drop-text-shadow] Adwaita: drop text shadows for buttons

[Jakub Steiner <jimmac src gnome org>]

commit 87f2ea30a30224a06f65c1a88dfebf63166c1623
Author: Jakub Steiner <jimmac gmail com>
Date:   Wed Apr 15 15:27:17 2020 +0200

    Adwaita: drop text shadows for buttons
    
    - People seem to misunderstand the unsharp-mask-like increase
      of visual contrast for "fuziness". That is not the reason for
      the change. The stylistic change of just going with flat
      text label allows to simplify the code and drop complexity.
    
    Fixes https://gitlab.gnome.org/GNOME/gtk/-/issues/2280

 gtk/theme/Adwaita/_common.scss  |  5 +----
 gtk/theme/Adwaita/_drawing.scss | 34 ----------------------------------
 2 files changed, 1 insertion(+), 38 deletions(-)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 351c309462..06223b06bd 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -902,10 +902,8 @@ button {
   // the dot is drawn by using two radial gradient, the first one is the actuall dot, the other
   // simulates the shadow labels and icons normally have in buttons.
   animation: needs_attention 150ms ease-in;
-  $_dot_shadow: _text_shadow_color(); // shadow color
 
-  background-image: radial-gradient(farthest-side, $_dot_color 96%, transparentize($_dot_color,1 )),
-                    radial-gradient(farthest-side, $_dot_shadow 95%, transparentize($_dot_shadow, 1));
+  background-image: radial-gradient(farthest-side, $_dot_color 96%, transparentize($_dot_color,1 ));
   background-size: 6px 6px, 6px 6px;
   background-repeat: no-repeat;
 
@@ -4162,7 +4160,6 @@ button.titlebutton {
 
   @extend %button_basic_flat;
 
-  @include _button_text_shadow;
 
   &:not(.menu) {
     border-radius: 9999px;
diff --git a/gtk/theme/Adwaita/_drawing.scss b/gtk/theme/Adwaita/_drawing.scss
index 3c1de0e34e..8aac39e1b4 100644
--- a/gtk/theme/Adwaita/_drawing.scss
+++ b/gtk/theme/Adwaita/_drawing.scss
@@ -123,17 +123,6 @@
   @else { @return darken($c, 10%); }
 }
 
-@function _text_shadow_color ($tc: $fg_color, $bg: $bg_color) {
-//
-// calculate the color of text shadows
-//
-// $tc is the text color
-// $bg is the background color
-//
-  $_lbg: lightness($bg)/100%;
-  @if lightness($tc)<50% { @return transparentize(white, 1-$_lbg/($_lbg*1.3)); }
-  @else { @return transparentize(black, $_lbg*0.8); }
-}
 
 @function _button_hilight_color($c) {
 //
@@ -149,26 +138,7 @@
   @else { @return transparentize(white, 0.98); }
 }
 
-@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
-//
-
-  $_shadow: _text_shadow_color($tc, $bg);
 
-  @if lightness($tc)<50% {
-    text-shadow: 0 1px $_shadow;
-    -gtk-icon-shadow: 0 1px $_shadow;
-  }
-  @else {
-    text-shadow: 0 -1px $_shadow;
-    -gtk-icon-shadow: 0 -1px $_shadow;
-  }
-}
 
 @mixin button($t, $c:$bg_color, $tc:$fg_color, $edge: none) {
 //
@@ -202,7 +172,6 @@
     $button_fill: if($variant == 'light', linear-gradient(to top, darken($c, 4%) 2px, $c),
                                           linear-gradient(to top, darken($c,1%) 2px, $c)) !global;
     background-image: $button_fill;
-    @include _button_text_shadow($tc, $c);
     @include _shadows(inset 0 1px $_hilight_color, $_button_edge, $_button_shadow);
   }
 
@@ -215,12 +184,10 @@
     border-bottom-color: if($c != $bg_color, _border_color($c, true), $alt_borders_color);
     @if $variant == 'light' {
       $button_fill: linear-gradient(to top, $c, lighten($c, 1%) 1px) !global;
-      @include _button_text_shadow($tc, lighten($c, 6%));
       @include _shadows(inset 0 1px _button_hilight_color(lighten($c, 6%)), $_button_edge, $_button_shadow);
     }
     @else {
       $button_fill: linear-gradient(to top, darken($c,1%), lighten($c, 1%) 1px) !global;
-      @include _button_text_shadow($tc,lighten($c, 6%));
       @include _shadows(inset 0 1px _button_hilight_color(darken($c, 2%)), $_button_edge, $_button_shadow);
     }
     background-image: $button_fill;
@@ -232,7 +199,6 @@
   //
     color: $tc;
     border-color: if($c != $bg_color, _border_color($c, true), $alt_borders_color);
-    @include _button_text_shadow($tc, $c);
     @if $variant == 'light' {
       background-image: linear-gradient(to bottom, lighten($c, 5%) 20%, $c 90%);
       @include _shadows(inset 0 1px _button_hilight_color(lighten($c, 6%)),