adwaita: Solve junction problem without border image

This genius piece of CSS colors only the top left (or top right in RTL)
pixel of the scrollbar junction.
Doing it this way is better because we don't have to upload a cairo node
every frame.

diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index bad7cfc929b49cb079c858ff3d75ed5e1eb0f8a9..dc56297ee6e14ab1827d6ebb1bf1d8a5a3afd722 100644 (file)
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -3760,17 +3760,30 @@ scrolledwindow {
 
 
   junction { // the small square between two scrollbars
-    border-color: transparent;
-    // the border image is used to add the missing dot between the borders, details, details, details...
-    border-image: linear-gradient(to bottom, $borders_color 1px, transparent 1px) 0 0 0 1 / 0 1px stretch;
-    background-color: $scrollbar_bg_color;
+    // Only color the top-left (or top right in RTL) pixel, to visually connect
+    // the borders of the two scrollbars.
+
+    background: $borders_color,
+                linear-gradient(to bottom, transparent 1px, $scrollbar_bg_color 1px),
+                linear-gradient(to right, transparent 1px, $scrollbar_bg_color 1px);
 
-    &:dir(rtl) { border-image-slice: 0 1 0 0; }
+    &:dir(rtl) {
+      background: $borders_color,
+                  linear-gradient(to bottom, transparent 1px, $scrollbar_bg_color 1px),
+                  linear-gradient(to left, transparent 1px, $scrollbar_bg_color 1px);
+    }
 
     &:backdrop {
-      border-image-source: linear-gradient(to bottom, $backdrop_borders_color 1px, transparent 1px);
-      background-color: $backdrop_scrollbar_bg_color;
       transition: $backdrop_transition;
+      background: $backdrop_borders_color,
+                  linear-gradient(to bottom, transparent 1px, $backdrop_scrollbar_bg_color 1px),
+                  linear-gradient(to right, transparent 1px, $backdrop_scrollbar_bg_color 1px);
+
+      &:dir(rtl) {
+        background: $backdrop_borders_color,
+                    linear-gradient(to bottom, transparent 1px, $backdrop_scrollbar_bg_color 1px),
+                    linear-gradient(to left, transparent 1px, $backdrop_scrollbar_bg_color 1px);
+      }
     }
   }
 }