[gtk/popup-shadow-width] popover: Don't include shadow border in input region

[Jonas Ådahl <jadahl src gnome org>]

commit f38a9df99de10da590f7aab7f52c198cc8700ac3
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Feb 11 09:50:26 2021 +0100

    popover: Don't include shadow border in input region
    
    This makes it possible to "click through" the shadow e.g. on the button
    that opened a popover, to hide the popover. The popover shadow isn't
    useful for anything, since it isn't used for triggering interactive
    resize and the like.

 gtk/gtkpopover.c | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)
---
diff --git a/gtk/gtkpopover.c b/gtk/gtkpopover.c
index 4fadbc1f0f..eef7d2ddde 100644
--- a/gtk/gtkpopover.c
+++ b/gtk/gtkpopover.c
@@ -1309,7 +1309,31 @@ gtk_popover_update_shape (GtkPopover *popover)
       cairo_region_destroy (region);
     }
   else
-    gdk_surface_set_input_region (priv->surface, NULL);
+    {
+      GtkCssNode *content_css_node;
+      GtkCssStyle *style;
+      GtkBorder shadow_width;
+      cairo_rectangle_int_t input_rect;
+      cairo_region_t *region;
+
+      content_css_node =
+        gtk_widget_get_css_node (GTK_WIDGET (priv->contents_widget));
+      style = gtk_css_node_get_style (content_css_node);
+      gtk_css_shadow_value_get_extents (style->background->box_shadow, &shadow_width);
+
+      input_rect.x = shadow_width.left;
+      input_rect.y = shadow_width.top;
+      input_rect.width =
+        gdk_surface_get_width (priv->surface) -
+        (shadow_width.left + shadow_width.right);
+      input_rect.height =
+        gdk_surface_get_height (priv->surface) -
+        (shadow_width.top + shadow_width.bottom);
+
+      region = cairo_region_create_rectangle (&input_rect);
+      gdk_surface_set_input_region (priv->surface, region);
+      cairo_region_destroy (region);
+    }
 }
 
 static int