[gtk/wip/chergert/popover-opaque-region: 2/3] window: use GtkNative API to update opaque region

[Christian Hergert <chergert src gnome org>]

commit 54ebd414639a006dea65c0bd8659362e8028f778
Author: Christian Hergert <chergert redhat com>
Date:   Thu Feb 10 16:23:16 2022 -0800

    window: use GtkNative API to update opaque region
    
    This switches to using the new GtkNative machinery for updating the
    opaque region. Some amount of local calculation is still required for
    determining when we should apply shadows, and this inherits what was
    done previous for that.
    
    Related #4689

 gtk/gtkwindow.c | 117 +++++++++-----------------------------------------------
 1 file changed, 19 insertions(+), 98 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index c36d16ca34..d9856d8b5e 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -4055,112 +4055,39 @@ out:
 }
 
 static void
-corner_rect (cairo_rectangle_int_t *rect,
-             const GtkCssValue     *value)
-{
-  rect->width = _gtk_css_corner_value_get_x (value, 100);
-  rect->height = _gtk_css_corner_value_get_y (value, 100);
-}
-
-static void
-subtract_decoration_corners_from_region (cairo_region_t        *region,
-                                         cairo_rectangle_int_t *extents,
-                                         GtkCssStyle           *style,
-                                         GtkWindow             *window)
-{
-  GtkWindowPrivate *priv = gtk_window_get_instance_private (window);
-  cairo_rectangle_int_t rect;
-
-  if (!priv->client_decorated ||
-      !priv->decorated ||
-      priv->fullscreen ||
-      priv->maximized)
-    return;
-
-  corner_rect (&rect, style->border->border_top_left_radius);
-  rect.x = extents->x;
-  rect.y = extents->y;
-  cairo_region_subtract_rectangle (region, &rect);
-
-  corner_rect (&rect, style->border->border_top_right_radius);
-  rect.x = extents->x + extents->width - rect.width;
-  rect.y = extents->y;
-  cairo_region_subtract_rectangle (region, &rect);
-
-  corner_rect (&rect, style->border->border_bottom_left_radius);
-  rect.x = extents->x;
-  rect.y = extents->y + extents->height - rect.height;
-  cairo_region_subtract_rectangle (region, &rect);
-
-  corner_rect (&rect, style->border->border_bottom_right_radius);
-  rect.x = extents->x + extents->width - rect.width;
-  rect.y = extents->y + extents->height - rect.height;
-  cairo_region_subtract_rectangle (region, &rect);
-}
-
-static void
-update_opaque_region (GtkWindow       *window,
-                      const GtkBorder *shadow)
+update_opaque_region (GtkWindow *window)
 {
   GtkWindowPrivate *priv = gtk_window_get_instance_private (window);
-  GtkWidget *widget = GTK_WIDGET (window);
-  cairo_region_t *opaque_region;
-  gboolean is_opaque = FALSE;
-  GtkCssStyle *style;
-
-  if (!_gtk_widget_get_realized (widget))
-    return;
+  gboolean subtract_decoration_corners;
+  gboolean subtract_shadow;
 
-  style = gtk_css_node_get_style (gtk_widget_get_css_node (GTK_WIDGET (window)));
-
-  is_opaque = gdk_rgba_is_opaque (gtk_css_color_value_get_rgba (style->background->background_color));
-
-  if (is_opaque && gtk_widget_get_opacity (widget) < 1.0)
-    is_opaque = FALSE;
-
-  if (is_opaque)
-    {
-      cairo_rectangle_int_t rect;
-      GtkCssBoxes css_boxes;
-      const graphene_rect_t *border_rect;
-      double native_x, native_y;
-
-      gtk_native_get_surface_transform (GTK_NATIVE (window), &native_x, &native_y);
-
-      gtk_css_boxes_init (&css_boxes, widget);
-      border_rect = gtk_css_boxes_get_border_rect (&css_boxes);
-
-      rect.x = native_x + border_rect->origin.x;
-      rect.y = native_y + border_rect->origin.y;
-      rect.width = border_rect->size.width;
-      rect.height = border_rect->size.height;
-
-      opaque_region = cairo_region_create_rectangle (&rect);
-
-      subtract_decoration_corners_from_region (opaque_region, &rect, style, window);
-    }
-  else
-    {
-      opaque_region = NULL;
-    }
+  subtract_decoration_corners = (priv->client_decorated &&
+                                 priv->decorated &&
+                                 !priv->fullscreen &&
+                                 !priv->maximized);
+  subtract_shadow = (priv->client_decorated &&
+                     priv->decorated &&
+                     priv->use_client_shadow &&
+                     !priv->maximized &&
+                     !priv->fullscreen);
 
-  gdk_surface_set_opaque_region (priv->surface, opaque_region);
-
-  cairo_region_destroy (opaque_region);
+  gtk_native_update_opaque_region (GTK_NATIVE (window),
+                                   NULL,
+                                   subtract_decoration_corners,
+                                   subtract_shadow,
+                                   RESIZE_HANDLE_SIZE);
 }
 
 static void
 update_realized_window_properties (GtkWindow *window)
 {
   GtkWindowPrivate *priv = gtk_window_get_instance_private (window);
-  GtkBorder shadow;
   GdkRectangle rect;
   GtkCssBoxes css_boxes;
   const graphene_rect_t *border_rect;
   double native_x, native_y;
 
-  get_shadow_width (window, &shadow);
-  update_opaque_region (window, &shadow);
+  update_opaque_region (window);
 
   if (!priv->client_decorated || !priv->use_client_shadow)
     return;
@@ -5227,13 +5154,7 @@ gtk_window_css_changed (GtkWidget         *widget,
 
   if (!_gtk_widget_get_alloc_needed (widget) &&
       (change == NULL || gtk_css_style_change_changes_property (change, GTK_CSS_PROPERTY_BACKGROUND_COLOR)))
-    {
-      GtkBorder shadow;
-
-      get_shadow_width (window, &shadow);
-
-      update_opaque_region (window, &shadow);
-    }
+    update_opaque_region (window);
 }
 
 /*