widget: Consider css margins when setting clip

This is optional for positive margins as they just increase the widget
allocation. However, with negative css margins, the allocation is
smaller than the clip.

This fixes scale sliders leaving a small trail behind.

diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 43c8b0c9327caca4cb9a16f22c5946a48d84fbe7..f45a3989dc77f0f66ebaaea714af41b12a60f8ca 100644 (file)
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -13447,6 +13447,7 @@ gtk_widget_set_clip (GtkWidget           *widget,
   GtkWidgetPrivate *priv;
   GtkBorder shadow;
   GtkAllocation allocation;
+  GtkBorder margin;
   GtkCssStyle *style;
 
   g_return_if_fail (GTK_IS_WIDGET (widget));
@@ -13480,13 +13481,14 @@ gtk_widget_set_clip (GtkWidget           *widget,
 
   /* Always untion the given clip with the widget allocation */
   /* ... and with the box shadow size */
-  allocation = priv->allocation;
   style = gtk_css_node_get_style (priv->cssnode);
+  allocation = priv->allocation;
+  get_box_margin (style, &margin);
   _gtk_css_shadows_value_get_extents (gtk_css_style_get_value (style, GTK_CSS_PROPERTY_BOX_SHADOW), &shadow);
-  allocation.x -= shadow.left;
-  allocation.y -= shadow.top;
-  allocation.width += shadow.left + shadow.right;
-  allocation.height += shadow.top + shadow.bottom;
+  allocation.x += margin.left - shadow.left;
+  allocation.y += margin.top - shadow.top;
+  allocation.width += shadow.left + shadow.right - margin.left - margin.right;
+  allocation.height += shadow.top + shadow.bottom - margin.top - margin.bottom;
   gdk_rectangle_union (&allocation, clip, &priv->clip);
 }