[gtk/small-caps: 16/19] textview: Don't leave embedded children behind

[Matthias Clasen <matthiasc src gnome org>]

commit 4c029af6cdd655d365ab6112857a8ea4ce6c7dcd
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Nov 5 18:54:06 2021 -0400

    textview: Don't leave embedded children behind
    
    When scrolling embedded widgets out of view,
    they sometimes get left behind because we don't
    reallocated them. To avoid that, move _all_ children
    out of view in size_allocate, and let the current
    child allocation plumbing move the visible ones
    back in place.

 gtk/gtktextview.c | 11 +++++++++++
 1 file changed, 11 insertions(+)
---
diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c
index 340d12b2d9..db23e9ad86 100644
--- a/gtk/gtktextview.c
+++ b/gtk/gtktextview.c
@@ -4409,6 +4409,8 @@ gtk_text_view_allocate_children (GtkTextView *text_view)
     {
       const AnchoredChild *child = iter->data;
       GtkTextIter child_loc;
+      GtkRequisition child_req;
+      GtkAllocation allocation;
 
       /* We need to force-validate the regions containing children. */
       gtk_text_buffer_get_iter_at_child_anchor (get_buffer (text_view),
@@ -4429,6 +4431,15 @@ gtk_text_view_allocate_children (GtkTextView *text_view)
         }
 
       gtk_text_layout_validate_yrange (priv->layout, &child_loc, 0, 1);
+
+      gtk_widget_get_preferred_size (child->widget, &child_req, NULL);
+
+      allocation.x = - child_req.width;
+      allocation.y = - child_req.height;
+      allocation.width = child_req.width;
+      allocation.height = child_req.height;
+
+      gtk_widget_size_allocate (child->widget, &allocation, -1);
     }
 }