[gtksourceview] gutter: allow renderers to overdraw

[Christian Hergert <chergert src gnome org>]

commit b39a4dd23972fe4691cb5a329901e289ef3551c2
Author: Christian Hergert <chergert redhat com>
Date:   Fri Apr 29 16:17:42 2022 -0700

    gutter: allow renderers to overdraw
    
    This can be useful to do fun things from renderers which might need to
    draw slightly over the textview content.

 gtksourceview/gtksourcegutter.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)
---
diff --git a/gtksourceview/gtksourcegutter.c b/gtksourceview/gtksourcegutter.c
index add9c387..3c623913 100644
--- a/gtksourceview/gtksourcegutter.c
+++ b/gtksourceview/gtksourcegutter.c
@@ -353,6 +353,24 @@ gtk_source_gutter_leave_cb (GtkSourceGutter          *gutter,
        _gtk_source_gutter_queue_draw (gutter);
 }
 
+static void
+gtk_source_gutter_root (GtkWidget *widget)
+{
+       GtkWidget *parent;
+
+       g_assert (GTK_SOURCE_IS_GUTTER (widget));
+
+       parent = gtk_widget_get_parent (widget);
+
+       /* The GtkTextViewChild has "overflow" set to Hidden and we
+        * want to allow drawing over that.
+        */
+       if (parent != NULL)
+       {
+               gtk_widget_set_overflow (parent, GTK_OVERFLOW_VISIBLE);
+       }
+}
+
 static void
 gtk_source_gutter_set_property (GObject      *object,
                                 guint         prop_id,
@@ -428,6 +446,7 @@ gtk_source_gutter_class_init (GtkSourceGutterClass *klass)
        widget_class->measure = gtk_source_gutter_measure;
        widget_class->size_allocate = gtk_source_gutter_size_allocate;
        widget_class->snapshot = gtk_source_gutter_snapshot;
+       widget_class->root = gtk_source_gutter_root;
 
        /**
         * GtkSourceGutter:view:
@@ -739,6 +758,7 @@ gtk_source_gutter_snapshot (GtkWidget   *widget,
        GtkTextIter cur, sel;
        gboolean needs_wrap_first = FALSE;
        gboolean needs_wrap_last = FALSE;
+       int clip_width = 0;
 
        g_clear_object (&gutter->lines);
 
@@ -845,10 +865,18 @@ gtk_source_gutter_snapshot (GtkWidget   *widget,
                                                   gutter->lines);
        }
 
+       clip_width = gtk_widget_get_width (widget);
+
+       /* Allow drawing over the left margin from renderers */
+       if (gutter->window_type == GTK_TEXT_WINDOW_LEFT)
+       {
+               clip_width += gtk_text_view_get_left_margin (text_view);
+       }
+
        gtk_snapshot_push_clip (snapshot,
                                &GRAPHENE_RECT_INIT (0,
                                                     0,
-                                                    gtk_widget_get_width (widget),
+                                                    clip_width,
                                                     gtk_widget_get_height (widget)));
 
        /* Now let the renderers draw the content for each line. Because