[gtksourceview] view: fix position of right-margin

[Christian Hergert <chergert src gnome org>]

commit cac686d42be6dfe420e9cb8896ff7732b4f72fbc
Author: Christian Hergert <chergert redhat com>
Date:   Mon Apr 11 20:55:29 2022 -0700

    view: fix position of right-margin

 gtksourceview/gtksourceview.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)
---
diff --git a/gtksourceview/gtksourceview.c b/gtksourceview/gtksourceview.c
index 3d5eaa0b..19cb4d94 100644
--- a/gtksourceview/gtksourceview.c
+++ b/gtksourceview/gtksourceview.c
@@ -2546,6 +2546,21 @@ gtk_source_view_paint_marks_background (GtkSourceView *view,
        g_array_free (numbers, TRUE);
 }
 
+static int
+get_left_gutter_size (GtkSourceView *view)
+{
+       GtkSourceViewPrivate *priv = gtk_source_view_get_instance_private (view);
+
+       if (priv->left_gutter != NULL)
+       {
+               GtkAllocation alloc;
+               gtk_widget_get_allocation (GTK_WIDGET (priv->left_gutter), &alloc);
+               return alloc.width;
+       }
+
+       return 0;
+}
+
 static void
 gtk_source_view_paint_right_margin (GtkSourceView *view,
                                     GtkSnapshot   *snapshot)
@@ -2569,7 +2584,7 @@ gtk_source_view_paint_right_margin (GtkSourceView *view,
                                                  '_');
        }
 
-       x = priv->cached_right_margin_pos + gtk_text_view_get_left_margin (text_view);
+       x = priv->cached_right_margin_pos + gtk_text_view_get_left_margin (text_view) + get_left_gutter_size 
(view);
 
        gtk_snapshot_append_color (snapshot,
                                   &priv->right_margin_line_color,