[gtksourceview] gutter: snapshot color node for current line

[Christian Hergert <chergert src gnome org>]

commit 01a72cc42d8239d0a4f71abc4afc2500b04e1a19
Author: Christian Hergert <chergert redhat com>
Date:   Tue Jul 20 15:47:03 2021 -0700

    gutter: snapshot color node for current line
    
    We can avoid a bunch of machinery here by just using a premixed color from
    the GtkSourceView when possible. Additionally, we can get closer to
    supporting generic coloring like #29 will require.

 gtksourceview/gtksourcegutter.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)
---
diff --git a/gtksourceview/gtksourcegutter.c b/gtksourceview/gtksourcegutter.c
index cdfb47c3..8f2cb649 100644
--- a/gtksourceview/gtksourcegutter.c
+++ b/gtksourceview/gtksourcegutter.c
@@ -26,7 +26,7 @@
 #include "gtksourcegutterlines-private.h"
 #include "gtksourcesignalgroup-private.h"
 #include "gtksourcestylescheme-private.h"
-#include "gtksourceview.h"
+#include "gtksourceview-private.h"
 #include "gtksourcegutterrenderer.h"
 #include "gtksourcegutterrenderer-private.h"
 
@@ -706,7 +706,6 @@ gtk_source_gutter_snapshot (GtkWidget   *widget,
 {
        GtkSourceGutter *gutter = GTK_SOURCE_GUTTER (widget);
        GtkTextView *text_view = GTK_TEXT_VIEW (gutter->view);
-       GtkStyleContext *style_context;
        const GList *list;
        GdkRectangle visible_rect;
        GtkTextIter begin;
@@ -721,8 +720,6 @@ gtk_source_gutter_snapshot (GtkWidget   *widget,
                return;
        }
 
-       style_context = gtk_widget_get_style_context (GTK_WIDGET (gutter));
-
        gtk_text_view_get_visible_rect (text_view, &visible_rect);
        gtk_text_view_get_iter_at_location (text_view, &begin,
                                            visible_rect.x, visible_rect.y);
@@ -752,6 +749,7 @@ gtk_source_gutter_snapshot (GtkWidget   *widget,
                if (cursor_line >= gtk_source_gutter_lines_get_first (gutter->lines) &&
                    cursor_line <= gtk_source_gutter_lines_get_last (gutter->lines))
                {
+                       GdkRGBA highlight;
                        gint y;
                        gint height;
 
@@ -761,17 +759,14 @@ gtk_source_gutter_snapshot (GtkWidget   *widget,
                                                                 &y,
                                                                 &height);
 
-                       gtk_style_context_save (style_context);
-                       gtk_style_context_add_class (style_context, "current-line-number");
-
-                       gtk_snapshot_render_background (snapshot,
-                                                       style_context,
-                                                       0,
-                                                       y,
-                                                       gtk_widget_get_width (widget),
-                                                       height);
+                       if (_gtk_source_view_get_current_line_number_background (gutter->view, &highlight))
+                       {
+                               int width = gtk_widget_get_width (widget);
 
-                       gtk_style_context_restore (style_context);
+                               gtk_snapshot_append_color (snapshot,
+                                                          &highlight,
+                                                          &GRAPHENE_RECT_INIT (0, y, width, height));
+                       }
                }
        }