[gtksourceview] map: darken slider while dragging

[Christian Hergert <chergert src gnome org>]

commit b818a0320cdcd5de4e28108cb21faec37a6156bb
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jun 28 22:17:54 2021 -0700

    map: darken slider while dragging
    
    In GTK, the slider is meant to be darker while being dragged. Since the
    typical use case here is to be a slider replacement, we should try to
    match that styling the best we can.

 gtksourceview/gtksourcemap.c | 42 +++++++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 11 deletions(-)
---
diff --git a/gtksourceview/gtksourcemap.c b/gtksourceview/gtksourcemap.c
index 6af138cd..a94647a5 100644
--- a/gtksourceview/gtksourcemap.c
+++ b/gtksourceview/gtksourcemap.c
@@ -428,9 +428,12 @@ gtk_source_map_rebuild_css (GtkSourceMap *map)
                                        "}\n"
                                        "slider:hover {"
                                        " background-color: alpha(%s,.35);"
+                                       "}\n"
+                                       "slider.dragging:hover {"
+                                       " background-color: alpha(%s,.5);"
                                        "}\n",
                                        foreground, background,
-                                       background, background);
+                                       background, background, background);
        }
 
        g_free (background);
@@ -957,9 +960,9 @@ gtk_source_map_drag_update (GtkSourceMap   *map,
 
 static void
 gtk_source_map_drag_begin (GtkSourceMap   *map,
-                          gdouble         start_x,
-                          gdouble         start_y,
-                          GtkGestureDrag *drag)
+                           double          start_x,
+                           double          start_y,
+                           GtkGestureDrag *drag)
 {
        GtkSourceMapPrivate *priv = gtk_source_map_get_instance_private (map);
 
@@ -967,11 +970,24 @@ gtk_source_map_drag_begin (GtkSourceMap   *map,
 
        gtk_gesture_set_state (GTK_GESTURE (drag), GTK_EVENT_SEQUENCE_CLAIMED);
        gtk_source_map_drag_update (map, 0, 0, drag);
+
+       gtk_widget_add_css_class (GTK_WIDGET (priv->slider), "dragging");
+}
+
+static void
+gtk_source_map_drag_end (GtkSourceMap   *map,
+                         double          start_x,
+                         double          start_y,
+                         GtkGestureDrag *drag)
+{
+       GtkSourceMapPrivate *priv = gtk_source_map_get_instance_private (map);
+
+       gtk_widget_remove_css_class (GTK_WIDGET (priv->slider), "dragging");
 }
 
 static void
 gtk_source_map_click_pressed (GtkSourceMap *map,
-                             int           n_presses,
+                              int           n_presses,
                               double        x,
                               double        y,
                               GtkGesture   *click)
@@ -1216,13 +1232,17 @@ gtk_source_map_init (GtkSourceMap *map)
        gtk_event_controller_set_propagation_phase (GTK_EVENT_CONTROLLER (drag),
                                                     GTK_PHASE_CAPTURE);
        g_signal_connect_swapped (drag,
-                                 "drag-begin",
-                                 G_CALLBACK (gtk_source_map_drag_begin),
-                                 map);
+                                 "drag-begin",
+                                 G_CALLBACK (gtk_source_map_drag_begin),
+                                 map);
+       g_signal_connect_swapped (drag,
+                                 "drag-end",
+                                 G_CALLBACK (gtk_source_map_drag_end),
+                                 map);
        g_signal_connect_swapped (drag,
-                                 "drag-update",
-                                 G_CALLBACK (gtk_source_map_drag_update),
-                                 map);
+                                 "drag-update",
+                                 G_CALLBACK (gtk_source_map_drag_update),
+                                 map);
        gtk_widget_add_controller (GTK_WIDGET (map),
                                   GTK_EVENT_CONTROLLER (g_steal_pointer (&drag)));