scale: Rearrange child widgets

Always keep the order:

 - [value]
 - [marks.top]
 - [marks.bottom]
 - trough

Which makes sense given the rendering order. Slider should be drawn
after the marks.

Makes it possible to simply remove the custom snapshot implementations
in scale and range. And Adwaita does not depend on the node order
anyway.

gtk/gtkrange.c

@@ -250,16 +250,6 @@ G_DEFINE_TYPE_WITH_CODE (GtkRange, gtk_range, GTK_TYPE_WIDGET,
 static guint signals[LAST_SIGNAL];
 static GParamSpec *properties[LAST_PROP];
 
-static void
-gtk_range_snapshot (GtkWidget   *widget,
-                    GtkSnapshot *snapshot)
-{
-  GtkRange *range = GTK_RANGE (widget);
-  GtkRangePrivate *priv = gtk_range_get_instance_private (range);
-
-  gtk_widget_snapshot_child (widget, priv->trough_widget, snapshot);
-}
-
 static void
 gtk_range_class_init (GtkRangeClass *class)
 {
@@ -275,7 +265,6 @@ gtk_range_class_init (GtkRangeClass *class)
   gobject_class->dispose = gtk_range_dispose;
 
   widget_class->measure = gtk_range_measure;
-  widget_class->snapshot = gtk_range_snapshot;
   widget_class->size_allocate = gtk_range_size_allocate;
   widget_class->unmap = gtk_range_unmap;
   widget_class->direction_changed = gtk_range_direction_changed;

gtk/gtkscale.c

@@ -79,22 +79,23 @@
  *
  * |[<!-- language="plain" -->
  * scale[.fine-tune][.marks-before][.marks-after]
+ * ├── [value][.top][.right][.bottom][.left]
  * ├── marks.top
  * │   ├── mark
  * │   ┊    ├── [label]
  * │   ┊    ╰── indicator
  * ┊   ┊
  * │   ╰── mark
- * ├── [value][.top][.right][.bottom][.left]
+ * ├── marks.bottom
- * ├── trough
+ * │   ├── mark
- * │   ├── [fill]
+ * │   ┊    ├── indicator
- * │   ├── [highlight]
+ * │   ┊    ╰── [label]
- * │   ╰── slider
+ * ┊   ┊
- * ╰── marks.bottom
+ * │   ╰── mark
- *     ├── mark
+ * ╰── trough
- *     ┊    ├── indicator
+ *     ├── [fill]
- *     ┊    ╰── [label]
+ *     ├── [highlight]
- *     ╰── mark
+ *     ╰── slider
  * ]|
  *
  * GtkScale has a main CSS node with name scale and a subnode for its contents,
@@ -197,8 +198,6 @@ static void     gtk_scale_measure (GtkWidget      *widget,
 static void     gtk_scale_get_range_border        (GtkRange       *range,
                                                    GtkBorder      *border);
 static void     gtk_scale_finalize                (GObject        *object);
-static void     gtk_scale_snapshot                (GtkWidget      *widget,
-                                                   GtkSnapshot    *snapshot);
 static void     gtk_scale_real_get_layout_offsets (GtkScale       *scale,
                                                    gint           *x,
                                                    gint           *y);
@@ -661,7 +660,6 @@ gtk_scale_class_init (GtkScaleClass *class)
   gobject_class->notify = gtk_scale_notify;
   gobject_class->finalize = gtk_scale_finalize;
 
-  widget_class->snapshot = gtk_scale_snapshot;
   widget_class->size_allocate = gtk_scale_size_allocate;
   widget_class->measure = gtk_scale_measure;
   widget_class->grab_focus = gtk_widget_grab_focus_self;
@@ -1093,14 +1091,9 @@ gtk_scale_set_draw_value (GtkScale *scale,
                                              "css-name", "value",
                                              "label", txt,
                                              NULL);
-
           g_free (txt);
 
-          if (priv->value_pos == GTK_POS_TOP || priv->value_pos == GTK_POS_LEFT)
+          gtk_widget_insert_after (priv->value_widget, GTK_WIDGET (scale), NULL);
-            gtk_widget_insert_after (priv->value_widget, GTK_WIDGET (scale), NULL);
-          else
-            gtk_widget_insert_before (priv->value_widget, GTK_WIDGET (scale), NULL);
-
           gtk_range_set_round_digits (GTK_RANGE (scale), priv->digits);
           update_value_position (scale);
           update_label_request (scale);
@@ -1469,25 +1462,6 @@ gtk_scale_measure (GtkWidget      *widget,
     }
 }
 
-static void
-gtk_scale_snapshot (GtkWidget   *widget,
-                    GtkSnapshot *snapshot)
-{
-  GtkScale *scale = GTK_SCALE (widget);
-  GtkScalePrivate *priv = gtk_scale_get_instance_private (scale);
-
-  if (priv->top_marks_widget)
-    gtk_widget_snapshot_child (widget, priv->top_marks_widget, snapshot);
-
-  if (priv->bottom_marks_widget)
-    gtk_widget_snapshot_child (widget, priv->bottom_marks_widget, snapshot);
-
-  if (priv->value_widget)
-    gtk_widget_snapshot_child (widget, priv->value_widget, snapshot);
-
-  GTK_WIDGET_CLASS (gtk_scale_parent_class)->snapshot (widget, snapshot);
-}
-
 static void
 gtk_scale_real_get_layout_offsets (GtkScale *scale,
                                    gint     *x,
@@ -1722,9 +1696,7 @@ gtk_scale_add_mark (GtkScale        *scale,
 
           gtk_widget_insert_after (priv->top_marks_widget,
                                    GTK_WIDGET (scale),
-                                   (priv->value_widget &&
+                                   priv->value_widget);
-                                    (priv->value_pos == GTK_POS_TOP || priv->value_pos == GTK_POS_LEFT)) ?
-                                     priv->value_widget : NULL);
           gtk_widget_add_css_class (priv->top_marks_widget, GTK_STYLE_CLASS_TOP);
         }
       marks_widget = priv->top_marks_widget;
@@ -1742,9 +1714,7 @@ gtk_scale_add_mark (GtkScale        *scale,
 
           gtk_widget_insert_before (priv->bottom_marks_widget,
                                     GTK_WIDGET (scale),
-                                    (priv->value_widget &&
+                                    gtk_range_get_trough_widget (GTK_RANGE (scale)));
-                                     (priv->value_pos == GTK_POS_BOTTOM || priv->value_pos == GTK_POS_RIGHT)) ?
-                                      priv->value_widget: NULL);
           gtk_widget_add_css_class (priv->bottom_marks_widget, GTK_STYLE_CLASS_BOTTOM);
         }
       marks_widget = priv->bottom_marks_widget;

testsuite/css/nodes/scale.nodes

@@ -35,17 +35,14 @@ window.background:dir(ltr)
         mark:dir(ltr)
           label:dir(ltr)
           indicator:dir(ltr)
-      trough:dir(ltr)
-        highlight.top:dir(ltr)
-        slider:dir(ltr)
       marks.bottom:dir(ltr)
         mark:dir(ltr)
           indicator:dir(ltr)
           label:dir(ltr)
+      trough:dir(ltr)
+        highlight.top:dir(ltr)
+        slider:dir(ltr)
     scale.horizontal.marks-after:dir(ltr)
-      trough:dir(ltr)
-        highlight.top:dir(ltr)
-        slider:dir(ltr)
       marks.bottom:dir(ltr)
         mark:dir(ltr)
           indicator:dir(ltr)
@@ -53,3 +50,6 @@ window.background:dir(ltr)
         mark:dir(ltr)
           indicator:dir(ltr)
           label:dir(ltr)
+      trough:dir(ltr)
+        highlight.top:dir(ltr)
+        slider:dir(ltr)