[gnome-control-center] power: Stop the brightness slider from jumping

[Robert Ancell <rancell src gnome org>]

commit 3a1d6295cd512c9c481e466ab4f209e6a70c4319
Author: Diego Escalante Urrelo <diegoe gnome org>
Date:   Mon Oct 21 02:29:15 2019 -0500

    power: Stop the brightness slider from jumping
    
    The GtkScale widget for screen brightness has a tendency to jump around
    because GtkRange defaults to NOT rounding values (round_digits = -1).
    
    This means that the widget is constantly set with values that have
    decimals (say 10.3) which it then tries to correct to fit the step size.
    
    The solution for this particular UI quirk is to make sure to set
    round-digits to 0, as that will force GtkRange to provide GtkScale with
    rounded-down numbers. See gtkrange.c.
    
    Fixes: https://gitlab.gnome.org/GNOME/gnome-settings-daemon/issues/405

 panels/power/cc-power-panel.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/panels/power/cc-power-panel.c b/panels/power/cc-power-panel.c
index 1cc689f27..f65a80730 100644
--- a/panels/power/cc-power-panel.c
+++ b/panels/power/cc-power-panel.c
@@ -1767,6 +1767,7 @@ add_brightness_row (CcPowerPanel  *self,
   gtk_scale_set_draw_value (GTK_SCALE (scale), FALSE);
   gtk_box_pack_start (GTK_BOX (box2), scale, TRUE, TRUE, 0);
   gtk_size_group_add_widget (self->level_sizegroup, scale);
+  gtk_range_set_round_digits (GTK_RANGE (scale), 0);
   g_signal_connect (scale, "value-changed",
                     G_CALLBACK (brightness_slider_value_changed_cb), self);