Add page argument to gtk_dial_new_with_range()

Make gain widget page_incr 3dB.

src/gtkdial.c

@@ -477,13 +477,18 @@ GtkWidget *gtk_dial_new(GtkAdjustment *adjustment) {
   );
 }
 
-GtkWidget *gtk_dial_new_with_range(double min, double max, double step) {
+GtkWidget *gtk_dial_new_with_range(
+  double min,
+  double max,
+  double step,
+  double page
+) {
   GtkAdjustment *adj;
   int digits;
 
   g_return_val_if_fail(min < max, NULL);
 
-  adj = gtk_adjustment_new(min, min, max, step, 10 * step, 0);
+  adj = gtk_adjustment_new(min, min, max, step, page, 0);
 
   if (step == 0.0) {
     digits = -1;

src/gtkdial.h

@@ -43,7 +43,12 @@ GType gtk_dial_get_type(void) G_GNUC_CONST;
 
 GtkWidget *gtk_dial_new(GtkAdjustment *adjustment);
 
-GtkWidget *gtk_dial_new_with_range(double min, double max, double step);
+GtkWidget *gtk_dial_new_with_range(
+  double min,
+  double max,
+  double step,
+  double page
+);
 
 void gtk_dial_set_has_origin(GtkDial *dial, gboolean has_origin);
 gboolean gtk_dial_get_has_origin(GtkDial *dial);

src/widget-gain.c

@@ -63,11 +63,16 @@ GtkWidget *make_gain_alsa_elem(struct alsa_elem *elem, int zero_is_off) {
   data->vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
   gtk_widget_set_hexpand(data->vbox, TRUE);
 
-  data->dial = gtk_dial_new_with_range(elem->min_val, elem->max_val, 1);
-
   data->scale = (float)(elem->max_dB - elem->min_dB) /
                        (elem->max_val - elem->min_val);
 
+  data->dial = gtk_dial_new_with_range(
+    elem->min_val,
+    elem->max_val,
+    1,
+    3 / data->scale
+  );
+
   // calculate 0dB value
   int zero_db_value = (int)((0 - elem->min_dB) / data->scale + elem->min_val);
 

src/window-levels.c

@@ -95,7 +95,7 @@ GtkWidget *create_levels_controls(struct alsa_card *card) {
         count_labels[j] = add_count_label(grid, j);
 
       // create the meter widget and attach to the grid
-      GtkWidget *meter = gtk_dial_new_with_range(-80, 0, 0);
+      GtkWidget *meter = gtk_dial_new_with_range(-80, 0, 0, 0);
       gtk_widget_set_sensitive(meter, FALSE);
       card->meters[meter_num++] = meter;
       gtk_grid_attach(GTK_GRID(grid), meter, j + 1, i + 1, 1, 1);