libgimpwidgets: new gimp_spin_scale_get_mnemonic_keyval() function.

This solves part of #8524, for properties displaying as spin scale, which have a
mnemonic, yet our code was not able to tell so.

libgimp/gimpproceduredialog.c

@@ -2106,9 +2106,12 @@ gimp_procedure_dialog_check_mnemonic (GimpProcedureDialog *dialog,
       g_list_free (labels);
     }
 
-  if (label                                                          &&
-      (mnemonic = gtk_label_get_mnemonic_keyval (GTK_LABEL (label))) &&
-      mnemonic != GDK_KEY_VoidSymbol)
+  if (label)
+    mnemonic = gtk_label_get_mnemonic_keyval (GTK_LABEL (label));
+  else if (GIMP_IS_SPIN_SCALE (widget))
+    mnemonic = gimp_spin_scale_get_mnemonic_keyval (GIMP_SPIN_SCALE (widget));
+
+  if (mnemonic != GDK_KEY_VoidSymbol)
     {
       duplicate = g_hash_table_lookup (dialog->priv->core_mnemonics, GINT_TO_POINTER (mnemonic));
       if (duplicate && g_strcmp0 (duplicate, id ? id : core_id) != 0)

libgimpwidgets/gimpspinscale.c

@@ -1484,3 +1484,20 @@ gimp_spin_scale_get_constrain_drag (GimpSpinScale *scale)
 
   return GET_PRIVATE (scale)->constrain_drag;
 }
+
+/**
+ * gimp_spin_scale_get_mnemonic_keyval:
+ * @scale: the #GimpSpinScale.
+ *
+ * If @scale has been set with a mnemonic key in its label text, this function
+ * returns the keyval used for the mnemonic accelerator.
+ *
+ * Returns: the keyval usable for accelerators, or [const@Gdk.KEY_VoidSymbol].
+ */
+const guint
+gimp_spin_scale_get_mnemonic_keyval (GimpSpinScale *scale)
+{
+  g_return_val_if_fail (GIMP_IS_SPIN_SCALE (scale), GDK_KEY_VoidSymbol);
+
+  return GET_PRIVATE (scale)->mnemonic_keyval;
+}

libgimpwidgets/gimpspinscale.h

@@ -52,32 +52,33 @@ struct _GimpSpinScaleClass
 };
 
 
-GType         gimp_spin_scale_get_type           (void) G_GNUC_CONST;
+GType         gimp_spin_scale_get_type            (void) G_GNUC_CONST;
 
-GtkWidget   * gimp_spin_scale_new                (GtkAdjustment *adjustment,
-                                                  const gchar   *label,
-                                                  gint           digits);
+GtkWidget   * gimp_spin_scale_new                 (GtkAdjustment *adjustment,
+                                                   const gchar   *label,
+                                                   gint           digits);
 
-void          gimp_spin_scale_set_label          (GimpSpinScale *scale,
-                                                  const gchar   *label);
-const gchar * gimp_spin_scale_get_label          (GimpSpinScale *scale);
+void          gimp_spin_scale_set_label           (GimpSpinScale *scale,
+                                                   const gchar   *label);
+const gchar * gimp_spin_scale_get_label           (GimpSpinScale *scale);
 
-void          gimp_spin_scale_set_scale_limits   (GimpSpinScale *scale,
-                                                  gdouble        lower,
-                                                  gdouble        upper);
-void          gimp_spin_scale_unset_scale_limits (GimpSpinScale *scale);
-gboolean      gimp_spin_scale_get_scale_limits   (GimpSpinScale *scale,
-                                                  gdouble       *lower,
-                                                  gdouble       *upper);
+void          gimp_spin_scale_set_scale_limits    (GimpSpinScale *scale,
+                                                   gdouble        lower,
+                                                   gdouble        upper);
+void          gimp_spin_scale_unset_scale_limits  (GimpSpinScale *scale);
+gboolean      gimp_spin_scale_get_scale_limits    (GimpSpinScale *scale,
+                                                   gdouble       *lower,
+                                                   gdouble       *upper);
 
-void          gimp_spin_scale_set_gamma          (GimpSpinScale *scale,
-                                                  gdouble        gamma);
-gdouble       gimp_spin_scale_get_gamma          (GimpSpinScale *scale);
+void          gimp_spin_scale_set_gamma           (GimpSpinScale *scale,
+                                                   gdouble        gamma);
+gdouble       gimp_spin_scale_get_gamma           (GimpSpinScale *scale);
 
-void          gimp_spin_scale_set_constrain_drag (GimpSpinScale *scale,
-                                                  gboolean       constrain);
-gboolean      gimp_spin_scale_get_constrain_drag (GimpSpinScale *scale);
+void          gimp_spin_scale_set_constrain_drag  (GimpSpinScale *scale,
+                                                   gboolean       constrain);
+gboolean      gimp_spin_scale_get_constrain_drag  (GimpSpinScale *scale);
 
+const guint   gimp_spin_scale_get_mnemonic_keyval (GimpSpinScale *scale);
 
 G_END_DECLS
 

libgimpwidgets/gimpwidgets.def

@@ -454,6 +454,7 @@ EXPORTS
         gimp_spin_scale_get_constrain_drag
         gimp_spin_scale_get_gamma
         gimp_spin_scale_get_label
+	gimp_spin_scale_get_mnemonic_keyval
         gimp_spin_scale_get_scale_limits
         gimp_spin_scale_get_type
         gimp_spin_scale_new