Gtk+-2: add eel_gtk_adjustment* functions again

This reverts https://github.com/mate-desktop/caja/commit/f02d495 for gtk2

fixes https://github.com/mate-desktop/caja/issues/659

2 files changed, 40 insertions, 1 deletions

diff --git a/eel/eel-gtk-extensions.c b/eel/eel-gtk-extensions.c
index e451bdbf..4969d7aa 100644
--- a/eel/eel-gtk-extensions.c
+++ b/eel/eel-gtk-extensions.c
@@ -353,6 +353,40 @@ eel_gtk_menu_tool_button_get_button (GtkMenuToolButton *tool_button)
     return button;
 }
 
+#if !GTK_CHECK_VERSION (3, 0, 0)
+/* The standard gtk_adjustment_set_value ignores page size, which
+ * disagrees with the logic used by scroll bars, for example.
+ */
+void
+eel_gtk_adjustment_set_value (GtkAdjustment *adjustment,
+                              float value)
+{
+    float upper_page_start, clamped_value;
+
+    g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
+
+    upper_page_start = MAX (gtk_adjustment_get_upper (adjustment) -
+                            gtk_adjustment_get_page_size (adjustment),
+                            gtk_adjustment_get_lower (adjustment));
+    clamped_value = CLAMP (value, gtk_adjustment_get_lower (adjustment), upper_page_start);
+    if (clamped_value != gtk_adjustment_get_value (adjustment))
+    {
+        gtk_adjustment_set_value (adjustment, clamped_value);
+        gtk_adjustment_value_changed (adjustment);
+    }
+}
+
+/* Clamp a value if the minimum or maximum has changed. */
+void
+eel_gtk_adjustment_clamp_value (GtkAdjustment *adjustment)
+{
+    g_return_if_fail (GTK_IS_ADJUSTMENT (adjustment));
+
+    eel_gtk_adjustment_set_value (adjustment,
+                                  gtk_adjustment_get_value (adjustment));
+}
+#endif
+
 /**
  * eel_gtk_label_make_bold.
  *
diff --git a/eel/eel-gtk-extensions.h b/eel/eel-gtk-extensions.h
index aec680f3..fd85c2db 100644
--- a/eel/eel-gtk-extensions.h
+++ b/eel/eel-gtk-extensions.h
@@ -63,7 +63,12 @@ GtkWidget *           eel_gtk_menu_tool_button_get_button             (GtkMenuTo
 
 /* GtkLabel */
 void                  eel_gtk_label_make_bold                         (GtkLabel             *label);
-
+#if !GTK_CHECK_VERSION (3, 0, 0)
+/* GtkAdjustment */
+void                  eel_gtk_adjustment_set_value                    (GtkAdjustment        *adjustment,
+        float                 value);
+void                  eel_gtk_adjustment_clamp_value                  (GtkAdjustment        *adjustment);
+#endif
 /* GtkTreeView */
 void                  eel_gtk_tree_view_set_activate_on_single_click  (GtkTreeView               *tree_view,
         gboolean                   should_activate);