diff --git a/src/st/st-theme-context.c b/src/st/st-theme-context.c
index cf6893492..eb24212e1 100644
--- a/src/st/st-theme-context.c
+++ b/src/st/st-theme-context.c
@@ -99,18 +99,6 @@ static void st_theme_context_get_property (GObject      *object,
                                            GValue       *value,
                                            GParamSpec   *pspec);
 
-static void
-st_theme_context_set_scale_factor (StThemeContext *context,
-                                   int             scale_factor)
-{
-  if (scale_factor == context->scale_factor)
-    return;
-
-  context->scale_factor = scale_factor;
-  g_object_notify_by_pspec (G_OBJECT (context), props[PROP_SCALE_FACTOR]);
-  st_theme_context_changed (context);
-}
-
 
 static void
 st_theme_context_finalize (GObject *object)
@@ -578,6 +566,27 @@ st_theme_context_get_scale_factor (StThemeContext *context)
   return context->scale_factor;
 }
 
+/**
+ * st_theme_context_set_scale_factor:
+ * @context: a #StThemeContext
+ * @factor: the new factor
+ *
+ * Set the new scale factor of @context.
+ */
+void
+st_theme_context_set_scale_factor (StThemeContext *context,
+                                   int             scale_factor)
+{
+  g_return_if_fail (ST_IS_THEME_CONTEXT (context));
+
+  if (scale_factor == context->scale_factor)
+    return;
+
+  context->scale_factor = scale_factor;
+  g_object_notify_by_pspec (G_OBJECT (context), props[PROP_SCALE_FACTOR]);
+  st_theme_context_changed (context);
+}
+
 /**
  * st_theme_context_get_resolution:
  * @context: a #StThemeContext
diff --git a/src/st/st-theme-context.h b/src/st/st-theme-context.h
index d7ccdff01..69245c0c3 100644
--- a/src/st/st-theme-context.h
+++ b/src/st/st-theme-context.h
@@ -62,6 +62,8 @@ StThemeNode *               st_theme_context_intern_node      (StThemeContext
                                                                StThemeNode                *node);
 
 int st_theme_context_get_scale_factor (StThemeContext *context);
+void st_theme_context_set_scale_factor (StThemeContext *context,
+                                        int             factor);
 
 double st_theme_context_get_resolution (StThemeContext *context);