fix compiler error.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1235 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/rtgui/common/region.c

@@ -175,7 +175,7 @@ void rtgui_region_init_rect(rtgui_region_t *region,
 	region->data = RT_NULL;
 }
 
-void rtgui_region_init_with_extents(rtgui_region_t *region, rtgui_rect_t *extents)
+void rtgui_region_init_with_extents(rtgui_region_t *region, const rtgui_rect_t *extents)
 {
 	region->extents = *extents;
 	region->data = RT_NULL;

components/rtgui/include/rtgui/region.h

@@ -47,7 +47,7 @@ typedef enum
 void rtgui_region_init(rtgui_region_t *region);
 void rtgui_region_init_rect(rtgui_region_t *region,
 	int x, int y, unsigned int width, unsigned int height);
-void rtgui_region_init_with_extents(rtgui_region_t *region, rtgui_rect_t *extents);
+void rtgui_region_init_with_extents(rtgui_region_t *region, const rtgui_rect_t *extents);
 void rtgui_region_fini (rtgui_region_t *region);
 
 void rtgui_region_translate (rtgui_region_t *region, int x, int y);