-static const char *kKeyDrawingName = "drawing_name";
-static const char *kKeyDrawingArea = "drawing_area";
+extern const char kKeyDrawingName[];
+extern const char kKeyDrawingArea[];
+extern const char kKeyDrawingRect[];
+extern const char kKeyX[];
+extern const char kKeyY[];
+extern const char kKeyWidth[];
+extern const char kKeyHeigh[];
+extern const char kKeyWidthPixel[];
+extern const char kKeyHeightPixel[];
+extern const char kKeyWidthMm[];
+extern const char kKeyHeightMm[];
+