add arc drawing and restructure draw functions

lv_draw/lv_draw_img.h

@@ -0,0 +1,51 @@
+/**
+ * @file lv_draw_img.h
+ *
+ */
+
+#ifndef LV_DRAW_IMG_H
+#define LV_DRAW_IMG_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "lv_draw.h"
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+
+#if USE_LV_IMG
+/**
+ * Draw an image
+ * @param coords the coordinates of the image
+ * @param mask the image will be drawn only in this area
+ * @param map_p pointer to a lv_color_t array which contains the pixels of the image
+ * @param opa opacity of the image (0..255)
+ */
+void lv_draw_img(const lv_area_t * coords, const lv_area_t * mask,
+             const lv_style_t * style, const void * src);
+#endif
+
+/**********************
+ *      MACROS
+ **********************/
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /*LV_TEMPL_H*/