add arc drawing and restructure draw functions

lv_draw/lv_draw_triangle.h

@@ -0,0 +1,51 @@
+/**
+ * @file lv_draw_triangle.h
+ *
+ */
+
+#ifndef LV_DRAW_TRIANGLE_H
+#define LV_DRAW_TRIANGLE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*********************
+ *      INCLUDES
+ *********************/
+#include "lv_draw.h"
+
+/*********************
+ *      DEFINES
+ *********************/
+
+/**********************
+ *      TYPEDEFS
+ **********************/
+
+/**********************
+ * GLOBAL PROTOTYPES
+ **********************/
+/*Experimental use for 3D modeling*/
+#define USE_LV_TRIANGLE 1
+
+#if USE_LV_TRIANGLE != 0
+/**
+ *
+ * @param points pointer to an array with 3 points
+ * @param mask the triangle will be drawn only in this mask
+ * @param color color of the triangle
+ */
+void lv_draw_triangle(const lv_point_t * points, const lv_area_t * mask, lv_color_t color);
+#endif
+
+/**********************
+ *      MACROS
+ **********************/
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /*LV_DRAW_TRIANGLE_H*/