Update the function documentation in the header files

lv_draw/lv_draw_vbasic.h

@@ -28,16 +28,44 @@
 /**********************
  * GLOBAL PROTOTYPES
  **********************/
-void lv_vfill(const area_t * cords_p, const area_t * mask_p, 
-                   color_t color, opa_t opa);
 
-void lv_vletter(const point_t * pos_p, const area_t * mask_p, 
-                     const font_t * font_p, uint8_t letter,
-                     color_t color, opa_t opa);
+/**
+ * Fill an area in the Virtual Display Buffer
+ * @param cords_p coordinates of the area to fill
+ * @param mask_p fill only o this mask
+ * @param color fill color
+ * @param opa opacity of the area (0..255)
+ */
+void lv_vfill(const area_t * cords_p, const area_t * mask_p,
+                color_t color, opa_t opa);
 
-void lv_vmap(const area_t * cords_p, const area_t * mask_p, 
-             const color_t * map_p, opa_t opa, bool transp, bool upscale,
-			 color_t recolor, opa_t recolor_opa);
+/**
+ * Draw a letter in the Virtual Display Buffer
+ * @param pos_p left-top coordinate of the latter
+ * @param mask_p the letter will be drawn only on this area
+ * @param font_p pointer to font
+ * @param letter a letter to draw
+ * @param color color of letter
+ * @param opa opacity of letter (0..255)
+ */
+void lv_vletter(const point_t * pos_p, const area_t * mask_p,
+                const font_t * font_p, uint8_t letter,
+                color_t color, opa_t opa);
+
+/**
+ * Draw a color map to the display
+ * @param cords_p coordinates the color map
+ * @param mask_p the map will drawn only on this area
+ * @param map_p pointer to a color_t array
+ * @param opa opacity of the map (ignored, only for compatibility with lv_vmap)
+ * @param transp true: enable transparency of LV_IMG_COLOR_TRANSP color pixels
+ * @param upscale true: upscale to double size
+ * @param recolor mix the pixels with this color
+ * @param recolor_opa the intense of recoloring
+ */
+void lv_vmap(const area_t * cords_p, const area_t * mask_p,
+            const color_t * map_p, opa_t opa, bool transp, bool upscale,
+            color_t recolor, opa_t recolor_opa);
 
 
 /**********************