Implement custom, opt-in hit-testing handlers for objects (#1318)

src/lv_core/lv_obj.h

@@ -128,6 +128,7 @@ enum {
     LV_SIGNAL_GET_TYPE, /**< LittlevGL needs to retrieve the object's type */
 
     /*Input device related*/
+    LV_SIGNAL_HIT_TEST,          /**< Advanced hit-testing */
     LV_SIGNAL_PRESSED,           /**< The object has been pressed*/
     LV_SIGNAL_PRESSING,          /**< The object is being pressed (called continuously while pressing)*/
     LV_SIGNAL_PRESS_LOST,        /**< User is still pressing but slid cursor/finger off of the object */
@@ -225,7 +226,8 @@ typedef struct _lv_obj_t
     uint8_t parent_event : 1;   /**< 1: Send the object's events to the parent too. */
     lv_drag_dir_t drag_dir : 3; /**<  Which directions the object can be dragged in */
     lv_bidi_dir_t base_dir : 2; /**< Base direction of texts related to this object */
-    uint8_t reserved : 3;       /**<  Reserved for future use*/
+    uint8_t adv_hittest : 1;    /**< 1: Use advanced hit-testing (slower) */
+    uint8_t reserved : 2;       /**<  Reserved for future use*/
     uint8_t protect;            /**< Automatically happening actions can be prevented. 'OR'ed values from
                                    `lv_protect_t`*/
     lv_opa_t opa_scale;         /**< Scale down the opacity by this factor. Effects all children as well*/
@@ -263,6 +265,12 @@ typedef struct
                                                ... [x]: "lv_obj" */
 } lv_obj_type_t;
 
+typedef struct _lv_hit_test_info_t
+{
+    lv_point_t *point;
+    bool result;
+} lv_hit_test_info_t;
+
 /**********************
  * GLOBAL PROTOTYPES
  **********************/
@@ -466,6 +474,13 @@ void lv_obj_report_style_mod(lv_style_t * style);
  */
 void lv_obj_set_hidden(lv_obj_t * obj, bool en);
 
+/**
+ * Set whether advanced hit-testing is enabled on an object
+ * @param obj pointer to an object
+ * @param en true: advanced hit-testing is enabled
+ */
+void lv_obj_set_adv_hittest(lv_obj_t * obj, bool en);
+
 /**
  * Enable or disable the clicking of an object
  * @param obj pointer to an object
@@ -808,6 +823,13 @@ const lv_style_t * lv_obj_get_style(const lv_obj_t * obj);
  */
 bool lv_obj_get_hidden(const lv_obj_t * obj);
 
+/**
+ * Get whether advanced hit-testing is enabled on an object
+ * @param obj pointer to an object
+ * @return true: advanced hit-testing is enabled
+ */
+bool lv_obj_get_adv_hittest(const lv_obj_t * obj);
+
 /**
  * Get the click enable attribute of an object
  * @param obj pointer to an object
@@ -914,6 +936,8 @@ lv_event_cb_t lv_obj_get_event_cb(const lv_obj_t * obj);
  * Other get
  *-----------------*/
 
+bool lv_obj_hittest(lv_obj_t * obj, lv_point_t * point);
+
 /**
  * Get the ext pointer
  * @param obj pointer to an object