capi: exposed Accessor apis

This patch adds basic Accessor API to the C bindings

src/bindings/capi/thorvg_capi.h

@@ -101,6 +101,11 @@ typedef struct _Tvg_Saver Tvg_Saver;
 */
 typedef struct _Tvg_Animation Tvg_Animation;
 
+/**
+* @brief A structure representing an object that enables iterating through a scene's descendents.
+*/
+typedef struct _Tvg_Accessor Tvg_Accessor;
+
 
 /**
 * @brief Enumeration specifying the engine type used for the graphics backend. For multiple backends bitwise operation is allowed.
@@ -2448,6 +2453,48 @@ TVG_API Tvg_Result tvg_animation_del(Tvg_Animation* animation);
 /************************************************************************/
 /* Accessor API                                                         */
 /************************************************************************/
+/*!
+* @brief Creates a new accessor object.
+*
+* @return A new accessor object.
+*
+* @note Experimental API
+*/
+TVG_API Tvg_Accessor* tvg_accessor_new();
+
+
+/*!
+* @brief Deletes the given accessor object.
+*
+* @param[in] accessor The accessor object to be deleted.
+*
+* @return Tvg_Result enumeration.
+* @retval TVG_RESULT_INVALID_ARGUMENT An invalid Tvg_Accessor pointer.
+*
+* @note Experimental API
+*/
+TVG_API Tvg_Result tvg_accessor_del(Tvg_Accessor* accessor);
+
+
+/*!
+* @brief Sets the paint of the accessor then iterates through its descendents.
+*
+* Iterates through all descendents of the scene passed through the paint argument
+* while calling func on each and passing the data pointer to this function. When
+* func returns false iteration stops and the function returns.
+*
+* @param[in] accessor A Tvg_Accessor pointer to the accessor object.
+* @param[in] paint A Tvg_Paint pointer to the scene object.
+* @param[in] func A function pointer to the function that will be execute for each child.
+* @param[in] data A void pointer to data that will be passed to the func.
+*
+* @return Tvg_Result enumeration.
+* @retval TVG_RESULT_INVALID_ARGUMENT An invalid Tvg_Accessor, Tvg_Paint, or function pointer.
+*
+* @note Experimental API
+*/
+TVG_API Tvg_Result tvg_accessor_set_paint(Tvg_Accessor* accessor, Tvg_Paint* paint, bool (*func)(Tvg_Paint* paint, void* data), void* data);
+
 
 /*!
 * @brief Generate a unique ID (hash key) from a given name.

src/bindings/capi/tvgCapi.cpp

@@ -903,6 +903,28 @@ TVG_API Tvg_Result tvg_animation_del(Tvg_Animation* animation)
 /* Accessor API                                                         */
 /************************************************************************/
 
+TVG_API Tvg_Accessor* tvg_accessor_new()
+{
+    return (Tvg_Accessor*) Accessor::gen();
+}
+
+
+TVG_API Tvg_Result tvg_accessor_del(Tvg_Accessor* accessor)
+{
+    if (!accessor) return TVG_RESULT_INVALID_ARGUMENT;
+    delete(reinterpret_cast<Accessor*>(accessor));
+    return TVG_RESULT_SUCCESS;
+}
+
+
+TVG_API Tvg_Result tvg_accessor_set(Tvg_Accessor* accessor, Tvg_Paint* paint, bool (*func)(Tvg_Paint* paint, void* data), void* data)
+{
+    if (!accessor) return TVG_RESULT_INVALID_ARGUMENT;
+    return (Tvg_Result) reinterpret_cast<Accessor*>(accessor)->set(static_cast<Picture*>(reinterpret_cast<Paint*>(paint)),
+        [func](const Paint* paint, void* data) { return func((Tvg_Paint*) paint, data); }, data);
+}
+
+
 TVG_API uint32_t tvg_accessor_generate_id(const char* name)
 {
     return Accessor::id(name);