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.
@@ -666,7 +671,7 @@ TVG_API Tvg_Result tvg_canvas_update_paint(Tvg_Canvas* canvas, Tvg_Paint* paint)
 * @return Tvg_Result enumeration.
 * @retval TVG_RESULT_INVALID_ARGUMENT An invalid Tvg_Canvas pointer.
 *
-* @note Clearing the buffer is unnecessary if the canvas will be fully covered 
+* @note Clearing the buffer is unnecessary if the canvas will be fully covered
 *       with opaque content, which can improve performance.
 * @note Drawing may be asynchronous if the thread count is greater than zero.
 *       To ensure drawing is complete, call tvg_canvas_sync() afterwards.
@@ -925,7 +930,7 @@ TVG_API Tvg_Paint* tvg_paint_duplicate(Tvg_Paint* paint);
  * @return Tvg_Result enumeration.
  * @retval TVG_RESULT_INVALID_ARGUMENT An invalid @p paint.
  * @retval TVG_RESULT_INSUFFICIENT_CONDITION If it failed to compute the bounding box (mostly due to invalid path information).
- *  
+ *
  * @see tvg_paint_get_obb()
  * @see tvg_canvas_update_paint()
  */
@@ -934,7 +939,7 @@ TVG_API Tvg_Result tvg_paint_get_aabb(const Tvg_Paint* paint, float* x, float* y
 
 /**
  * @brief Retrieves the object-oriented bounding box (OBB) of the paint object in canvas space.
- * 
+ *
  * This function returns the bounding box of the paint, as an oriented bounding box (OBB) after transformations are applied.
  *
  * @param[in] paint The Tvg_Paint object of which to get the bounds.
@@ -943,7 +948,7 @@ TVG_API Tvg_Result tvg_paint_get_aabb(const Tvg_Paint* paint, float* x, float* y
  * @return Tvg_Result enumeration.
  * @retval TVG_RESULT_INVALID_ARGUMENT @p paint or @p pt4 is invalid.
  * @retval TVG_RESULT_INSUFFICIENT_CONDITION If it failed to compute the bounding box (mostly due to invalid path information).
- * 
+ *
  * @see tvg_paint_get_aabb()
  * @see tvg_canvas_update_paint()
  *
@@ -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);