eina: document quadtree

Reviewers: cedric, ajwillia.ms

Subscribers: segfaultxavi, jpeg

Differential Revision: https://phab.enlightenment.org/D5522

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>

diff --git a/src/lib/eina/eina_quadtree.h b/src/lib/eina/eina_quadtree.h
index 2638d8b..ad23bc3 100644 (file)
--- a/src/lib/eina/eina_quadtree.h
+++ b/src/lib/eina/eina_quadtree.h
@@ -23,31 +23,179 @@
 
 #include "eina_inlist.h"
 
-typedef struct _Eina_QuadTree      Eina_QuadTree;
+/**
+ * @addtogroup Eina_Data_Types_Group Data Types
+ *
+ * @{
+ */
+
+/**
+ * @typedef Eina_QuadTree
+ *
+ * A quadtree is a data structure where each node contains four child
+ * nodes.  It can be used to partition 2D spaces through subdivision
+ * into quadrants.
+ */
+typedef struct _Eina_QuadTree Eina_QuadTree;
+
+/**
+ * @typedef Eina_QuadTree_Item
+ *
+ * A quadtree item is a holder for (void *) data items inside a
+ * quadtree, that includes some state tracking for lifecycle management
+ * and optimization purposes.
+ */
 typedef struct _Eina_QuadTree_Item Eina_QuadTree_Item;
 
+/**
+ * @typedef Eina_Quad_Direction
+ */
 typedef enum {
    EINA_QUAD_LEFT,
    EINA_QUAD_RIGHT,
    EINA_QUAD_BOTH
 } Eina_Quad_Direction;
 
+/**
+ * @typedef Eina_Quad_Callback
+ *
+ * Signature for a callback routine used to determine the location of an
+ * object within a quadtree.  These are used in sorting by determining
+ * where in the tree the given data @p object belongs, using @p middle
+ * as the division line for the two halves of the space.
+ */
 typedef Eina_Quad_Direction (*Eina_Quad_Callback)(const void *object, size_t middle);
 
-EAPI Eina_QuadTree      *eina_quadtree_new(size_t w, size_t h, Eina_Quad_Callback vertical, Eina_Quad_Callback horizontal);
-EAPI void                eina_quadtree_free(Eina_QuadTree *q);
-EAPI void                eina_quadtree_resize(Eina_QuadTree *q, size_t w, size_t h);
+/**
+ * @brief Constructs a quadtree object.
+ *
+ * @param[in] w The geometric width of the quadtree.
+ * @param[in] h The geometric height of the quadtree.
+ * @param[in] vertical The callback for vertical direction determination.
+ * @param[in] horizontal The callback for horizontal direction determination.
+ * @return The newly allocated and initialized quadtree, or @c NULL on error.
+ *
+ * The vertical and horizontal callbacks are used to assist in
+ * determining which quadrant a given data item belongs to.
+ */
+EAPI Eina_QuadTree *eina_quadtree_new(size_t w, size_t h, Eina_Quad_Callback vertical, Eina_Quad_Callback horizontal);
+
+/**
+ * @brief Destructs quadtree and its data.
+ *
+ * @param[in] q The quadtree to be freed.
+ *
+ * Frees the memory for the Eina_QuadTree object, and any memory used by
+ * its change tracking and garbage collection internals.
+ */
+EAPI void eina_quadtree_free(Eina_QuadTree *q);
 
-EAPI void                eina_quadtree_cycle(Eina_QuadTree *q);
-EAPI void                eina_quadtree_increase(Eina_QuadTree_Item *object);
+/**
+ * @brief Changes the width and height of the quadtree.
+ *
+ * @param[in,out] q The quadtree to resize.
+ * @param[in] w The new geometric width for the quadtree.
+ * @param[in] h The new geometric height for the quadtree.
+ *
+ * Sets the width and height of the quadtree, but the actual update is
+ * done lazily.
+ */
+EAPI void eina_quadtree_resize(Eina_QuadTree *q, size_t w, size_t h);
+
+/**
+ * @brief Sets the quadtree's index to 0.
+ *
+ * @param[in,out] q The quadtree to cycle.
+ */
+EAPI void eina_quadtree_cycle(Eina_QuadTree *q);
+
+/**
+ * @brief Increases the index of the quadtree item by one.
+ *
+ * @param[in,out] object The quadtree item to increase.
+ *
+ * If necessary, records that the root is no longer sorted.
+ */
+EAPI void eina_quadtree_increase(Eina_QuadTree_Item *object);
 
+/**
+ * @brief Inserts a data object into the quadtree.
+ *
+ * @param[in,out] q The quadtree to add @p object to.
+ * @param[in] object A data object to store in the quadtree.
+ * @return Pointer to the stored quadtree item.
+ *
+ * Creates an Eina_QuadTree_Item (or recycles one from the quadtree's
+ * trash) and stores the data @p object in it, then arranges to lazily
+ * insert the item into the quadtree (i.e. insertion is delayed until
+ * it needs to be used.)
+ */
 EAPI Eina_QuadTree_Item *eina_quadtree_add(Eina_QuadTree *q, const void *object);
-EAPI Eina_Bool           eina_quadtree_del(Eina_QuadTree_Item *object);
-EAPI Eina_Bool           eina_quadtree_change(Eina_QuadTree_Item *object);
-EAPI Eina_Bool           eina_quadtree_hide(Eina_QuadTree_Item *object);
-EAPI Eina_Bool           eina_quadtree_show(Eina_QuadTree_Item *object);
 
-EAPI Eina_Inlist        *eina_quadtree_collide(Eina_QuadTree *q, int x, int y, int w, int h);
-EAPI void               *eina_quadtree_object(Eina_Inlist *list);
+/**
+ * @brief Deletes a given quadtree item from the quadtree.
+ *
+ * @param[in] object The quadtree item to be deleted.
+ * @return #EINA_TRUE on success, #EINA_FALSE otherwise.
+ *
+ * Moves the item to the quadtree's internal garbage heap for later
+ * reclamation.
+ */
+EAPI Eina_Bool eina_quadtree_del(Eina_QuadTree_Item *object);
+
+/**
+ * @brief Marks an object within the quadtree as needing changed.
+ *
+ * @param[in,out] object The object that has changed.
+ * @return #EINA_TRUE if change successfully noted, or #EINA_FALSE otherwise.
+ */
+EAPI Eina_Bool eina_quadtree_change(Eina_QuadTree_Item *object);
+
+/**
+ * @brief Sets @p object invisible.
+ *
+ * @param[in,out] object The item within the quadtree to hide.
+ * @return #EINA_TRUE if @p object was successfully hidden, or
+ *         #EINA_FALSE if it wasn't in the quadtree.
+ */
+EAPI Eina_Bool eina_quadtree_hide(Eina_QuadTree_Item *object);
+
+/**
+ * @brief Sets @p object to visible.
+ *
+ * @param[in,out] object The item within the quadtree to show.
+ * @return #EINA_TRUE if @p object was successfully shown, or
+ *         #EINA_FALSE if it wasn't in the quadtree.
+ */
+EAPI Eina_Bool eina_quadtree_show(Eina_QuadTree_Item *object);
+
+/**
+ * @brief Retrieves items in quadtree inside the target geometry.
+ *
+ * @param[in,out] q The quadtree to recompute.
+ * @param[in] x New target X coordinate.
+ * @param[in] y New target Y coordinate.
+ * @param[in] w New target width.
+ * @param[in] h New target height.
+ * @return The list of collided items or @c NULL on error.
+ *
+ * Forces a rebuild and resort of the quadtree if needed due to pending
+ * changes, then performs a collision detection to find items whose
+ * geometry is contained within or intersects the given target geometry.
+ */
+EAPI Eina_Inlist *eina_quadtree_collide(Eina_QuadTree *q, int x, int y, int w, int h);
+
+/**
+ * @brief Retrieves the quadtree item's data for the given inline list.
+ *
+ * @param[in] list The inline list item to lookup
+ * @return The contained data object in the Eina_QuadTree_Item, or @c
+ *         NULL if none could be found.
+ */
+EAPI void *eina_quadtree_object(Eina_Inlist *list);
+
+/**
+ * @}
+ */
 
 #endif