revert jasper's way overzealous fix in png-write.cpp rev 13700; new fix in item_rende...

[inkscape.git] / src / display / nr-filter-slot.h

diff --git a/src/display/nr-filter-slot.h b/src/display/nr-filter-slot.h
index 74cf7e003a1cf869576eec371d108ae26cbd6697..09190a9b0a105502d76df79a27d76aaea9f26dfc 100644 (file)
--- a/src/display/nr-filter-slot.h
+++ b/src/display/nr-filter-slot.h
@@ -16,17 +16,45 @@
 
 #include "libnr/nr-pixblock.h"
 
+struct NRArenaItem;
+
 namespace NR {
 
 class FilterSlot {
 public:
-    FilterSlot();
-    FilterSlot(int slots);
+    /** Creates a new FilterSlot object.
+     * First parameter specifies the amount of slots this SilterSlot
+     * should reserve beforehand. If a negative number is given,
+     * two slots will be reserved.
+     * Second parameter specifies the arena item, which should be used
+     * for background accesses from filters.
+     */
+    FilterSlot(int slots, NRArenaItem const *item);
+    /** Destroys the FilterSlot object and all its contents */
     ~FilterSlot();
 
+    /** Returns the pixblock in specified slot.
+     * Parameter 'slot' may be either an positive integer or one of
+     * pre-defined filter slot types: NR_FILTER_SLOT_NOT_SET,
+     * NR_FILTER_SOURCEGRAPHIC, NR_FILTER_SOURCEALPHA,
+     * NR_FILTER_BACKGROUNDIMAGE, NR_FILTER_BACKGROUNDALPHA,
+     * NR_FILTER_FILLPAINT, NR_FILTER_SOURCEPAINT.
+     * If the defined filter slot is not set before, this function
+     * returns NULL. Also, that filter slot is created in process.
+     */
     NRPixBlock *get(int slot);
+
+    /** Sets or re-sets the pixblock associated with given slot.
+     * If there was a pixblock already assigned with this slot,
+     * that pixblock is destroyed.
+     * Pixblocks passed to this function should be considered
+     * managed by this FilterSlot object.
+     * Pixblocks passed to this function should be reserved with
+     * c++ -style new-operator.
+     */
     void set(int slot, NRPixBlock *pb);
 
+    /** Returns the number of slots in use. */
     int get_slot_count();
 
 private:
@@ -36,6 +64,11 @@ private:
 
     int _last_out;
 
+    NRArenaItem const *_arena_item;
+
+    /** Returns the table index of given slot. If that slot does not exist,
+     * it is created. Table index can be used to read the correct
+     * pixblock from _slot */
     int _get_index(int slot);
 };