efl_ui/table: optimize position_set operations with tables

if a table is moved and no other changes are made to the table or its children,
e.g., if the table is scrolled, then there is no need to loop over the table's
items repeatedly in order to accurately calculate all the item geometries
and positions.

instead, simply apply an offset from the last table calc position to each child
item and handle the position changes more transparently

this yields roughly a 12% perf improvement to the 'efl.ui.scroller simple2' test
and brings rendering up to nearly 60fps

Reviewed-by: Cedric BAIL <cedric.bail@free.fr>
Differential Revision: https://phab.enlightenment.org/D9346

src/lib/elementary/efl_ui_table.c

@@ -174,7 +174,7 @@ EOLIAN static void
 _efl_ui_table_efl_gfx_entity_size_set(Eo *obj, Efl_Ui_Table_Data *_pd EINA_UNUSED, Eina_Size2D sz)
 {
    efl_gfx_entity_size_set(efl_super(obj, MY_CLASS), sz);
-   efl_canvas_group_change(obj);
+   efl_pack_layout_request(obj);
 }
 
 EOLIAN static void
@@ -508,8 +508,9 @@ _efl_ui_table_efl_pack_unpack_all(Eo *obj, Efl_Ui_Table_Data *pd)
 }
 
 EOLIAN static void
-_efl_ui_table_efl_pack_layout_layout_request(Eo *obj, Efl_Ui_Table_Data *pd EINA_UNUSED)
+_efl_ui_table_efl_pack_layout_layout_request(Eo *obj, Efl_Ui_Table_Data *pd)
 {
+   pd->full_recalc = EINA_TRUE;
    efl_canvas_group_need_recalculate_set(obj, EINA_TRUE);
 }
 

src/lib/elementary/efl_ui_table_layout.c

@@ -218,6 +218,27 @@ _efl_ui_table_regular_item_size_get(Table_Calc *table_calc, Item_Calc *item, Ein
           - item->hints[axis].margin[0] - item->hints[axis].margin[1];
 }
 
+/* this function performs a simplified layout when the table has changed position
+ * but no other changes have occurred, e.g., when a table is being scrolled
+ */
+static void
+_efl_ui_table_layout_simple(Efl_Ui_Table *ui_table, Efl_Ui_Table_Data *pd)
+{
+   Table_Item *ti;
+   Eina_Position2D pos = efl_gfx_entity_position_get(ui_table);
+
+   EINA_INLIST_FOREACH(EINA_INLIST_GET(pd->items), ti)
+     {
+        Eina_Position2D child_pos = efl_gfx_entity_position_get(ti->object);
+
+        efl_gfx_entity_position_set(ti->object,
+          EINA_POSITION2D(pos.x - pd->last_pos.x + child_pos.x,
+                          pos.y - pd->last_pos.y + child_pos.y));
+     }
+   pd->last_pos = pos;
+   efl_event_callback_call(ui_table, EFL_PACK_EVENT_LAYOUT_UPDATED, NULL);
+}
+
 void
 _efl_ui_table_custom_layout(Efl_Ui_Table *ui_table, Efl_Ui_Table_Data *pd)
 {
@@ -231,14 +252,19 @@ _efl_ui_table_custom_layout(Efl_Ui_Table *ui_table, Efl_Ui_Table_Data *pd)
    Eina_Bool do_free;
 
    count = pd->count;
-
    if (!count)
      {
         efl_gfx_hint_size_restricted_min_set(ui_table, EINA_SIZE2D(0, 0));
         return;
      }
-
+   if (!pd->full_recalc)
+     {
+        _efl_ui_table_layout_simple(ui_table, pd);
+        return;
+     }
    _efl_ui_container_layout_init(ui_table, table_calc.layout_calc);
+   pd->last_pos.x = table_calc.layout_calc[0].pos - table_calc.layout_calc[0].margin[0];
+   pd->last_pos.y = table_calc.layout_calc[1].pos - table_calc.layout_calc[1].margin[0];
 
    table_calc.want[0] = table_calc.want[1] = 0;
    table_calc.weight_sum[0] = table_calc.weight_sum[1] = 0;
@@ -391,6 +417,7 @@ _efl_ui_table_custom_layout(Efl_Ui_Table *ui_table, Efl_Ui_Table_Data *pd)
                          + (table_calc.layout_calc[1].pad *
                             table_calc.cell_calc[1][rows - 1].index);
 
+   pd->full_recalc = EINA_FALSE;
    efl_gfx_hint_size_restricted_min_set(ui_table,
                                         EINA_SIZE2D(table_calc.want[0],
                                                     table_calc.want[1]));

src/lib/elementary/efl_ui_table_private.h

@@ -44,11 +44,13 @@ struct _Efl_Ui_Table_Data
    struct {
       double h, v;
    } align;
+   Eina_Position2D last_pos;
    Eina_Bool cols_recalc : 1;
    Eina_Bool rows_recalc : 1;
    Eina_Bool linear_recalc : 1;
    Eina_Bool homogeneoush : 1;
    Eina_Bool homogeneousv : 1;
+   Eina_Bool full_recalc : 1; //whether to force full recalc
 };
 
 struct _Table_Item_Iterator