This step applies only to color index groups. If the GL command that invokes the pixel transfer operation requires that RGBA component pixel groups be generated, then a conversion is performed at this step. RGBA component pixel groups are required if
entries for some integer value of n
(n may be different for each table).
For each table,
the index is first rounded to the nearest integer;
the result is ANDed with 
,
and the resulting value used as an address into the table.
The indexed value becomes an R, G, B, or A value, as appropriate.
The group of four elements so obtained replaces the index,
changing the group's type to RGBA component.
If RGBA component groups are not required,
and if MAP_COLOR is enabled,
then the index is looked up in the PIXEL_MAP_I_TO_I
table (otherwise, the index is not looked up).
Again,
the table must have 
entries for some integer n,
and the integer part of the index is ANDed with 
,
producing a value.
This value addresses the table,
and the value in the table replaces the index.
The floating-point table value is first rounded to a fixed-point
value with unspecified precision.
The group's type remains color index.