update
Description:
Update indices of attributes in this for a change in the text they refer to.
The change that this function applies is removing remove
bytes at position pos
and inserting add
bytes
instead.
Attributes that fall entirely in the (pos
, pos
+ remove
) range are removed.
Attributes that start or end inside the (pos
, pos
+ remove
) range are shortened to reflect the removal.
Attributes start and end positions are updated if they are behind pos
+ remove
.
Parameters:
this |
a `PangoAttrList` |
pos |
the position of the change |
remove |
the number of removed bytes |
add |
the number of added bytes |