gtk_cell_area_foreach_alloc() itterates over an allocated list of cells
and calls a callback with the cell's allocation until the callback returns
TRUE.
- Removed vfunc get_cell_allocation() and implemented
gtk_cell_area_get_cell_allocation() using foreach_alloc()
- Added gtk_cell_area_get_cell_at_position() using foreach_alloc()
- Removed GtkCellAreaBox ->event() implementation and implemented
mouse "click" cell activation in GtkCellArea class directly using
gtk_cell_area_get_cell_at_position().
2588165bfb
