1998-09-17  Miguel de Icaza  <miguel@nuclecu.unam.mx>

	* src/sheet-view.c (sheet_view_row_size_changed,
	sheet_view_col_size_changed): If there is a selection of columns
	or rows, change the sizes of all of the columns.

	* src/sheet.c (sheet_row_get_distance, sheet_col_get_distance):
	optimized to be O(n) instead of O(n^2) using
	(col_row_distance): new routine to compute distances.

	* src/sheet-view.c (sheet_view_redraw_cell_region): Add the
	scrolling offset to the x and y positions to draw properly

	* src/xml-io.c (readXmlSheet): Call sheet_set_zoom_factor to
	initialize the ->pixels field.

Ok, the new display engine is now in place.

The design bug with the exposures has now been fixed.

Now, back to more mundane tasks.

Miguel.

Today it probably does not compile, but I have to leave now.

This is basically the framework for getting computations working.

My current approach is to register areas of interest for a cell.
This is not perfect, but good enough:

	The idea is to walk the expression tree and look for
	cell references (cell references or ranges) and register
	those areas of "interest" for a cell.

	When a new text is entered into a cell, the "regions" of
	interest list is checked and if a match is found, then
	the cells on that region of interest are queued for
	recomputation.

Of course, I do not know yet how to handle the recursive references.

One option is to keep a counter (that starts at zero) during
recomputation, ie something like:

eval_cell (Cell *cell)
{
	cell->use_count++;
	if (cell->use_count > threshold)
		return "Cycle too depth";
	...
	on value lookup:
		eval_cell (cell);
	...
	cell->use_count--;
}