General Structure
|
|
|       |                                  |     |
|       +----------------------------------+     | loading buffer
|       +----------------------------------+     | (rows loading or unloading while scrolling)
|       |                                  |     |
|       |               row                |     |
|       |                                  |     |
|       +----------------------------------+     |
|                                               -+
|                                               -+
|       +----------------------------------+     | scroll buffer
|       |                                  |     | (loaded rows)
|       |               row                |     |
|       |                                  |     |
|       +----------------------------------+     |
|       +----------------------------------+     |
|       |                                  |     |
|       |               row                |     |
|       |                                  |     |
|       +----------------------------------+     |
|                                               -+
|     +-visible-area-------------------------+
|     |                                      |
|     | +----------------------------------+ |
|     | | +========+ +--------+ +--------+ | |
|     | | |  ref   | |        | |        | | |
|     | | +========+ +--------+ +--------+ | |
|     | +----------------------------------+ |
|     | +----------------------------------+ |
|     | | +--------+ +--------+ +--------+ | |
|     | | | block  | |        | |        | | |
|     | | +--------+ +--------+ +--------+ | |
|     | +----------------------------------+ |
|     | +----------------------------------+ |
|     | |                                  | |
|     | |               row                | |
|     | |                                  | |
|     | +----------------------------------+ |
|     |                                      |
|     +--------------------------------------+
|                                               -+
|       +----------------------------------+     | scroll buffer
|       |                                  |     | (loaded rows)
|       |               row                |     |
|       |                                  |     |
|       +----------------------------------+     |
|       +----------------------------------+     |
|       |                                  |     |
|       |               row                |     |
|       |                                  |     |
|       +----------------------------------+     |
|                                               -+
|                                               -+
|       +----------------------------------+     | loading buffer
|       |                                  |     | (rows loading or unloading while scrolling)
|       |               row                |     |
|       |                                  |     |
|       +----------------------------------+     |
|       +----------------------------------+     |
|       |                                  |     |
|
|
	elements
		view / visible area
		scroll buffer
		loading/unloading buffer
	operation/actions
		scroll
		resize
		filter
	positioning
		reference block
		| a block top-left of the visible area.
		|
		| this block must remain in the same position during any operations 
		| with the content of grid. including:
		| 	- resizing
		| 	- filtering
		|
		| there is only one exception: arity of the grid -- the top-most row
		| must always be full. thus moving the reference left of right, but 
		| never up or down.

.
| vim:set spell ts=4 sw=4 :