Posted By
SVS
on 2009-07-02
07:14:04
 |  Re: SVS Calc
>>tell us how the program translates row and column coordinates into screen position
Well:
System keeps note of the current coordinates of top-left corner of visible grid.
Then when it has to redraw the screen it "knows" from where element of array to start. For example: if top-left corner is B5, system will pick element (2,5) from cells array (2 is for B).
Only a few jobs need the screen updating of only a cell (for example cell input). Anyway in these case the whole row of cells is redrawn.
All other cases need to redraw the whole screen. This is obtained by redrawing every column of cells. To draw columns infact has the advantage to calculate the mask for print using only *once* (column title), and then all other cells below will use the same mask.
Every moving of cursor cell, and every scrolling will update the columns/rows titles too, in order to show hilighted the column and row of the cursor. When manage cursor-cell, the visualization routine is deviated to proper special visualization.
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