Greetings from Lyon, France,
In this kind of transformation, a *reverse* procedure to fill in the
result from the source is typically needed with signature like
type TReverseProj = object
// parameters to memorize
procedure set( { some parameters} );
procedure reverse(target_line, target_column :integer ; var
source_line, source_column :integer);
end;
procedure TReverseProj.set( { some parameters} );
begin
// setting the parameters for the reverse transformation
end;
procedure TReverseProj.reverse(target_line, target_column :integer ; var
source_line, source_column :integer);
begin
// applying the reverse transformation
end;
It is likely that the source position for "same_line_next
column_in_target" can be written more simply that the full reverse (to
be checked in equations, write on a paper reverse for (i,j) and (i,j+1)
and see what is the difference).
To take benefit of this the last returned position must be memorized in
the object and a routine added with signature like
procedure TReverseProj.shift_tarjet_cell(var
source_line_for_shifted_cell, source_column_for_shifted_cell :integer);
begin
// shifting source according to the shift in cell
end;
So the full reverse will be called only at the begin of each line
For generality calculation and storage must be handled in floating point
(single, double...) ; just the result is rounded.
Regards,
Etienne.
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