Difference between revisions of "SortTPASpiral"

Latest revision as of 17:13, 25 November 2012

The default spiral format is defined as moving in the sequential directions "up, right, down, left" on a bitmap image. This translates to "-y, x, y, -x" in coordinates.

Definition

procedure SortTPASpiral(var TPA: TPointArray);

Availability

SCAR Divi 3.38 > Current

Description

Sorts a given TPointArray TPA in a spiral pattern, spiraling out from the origin (0, 0) using the fast ShellSort algorithm. An extended function with additional functionality is available as SortTPASpiralEx.

Example

var
  TPA: TPointArray;
  
begin   
  TPA := TPAFromBox(Box(-1, -1, 1, 1));
  SortTPASpiral(TPA);
  WriteLn(TPAToStr(TPA));              
end.

Output:

(0,0);(0,-1);(1,-1);(1,0);(1,1);(0,1);(-1,1);(-1,0);(-1,-1)

See Also

• SortTPASpiralEx
• SortTPA