24-Bit Bitmap um 90 grad drehen - Resourcen-Optimierung

[Renate Schaaf]

Zitat:

Gerne. Was meinst Du mit nur 2 mal aufrufen?

So in etwa:

Delphi-Quellcode:

procedure Drehe90Rechts24NurPointers(bm: TBitmap);
var
  P, Pend, Pdest: PRGBTriple;
  x, y, b, h: Integer;
  RowOut: PByte;
  help: TBitmap;
var
  Offs, OffsDest: NativeInt;
begin
  help := TBitmap.create;
  help.pixelformat := pf24bit;

  b := bm.height;
  h := bm.width;

  help.SetSize(b, h);
  RowOut := help.scanline[0];
  Pend := bm.scanline[bm.height - 1];
  Offs := ((h * 24 + 31) and not 31) div 8;
  OffsDest := ((b * 24 + 31) and not 31) div 8;
  for y := 0 to h - 1 do
  begin
    P := Pend;
    inc(P, y);
    Pdest := PRGBTriple(RowOut);
    for x := 0 to b - 1 do
    begin
      Pdest^ := P^;
      inc(Pdest);
      inc(NativeInt(P), Offs);
    end;
    dec(RowOut, OffsDest);
  end;

  bm.Assign(help);
  help.free;
 end;