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

[striderx]

Nachtrag der Vollständigkeit halber

Delphi-Quellcode:

function GDIPRotateFlipBitmap(ABitmap:  tBitmap;  Mode:  RotateFlipType):  Boolean;

var
  BM:         tBitmap;
  GR:         tGPGraphics;
  AGPBitmap:  tGPBitmap;
  AStatus:    Status;
  W:          Integer;

begin
  if Mode = RotateNoneFlipNone then begin
     Result := True;
     Exit;
  end;
  
  BM := tBitmap.Create;      
  BM.Assign(ABitmap);        
  AGPBitmap := tGPBitmap.Create(BM.Handle, 0);  
  
  AGPBitmap.RotateFlip(Mode);
  
  if (ABitmap.Width <> ABitmap.Height) and
>     (Mode in [Rotate90FlipNone, Rotate270FlipNone,
>               Rotate90FlipX, Rotate270FlipX,
>               Rotate90FlipY, Rotate270FlipY,
>               Rotate90FlipXY, Rotate270FlipXY]) then begin
     W := ABitmap.Width;
     ABitmap.Width  := ABitmap.Height;
     ABitmap.Height := W;
  end;
  
  GR := tGPGraphics.Create(ABitmap.Canvas.Handle);
  GR.DrawImage(AGPBitmap, 0, 0);
  AStatus := GR.GetLastStatus;
  
  Result := (AStatus = OK);
  
  AGPBitmap.Free;
  BM.Free;
  GR.Free;
end;