{ author: DBR ©2001 (Detlef Brettschneider, germany) }
{ http://home.pages.at/dbr-software/delphi/ }
{ dbr.software@freenet.de }

unit rotate;

interface

uses Graphics, SysUtils;

type
  work = (grad90, grad180, grad270, horz, vert);
  b3 = array[0..2] of byte;

var
  a: array of array of b3;

procedure rotate_flip(bmp: tbitmap; art: work);

implementation

procedure rotate_flip(bmp: tbitmap; art: work);
var
  x, y, h, w, w3: word;
  p: pbytearray;
  i: byte;
  procedure rechnen(b, c: word);
  var j: byte;
  begin
    for j := 0 to 2 do p[x + j] := a[b][c][j];
  end;
begin
  bmp.pixelformat := pf24bit;
  setlength(a, bmp.height);
  h := bmp.height - 1;
  for x := 0 to h do setlength(a[x], bmp.width);
  w3 := bmp.width * 3 - 1;
  for y := 0 to h do begin
    p := bmp.scanline[y];
    x := 0;
    while x <= w3 do begin
      for i := 0 to 2 do a[h - y][x div 3][i] := p[x + i];
      inc(x, 3);
    end;
  end;
  if (art = grad90) or (art = grad270) then begin
    x := bmp.height;
    bmp.height := bmp.width;
    bmp.width := x;
    h := bmp.height - 1;
    w3 := bmp.width * 3 - 1;
  end;
  w := bmp.width - 1;
  for y := 0 to h do begin
    p := bmp.scanline[y];
    x := 0;
    while x <= w3 do begin
      case art of
        vert: rechnen(y, x div 3);
        grad90: rechnen(x div 3, y);
        grad180: rechnen(y, w - x div 3);
        horz: rechnen(h - y, w - x div 3);
      else rechnen(w - x div 3, h - y);
      end;
      inc(x, 3);
    end;
  end;
  a := nil;
end;

end.


=============================================================

Sorry, but I speak German only.



Look at the Attachment.



Many greetings

DBR



// Examples

uses rotate;


procedure TForm1.Button1Click(Sender: TObject);

var bmp:TBitmap;

begin

bmp:=TBitmap.create;
bmp.loadfromfile('d:\bilder\corel044.bmp');
canvas.draw(0,0,bmp);
rotate_flip(bmp,horz);

{
rotate_flip(bmp,horz);
rotate_flip(bmp,vert);
rotate_flip(bmp,grad90);
rotate_flip(bmp,grad180);
rotate_flip(bmp,grad270);
}

canvas.Draw(0,bmp.height,bmp);

end;


procedure TForm1.Button2Click(Sender: TObject);

begin
  rotate_flip(image1.picture.bitmap,grad90);
  image1.refresh;
end;