Rotate img

procedure Rotate90(Source: TGraphic; Target: TJpegImage);
var
SourceBmp, TargetBmp: TBitmap;
r, c: Integer;
x, y: Integer;
begin
SourceBmp := TBitmap.Create;
SourceBmp.Assign(Source);
TargetBmp := TBitmap.Create;
TargetBmp.Width := SourceBmp.Height;
TargetBmp.Height := SourceBmp.Width;
for r := 0 to SourceBmp.Height - 1 do
begin
for c := 0 to SourceBmp.Width - 1 do
begin
//x := (SourceBmp.Height-1) - r; // -90
//y := c; //-90
x := r; //90
y := (SourceBmp.Width-1) - c; //90
// look into Bitmap.ScanLine for faster pixel access
TargetBmp.Canvas.Pixels[x, y] := SourceBmp.Canvas.Pixels[c, r];
end;
end;
Target.Assign(TargetBmp);
SourceBmp.Free;
TargetBmp.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
Jpeg: TJPEGImage;
begin
Jpeg := TJPEGImage.Create;
Rotate90(Image1.Picture.Graphic, Jpeg);
Image1.Picture.Assign(Jpeg);
Jpeg.Free;
end;




//http://www.efg2.com/Lab/ImageProcessing/FlipReverseRotate.htm
//http://stackoverflow.com/questions/11864236/what-is-the-fastest-way-to-rotate-a-jpg-image-file
//http://www.delphigroups.info/2/12/317243.html
//http://www.efg2.com/Lab/Library/Delphi/Graphics/ImageProcessing.htm