Delphi 7 TImage and TImageList

Question

let me be whole private

the code

procedure TForm1.Image1Click(Sender: TObject);
begin
  inc(i);
  ImageList1.GetIcon(i mod 4,Image1.Picture.Icon);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  i:=0;
  ImageList1.GetIcon(i mod 4,Image1.Picture.Icon);
end;

How to stretch an icon from a list so that it matches the size of Image1?

Answer 1

procedure TForm1.Image1Click(Sender: TObject);
var
  icon: TIcon;
begin
  inc(i);
  Image1.Canvas.FillRect(ClientRect);      
  icon := TIcon.Create;
  try
    ImageList1.GetIcon(i mod 4, icon);
    DrawIconEx(Image1.Canvas.Handle, 0, 0, icon.Handle, Image1.Width, Image1.Height, 0, 0, DI_NORMAL);
  finally
    icon.Free;
  end
end;

Best approach

Using Delphi is sometimes a little awkward, as the degree of collaboration between VCL and the native Windows API is somewhat unclear. If the code above does not work (I feel this is a leak of icons), here is a clean native approach ( uses ImgList, CommCtrl):

procedure TForm1.Image1Click(Sender: TObject);
var
  icon: HICON;
begin
  inc(i);
  Image1.Canvas.FillRect(ClientRect);
  icon := ImageList_GetIcon(ImageList1.Handle, i mod 4, ILD_NORMAL);
  try
    DrawIconEx(Image1.Canvas.Handle, 0, 0, icon, Image1.Width, Image1.Height, 0, 0, DI_NORMAL);
  finally
    DestroyIcon(icon);
  end
end;