[SOLVED] Bitmap showing up as on black

[tudi_x]

hi All,
i started working with bitmaps and got into issues at the code below.
basically i loaded some images into a images list and want to push to a TImage a stretched version so it fits the TImage dimensions.
please advise what i can do so buffer2 saves as original image stretched but not on black (like film negative).

Code: Pascal  [Select][+][-]

1. unit main;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls, StdCtrls;
9.  
10. type
11.   TForm1 = class(TForm)
12.     Button1: TButton;
13.     Image1: TImage;
14.     ImageList1: TImageList;
15.     procedure Button1Click(Sender: TObject);
16.   end;
17.  
18. var
19.   Form1: TForm1;
20.  
21. implementation
22.  
23. {$R *.lfm}
24.  
25. procedure TForm1.Button1Click(Sender: TObject);
26. var
27.   buffer1: TBitmap;
28.   buffer2: TBitmap;
29.  
30. begin
31.   try
32.     buffer1 := TBitmap.Create;
33.     buffer2 := TBitmap.Create;
34.  
35.     ImageList1.GetBitmap(0, buffer1);
36.     buffer1.SaveToFile('buff1.bmp');
37.  
38.     buffer2.SetSize(Image1.Width, Image1.Height);
39.     buffer2.Canvas.StretchDraw(Rect(0, 0, Image1.Width, Image1.Height), buffer1);
40.     buffer2.SaveToFile('buff2.bmp');
41.  
42.     Image1.Canvas.Clear;
43.     Image1.Canvas.Draw(0, 0, buffer2);
44.  
45.   finally
46.     FreeAndNil(buffer1);
47.     FreeAndNil(buffer2);
48.   end;
49. end;
50.  
51. end.
52.  

thank you

Lazarus 1.8RC4, cross platform

[howardpc]

You could try this

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button1Click(Sender: TObject);
2. var
3.   bmp: TBitmap;
4. begin
5.   bmp:=TBitmap.Create;
6.   try
7.     bmp.SetSize(ImageList.Height, ImageList.Height);
8.     bmp.Canvas.Brush.Color:=clBtnFace; // or whatever background color you wish
9.     bmp.Canvas.FillRect(bmp.Canvas.ClipRect);
10.     ImageList.Draw(bmp.Canvas, 0, 0, 0);
11.     Image1.Canvas.StretchDraw(Image1.ClientRect, bmp);
12.   finally
13.     bmp.Free;
14.   end;
15. end;

[tudi_x]

thank you again.
now i understood that i was missing a background to the bitmap.
below now works:

Code: Pascal  [Select][+][-]

1.     buffer2.SetSize(Image1.Width, Image1.Height);
2.     buffer2.Canvas.Brush.Color:= clBtnFace;
3.     buffer2.Canvas.FillRect(buffer2.Canvas.ClipRect);
4.     buffer2.Canvas.StretchDraw(Rect(0, 0, Image1.Width, Image1.Height), buffer1);
5.     buffer2.SaveToFile('buff2.bmp');