Hi!

Currently I'm trying to use TForm.GetFormImage method to make a minimap (something similar to Sublime Text editor) of a big form (the parent of this big form is a TScrollbox on this application).

But, using Qt or GTK2, Lazarus 1.6.3 or trunk, I got the same black bitmap.

So, I created a empty application (just one form with some buttons) and the result is the same.

The code that should make a screenshot of my form is:

procedure TForm1.Button3Click(Sender: TObject);
var
  bmp: TBitmap;
begin
  bmp:=Form1.GetFormImage;
  try
    bmp.SaveToFile(ExtractFilePath(Application.ExeName)+'form.bmp');
  finally
    FreeAndNil(bmp);
  end;
end;

Am I using the method GetFormImage right?

If yes, what's the alternative method to make a screenshot of a form?

Should I fill a bug report for this issue?

Hi,

Am I using the method GetFormImage right?

Yes,

Should I fill a bug report for this issue?

No.

Please try this:
var
  bmp: TBitmap;
begin
  bmp:=Form1.GetFormImage;
  try
    *bmp.Canvas.Changed;*
    bmp.SaveToFile(ExtractFilePath(Application.ExeName)+'form.bmp');
  finally
    FreeAndNil(bmp);
  end;
end;

On Mon, Dec 26, 2016 at 9:38 PM, Fabio Luis Girardi via Lazarus <

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It worked. Thanks!

Why is necessary to call the TCanvas.Changed after TForm1.GetFormImage?

2016-12-26 17:58 GMT-02:00 Balázs Székely :

But Delphi does not require the bmp.Canvas.Changed. Shouldn't it be added to the GetFormImage internally to make this simple code Delphi-compatible?

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But Delphi does not require the bmp.Canvas.Changed. Shouldn't it be added to the GetFormImage internally to make this simple code Delphi-compatible?

That's a good idea. The current behavior is confusing.

On Tue, Dec 27, 2016 at 1:40 AM, Werner Pamler via Lazarus <

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See comments: http://bugs.freepascal.org/view.php?id=25448

Kind regards

Michl
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Somebody with good knowledge of the graphics code should fix it. I remember I tried over 2 years ago but failed.

Juha
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Il 27/12/2016 17:49, Juha Manninen via Lazarus ha scritto:

Somebody with good knowledge of the graphics code should fix it. I remember I tried over 2 years ago but failed.

Just adding a line to GetFormImage does the trick:

Giuliano

The method TWinControl.PaintTo doesn't refresh the RawImage.Data, like it is done in TRasterImage.Draw. It isn't only a issue for the method GetFormImage. I fixed it in revision 53790. As far as I can see, there are no additional calls done, as the needed one (e.g. TWin32WidgetSet.RawImage_FromBitmap is only called one time before saving to stream).

Hope, it works now as expected. If not, please report.

Michl