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Ed Dressel · Guest

I've tried to create a simple slide show for showing *.jpg files found in a
selected directory, but what seems should be easy is in fact not: inbetween
images (I have two images (TImage) for buffering the up coming slide and
load the image in a separate thread). Switching between the two images can
sometimes take a moment, othertimes its quick.

My code is quite clean, using a timer it just toggles the visiblity of two
images (calling SendToBack removes some flicker, but I still get dead spots
inbetween showing the images):

if not Image1.Visible then
begin
Image1.SendToBack;
Image1.Visible := True;
Image2.Visible := False;
end
else
begin
Image2.SendToBack;
Image2.Visible := True;
Image1.Visible := False;
end;

I also tried LockWindowHandle before calling the code above and that
guarentees that the flicker will occur.

Any easy way of removing the flicker?

Thanks
Ed Dressel

Nils Haeck · Guest

What about using just one TImage?

You can easily load a JPEG in a TBitmap, using something like

procedure LoadJpegInBitmap(Name: string; Bitmap: TBitmap);
begin
AJpeg := TJpegImage.Create;
try
AJpeg.LoadFromFile(Name);
Bitmap.Assign(AJpeg);
finally
AJpeg.Free;
end;
end;

Next, when you have the bitmap, you can simply assign it to the image:

Image1.Picture.Bitmap.Assign(MyBitmap);

This should reduce flicker. You can reuse MyBitmap or create it before each
load as you wish.

An additional way to reduce flicker is by setting Image1.DoubleBuffered :=
True;

Kind regards,

Nils Haeck
www.simdesign.nl

"Ed Dressel" <none> wrote

Uwe · Guest

Hi Ed

Did you try Kambiz' TPicShow? Great slide show component, and free with
source! Maybe it gives you some ideas.

URL: http://www.delphiarea.com/products/picshow/

Cheers
Uwe

The Delphi Pool
http://www.lmc-mediaagentur.de/dpool.htm