Board index » delphi » Display Gif or Jpeg Images on dbImage

David Gurevitz

Delphi Developer
Wed, 03 Oct 2001 03:00:00 GMT

Display Gif or Jpeg Images on dbImage

Ive been using a paradox database with a graphic field to store images.

If I use bmp files, I can display them on a dbImage, but if I use gif or
jpeg, I get only blank screens.
I can display them on a Iame, but not on a dbImage.

Any ideas on how to solve that?

Thanks in advance
David Gurevitz
g...@centroin.com.br

 
Brian Bushay Tea

Delphi Developer
Thu, 04 Oct 2001 03:00:00 GMT

Re:Display Gif or Jpeg Images on dbImage


Quote
>Ive been using a paradox database with a graphic field to store images.

>If I use bmp files, I can display them on a dbImage, but if I use gif or
>jpeg, I get only blank screens.
>I can display them on a Iame, but not on a dbImage.

You will not be able to display Jpegs in a tdbimage.  You can write code to read
a jpeg from a blob field and display it in a timage.

here is some code to help you get started
procedure TForm1.Table1AfterScroll(DataSet: TDataSet);
var
  MS: TMemoryStream;
  J1: TJPEGImage;
begin
  J1 := TJPEGImage.Create;
  MS := TMemoryStream.Create;
  try
    TBlobField(DataSet.fieldbyName('yourJpeg')).SaveToStream(MS);
    MS.Seek(soFromBeginning, 0);
    with J1 do begin
      PixelFormat := jf24Bit;
      Scale := jsFullSize;
      Grayscale := False;
      Performance := jpBestQuality;
      ProgressiveDisplay := True;
      ProgressiveEncoding := True;
      LoadFromStream(MS);
    end;
    Image1.Picture.Graphic.Assign(J1);
  finally
    J1.Free;
    MS.Free;
  end;
end;

--
Brian Bushay (TeamB)
Bbus...@NMPLS.com

David Gurevit

Delphi Developer
Thu, 04 Oct 2001 03:00:00 GMT

Re:Display Gif or Jpeg Images on dbImage


Thanks fro your answeer Brian.

But in that case, is it a good idea to save the graphic in a Blob field, or it will
be better to save only the full path/name of the jpeg file and open it on a TImage?

What will be the best/quicker way?

Thanks
David

Quote
Brian Bushay TeamB wrote:
> >Ive been using a paradox database with a graphic field to store images.

> >If I use bmp files, I can display them on a dbImage, but if I use gif or
> >jpeg, I get only blank screens.
> >I can display them on a Iame, but not on a dbImage.

> You will not be able to display Jpegs in a tdbimage.  You can write code to read
> a jpeg from a blob field and display it in a timage.

> here is some code to help you get started
> procedure TForm1.Table1AfterScroll(DataSet: TDataSet);
> var
>   MS: TMemoryStream;
>   J1: TJPEGImage;
> begin
>   J1 := TJPEGImage.Create;
>   MS := TMemoryStream.Create;
>   try
>     TBlobField(DataSet.fieldbyName('yourJpeg')).SaveToStream(MS);
>     MS.Seek(soFromBeginning, 0);
>     with J1 do begin
>       PixelFormat := jf24Bit;
>       Scale := jsFullSize;
>       Grayscale := False;
>       Performance := jpBestQuality;
>       ProgressiveDisplay := True;
>       ProgressiveEncoding := True;
>       LoadFromStream(MS);
>     end;
>     Image1.Picture.Graphic.Assign(J1);
>   finally
>     J1.Free;
>     MS.Free;
>   end;
> end;

> --
> Brian Bushay (TeamB)
> Bbus...@NMPLS.com

Brian Bushay Tea

Delphi Developer
Fri, 05 Oct 2001 03:00:00 GMT

Re:Display Gif or Jpeg Images on dbImage


Quote
>But in that case, is it a good idea to save the graphic in a Blob field, or it will
>be better to save only the full path/name of the jpeg file and open it on a TImage?

>What will be the best/quicker way?

With a database of any size you will end up with a lot of files.   I believe
storing them in a blob field is the easier option from a maintenance stand
point.  

--
Brian Bushay (TeamB)
Bbus...@NMPLS.com

David Gurevit

Delphi Developer
Fri, 05 Oct 2001 03:00:00 GMT

Re:Display Gif or Jpeg Images on dbImage


Thanks, Brian.

Other question:
I was using a dbImage to assign a bmp value to a Blob field. This doesn't function to
Jpeg files.
How do I assign a Jpeg value to a Blob field directly?

Regards
David

Quote
Brian Bushay TeamB wrote:
> >But in that case, is it a good idea to save the graphic in a Blob field, or it will
> >be better to save only the full path/name of the jpeg file and open it on a TImage?

> >What will be the best/quicker way?

> With a database of any size you will end up with a lot of files.   I believe
> storing them in a blob field is the easier option from a maintenance stand
> point.

> --
> Brian Bushay (TeamB)
> Bbus...@NMPLS.com

Brian Bushay Tea

Delphi Developer
Sat, 06 Oct 2001 03:00:00 GMT

Re:Display Gif or Jpeg Images on dbImage


Quote
>How do I assign a Jpeg value to a Blob field directly?

You can use the Tblobfield loadfromFile and LoadFromStream methods to store a
jpeg.  The Tjpegimage has a SaveToStream

--
Brian Bushay (TeamB)
Bbus...@NMPLS.com

Other Threads

1. Displaying GIF/JPEG/RIP/ or PCX images

2. jpeg/bmp/gif in dbimage

3. DBImage can't display JPEG

4. How to display jpeg picture in DBImage?

5. Using DBImage to store JPEG images to database

6. How to support JPEG Image with DBImage in SQLServer7

7. Need to display gif/jpeg in program

8. Text on GIF / JPEG / BMP image

9. GIF and JPEG image sizes

10. Help: Extracting size from GIF and JPEG image files