From: "Earl F. Glynn" <e f g 2 @ e f g 2 . c o m>
Newsgroups: borland.public.delphi.documentation
Subject: Error in TBitmap.SaveToClipboardFormat Help example since D3
Date: Sat, 5 Jul 2003 02:06:28 -0500
Lines: 156
Organization: efg's Computer Lab
Xref: newsgroups.borland.com borland.public.delphi.documentation:1633

In D7 Professional, try this:


  Help | Delphi Help | Index | TBitmap
  Select topic:  SaveToClipboardFormat | Display

The Delphi syntax is correct, but the example is not:

  procedure SaveToClipboardFormat(var AFormat: Word; var AData: THandle; var
  APalette: HPALETTE); override;

Select Delphi example (ignore C++ example and C++ syntax )


Here's the SaveToClipboardFormat example from the help documentation:

procedure TForm1.Button1Click(Sender: TObject);

var

  MyFormat : Word;

  Bitmap : TBitMap;

  AData,APalette : THandle;

begin

  Bitmap := TBitmap.Create;

  try

    Bitmap.LoadFromFile('c:\Program Files\Common Files\Borland
Shared\Images\Splash\256color\factory.bmp');

    Bitmap.SaveToClipBoardFormat(MyFormat,AData,APalette);

    ClipBoard.SetAsHandle(MyFormat,AData);

  finally

    Bitmap.Free;

  end;

end;



Why doesn't this example have the needed "uses" statement?  (FWIW, there are
other Help examples that don't show which units are needed -- this is quite
frustrating.)


USES clipbrd;

With the needed "uses", this code doesn't compile.  The following error is
seen:


[Error] Unit1.pas(38):  Types of actual and formal var parameters must be
indentical


I'd guess a novice might not know to change

  AData,APalette : THandle;

to

  AData: THandle;
  APalette:  hPalette;

In D6, help you don't need to ignore the C++ example, but the same problem
exists.  The syntax is correct in help, but the code in the example doesn't
compile and must be changed (and the "uses" must be added, too.).

D5 has the same problem as D6.

In D4 the same problem existed.  The relative path seems to be wrong on my
D4 installation since files were moved to C:\Program Files\Commons
Files\Borland:

Bitmap.LoadFromFile('..\Images\Splash\256color\factory.bmp');

Needed to be:

Bitmap.LoadFromFile('C:\Program Files\Common Files\Borland
Shared\Images\Splash\256Color\factory.bmp');

The D3 online help said this (as does the D7 online help):

procedure SaveToClipboardFormat(var AFormat: Word; var AData: THandle; var
APalette: HPALETTE); override;

The D3 Code compiled and executed since back then a THandle and a hPalette
must have been equivalent:

USES Clipbrd;   //  Missing in D3 and later Help example

procedure TForm1.Button1Click(Sender: TObject);

var

  MyFormat : Word;

  Bitmap : TBitMap;

  AData,APalette : THandle;  // compiles OK in D3 but not D4, D5, D6, D7

begin

  try

    Bitmap := TBitmap.Create;

    Bitmap.LoadFromFile('C:\Program Files\Borland\Delphi
3\Images\Splash\256color\factory.bmp');

    Bitmap.SaveToClipBoardFormat(MyFormat,AData,APalette);

    ClipBoard.SetAsHandle(MyFormat,AData);

  finally

    Bitmap.Free;

  end;

end;


In the D3 help, the "TRY" above should have been after the TBitmap.Create,
instead of before - and even gave a warning in D3.

The fix now required in D7 (and D4/D5/D6) and which would have worked in D3:

  APalette:  hPalette;

This problem didn't exist in D2 since D2's TBitmap didn't support a
SaveToClipBoardFormat method.


So maybe this can somehow get fixed in the D8 help?  -- Sure wish there was
an online version of help that was updated the day after such a problem was
discovered.

--
efg -- Earl F. Glynn, Overland Park, KS  USA

efg's Computer Lab:  http://www.efg2.com/Lab
Mirror:  http://homepages.borland.com/efg2lab/Default.htm