TBitmap.LoadFromClipboardFormat method
lazarus / 39-Graphics

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skywriter · 2007-07-27 12:07

The story so far.
Application contains
Form1:TForm,
Image1:TImage,
Button1:TButton
both in Lazarus and in Delphi project.

In Lazarus project:

procedure TForm1.BitBtn1Click(Sender: TObject);
var
  BMP : TBitmap;
begin
  BMP := TBitmap.Create;
  BMP.LoadFromClipboardFormat( CF_BITMAP );
  Image1.Picture.Bitmap.Assign( BMP );
end;

In Delphi project:

procedure TForm1.Button1Click(Sender: TObject);
var
  BMP : TBitmap;
begin
  BMP := TBitmap.Create;
  BMP.LoadFromClipboardFormat(CF_Bitmap,
ClipBoard.GetAsHandle(CF_Bitmap), 0);
  Image1.Picture.Bitmap.Assign( BMP );
end;

Then i copy part of image from MS Paint into clipboard.
After that, when i press "Button1" in Delphi project i see the same
copied part of image on the form.  When i press "Button1" in Lazarus
project there nothing happens.

What i do wrong?

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arnoldb · 2007-07-27 13:16

Slightly confusing...  You are trapping a BitBtn1Click in Lazarus, yet
you say you have a Button1:TButton
Do you have a Button1Click event assigned in Lazarus to Button1's
onclick, or is BitBtn1Click assigned to button1's onclick in Lazarus?

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wile64 · 2007-07-27 15:50

I use this
Bitmap.LoadFromClipboardFormat(PredefinedClipboardFormat(pcfPixmap));
who run well…

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skywriter · 2007-07-30 09:07

arnoldb: I think type of button control doesn't matter in this case.

Quote from: "wile64"I use this
Bitmap.LoadFromClipboardFormat(PredefinedClipboardFormat(pcfPixmap));
who run well…

Tried. Result is the same as with BMP.LoadFromClipboardFormat(
CF_BITMAP ). I went ste-by-step to method

Code: [Select]function TClipboard.AssignToGraphic(Dest: TGraphic;
FormatID: TClipboardFormat
  ): boolean;
var
  MemStream: TMemoryStream;
begin
  Result:=false;
  if FormatID=0 then exit;
  MemStream:=TMemoryStream.Create;
  try
    if not GetFormat(FormatID,MemStream) then exit;
    MemStream.Position:=0;
    Dest.LoadFromMimeStream(MemStream,ClipboardFormatToMimeType(Format
ID));
  finally
    MemStream.Free;
  end;
  Result:=true;
end;

and i saw GetFormat(FormatID,MemStream) returns false. Where is bug?
I need this feature to get snapshot from clipboard as in method
 TVideo.CapGrabFrame(Destination: TBitmap) of "SysRec"
project...Please help! :cry:

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skywriter · 2007-08-03 05:53

wile64: Can you tell which version of Lazarus you use and example of
code properly works?
I believe the bug must be fixed. No matter is this my bug or Lazarus-
developers bug.

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skywriter · 2007-08-09 08:37

while64:

What about this (file \lazarus\lcl\include\intfbaselcl.inc):
Code: [Select]
// the clipboard functions are internally used by TClipboard
function TWidgetSet.ClipboardFormatToMimeType(FormatID:
TClipboardFormat): string;
begin
  Result := '';
end;


How it can work at all?!

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skywriter · 2007-08-10 08:48

Temporarily found usable workaround: function capFileSaveDIB of VfW
then TBitmap.LoadFromFile.

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Marc · 2007-08-14 09:03

TWidgetSet.xxx only contains empty "abstract" methods and functions.
The real implementation is done in the derived widgetset like
TWSWin32Widgetset or TWSgtkWidgetset