Commands > Load PDF

When loading an encrypted PDF file (which uses a non-empty password) a message box to enter the password will pop up.

To prevent this You can use

COMPDF_SetLoadPassword = 120

Sets master load password. This can also be done in the NeedPassword event!

COMPDF_AddPassword = 122

Adds a password to the list of passwords to be used.

COMPDF_ClearPasswords = 121

Clear the complete list of passwords.

When using the VCL it is better to use the high level load methods.

COMPDF_FastLoad = 99

Loads but do not display a PDF file. The name is passed as StrParam. The result value is the count of pages.

COMPDF_UpdatePages = 107

Force the update of the bookmark and scroller. This is not required for the load methods below.

COMPDF_Clear = 100

Removes all loaded PDF data and closes any streams opened by the component.

COMPDF_Load = 101

Load a PDF file. If IntPar=1 the file will be copied to memory - this makes it possible to delete, move or overwrite the original file.

The result value is the count of pages.

COMPDF_Append = 102

Appends a PDF file. If IntPar=1 the file will be copied to memory - this makes it possible to delete, move or overwrite the original file.

The result value is the count of pages.

COMPDF_AppendHGlobal = 103

COMPDF_LoadEHGlobal = 95

Load or append the PDF data from a HGLOBAL memory handle.

COMPDF_AppendIStream = 104

COMPDF_LoadIStream = 96

LOad or append PDF from a COM stream. IntParam is an interface pointer.

COMPDF_AppendIStreamKeepOpen = 108

Works like COMPDF_AppendIStream but keep the stream open!

COMPDF_AppendEStream = 105 (create copy)

COMPDF_LoadEStream = 97 (create copy)

COMPDF_AppendEPStream = 106 (keep stream open)

COMPDF_LoadEPStream = 98 (keep stream open)

Load or Append PDF from an event stream. Event streams are implemented as a structure with 3 function pointers.

The first 2 create a copy of the data, the second 2 keep the stream open.

The WPViewPDF VCL uses this streams internally.

Definition:

TEventStreamFkt = packed

record

OnStreamRead: function(data: Pointer; buffer: Pointer; len: Integer)

: Integer;

stdcall;

OnStreamWrite: function(data: Pointer; buffer: Pointer; len: Integer)

: Integer;

stdcall;

OnStreamSeek: function(data: Pointer; Offset: Integer; Origin: Integer)

: Integer;

stdcall;

Stream: TStream;

end;

function ReadEvent(data: Pointer; buffer: Pointer; len: Integer): Integer;

stdcall;

begin

Result := PEventStreamFkt(data).Stream.Read(PAnsiChar(buffer)^, len);

end;

function WriteEvent(data: Pointer; buffer: Pointer; len: Integer): Integer;

stdcall;

begin

Result := PEventStreamFkt(data).Stream.Write(PAnsiChar(buffer)^, len);

end;

function SeekEvent(data: Pointer; Offset: Integer; Origin: Integer): Integer;

stdcall;

begin

Result := PEventStreamFkt(data).Stream.Seek(Offset, Origin);

end;

Usage:

function TWPViewPDF.LoadFromStream(Stream: TStream; WithClear: Boolean = false): Boolean;

var

events: TEventStreamFkt;

begin

events.Stream := Stream;

events.OnStreamRead := Addr(ReadEvent);

events.OnStreamWrite := Addr(WriteEvent);

events.OnStreamSeek := Addr(SeekEvent);

try

if WithClear then

begin

if FEngineVersion < 3000 then

begin

CommandEx(COMPDF_Clear, 0);

Result := CommandEx(COMPDF_AppendEStream, Cardinal(@events)) = 0;

end

else

Result := CommandEx(COMPDF_LoadEStream, Cardinal(@events)) = 0

end

else

Result := CommandEx(COMPDF_AppendEStream, Cardinal(@events)) = 0;

except

Result := false;

end;