How to create Virtual Printer using Delphi

 

Examples

◊ Sample Client application used for testing and development purposes. This application demonstrates how to use an INI file to write print job information and paths to the generated files.
Download Sample Client Application: Virtual Printer for Delphi

◊ Print Previewer - a sample application demonstrating the features of the virtual printer. Print Previewer, which may be used in custom client applications, provides detailed information about printed files and displays the EMF files inside a form. The sample contains code that outputs the metafile to the screen.
Download Print Previewer: Virtual Printer for Delphi

◊ Printer Configuration - a sample utility for configuring the virtual printer. This utility permits setting such parameters as the client application path, transfer mode of the INI file path, and the folder to save the generated files. (The printer may print to EMF, PDF, TXT, JPEG, TIFF, or BMP files.)
Download Printer Configuration: Virtual Printer for Delphi

◊ How to print files programmatically using the ShellExecute function

 

How to print files programmatically using the ShellExecute function

The code sample below demonstrates how to print files programmatically on either a physical or a virtual printer using the ShellExecute function. It also demonstrates how to change the default system printer.

function GetDefaultPrinter(szPrinter:PAnsiChar; var bufferSize:DWORD):
BOOL; stdcall; external 'winspool.drv' name 'GetDefaultPrinterA';

function SetDefaultPrinter(szPrinter:PAnsiChar):
BOOL; stdcall; external 'winspool.drv' name 'SetDefaultPrinterA';

procedure PrintDocumentUsingShellExecute (szPrinter: String,  szDocumentPath: String)
    var
    szDefaultPrinter, szNamePrinterBuff: String;
    bufferSize: DWord;

    begin
    
    // get the default printer
    SetLength(szDefaultPrinter, MAX_PATH);
    bufferSize:= MAX_PATH;
    GetDefaultPrinter(Pchar(szDefaultPrinter), bufferSize);
    szDefaultPrinter:= String (PChar(szDefaultPrinter));

    //change the default printer
    if(szPrinter <> szDefPrinter)
    then SetDefaultPrinter(PChar(szPrinter));

    // send the document  to the print
    ShellExecute(0, 'print', PChar(szDocumentPath), nil, nil, SW_HIDE);  

    //set default printer back to original
    if(szPrinter <> szDefaultPrinter)
    then SetDefaultPrinter(PChar(szDefaultPrinter));

    end;

Then it's necessary to call these functions with the required parameters. For example, you can print MS Word and PDF documents this way:

PrintDocumentUsingShellExecute('Your Virtual Printer', 'c:\Documents\AnyDocument.doc')
PrintDocumentUsingShellExecute('Your Virtual Printer', 'c:\ Documents \AnyDocument.pdf')