Printing PDF Documents with PDFium VCL in Delphi

Printing PDF documents with accurate rendering and proper scaling is a common requirement. The Print PDF demo shows how to implement professional PDF printing with preview, page selection, and quality options using PDFium VCL Component.

Overview

This comprehensive demo provides a complete printing solution including print preview, page range selection, quality settings, scaling options, and recent file history. It demonstrates best practices for PDF printing in Delphi applications.

Key Features

Print Preview – Visual preview before printing
Page Selection – Print all pages or specific ranges
Quality Settings – Draft, normal, and high-quality modes
Scaling Options – Fit to page, shrink to fit, or no scaling
Multiple Copies – Print multiple copies with collation
Progress Tracking – Visual feedback during printing
Recent Files – Quick access to previously printed documents

PDFium DLL Requirements

Before running any PDFium VCL application, ensure the PDFium DLL files are installed:

pdfium32.dll / pdfium64.dll – Standard versions (~5-6 MB)
pdfium32v8.dll / pdfium64v8.dll – With V8 JavaScript engine (~23-27 MB)

Installation: Run PDFiumVCL\DLLs\CopyDlls.bat as Administrator to automatically copy the DLLs to Windows system directories.

Basic PDF Printing

procedure PrintPdfSimple(const FileName: string);
var
  Pdf: TPdf;
  I: Integer;
  Bitmap: TBitmap;
begin
  Pdf := TPdf.Create(nil);
  try
    Pdf.FileName := FileName;
    Pdf.Active := True;
    
    Printer.Title := Pdf.Title;
    Printer.BeginDoc;
    try
      for I := 1 to Pdf.PageCount do
      begin
        if I &gt; 1 then
          Printer.NewPage;
          
        Pdf.PageNumber := I;
        
        // Render page to printer
        Bitmap := Pdf.RenderPage(
          0, 0, 
          Printer.PageWidth, 
          Printer.PageHeight, 
          ro0, 
          [rePrinting]
        );
        try
          PrintBitmap(Printer, Bitmap);
        finally
          Bitmap.Free;
        end;
      end;
    finally
      Printer.EndDoc;
    end;
    
  finally
    Pdf.Active := False;
    Pdf.Free;
  end;
end;

procedure PrintPdfSimple(const FileName: string);

var

Pdf: TPdf;

I: Integer;

Bitmap: TBitmap;

begin

Pdf := TPdf.Create(nil);

try

Pdf.FileName := FileName;

Pdf.Active := True;

Printer.Title := Pdf.Title;

Printer.BeginDoc;

try

for I := 1 to Pdf.PageCount do

begin

if I > 1 then

Printer.NewPage;

Pdf.PageNumber := I;

// Render page to printer

Bitmap := Pdf.RenderPage(

0, 0,

Printer.PageWidth,

Printer.PageHeight,

ro0,

[rePrinting]

);

try

PrintBitmap(Printer, Bitmap);

finally

Bitmap.Free;

end;

finally

Printer.EndDoc;

end;

finally

Pdf.Active := False;

Pdf.Free;

end;

Printing Bitmap to Printer

procedure PrintBitmap(Printer: TPrinter; Bitmap: TBitmap);
var
  InfoHeaderSize, ImageSize: DWORD;
  InfoHeader: PBitmapInfo;
  Image: Pointer;
begin
  GetDIBSizes(Bitmap.Handle, InfoHeaderSize, ImageSize);
  
  InfoHeader := AllocMem(InfoHeaderSize);
  try
    Image := AllocMem(ImageSize);
    try
      GetDIB(Bitmap.Handle, 0, InfoHeader^, Image^);
      
      StretchDIBits(
        Printer.Canvas.Handle,
        0, 0, Bitmap.Width, Bitmap.Height,
        0, 0, Bitmap.Width, Bitmap.Height,
        Image, InfoHeader^,
        DIB_RGB_COLORS, SRCCOPY
      );
    finally
      FreeMem(Image);
    end;
  finally
    FreeMem(InfoHeader);
  end;
end;

procedure PrintBitmap(Printer: TPrinter; Bitmap: TBitmap);

var

InfoHeaderSize, ImageSize: DWORD;

InfoHeader: PBitmapInfo;

Image: Pointer;

begin

GetDIBSizes(Bitmap.Handle, InfoHeaderSize, ImageSize);

InfoHeader := AllocMem(InfoHeaderSize);

try

Image := AllocMem(ImageSize);

try

GetDIB(Bitmap.Handle, 0, InfoHeader^, Image^);

StretchDIBits(

Printer.Canvas.Handle,

0, 0, Bitmap.Width, Bitmap.Height,

Image, InfoHeader^,

DIB_RGB_COLORS, SRCCOPY

);

finally

FreeMem(Image);

end;

finally

FreeMem(InfoHeader);

end;

Complete Printing with Options

procedure TFormMain.PrintPDFPages;
var
  FromPage, ToPage, Page, Copy, CopyCount: Integer;
  FirstPage: Boolean;
  Bitmap: TBitmap;
  ScaleX, ScaleY, Scale: Double;
  DestWidth, DestHeight: Integer;
  Dpi: Integer;
begin
  // Get print quality DPI
  case cmbQuality.ItemIndex of
    0: Dpi := 150;  // Draft
    1: Dpi := 300;  // Normal
    2: Dpi := 600;  // High
  else
    Dpi := 300;
  end;
  
  // Determine page range
  if radAllPages.Checked then
  begin
    FromPage := 1;
    ToPage := Pdf.PageCount;
  end
  else
  begin
    FromPage := StrToIntDef(edtFromPage.Text, 1);
    ToPage := StrToIntDef(edtToPage.Text, Pdf.PageCount);
  end;
  
  // Handle copies and collation
  if chkCollate.Checked then
    CopyCount := 1  // Will repeat entire job
  else
    CopyCount := spnCopies.Value;
    
  FProcessing := True;
  FCancelled := False;
  
  Printer.Title := ExtractFileName(Pdf.FileName);
  Printer.BeginDoc;
  try
    FirstPage := True;
    progressPrint.Max := (ToPage - FromPage + 1) * spnCopies.Value;
    progressPrint.Position := 0;
    
    for Page := FromPage to ToPage do
    begin
      for Copy := 1 to CopyCount do
      begin
        if FCancelled then
          Break;
          
        if FirstPage then
          FirstPage := False
        else
          Printer.NewPage;
          
        Pdf.PageNumber := Page;
        
        // Calculate scaling based on settings
        case cmbScaling.ItemIndex of
          0: // No scaling
          begin
            DestWidth := Round(Pdf.PageWidth * Dpi / 72);
            DestHeight := Round(Pdf.PageHeight * Dpi / 72);
          end;
          
          1: // Fit to page
          begin
            ScaleX := Printer.PageWidth / (Pdf.PageWidth * Dpi / 72);
            ScaleY := Printer.PageHeight / (Pdf.PageHeight * Dpi / 72);
            Scale := Min(ScaleX, ScaleY);
            DestWidth := Round(Pdf.PageWidth * Dpi / 72 * Scale);
            DestHeight := Round(Pdf.PageHeight * Dpi / 72 * Scale);
          end;
          
          2: // Shrink to fit (only if needed)
          begin
            ScaleX := Printer.PageWidth / (Pdf.PageWidth * Dpi / 72);
            ScaleY := Printer.PageHeight / (Pdf.PageHeight * Dpi / 72);
            Scale := Min(ScaleX, ScaleY);
            if Scale &gt; 1 then Scale := 1;
            DestWidth := Round(Pdf.PageWidth * Dpi / 72 * Scale);
            DestHeight := Round(Pdf.PageHeight * Dpi / 72 * Scale);
          end;
        end;
        
        // Render and print
        Bitmap := Pdf.RenderPage(0, 0, DestWidth, DestHeight,
          ro0, [rePrinting, reAnnotations]);
        try
          PrintBitmap(Printer, Bitmap);
        finally
          Bitmap.Free;
        end;
        
        progressPrint.Position := progressPrint.Position + 1;
        Application.ProcessMessages;
      end;
      
      if FCancelled then
        Break;
    end;
    
  finally
    Printer.EndDoc;
    FProcessing := False;
  end;
end;

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procedure TFormMain.PrintPDFPages;

var

FromPage, ToPage, Page, Copy, CopyCount: Integer;

FirstPage: Boolean;

Bitmap: TBitmap;

ScaleX, ScaleY, Scale: Double;

DestWidth, DestHeight: Integer;

Dpi: Integer;

begin

// Get print quality DPI

case cmbQuality.ItemIndex of

0: Dpi := 150; // Draft

1: Dpi := 300; // Normal

2: Dpi := 600; // High

else

Dpi := 300;

end;

// Determine page range

if radAllPages.Checked then

begin

FromPage := 1;

ToPage := Pdf.PageCount;

end

else

begin

FromPage := StrToIntDef(edtFromPage.Text, 1);

ToPage := StrToIntDef(edtToPage.Text, Pdf.PageCount);

end;

// Handle copies and collation

if chkCollate.Checked then

CopyCount := 1 // Will repeat entire job

else

CopyCount := spnCopies.Value;

FProcessing := True;

FCancelled := False;

Printer.Title := ExtractFileName(Pdf.FileName);

Printer.BeginDoc;

try

FirstPage := True;

progressPrint.Max := (ToPage - FromPage + 1) * spnCopies.Value;

progressPrint.Position := 0;

for Page := FromPage to ToPage do

begin

for Copy := 1 to CopyCount do

begin

if FCancelled then

Break;

if FirstPage then

FirstPage := False

else

Printer.NewPage;

Pdf.PageNumber := Page;

// Calculate scaling based on settings

case cmbScaling.ItemIndex of

0: // No scaling

begin

DestWidth := Round(Pdf.PageWidth * Dpi / 72);

DestHeight := Round(Pdf.PageHeight * Dpi / 72);

end;

1: // Fit to page

begin

ScaleX := Printer.PageWidth / (Pdf.PageWidth * Dpi / 72);

ScaleY := Printer.PageHeight / (Pdf.PageHeight * Dpi / 72);

Scale := Min(ScaleX, ScaleY);

DestWidth := Round(Pdf.PageWidth * Dpi / 72 * Scale);

DestHeight := Round(Pdf.PageHeight * Dpi / 72 * Scale);

end;

2: // Shrink to fit (only if needed)

begin

ScaleX := Printer.PageWidth / (Pdf.PageWidth * Dpi / 72);

ScaleY := Printer.PageHeight / (Pdf.PageHeight * Dpi / 72);

Scale := Min(ScaleX, ScaleY);

if Scale > 1 then Scale := 1;

DestWidth := Round(Pdf.PageWidth * Dpi / 72 * Scale);

DestHeight := Round(Pdf.PageHeight * Dpi / 72 * Scale);

end;

// Render and print

Bitmap := Pdf.RenderPage(0, 0, DestWidth, DestHeight,

ro0, [rePrinting, reAnnotations]);

try

PrintBitmap(Printer, Bitmap);

finally

Bitmap.Free;

end;

progressPrint.Position := progressPrint.Position + 1;

Application.ProcessMessages;

end;

if FCancelled then

Break;

end;

finally

Printer.EndDoc;

FProcessing := False;

end;

Using Print Dialog

procedure TFormMain.btnPrintClick(Sender: TObject);
begin
  if not FileExists(edtPdfFile.Text) then
  begin
    ShowError('Please select a valid PDF file first.');
    Exit;
  end;
  
  // Setup print dialog
  PrintDialog.MinPage := 1;
  PrintDialog.MaxPage := Pdf.PageCount;
  PrintDialog.FromPage := 1;
  PrintDialog.ToPage := Pdf.PageCount;
  PrintDialog.Options := [poPageNums, poSelection];
  
  if PrintDialog.Execute then
  begin
    PrintPDFPages;
  end;
end;

procedure TFormMain.btnPrintClick(Sender: TObject);

begin

if not FileExists(edtPdfFile.Text) then

begin

ShowError('Please select a valid PDF file first.');

Exit;

end;

// Setup print dialog

PrintDialog.MinPage := 1;

PrintDialog.MaxPage := Pdf.PageCount;

PrintDialog.FromPage := 1;

PrintDialog.ToPage := Pdf.PageCount;

PrintDialog.Options := [poPageNums, poSelection];

if PrintDialog.Execute then

begin

PrintPDFPages;

end;

Print Preview

procedure TFormMain.UpdatePreview;
var
  PreviewWidth, PreviewHeight: Integer;
  Scale: Double;
begin
  if not Pdf.Active then
    Exit;
    
  Pdf.PageNumber := FCurrentPreviewPage;
  
  // Calculate preview size to fit panel
  Scale := Min(
    pnlPreview.Width / Pdf.PageWidth,
    pnlPreview.Height / Pdf.PageHeight
  ) * (FCurrentZoom / 100);
  
  PreviewWidth := Round(Pdf.PageWidth * Scale);
  PreviewHeight := Round(Pdf.PageHeight * Scale);
  
  // Render preview
  FPreviewBitmap.Free;
  FPreviewBitmap := Pdf.RenderPage(
    0, 0, PreviewWidth, PreviewHeight,
    ro0, [reAnnotations], clWhite
  );
  
  // Display in image control
  imgPreview.Picture.Assign(FPreviewBitmap);
  
  // Update page info
  lblPageInfo.Caption := Format('Page %d of %d',
    [FCurrentPreviewPage, Pdf.PageCount]);
end;

procedure TFormMain.UpdatePreview;

var

PreviewWidth, PreviewHeight: Integer;

Scale: Double;

begin

if not Pdf.Active then

Exit;

Pdf.PageNumber := FCurrentPreviewPage;

// Calculate preview size to fit panel

Scale := Min(

pnlPreview.Width / Pdf.PageWidth,

pnlPreview.Height / Pdf.PageHeight

) * (FCurrentZoom / 100);

PreviewWidth := Round(Pdf.PageWidth * Scale);

PreviewHeight := Round(Pdf.PageHeight * Scale);

// Render preview

FPreviewBitmap.Free;

FPreviewBitmap := Pdf.RenderPage(

0, 0, PreviewWidth, PreviewHeight,

ro0, [reAnnotations], clWhite

);

// Display in image control

imgPreview.Picture.Assign(FPreviewBitmap);

// Update page info

lblPageInfo.Caption := Format('Page %d of %d',

[FCurrentPreviewPage, Pdf.PageCount]);

end;

Preview Navigation

procedure TFormMain.btnFirstPageClick(Sender: TObject);
begin
  if Pdf.Active then
  begin
    FCurrentPreviewPage := 1;
    edtPreviewPage.Text := '1';
    UpdatePreview;
  end;
end;

procedure TFormMain.btnPrevPageClick(Sender: TObject);
begin
  if Pdf.Active and (FCurrentPreviewPage &gt; 1) then
  begin
    Dec(FCurrentPreviewPage);
    edtPreviewPage.Text := IntToStr(FCurrentPreviewPage);
    UpdatePreview;
  end;
end;

procedure TFormMain.btnNextPageClick(Sender: TObject);
begin
  if Pdf.Active and (FCurrentPreviewPage &lt; Pdf.PageCount) then
  begin
    Inc(FCurrentPreviewPage);
    edtPreviewPage.Text := IntToStr(FCurrentPreviewPage);
    UpdatePreview;
  end;
end;

procedure TFormMain.btnLastPageClick(Sender: TObject);
begin
  if Pdf.Active then
  begin
    FCurrentPreviewPage := Pdf.PageCount;
    edtPreviewPage.Text := IntToStr(FCurrentPreviewPage);
    UpdatePreview;
  end;
end;

procedure TFormMain.btnFirstPageClick(Sender: TObject);

begin

if Pdf.Active then

begin

FCurrentPreviewPage := 1;

edtPreviewPage.Text := '1';

UpdatePreview;

end;

procedure TFormMain.btnPrevPageClick(Sender: TObject);

begin

if Pdf.Active and (FCurrentPreviewPage > 1) then

begin

Dec(FCurrentPreviewPage);

edtPreviewPage.Text := IntToStr(FCurrentPreviewPage);

UpdatePreview;

end;

procedure TFormMain.btnNextPageClick(Sender: TObject);

begin

if Pdf.Active and (FCurrentPreviewPage < Pdf.PageCount) then

begin

Inc(FCurrentPreviewPage);

edtPreviewPage.Text := IntToStr(FCurrentPreviewPage);

UpdatePreview;

end;

procedure TFormMain.btnLastPageClick(Sender: TObject);

begin

if Pdf.Active then

begin

FCurrentPreviewPage := Pdf.PageCount;

edtPreviewPage.Text := IntToStr(FCurrentPreviewPage);

UpdatePreview;

end;

Zoom Control

procedure TFormMain.cmbZoomChange(Sender: TObject);
begin
  case cmbZoom.ItemIndex of
    0: FCurrentZoom := 50;
    1: FCurrentZoom := 75;
    2: FCurrentZoom := 100;
    3: FCurrentZoom := 125;
    4: FCurrentZoom := 150;
    5: FCurrentZoom := 200;
  else
    FCurrentZoom := 100;
  end;
  
  UpdatePreview;
end;

procedure TFormMain.cmbZoomChange(Sender: TObject);

begin

case cmbZoom.ItemIndex of

0: FCurrentZoom := 50;

1: FCurrentZoom := 75;

2: FCurrentZoom := 100;

3: FCurrentZoom := 125;

4: FCurrentZoom := 150;

5: FCurrentZoom := 200;

else

FCurrentZoom := 100;

end;

UpdatePreview;

end;

Handling Page Rotation

function GetPrintRotation(Rotation: TRotation): TRotation;
begin
  // Adjust rotation for printing (printer coordinate system)
  case Rotation of
    ro90:  Result := ro270;
    ro270: Result := ro90;
  else
    Result := Rotation;
  end;
end;

// Use in printing
Bitmap := Pdf.RenderPage(0, 0, Width, Height,
  GetPrintRotation(Pdf.PageRotation), [rePrinting]);

function GetPrintRotation(Rotation: TRotation): TRotation;

begin

// Adjust rotation for printing (printer coordinate system)

case Rotation of

ro90: Result := ro270;

ro270: Result := ro90;

else

Result := Rotation;

end;

// Use in printing

Bitmap := Pdf.RenderPage(0, 0, Width, Height,

GetPrintRotation(Pdf.PageRotation), [rePrinting]);

Save/Load Settings

procedure TFormMain.SaveSettings;
var
  Ini: TIniFile;
begin
  Ini := TIniFile.Create(FSettingsFile);
  try
    Ini.WriteInteger('Print', 'Quality', cmbQuality.ItemIndex);
    Ini.WriteInteger('Print', 'Scaling', cmbScaling.ItemIndex);
    Ini.WriteInteger('Print', 'Copies', spnCopies.Value);
    Ini.WriteBool('Print', 'Collate', chkCollate.Checked);
    Ini.WriteInteger('Preview', 'Zoom', FCurrentZoom);
  finally
    Ini.Free;
  end;
end;

procedure TFormMain.LoadSettings;
var
  Ini: TIniFile;
begin
  if FileExists(FSettingsFile) then
  begin
    Ini := TIniFile.Create(FSettingsFile);
    try
      cmbQuality.ItemIndex := Ini.ReadInteger('Print', 'Quality', 1);
      cmbScaling.ItemIndex := Ini.ReadInteger('Print', 'Scaling', 1);
      spnCopies.Value := Ini.ReadInteger('Print', 'Copies', 1);
      chkCollate.Checked := Ini.ReadBool('Print', 'Collate', False);
      FCurrentZoom := Ini.ReadInteger('Preview', 'Zoom', 100);
    finally
      Ini.Free;
    end;
  end;
end;

procedure TFormMain.SaveSettings;

var

Ini: TIniFile;

begin

Ini := TIniFile.Create(FSettingsFile);

try

Ini.WriteInteger('Print', 'Quality', cmbQuality.ItemIndex);

Ini.WriteInteger('Print', 'Scaling', cmbScaling.ItemIndex);

Ini.WriteInteger('Print', 'Copies', spnCopies.Value);

Ini.WriteBool('Print', 'Collate', chkCollate.Checked);

Ini.WriteInteger('Preview', 'Zoom', FCurrentZoom);

finally

Ini.Free;

end;

procedure TFormMain.LoadSettings;

var

Ini: TIniFile;

begin

if FileExists(FSettingsFile) then

begin

Ini := TIniFile.Create(FSettingsFile);

try

cmbQuality.ItemIndex := Ini.ReadInteger('Print', 'Quality', 1);

cmbScaling.ItemIndex := Ini.ReadInteger('Print', 'Scaling', 1);

spnCopies.Value := Ini.ReadInteger('Print', 'Copies', 1);

chkCollate.Checked := Ini.ReadBool('Print', 'Collate', False);

FCurrentZoom := Ini.ReadInteger('Preview', 'Zoom', 100);

finally

Ini.Free;

end;

Use Cases

Document Printing – High-quality printing of PDF documents
Batch Printing – Print multiple documents in sequence
Report Distribution – Print reports for distribution
Proof Printing – Print proofs before final production

Conclusion

The Print PDF demo shows how to implement professional PDF printing with PDFium VCL. From simple single-page printing to advanced multi-copy jobs with preview and quality settings, the component provides everything you need.

The RenderPage method with the rePrinting option ensures optimal output for printers, while the preview functionality lets users verify their settings before printing.

Add professional PDF printing to your applications with PDFium Delphi Component.