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Programerski primeri PDFium VCL

Osnovne operacije z dokumenti

Nalaganje in prikaz dokumenta PDF

Pdf1.FileName := 'C:\MyDocument.pdf';
Pdf1.Active := True;
ShowMessage('Pages: ' + IntToStr(Pdf1.PageCount));
ShowMessage('Title: ' + Pdf1.Title);
ShowMessage('Author: ' + Pdf1.Author);

var
  Stream: TMemoryStream;
begin
  Stream := TMemoryStream.Create;
  try
    Stream.LoadFromFile('C:\MyDocument.pdf');
    Pdf1.LoadDocument(Stream, True);
    Pdf1.Active := True;
    ShowMessage('PDF loaded from stream');
  finally
    Stream.Free;
  end;
end;

Ustvarjanje novega dokumenta PDF

Pdf1.CreateDocument;
Pdf1.Active := True;
Pdf1.AddPage(0, 612, 792);
Pdf1.PageNumber := 1;
Pdf1.AddText('Hello World!', 'Arial', 12, 100, 700, clBlack, $FF, 0.0);
Pdf1.UpdatePage;
Pdf1.SaveAs('C:\NewDocument.pdf');
Pdf1.Active := False;

Operacije z besedilom

Izvlek besedila iz PDF

var
  PageText: WString;
  RectText: WString;
begin
  Pdf1.PageNumber := 1;
  PageText := Pdf1.Text;
  Memo1.Text := PageText;
  RectText := Pdf1.TextInRectangle(100, 100, 500, 200);
  ShowMessage('Text in rectangle: ' + RectText);
end;

Iskanje besedila

var
  Position: Integer;
begin
  Position := Pdf1.FindFirst('Hello', [seCaseSensitive]);
  while Position >= 0 do
  begin
    ShowMessage('Found at character: ' + IntToStr(Position));
    Position := Pdf1.FindNext;
  end;
end;

Dodajanje besedila z oblikovanjem

Pdf1.PageNumber := 1;
Pdf1.AddText('Document Title', 'Times New Roman', 16, 100, 750, clBlue);
Pdf1.AddText('This is the document content.', 'Arial', 12, 100, 700, clBlack);
Pdf1.UpdatePage;

Pregled metapodatkov znakov in pisav

var
  I: Integer;
  MetricSize: Single;
  FontBytes: TBytes;
begin
  Pdf1.PageNumber := 1;
  for I := 0 to Pdf1.ObjectCount - 1 do
    if Pdf1.ObjectType[I] = otText then
    begin
      MetricSize := 12.0;
      FontBytes := Pdf1.FontData[I];
      Memo1.Lines.Add('Object ' + IntToStr(I));
      Memo1.Lines.Add('Base name: ' + Pdf1.FontBaseName[I]);
      Memo1.Lines.Add('Family: ' + Pdf1.FontFamilyName[I]);
      Memo1.Lines.Add('Embedded: ' + BoolToStr(Pdf1.FontIsEmbedded[I], True));
      Memo1.Lines.Add('Weight: ' + IntToStr(Pdf1.FontWeight[I]));
      Memo1.Lines.Add('Italic angle: ' + IntToStr(Pdf1.FontItalicAngle[I]));
      Memo1.Lines.Add('Ascent: ' + FloatToStr(Pdf1.FontAscent[I, MetricSize]));
      Memo1.Lines.Add('Descent: ' + FloatToStr(Pdf1.FontDescent[I, MetricSize]));
      Memo1.Lines.Add('Font data bytes: ' + IntToStr(Length(FontBytes)));
    end;

  if Pdf1.CharacterCount > 0 then
  begin
    Memo1.Lines.Add('First character size: ' + FloatToStr(Pdf1.CharacterFontSize[0]));
    Memo1.Lines.Add('First character weight: ' + IntToStr(Pdf1.CharacterFontWeight[0]));
    Memo1.Lines.Add('First character angle: ' + FloatToStr(Pdf1.CharacterAngle[0]));
  end;
end;

Projekti Demo\Delphi\FontProperties, Demo\CBuilder\FontProperties in Demo\Lazarus\FontProperties prikazujejo iste metapodatke prek TPdf in TPdfView

Ustvarjanje večkategornega poročila o izvleku vsebine

Projekti Demo\Delphi\ContentExtractionLab, Demo\CBuilder\ContentExtractionLab in Demo\Lazarus\ContentExtractionLab pretvorijo izvlek vsebine v enoten potek dela. Odprejo ali ustvarijo PDF, uporabnikom omogočijo izbiro metapodatkov, besedila strani, objektov strani, slik, prilog, povezav, opomb, zaznamkov ter metrik pisave / znakov, nato pa ustvarijo povzetek in podrobno poročilo TXT ali JSON. Laboratorij vključuje tudi izbiro kategorij vse ali nič, kopiranje poročila v odložišče in shranjevanje izvornega PDF, tako da lahko uporabniki ustvarjeni vzorčni PDF obdržijo poleg poročila o izvleku. Starejši prikazi ExtractText, ExtractImages, Attachment in FontProperties ostajajo osredotočeni primeri; ExtractText podpira možnosti obsega strani in ločil strani za izdelavo izhoda besedila po posameznih straneh v Delphi, C++Builder in Lazarus, medtem ko je ContentExtractionLab prečni vzorčni primer inventarja

Operacije z obrazci

Delo z obrazčnimi polji

var
  I: Integer;
  FieldInfo: TPdfFormFieldInfo;
begin
  Pdf1.FormField[0] := 'John';
  for I := 0 to Pdf1.FormFieldCount - 1 do
  begin
    FieldInfo := Pdf1.FormFieldInfo[I];
    ShowMessage(FieldInfo.Name + ': ' + Pdf1.FormField[I]);
  end;
end;

Zravnanje izpolnjenih vrednosti obrazca na stran

// Without flattening, FormField[i] := value writes only the /V entry —
// the visible appearance comes from the /AP stream and may not refresh
// GenerateFormAppearances regenerates /AP for every widget, then
// FlattenAllPages bakes every page's annotations and widgets into
// permanent, non-editable content
Pdf1.FileName := 'C:\Application.pdf';
Pdf1.Active := True;
Pdf1.FormField[0] := 'John Smith';
Pdf1.FormField[1] := 'john@example.com';
Pdf1.GenerateFormAppearances;
if Pdf1.FlattenAllPages then
  Pdf1.SaveAs('C:\Application.flat.pdf');
Pdf1.Active := False;

Operacije s slikami

Izvlek slik

var
  I: Integer;
  Bitmap: TBitmap;
begin
  for I := 0 to Pdf1.BitmapCount - 1 do
  begin
    Bitmap := Pdf1.Bitmap[I];
    try
      Bitmap.SaveToFile('C:\ExtractedImage' + IntToStr(I) + '.bmp');
    finally
      Bitmap.Free;
    end;
  end;
end;

Dodajanje slik

var
  JpegStream: TFileStream;
begin
  JpegStream := TFileStream.Create('C:\MyImage.jpg', fmOpenRead or fmShareDenyWrite);
  try
    Pdf1.AddJpegImage(JpegStream, 100, 500, 200, 150);
  finally
    JpegStream.Free;
  end;
  Pdf1.AddPicture(Image1.Picture, 100, 300, 150, 100);
  Pdf1.UpdatePage;
end;

Operacije z opombami

Delo z opombami

var
  I: Integer;
  Annotation: TPdfAnnotation;
begin
  for I := 0 to Pdf1.AnnotationCount - 1 do
  begin
    Annotation := Pdf1.Annotation[I];
    ShowMessage('Annotation ' + IntToStr(I) + ': ' + Annotation.ContentsText);
  end;
end;

Operacije risanja

Risanje oblik

Pdf1.CreatePath(100, 100, 200, 150, fmAlternate, clYellow, $FF, True, clBlack, $FF, 2.0);
Pdf1.AddPath;

Pdf1.CreatePath(100, 100, fmNone, clBlack, $FF, True, clRed, $FF, 3.0);
Pdf1.LineTo(200, 100);
Pdf1.LineTo(150, 200);
Pdf1.ClosePath;
Pdf1.AddPath;
Pdf1.UpdatePage;

Krmarjenje in zaznamki

Delo z zaznamki

var
  I: Integer;
  Bookmarks: TBookmarks;
begin
  Bookmarks := Pdf1.Bookmarks;
  for I := 0 to Length(Bookmarks) - 1 do
    ShowMessage(Bookmarks[I].Title + ' -> Page ' + IntToStr(Bookmarks[I].PageNumber));
end;

Delo s poimenovanimi cilji

var
  I: Integer;
  Destination: TDestination;
begin
  for I := 0 to Pdf1.DestinationCount - 1 do
  begin
    Destination := Pdf1.Destination[I];
    if Destination.Name = 'Chapter1' then
    begin
      Pdf1.PageNumber := Destination.PageNumber;
      Break;
    end;
  end;
end;

Operacije s prilogami

Delo s prilogami

var
  I: Integer;
  AttachmentData: TBytes;
  AttachmentName: WString;
  FileStream: TFileStream;
begin
  for I := 0 to Pdf1.AttachmentCount - 1 do
  begin
    AttachmentName := Pdf1.AttachmentName[I];
    AttachmentData := Pdf1.Attachment[I];
    FileStream := TFileStream.Create('C:\Extracted_' + string(AttachmentName), fmCreate);
    try
      if Length(AttachmentData) > 0 then
        FileStream.WriteBuffer(AttachmentData[0], Length(AttachmentData));
    finally
      FileStream.Free;
    end;
  end;
  if Pdf1.CreateAttachment('MyFile.txt') then
    Pdf1.Attachment[Pdf1.AttachmentCount - 1] := TFile.ReadAllBytes('C:\MyFile.txt');
end;

Upravljanje strani

Operacije strani

Pdf1.AddPage(Pdf1.PageCount + 1, 612, 792);
Pdf1.AddPage(Pdf1.PageCount + 1, 595, 842);
Pdf1.AddPage(Pdf1.PageCount + 1, 400, 600);

var
  SourcePdf: TPdf;
begin
  SourcePdf := TPdf.Create(nil);
  try
    SourcePdf.FileName := 'C:\SourceDocument.pdf';
    SourcePdf.Active := True;
    Pdf1.ImportPages(SourcePdf, '1', Pdf1.PageCount + 1);
  finally
    SourcePdf.Free;
  end;
end;

if Pdf1.PageCount > 1 then
  Pdf1.DeletePage(Pdf1.PageCount);

Shranjevanje in stiskanje

Shranjevanje s stiskanjem

// Create a compressed PDF document
Pdf1.CreateDocument;
Pdf1.Compressed := True; // ensure all streams are FlateDecode compressed (default)
Pdf1.Active := True;
Pdf1.AddPage(0, 595, 842); // A4 size
Pdf1.AddText('Hello World!', 'Arial', 24, 100, 700, clBlack, $FF, 0.0);
Pdf1.SaveAs('C:\Compressed.pdf');
Pdf1.Active := False;

// Save with options
Pdf1.SaveAs('C:\Output.pdf', saIncremental); // incremental save
Pdf1.SaveAs('C:\NoSecurity.pdf', saRemoveSecurity); // remove security

// Save to a specific PDF version target. The PDF version validator rejects
// any feature introduced after the chosen target (JBIG2Decode, MarkInfo,
// AES encryption, Polygon / Caret / Watermark / Redact annotations, ...)
if not Pdf1.SaveAs('C:\Legacy15.pdf', saNone, pv15) then
  ShowMessage('Save rejected: document contains features newer than PDF 1.5');

Ustvarjanje arhivskega izhoda PDF/A-1b

// SaveAsPdfA post-processes the base save with an incremental update that
// injects an XMP metadata stream, an sRGB ICC OutputIntent, and an updated
// document catalog so the result is PDF/A-1b conformant. The bundled
// sRGB IEC61966-2.1 profile is used automatically when no custom profile
// is supplied
Pdf1.FileName := 'C:\Report.pdf';
Pdf1.Active := True;
if Pdf1.SaveAsPdfA('C:\Report.pdfa.pdf', pac1b) then
  ShowMessage('Saved PDF/A-1b archive');

// PDF/A with a custom ICC profile (CMYK printing pipelines for example)
var
  Opts: TPdfASaveOptions;
begin
  Opts := Default(TPdfASaveOptions);
  Opts.Conformance    := pac1b;
  Opts.IccProfileData := TFile.ReadAllBytes('C:\Profiles\Coated_GRACoL_2006.icc');
  Pdf1.SaveAsPdfA('C:\Report.cmyk.pdfa.pdf', Opts);
end;

// In-memory PDF/A output
var
  Stream: TMemoryStream;
begin
  Stream := TMemoryStream.Create;
  try
    Opts := Default(TPdfASaveOptions);
    Opts.Conformance := pac1b;
    if Pdf1.SaveAsPdfAToStream(Stream, Opts) then
      UploadToArchive(Stream);
  finally
    Stream.Free;
  end;
end;

Preverjanje skladnosti PDF/A

var
  Validation: TPdfAValidationResult;
  Issue: TPdfAValidationIssue;
begin
  Pdf1.FileName := 'C:\Incoming\report.pdf';
  Pdf1.Active   := True;

  // Cheap header-style probe — reads the conformance without iterating
  // the full validator. Result: pacNone, pac1a, pac1b, pac2b, pac3b, or
  // pacUnknown
  case Pdf1.PdfAConformance of
    pac1b: Status.Caption := 'PDF/A-1b';
    pac2b: Status.Caption := 'PDF/A-2b';
    pacNone: Status.Caption := 'Not PDF/A';
  else
    Status.Caption := 'Unknown conformance';
  end;

  // Full validator with per-issue diagnostics
  Validation := Pdf1.ValidatePdfA;
  Memo1.Lines.Add('Conformance: ' + GetEnumName(TypeInfo(TPdfAConformance),
    Ord(Validation.Conformance)));
  for Issue in Validation.Issues do
    Memo1.Lines.Add('- ' + Issue.Description);
end;

Pregled več standardov PDF v StandardsLab

Projekti Demo\Delphi\StandardsLab, Demo\CBuilder\StandardsLab in Demo\Lazarus\StandardsLab naložijo ali ustvarijo PDF, zaženejo ValidatePdfA, ValidatePdfUa, ValidatePdfE, ValidatePdfX, ValidatePdfR in ValidatePdfVT, nato pa v eni mreži prikažejo vsako zaznano raven skladnosti in število težav. Gumbi za shranjevanje kličejo SaveAsPdfA, SaveAsPdfUa, SaveAsPdfE, SaveAsPdfX, SaveAsPdfR in SaveAsPdfVT, tako da je potek dela z izhodnimi oznakami viden brez pisanja lastnega ogrodja

Ustvarjanje poročil predhodnega pregleda

Enota FPdfPreflightReport ovije ValidatePdfA, ValidatePdfUa, ValidatePdfE, ValidatePdfX, ValidatePdfR in ValidatePdfVT v en sam objekt poročila. Demo\Delphi\PreflightReport, Demo\Lazarus\PreflightReport in Demo\CBuilder\PreflightReport uporabnikom omogočajo izbiro standardov, ustvarjanje povzetka, pregled stanja, prioritete, kategorij težav, števil kategorij, naslednjih dejanj, kod težav in priporočenih dejanj, preklapljanje predogleda med besedilom, Markdown, JSON in CSV ter izvoz poročil TXT, HTML, Markdown, JSON ali CSV. Vzorčni program Delphi GUI doda tudi predogled Action Plan, ki neustrezne standarde, prioritete, kode težav in priporočila strne v kontrolni seznam za odpravo. Demo\Delphi\PreflightReportCli izpostavi isto pot poročila kot konzolni potek dela z vhodnimi / izhodnimi argumenti, neobveznim geslom, izbiro izhodne oblike, vključno z plan / actionplan, filtriranjem standardov, neobveznim vdelovanjem poročila z eno datoteko attach=output.pdf, kode za izhod CI failon=, obdelavo batch=list.txt, pregledovanje imenika batchdir=folder z neobvezno rekurzijo in stabilno obdelavo po razvrščeni poti, usmerjanje poročil outdir=reports, imena poročil, varna pred trki pri podvojenih vhodnih imenih datotek, povzetke TXT / JSON / HTML s skupnimi in standardnimi statusnimi vsotami, manifeste vrstic CSV s ponovljenimi nastavitvami izvajanja za vsak element in vzorčni način brez argumentov za skripte in opravila CI. Ustvarjeno poročilo pove, da vgrajeni preverjalniki pokrivajo preverjanja na ravni markerjev in izbranih datotek, tako da lahko celoten predhodni pregled vsebine še vedno prepustite namenski validacijski napravi

Tokovno nalaganje in veliki dokumenti

Nalaganje PDF na zahtevo z LoadCustomDocument

// LoadCustomDocument lets PDFium pull blocks from any seekable TStream on
// demand. The stream is NOT copied into memory, so multi-GB PDFs, remote
// HTTP body streams, and database-backed sources are all viable without
// an up-front buffer
var
  FileStream: TFileStream;
begin
  // Read-from-file streaming (no in-memory copy)
  FileStream := TFileStream.Create('C:\Huge.pdf',
    fmOpenRead or fmShareDenyWrite);
  Pdf1.LoadCustomDocument(FileStream, True{AOwnsStream});
  // ^^ ownership transferred — Pdf1 frees FileStream on UnloadDocument
  Pdf1.Active := True;
  ShowMessage('Pages: ' + IntToStr(Pdf1.PageCount));
end;

// Externally-owned stream (caller frees it after UnloadDocument)
var
  Stream: TFileStream;
begin
  Stream := TFileStream.Create('C:\Live.pdf',
    fmOpenRead or fmShareDenyNone);
  try
    Pdf1.LoadCustomDocument(Stream, False);
    Pdf1.Active := True;
    DoWork;
    Pdf1.Active := False;
  finally
    Stream.Free;
  end;
end;

Asinhrono preklicevanje in postopen izris

Sodelovalni žetoni za preklic

// FPdfAsync exposes IPdfCancellationToken /
// IPdfCancellationTokenSource for cancel-from-UI semantics that work
// across the long-running export and render paths
uses FPdfAsync;

var
  CancelSource: IPdfCancellationTokenSource;
  CancelToken:  IPdfCancellationToken;
begin
  CancelSource := PdfCancellationTokenSource;
  CancelToken  := CancelSource.Token;

  // ... user clicks Cancel
  CancelSource.Cancel;

  // The worker periodically checks CancelToken.IsCancelled, or the render
  // path polls it through PDFium's IFSDK_PAUSE callback
  if CancelToken.IsCancelled then
    Memo1.Lines.Add('Cancelled by user');
end;

Preklicevljiv postopen izris strani

// RenderPageProgressive lets a long high-DPI render abort mid-page when
// the user clicks Cancel, instead of blocking the caller until done
var
  Status: TPdfProgressiveStatus;
  Bitmap: TBitmap;
begin
  Bitmap := TBitmap.Create;
  try
    Bitmap.PixelFormat := pf32bit;
    Bitmap.SetSize(2480, 3508); // A4 @ 300 DPI

    Status := Pdf1.RenderPageProgressive(Bitmap, 0, 0, Bitmap.Width,
      Bitmap.Height, CancelToken, ro0, [reAnnotations], clWhite);

    case Status of
      prsDone:      SaveBitmap(Bitmap);
      prsCancelled: Memo1.Lines.Add('Render cancelled — partial result available');
      prsFailed:    Memo1.Lines.Add('PDFium reported FPDF_RENDER_FAILED');
    end;
  finally
    Bitmap.Free;
  end;
end;

Izrisi v ozadni niti s TPdfFuture

// TPdfFuture<T> spins up a worker on a background thread and posts a
// TPdfFutureResult<T> envelope back to the main thread
//
// Important: TPdf serializes render calls per instance, but the worker still
// owns dispatch and document lifetime. Do not mutate a TPdf while a render is
// in flight; batch export usually keeps one TPdf per file
type
  TRenderResult = record
    Bitmap : TBitmap;
    PageNo : Integer;
  end;

var
  Future: TPdfFuture<TRenderResult>;
begin
  Future := TPdfFuture<TRenderResult>.Create(
    function (const ACancelToken: IPdfCancellationToken): TRenderResult
    var
      LocalPdf: TPdf;
    begin
      LocalPdf := TPdf.Create(nil);
      try
        LocalPdf.FileName := 'C:\Huge.pdf';
        LocalPdf.Active   := True;
        LocalPdf.PageNumber := 1;
        Result.Bitmap := LocalPdf.RenderPage(0, 0, 2480, 3508);
        Result.PageNo := 1;
      finally
        LocalPdf.Free;
      end;
    end,
    procedure (const AResult: TPdfFutureResult<TRenderResult>)
    begin
      case AResult.State of
        pfsSuccess:   PaintBitmapToView(AResult.Value.Bitmap);
        pfsCancelled: Log.Add('Cancelled');
        pfsFailed:    Log.Add('Worker failed: ' + AResult.ErrorMessage);
      end;
    end);
end;

Transformacijske matrike

Sestavljanje Translate / Scale / Rotate / Skew

// FPdfMatrix wraps PDFium's FS_MATRIX so callers can build a transform
// declaratively and hand it to FPDFPageObj_SetMatrix
uses FPdfMatrix, FPdfView;

var
  M: TPdfMatrix;
  RawMatrix: FS_MATRIX;
  PageObj: FPDF_PAGEOBJECT;
begin
  M := TPdfMatrix.Create;
  try
    M.Translate(72, 200);       // move 1in right, ~2.8in up
    M.Scale(0.5, 0.5);          // half-size stamp
    M.Rotate(15);               // 15-degree CCW rotation
    // M.HorizontalFlip;
    // M.VerticalFlip;
    // M.CentralFlip;
    // M.Skew(10, 5);
    // M.Multiply(Other);       // post-multiply with another matrix

    // Apply to any PDFium page object (text / path / image / form XObject)
    RawMatrix := M.Handle;
    FPDFPageObj_SetMatrix(PageObj, RawMatrix);
  finally
    M.Free;
  end;
end;

Sestava strani

Uvoz podniza strani po indeksu

// ImportPagesByIndex copies an explicit zero-based index array from a
// source PDF into this document. InsertAt = 0 inserts before page 1;
// PageCount appends
var
  Source: TPdf;
begin
  Source := TPdf.Create(nil);
  try
    Source.FileName := 'C:\Report.pdf';
    Source.Active   := True;

    // Import pages 0, 2, 4 (one-based: pages 1, 3, 5) from Source
    // and append them at the end of Pdf1
    Pdf1.ImportPagesByIndex(Source, [0, 2, 4], Pdf1.PageCount);

    // Empty array imports every source page
    // Pdf1.ImportPagesByIndex(Source, [], 0);
  finally
    Source.Free;
  end;
end;

Kombinirani izhod N-up

// ImportNPagesToOne returns a brand-new TPdf whose pages are NumX*NumY
// composites of THIS document. OutputWidth/Height are PDF user units
// (1 unit = 1/72 in)
var
  Composite: TPdf;
begin
  Pdf1.FileName := 'C:\Slides.pdf';
  Pdf1.Active   := True;
  // 4-up A4 landscape: 842 x 595 pt, 2 columns x 2 rows
  Composite := Pdf1.ImportNPagesToOne(842, 595, 2, 2);
  try
    if Composite <> nil then
      Composite.SaveAs('C:\Slides_4up.pdf');
  finally
    Composite.Free;
  end;
end;

Preurejanje strani na mestu

// MovePages takes the zero-based indices of the pages to move plus the
// destination index for the first moved page after the move completes
// Other pages shift around the moved block so the document length stays
// the same
//
// Primer: in a 5-page document with pages numbered [0,1,2,3,4],
// MovePages([2, 3], 0) reorders to [2, 3, 0, 1, 4]
if not Pdf1.MovePages([2, 3], 0) then
  ShowMessage('Invalid indices passed to MovePages');

Dodajanje vodnega žiga prek ponovne uporabe strani Form XObject

// CreateXObjectFromPage manufactures a reusable Form XObject handle from
// any page of any other TPdf. Stamp that handle onto as many pages of
// THIS document as you want — each stamp is a single PDFium page object
// that can be positioned, scaled, and rotated through the matrix API
uses FPdfMatrix, FPdfView;

var
  WatermarkSource: TPdf;
  XObj:            TPdfXObject;
  PageObj:         FPDF_PAGEOBJECT;
  M:               TPdfMatrix;
  RawMatrix:       FS_MATRIX;
  I:               Integer;
begin
  WatermarkSource := TPdf.Create(nil);
  try
    WatermarkSource.FileName := 'C:\Watermarks\Confidential.pdf';
    WatermarkSource.Active   := True;

    // Wrap page 0 of WatermarkSource as a reusable XObject
    XObj := Pdf1.CreateXObjectFromPage(WatermarkSource, 0);
    try
      for I := 1 to Pdf1.PageCount do
      begin
        Pdf1.PageNumber := I;
        PageObj := Pdf1.InsertFormObjectFromXObject(XObj);
        if PageObj = nil then Continue;

        // Centre the watermark on the page
        M := TPdfMatrix.Create;
        try
          M.Scale(0.5, 0.5);
          M.Translate(0.25 * Pdf1.PageWidth, 0.5 * Pdf1.PageHeight);
          RawMatrix := M.Handle;
          FPDFPageObj_SetMatrix(PageObj, RawMatrix);
        finally
          M.Free;
        end;

        Pdf1.UpdatePage;
      end;
    finally
      XObj.Free; // closes the FPDF_XOBJECT handle
    end;

    Pdf1.SaveAs('C:\Watermarked.pdf');
  finally
    WatermarkSource.Free;
  end;
end;

Projekti Demo\Delphi\WatermarkStamp, Demo\Lazarus\WatermarkStamp in Demo\CBuilder\WatermarkStamp ta vzorec pretvorijo v zaganjljiv potek dela: ustvarijo ciljni PDF in ponovno uporaben PDF za žig, stran žiga ovijejo s CreateXObjectFromPage, isti Form XObject vstavijo na vsako ciljno stran, uporabijo transformacije TPdfMatrix za osredinjene vodne žige in žige v zgornjem desnem kotu ter pred shranjevanjem rezultata dodajo neobvezne oznake številk strani

Vstavljanje slik (neposredni preobremenitvi AddImage)

Dodajanje registrirane slikovne datoteke ali TBitmap

// AddImage(FileName) accepts any format registered with the VCL or LCL
// graphics units (BMP, PNG via PngImage, JPG, ...)
Pdf1.AddImage('C:\Photo.png', 100, 500, 200, 150);

// AddImage(TBitmap) skips the TPicture intermediary, ideal when the
// bitmap already comes from rendering or batch generation work
var
  Bitmap: TBitmap;
begin
  Bitmap := Pdf1.RenderPage(0, 0, 595, 842);
  try
    Pdf1.PageNumber := 2;
    Pdf1.AddImage(Bitmap, 50, 50, 250, 350);
    Pdf1.UpdatePage;
  finally
    Bitmap.Free;
  end;
end;

Projekti Demo\Delphi\ImageToPDF, Demo\CBuilder\ImageToPDF in Demo\Lazarus\ImageToPDF to pretvorijo v popoln paketni potek dela: izberite več slikovnih datotek, si oglejte predogled izbranega elementa, ustvarite eno stran PDF na sliko, vsako sliko prilagodite strani A4 v pokončni ali ležeči postavitvi, shranite rezultat in odprite ustvarjeni PDF

Označevanje iskanja v pregledovalniku

Poudarjanje vsakega zadetka na trenutni strani

var
  MatchCount: Integer;
begin
  // Paint a clYellow mask over every match on the view's current page
  // Switching to a different page clears the highlight automatically
  PdfView1.HighlightColor := clYellow;
  MatchCount := PdfView1.HighlightSearchText('invoice', False{Case}, True{Word});
  Status.Caption := Format('%d match(es) on this page', [MatchCount]);

  // Programmatically remove the overlay before the page changes
  PdfView1.ClearHighlight;
end;

Postavitev pregledovalnika in barva strani

Način prilagajanja in ozadje strani

// FitMode keeps long documents framed during Resize or page changes
// Setting Zoom directly cancels FitMode (it reverts to pfmNone)
PdfView1.FitMode := pfmFitPage;       // whole page in viewport
// PdfView1.FitMode := pfmFitWidth;   // page width matches viewport width
// PdfView1.FitMode := pfmActualSize; // 100%

// PageColor decouples the rendered PDF page from the host control's Color
// — typical dark-mode viewer setup keeps the scroll area dark while the
// PDF page stays paper-white
PdfView1.Color     := clBlack;        // scroll area
PdfView1.PageColor := clWhite;        // PDF page background

// Optional drop shadow and page border to lift the page off a dark bg
PdfView1.PageShadowSize  := 6;
PdfView1.PageShadowColor := $00404040;
PdfView1.PageBorderColor := clGray;

Raziskovanje interakcije pregledovalnika v ViewerInteractionLab

Projekti Demo\Delphi\ViewerInteractionLab, Demo\CBuilder\ViewerInteractionLab in Demo\Lazarus\ViewerInteractionLab ohranjajo sodoben interaktivni vmesnik TPdfView v eni kompaktni obliki: odprite ali ustvarite vzorčni PDF, preklopite DisplayMode, uporabite FitMode, spremenite PageColor, zavrtite strani, poudarite zadetke iskanja na trenutni strani s HighlightSearchText, omogočite ali onemogočite izbiro besedila uporabnika, preglejte SelectedText, pokličite SelectAll, CopySelectionToClipboard in ClearSelection ter opazujte, kako se koordinate DeviceToPage posodabljajo v vrstici stanja, medtem ko se miška premika po strani

Iskanje in izbira besedila v SearchAndSelect

Projekti Demo\Delphi\SearchAndSelect, Demo\CBuilder\SearchAndSelect in Demo\Lazarus\SearchAndSelect pretvorijo potek dela pregledovalnika za iskanje in izbiro v samostojne vzorce. Odprejo ali ustvarijo PDF, prikažejo rezultate iskanja po vseh straneh s številko strani, indeksom znaka in predoglednim besedilom, podpirajo navigacijo Previous / Next in skakanje na rezultat z dvojnim klikom, poudarjajo zadetke na trenutni strani z HighlightSearchText, izpostavijo možnosti ujemanja velikih/malih črk in celotne besede, preklapljajo AllowUserTextSelection, predogledujejo SelectedText, iz gumbov sprožajo SelectAll, CopySelectionToClipboard in ClearSelection ter omogočajo preklapljanje med enim in razpršenim načinom prikaza

Branje nastavitev tiskanja PDF v PrintPreferences

Projekti Demo\Delphi\PrintPreferences, Demo\CBuilder\PrintPreferences in Demo\Lazarus\PrintPreferences pred tiskanjem preberejo avtorjeve nastavitve tiskanja. Prikažejo PrintCopies, PrintPageRanges, PrintScaling in PrintPaperHandling, lahko kopirajo avtorjeve izvode in razpone v tiskalne vnose ter pokažejo, kako SetPdfPrintPaperHandlingDevMode preslika namen obojestranskega tiskanja PDF v Windows DEVMODE

Standardno tiskanje PDF v PrintPDF

Projekti Demo\Delphi\PrintPDF, Demo\CBuilder\PrintPDF in Demo\Lazarus\PrintPDF prikazujejo standardni potek tiskanja: odprite PDF, si oglejte predogled strani, izberite razpone strani in kopije v tiskalnem pogovornem oknu platforme, upoštevajte način združevanja izpisov, vsako stran izrišite prek TPdf.RenderPage in prikažite napredek tiskanja s preklicem. Vzorčni program Delphi sprejme tudi povlečene datoteke PDF za hitro nalaganje

Hitri večstranski ogled v MultiPageViewer

Projekti Demo\Delphi\MultiPageViewer, Demo\CBuilder\MultiPageViewer in Demo\Lazarus\MultiPageViewer preizkušajo neprekinjen, razpršen in naslovnici prilagojen ogled z običajnim krmarjenjem po straneh in poteki povečave. Uporabni so tudi za preizkus hitrosti odpiranja do prve strani in odzivnosti izrisa pri zelo velikih PDF-jih: v testih velikih datotek lahko dokumenti 2.x GB, zaradi katerih Acrobat ali Foxit potrebujeta 20-30 sekund do prvega pogleda, skozi pot pregledovalnika PDFiumPas postanejo uporabni skoraj takoj

Pregled vzporedno v SplitView

Projekti Demo\Delphi\SplitView, Demo\CBuilder\SplitView in Demo\Lazarus\SplitView prikazujejo pregled PDF vzporedno. Vzorci C++Builder in Lazarus se osredotočajo na primerjavo v dveh ali treh podoknih, izbiro aktivnega pogleda, neobvezne sinhronizirane ukaze za krmarjenje, deljene prednastavitve povečave in vrtenje za izbrani pogled ali vse naložene poglede. Uporabite te vzorce za primerjavo velikih dokumentov, pri čemer ostane prvi uporaben pogled in nadaljnji izris strani odziven; iste datoteke PDF velikosti 2.x GB, ki jih Acrobat ali Foxit morda odpirata 20-30 sekund, lahko v poti pregledovalnika PDFiumPas postanejo uporabne skoraj takoj

Pregled tveganj PDF v SecurityAudit

Projekti Demo\Delphi\SecurityAudit, Demo\CBuilder\SecurityAudit in Demo\Lazarus\SecurityAudit odprejo PDF samo za branje in prikažejo stanje dovoljenj, vdelane priloge, dejanja JavaScript dokumenta, opombe povezav URI in Launch, spletne povezave, povzetke podpisov, stanje XFA, razpoložljivost pomožnih funkcij V8 in povratne klice za nepodprte funkcije. Enake vrstice povzetka in najdb lahko shranite ali kopirate kot poročilo TXT ali shranite kot strukturiran JSON. Namenjeni so kot tveganostne plošče gostiteljskih aplikacij, ne kot zaznavanje zlonamerne programske opreme

Obravnava povezav v pregledovalniku

Varno sledenje s klikom in seznami dovoljenih dejanj

// LinkOptions controls automatic handling of the four PDF link action
// types. Defaults enable goto and URI only; launch (run a program) and
// embedded GotoR (jump to another file) stay OFF so a stray click cannot
// run arbitrary code
PdfView1.LinkOptions :=
  [loAutoGoto, loAutoOpenURI];  // safe defaults

// OnAnnotationLinkClick fires for in-document destinations (page jumps,
// named destinations, action chains). Mark Handled = True to prevent the
// view from auto-following the link
procedure TForm1.PdfView1AnnotationLinkClick(Sender: TObject;
  LinkIndex: Integer; const Action: TPdfAction;
  var Handled: Boolean);
begin
  if Action.Kind = paUri then
  begin
    if MessageDlg('Open ' + Action.Uri + '?', mtConfirmation, [mbYes, mbNo], 0)
      <> mrYes then
      Handled := True;  // suppress auto-handling
  end;
end;

// OnWebLinkClick fires for URI strings discovered by PDFium's web-link
// scanner (auto-detected URLs in the text stream, even without an
// /A <</S/URI...>> annotation)
procedure TForm1.PdfView1WebLinkClick(Sender: TObject;
  WebLinkIndex: Integer; const Url: WString;
  var Handled: Boolean);
begin
  Log.Add('Web link clicked: ' + string(Url));
end;

Urejanje gradnikov obrazca v pregledovalniku

Izbira ter Undo / Redo

// On the focused AcroForm widget, six new methods drive PDFium's form
// edit history. All six short-circuit safely if no widget is focused or
// the document carries no AcroForm
procedure TForm1.btnSelectAllClick(Sender: TObject);
begin
  PdfView1.SelectAllFormText;
  EditMenuCopy.Caption := 'Copy: ' + string(PdfView1.GetSelectedFormText);
end;

procedure TForm1.btnUndoClick(Sender: TObject);
begin
  btnUndo.Enabled := PdfView1.FormCanUndo;
  btnRedo.Enabled := PdfView1.FormCanRedo;
  if PdfView1.FormCanUndo then
    PdfView1.FormUndo;
end;

procedure TForm1.btnRedoClick(Sender: TObject);
begin
  if PdfView1.FormCanRedo then
    PdfView1.FormRedo;
end;

Zaklepanje pregledovalnika za kioske

Onemogočanje potez za krmarjenje po straneh

// All three default to True so existing apps upgrade with no behaviour
// change. Flip them False for kiosks, preview panes, or read-only
// embeddings without subclassing TPdfView
PdfView1.AllowUserPageChange       := False;  // PgUp/PgDn/Ctrl+Domov/End
PdfView1.ChangePageOnMouseScrolling := False; // wheel up/down jumps
PdfView1.AllowUserTextSelection    := False;  // mouse/keyboard text selection

// Ctrl+wheel is reserved for zoom and is skipped by the navigation
// handler regardless of ChangePageOnMouseScrolling.

Stranski panel s sličicami

Povezovanje TPdfThumbnailView s TPdfView

// TPdfThumbnailView (unit FPdfThumbnail) renders one page thumbnail per
// row in a scrollable side panel
uses FPdfThumbnail;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ThumbView.Pdf              := Pdf1;
  ThumbView.ThumbnailWidth   := 120;
  ThumbView.ThumbnailHeight  := 160;
  ThumbView.SelectionColor   := $00CFA85F;  // warm highlight
  ThumbView.OnPageClick      := ThumbViewPageClick;
end;

procedure TForm1.ThumbViewPageClick(Sender: TObject; PageIndex: Integer);
begin
  PdfView1.PageNumber := PageIndex + 1; // PageIndex is zero-based
end;

procedure TForm1.PdfView1PageNumberSpremenjeno(Sender: TObject);
begin
  ThumbView.CurrentPageIndex := PdfView1.PageNumber - 1;
end;

Sodelovalno preklicevljiv paketni izvoz

Več datotek PDF v JPG z napredkom po datoteki in po strani

// Pattern used by Demo\Delphi\BatchExport, Demo\CBuilder\BatchExport,
// and Demo\Lazarus\BatchExport. One TPdf per file, IPdfCancellationToken
// for cancel-from-UI, TPdfStreamAdapter for buffered file load
uses FPdfAsync;

procedure ExportBatch(const Files: TArray<string>;
  const OutDir: string; DPI: Integer; Quality: Integer;
  const ACancelToken: IPdfCancellationToken);
var
  I, J: Integer;
  Job:  TPdf;
  Bmp:  TBitmap;
  Jpeg: TJPEGImage;
begin
  for I := 0 to High(Files) do
  begin
    if ACancelToken.IsCancelled then Break;
    OverallProgress.Position := I;

    Job := TPdf.Create(nil);
    try
      Job.FileName := Files[I];
      Job.Active   := True;
      PageProgress.Max := Job.PageCount;

      for J := 1 to Job.PageCount do
      begin
        if ACancelToken.IsCancelled then Break;
        PageProgress.Position := J;

        Job.PageNumber := J;
        Bmp := Job.RenderPage(
          0, 0,
          Round(Job.PageWidth  * DPI / 72),
          Round(Job.PageHeight * DPI / 72));
        try
          Jpeg := TJPEGImage.Create;
          try
            Jpeg.CompressionQuality := Quality;
            Jpeg.Assign(Bmp);
            Jpeg.SaveToFile(Format('%s\%s.p%.3d.jpg',
              [OutDir, ExtractFileName(Files[I]), J]));
          finally
            Jpeg.Free;
          end;
        finally
          Bmp.Free;
        end;
      end;
    finally
      Job.Free;
    end;
  end;
end;

Koordinate pregledovalnika in preverjanje zadetkov

Prilagoditev trenutne strani in pregled besedila pod miško

procedure FitCurrentPage;
begin
  PdfView1.Zoom := PdfView1.PageZoom[PdfView1.PageNumber];
end;

procedure InspectViewerPoint(X, Y: Integer);
var
  PageNo: Integer;
  PageX, PageY: Double;
  CharIndex: Integer;
  Ch: WString;
begin
  PageNo := PdfView1.PageNumber;
  if not PdfView1.DeviceToPage(X, Y, PageNo, PageX, PageY) then
    Exit;

  CharIndex := PdfView1.CharacterIndexAtPos(X, Y, 8, 8);
  if CharIndex >= 0 then
  begin
    Ch := PdfView1.Text(CharIndex, 1);
    ShowMessage(Format('Page %d, X %.2f, Y %.2f, character %s',
      [PageNo, PageX, PageY, string(Ch)]));
  end;
end;

Obravnava napak

Robustne operacije PDF

function LoadPdfSafely(const FileName: string): Boolean;
begin
  Result := False;
  if not FileExists(FileName) then
    Exit;
  try
    Pdf1.FileName := FileName;
    Pdf1.Active := True;
    Result := Pdf1.Active;
  except
    Result := False;
  end;
end;

function ExtractTextSafely(PageNo: Integer): WString;
begin
  Result := '';
  if not Pdf1.Active then
    Exit;
  if (PageNo < 1) or (PageNo > Pdf1.PageCount) then
    Exit;
  Pdf1.PageNumber := PageNo;
  Result := Pdf1.Text;
end;

Označeni PDF in dostopnost

Zaznavanje označenega PDF in prehod po drevesu strukture

// IsTagged is a cheap catalog probe — True when /StructTreeRoot exists
// StructureElements materialises the tree into a flat array of
// TPdfStructureElement records with type, title, alternate text, actual
// text, expansion text, language, level, parent index, and child / marked
// content / attribute counts
var
  Elements: TPdfStructureElements;
  I: Integer;
begin
  if not Pdf1.IsTagged then
  begin
    Log.Add('Document is NOT tagged — accessibility tools may struggle.');
    Exit;
  end;
  if Pdf1.Language = '' then
    Log.Add('Tagged PDF without /Lang — fails PDF/UA.');

  Elements := Pdf1.StructureElements;
  for I := 0 to High(Elements) do
    Log.Add(StringOfChar(' ', Elements[I].Level * 2)
      + Elements[I].StructType + ' "' + Elements[I].Title + '"');
end;

Izbira načina tiskanja

Nastavljanje načina tiskanja EMF / PostScript / image-mask

// SetPdfPrintMode is a global function that maps to PDFium's
// FPDF_SetPrintMode. Use the matching TPdfPrintMode value for the
// printer driver in use
SetPdfPrintMode(pmEmf);                   // GDI EMF (default)
// SetPdfPrintMode(pmTextOnly);           // text-only rendering
// SetPdfPrintMode(pmPostScript2);        // PostScript Level 2
// SetPdfPrintMode(pmPostScript3);        // PostScript Level 3
// SetPdfPrintMode(pmPostScript2PassThrough);
// SetPdfPrintMode(pmPostScript3PassThrough);
// SetPdfPrintMode(pmEmfImageMasks);      // EMF + image masks
// SetPdfPrintMode(pmPostScript3Type42);  // PostScript 3 + Type 42 fonts

Branje avtorjevih nastavitev tiskanja

// PrintCopies, PrintPageRanges, PrintScaling, and PrintPaperHandling are
// the viewer-preference dictionary entries — they encode what the
// document author wanted PDF readers to default to
var
  Ranges: TPrintPageRanges;
  Range: TPrintPageRange;
begin
  ShowMessage('Suggested copies: ' + IntToStr(Pdf1.PrintCopies));
  ShowMessage('Print scaling: ' + GetEnumName(TypeInfo(TPrintScaling),
    Ord(Pdf1.PrintScaling)));

  Ranges := Pdf1.PrintPageRanges; // one-based ranges
  for Range in Ranges do
    Log.Add(Format('Pages %d..%d', [Range.First, Range.Last]));

  if SetPdfPrintPaperHandlingDevMode(PrinterDevMode, Pdf1.PrintPaperHandling) then
    ApplyPrinterDevMode(PrinterDevMode);
end;

Dejanja JavaScript dokumenta

Naštevanje JavaScript iz imenskega drevesa

// Document-level JavaScript is stored in the /Names /JavaScript name
// tree. JavaScriptAction[i] returns one entry; JavaScriptActions returns
// the full array
var
  I: Integer;
  Action: TPdfJavaScriptAction;
begin
  for I := 0 to Pdf1.JavaScriptActionCount - 1 do
  begin
    Action := Pdf1.JavaScriptAction[I];
    Memo1.Lines.Add('Name:   ' + string(Action.Name));
    Memo1.Lines.Add('Script: ' + string(Action.Script));
    Memo1.Lines.Add('---');
  end;
end;

Nasveti za učinkovitost

Optimizacija operacij PDF

procedure ProcessMultiplePages;
var
  I: Integer;
  PageText: WString;
begin
  for I := 1 to Pdf1.PageCount do
  begin
    Pdf1.PageNumber := I;
    PageText := Pdf1.Text;
    ProcessPageText(PageText);
  end;
end;

procedure SetOptimalRenderOptions;
begin
  PdfView1.Options := [reAnnotations, reLcd];
end;

// Zero-copy render path (default since v1.21.0): RenderPage writes
// directly into the destination TBitmap's DIB buffer when callers pass a
// pre-allocated bitmap, avoiding one width * height * 4 bytes copy
procedure RenderIntoCallerBitmap(Bitmap: TBitmap);
begin
  Bitmap.PixelFormat := pf32bit;
  Bitmap.SetSize(2480, 3508); // A4 @ 300 DPI
  Pdf1.RenderPage(Bitmap, 0, 0, Bitmap.Width, Bitmap.Height);
end;