PDFium VCL Component Features

Core Components

• TPdf - Main PDF document handling component for opening, navigating, extracting text, and editing PDF documents
• TPdfView - Visual component for displaying and interacting with PDF pages
• TPdfThumbnailView - Scrollable thumbnail side panel for page navigation

Document Operations

• Document Loading - Load PDF files from disk, memory streams, byte arrays, or on-demand TStream adapters via LoadCustomDocument. PDFium reads blocks on demand so multi-GB documents and remote / database-backed sources do not need an up-front in-memory copy.
• Password Protection - Open password-protected PDF documents and report effective UserPermissions for the authenticated session
• Document Creation - Build new PDF documents from scratch with CreateDocument, AddPage, AddText, AddImage, AddPicture, AddJpegImage, and CreatePath
• Document Saving - Save modified documents with various options (incremental, remove security) and explicit PDF target versions from PDF 1.0 through PDF 1.7
• PDF/A-1b Output - SaveAsPdfA / SaveAsPdfAToStream post-process 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. Custom ICC profiles are supported through TPdfASaveOptions.IccProfileData.
• PDF/A Validation - ValidatePdfA and the read-only PdfAConformance property scan an open document for XMP pdfaid markers, OutputIntent with embedded ICC, encryption presence, and report the conformance level (pac1a, pac1b, pac2b, pac3b, pacNone, or pacUnknown) plus a list of TPdfAValidationIssue entries describing each problem found
• PDF Version Compliance Validator - When SaveAs targets PDF 1.0 through PDF 1.7 the writer rejects any dictionary entry, filter, annotation subtype, action type, font, colour space, or encryption parameter introduced after the chosen target version (e.g. JBIG2Decode, MarkInfo, OutputIntents, AES / AES-256, Polygon / Caret / Watermark / Redact annotations, JavaScript / Trans / SetState actions)
• Stream Compression - Automatic FlateDecode compression ensures all PDF streams are optimally compressed when saving; set Compressed := False to opt out for debug pipelines
• Document Merging - Import pages from other PDF documents
• Page Subset Import - ImportPagesByIndex copies an explicit zero-based index array from a source document, with InsertAt = 0 to insert before page 1 or InsertAt = PageCount to append. Pass an empty index array to import every source page.
• N-up Composition - ImportNPagesToOne returns a brand-new TPdf whose pages are NumX×NumY composites of the source document's pages, sized in PDF user units (1 unit = 1/72 in)
• Page Reordering - MovePages reorders pages in place using a zero-based index array and a destination index for the first moved page
• Form XObject Page Reuse - CreateXObjectFromPage manufactures a reusable TPdfXObject handle from any page of another document; InsertFormObjectFromXObject inserts ONE copy of the wrapped page into the current page. Ideal for watermarks, template overlays, and "stamp one page onto many" workflows. The destination page object can be positioned, scaled, and rotated through FPDFPageObj_SetMatrix and the TPdfMatrix helpers.
• Page Management - Add, delete, and manipulate individual pages; AddPage(0, ...) inserts the very first page and activates it immediately
• Page Boxes - Read and write MediaBox, CropBox, BleedBox, TrimBox, and ArtBox on the current page
• Catalog Language - Read and write the document language stored in the catalog /Lang entry
• Trailer File IDs - Read permanent and changing trailer /ID entries as binary bytes
• Document JavaScript Actions - Enumerate document-level JavaScript name-tree action names and scripts
• Tagged PDF Structure Tree - Inspect logical structure elements, accessibility text, language, marked-content IDs, and hierarchy for tagged PDF pages
• Viewer Preferences - Read PrintCopies, PrintPageRanges, PrintScaling, and PrintPaperHandling from the document's viewer-preference dictionary; saved PDFs default to a Fit Height first-page open action

Text Operations

• Text Extraction - Extract text from PDF pages with character-level precision via Text, TextInRectangle, indexed Character, CharacterRectangle, and CharacterOrigin properties
• Text Search - Find text with case-sensitive, whole word, and consecutive search options using FindFirst, FindNext, FindPrevious
• Search Highlight Overlay - TPdfView.HighlightSearchText scans the current view page and paints a real alpha-blended HighlightColor overlay over every match on each redraw, returning the match count. ClearHighlight removes the overlay; navigating to a different page clears it automatically because matches are page-specific. HighlightColor defaults to clYellow and is published so applications can theme it.
• Character Properties - Access font size, weight, angle, and positioning for individual characters with the CharacterAngle, CharacterFontSize, CharacterFontWeight, CharacterGenerated, CharacterIsHyphen, and CharacterMapError indexed properties
• European Character Support - AddText automatically loads and caches the matching system TrueType font before creating a text object, so accented Czech, French, German, Spanish, Portuguese, Polish, and Turkish characters that PDFium's built-in standard fonts cannot represent now render correctly without any code change
• Text Addition - Add new text to PDF pages with custom fonts, colours, transparency, and rotation
• Text Object Positioning - Set per-character positions for existing text objects through SetTextPositions and TPdfSingleArray
• Font Information - Retrieve font properties including family name, embedding status, italic angle, ascent / descent, and raw font data on a per-page-object basis

Annotation Support

• Annotation Types - Support for text, link, highlight, underline, strikeout, and many other annotation types
• Annotation Creation - Create new annotations programmatically
• Annotation Editing - Modify existing annotation properties including colour, transparency, and content
• Link Annotations - Handle internal and external links with action support

Form Support

• Form Types - Support for AcroForm and XFA forms
• Form Fill - Interactive form filling with JavaScript support
• V8 DLL Selection - Set EnableV8Engine before loading to use pdfium.v8.dll from the matching DLLs\Win32 or DLLs\Win64 folder and query V8/XFA helper availability via V8FeaturesAvailable, XfaBStrHelpersAvailable, and GetRecommendedV8Flags
• Field Access - Read and write form field values by index or position
• Field Information - Access field type, flags, name, and other properties
• Field Flags - Update AcroForm field flags by index or position through SetFormFieldFlags / SetFormFieldFlagsAt, including read-only, required, password, and multi-select flags
• Form Flattening - GenerateFormAppearances regenerates the /AP appearance stream for every form widget on every page, and FlattenPage / FlattenAllPages bake annotations and form fields into static page content (non-editable)
• Form Widget Text Selection & Undo / Redo - On the focused AcroForm widget the view exposes GetSelectedFormText (currently selected text), SelectAllFormText (select every character), and FormUndo / FormRedo / FormCanUndo / FormCanRedo (drive PDFium's per-widget edit history). All six short-circuit safely when the view is inactive or no widget is focused.

Image Operations

• Image Extraction - Extract bitmaps from PDF pages with the indexed Bitmap property; iterate BitmapCount to save every image to disk
• JPEG Insertion - AddJpegImage takes a TStream of raw JPEG bytes and embeds the image as a /DCTDecode XObject without re-encoding
• Picture Support - AddPicture accepts a TPicture object with automatic format conversion through the registered VCL/LCL graphic classes
• Direct Image Insertion - AddImage(FileName) recognises any format registered with the VCL or LCL graphics units (BMP, PNG via PngImage, JPG, ...) and shares the AddPicture pipeline. AddImage(TBitmap) skips the TPicture intermediary, which simplifies callers that already hold a TBitmap from rendering or batch generation work.
• Image ICC Profile - Image page objects expose their embedded ICC profile data when present (binding for FPDFImageObj_GetIccProfileDataDecoded)
• Thumbnail Generation - Generate page thumbnail bitmaps via the Thumbnail property

Helper Units

• Async Infrastructure - FPdfAsync exposes IPdfCancellationToken / IPdfCancellationTokenSource for cooperative cancel-from-UI semantics, a reusable PdfNoCancellationToken singleton, and a lightweight TPdfFuture<T> helper that runs a worker on a background thread and posts a TPdfFutureResult<T> envelope back to the main thread, distinguishing success, cancellation, and failure cases
• Stream Adapter - TPdfStreamAdapter bridges a Pascal TStream to PDFium's FPDF_FILEACCESS callbacks so LoadCustomDocument reads blocks on demand instead of buffering the entire PDF in memory
• Matrix Composition - FPdfMatrix wraps PDFium's FS_MATRIX with an OO API for Translate, Scale, Rotate, HorizontalFlip, VerticalFlip, CentralFlip, Skew, and Multiply. Multiply snapshots the six matrix elements before computing the new row values, avoiding the alternative-Pascal-implementation pitfall where earlier elements get overwritten during the same call and produce incorrect compositions.
• Cancellable Progressive Rendering - TPdf.RenderPageProgressive drives PDFium's FPDF_RenderPageBitmap_Start + RenderPage_Continue loop and polls an IPdfCancellationToken between iterations via the IFSDK_PAUSE callback so long high-DPI renders can abort mid-page instead of blocking until completion. Returns a TPdfProgressiveStatus of prsDone, prsCancelled, or prsFailed.
• Zero-Copy Render Path - RenderPage / RenderTile / RenderPageProgressive write PDFium output directly into the destination TBitmap's DIB buffer instead of staging through an internal buffer, saving one width × height × 4 bytes memory copy per render - most noticeable at high DPI (thumbnail panels, print-quality export, batch export). A per-scanline fallback path is preserved when the destination DIB cannot be wrapped safely.

Drawing Operations

• Path Drawing - Create paths with lines, Bezier curves, and closed shapes
• Object Removal - Remove page objects and regenerate page content from TPdf or TPdfView
• Fill and Stroke - Configure fill mode, colours, transparency, and stroke properties
• Blend Modes - Support for various PDF blend modes
• Line Styles - Configure line cap, line join, and stroke width

Digital Signatures

• Signature Detection - Detect and enumerate digital signatures in PDF documents
• Signature Information - Access signature contents, byte range, sub-filter, reason, and time
• MDP Permissions - Query document modification detection and prevention permissions

Attachment Support

• Attachment Access - Read, create, modify, and delete embedded file attachments
• Attachment Names - Access attachment filenames
• Attachment Types - Read embedded file MIME subtype values when present

Navigation

• Bookmarks - Navigate document bookmarks with hierarchical support via the Bookmarks array, BookmarkChildren, HasBookmarkChildren, and BookmarkFrom traversal helpers
• Named Destinations - Access named destinations by index or name through Destination, DestinationByName, and DestinationCount
• Page Labels - Retrieve page labels for each page via PageLabel; useful when documents use Roman numerals for front matter
• Web Links - Detect and navigate web links on pages with WebLink, WebLinkCount, and TPdfView.WebLinkAtPos
• Link Annotations - Access link annotations with action and destination information through LinkAnnotation, LinkAnnotationCount, and TPdfView.LinkAnnotationAtPos
• Safe Link Click Handling - TPdfView raises OnAnnotationLinkClick / OnWebLinkClick events before automatic goto / URI handling, with launch actions disabled by default. Link click detection runs only when the gesture is a click rather than a drag, using a fresh MouseDown anchor so panning gestures still flow through the existing scroll path unchanged.

Rendering

• High-Quality Rendering - Render pages to device context, bitmap, or tile through RenderPage / RenderTile, with zero-copy direct writes into the destination DIB buffer
• Cancellable Progressive Rendering - RenderPageProgressive drives PDFium's progressive loop and polls an IPdfCancellationToken between iterations, returning prsDone, prsCancelled, or prsFailed. The bitmap holds the partial work done so far when cancelled.
• Render Options - LCD text optimisation (reLcd), annotations (reAnnotations), greyscale, and printing mode flags
• Skia Hooks - Low-level FPDF_RenderPageSkia and FPDF_FFLDrawSkia bindings are available when callers provide an external SkCanvas (depends on bundled DLL exports)
• Print Mode Selection - Set EMF, text-only, PostScript, pass-through, image-mask, and Type 42 PDFium print modes via SetPdfPrintMode with TPdfPrintMode
• Async Overlay - TPdfView can display an opt-in loading overlay while application-owned workers render with separate TPdf instances
• Page Rotation - Support for 0, 90, 180, and 270 degree rotation (ro0, ro90, ro180, ro270)
• Transparency Detection - Transparent property reports whether any object on the current page has transparency, including blend modes and partial alpha

Viewing (TPdfView)

• Display Modes - dmSingleContinuous, dmTwoPageContinuous, and dmTwoPageContinuousWithCover (the cover page stands alone, then continues with two-page spreads). The unit-level ComputeSpreadPages helper exposes the spread-page math without instantiating a viewer.
• Fit Mode - FitMode chooses how the page sits in the viewport: pfmNone (manual zoom), pfmActualSize (100%), pfmFitPage (whole page fits in the viewport), and pfmFitWidth (page width matches viewport width). The active fit mode is re-applied automatically on Resize and when the current page changes; setting Zoom directly cancels the active fit mode (FitMode reverts to pfmNone), matching the standard PDF viewer convention.
• Zoom Control - Variable zoom with PageZoom, PageWidthZoom, PageHeightZoom, and ActualSizeZoom per-page helpers
• Page Colour - PageColor decouples the rendered PDF page background from the surrounding control's Color. Default is clWhite, so PDF pages now render as paper-white regardless of the host application's theme. Dark-mode viewers can keep the scroll area dark while leaving the actual PDF page white (or any colour the application picks).
• Interactive Text Selection - End-user drag-to-select text on PDF pages, with hit-test auto-switching between selection and pan: clicking on a character starts a selection drag, clicking on whitespace pans. Double-click selects the word, triple-click selects the line, Ctrl+A selects the page (both pages in spread mode), Ctrl+C copies as CF_UNICODETEXT, Shift+arrows extend selection, hover over text switches the cursor to crIBeam, and dragging into a viewer edge auto-scrolls the page. New published SelectionColor and OnSelectionChange; new public HasSelection, SelectedText, SelectionCharCount, ClearSelection, SelectAll, CopySelectionToClipboard. Spread display modes select across both visible pages with CR/LF joining. A default right-click Copy popup is auto-attached when the host has not assigned its own PopupMenu. Gated by the v1.17.0 AllowUserTextSelection flag for kiosk hosts.
• Coordinate Mapping - Convert between viewer device coordinates and PDF page coordinates with DeviceToPage / PageToDevice, including overloads that take a TRect and return a TPdfRectangle
• Text Selection and Hit Testing - Resolve characters under viewer points with CharacterIndexAtPos and paint text selection highlights via PaintSelection
• Mouse & Keyboard - Full input device support with mouse drag scrolling, PgUp / PgDn / Ctrl+Home / Ctrl+End shortcuts, and wheel-up / wheel-down page navigation. Ctrl+wheel is reserved for application zoom and skipped by the navigation handler.
• User Input Lock-Down - AllowUserPageChange controls keyboard page shortcuts, ChangePageOnMouseScrolling controls wheel page jumps, and AllowUserTextSelection controls mouse / keyboard text-selection input. All three default to True; flip them False to lock down kiosks, preview panes, or read-only embeddings without subclassing.
• Async Render Overlay - AsyncRendering, LoadingText, and LoadingColor draw a small "Loading..." indicator over the rendered page so applications using their own worker for long renders share a consistent visual affordance. Defaults preserve existing behaviour. TPdf now serialises render and page-unload calls per instance; applications still own worker dispatch and must avoid mutating a document while a render is in flight.
• Safe Link Click Handling - LinkOptions is a published set that controls automatic behaviour for the four PDF link action types: loAutoGoto (page jump), loAutoOpenURI (ShellExecute), loAutoLaunch (ShellExecute), and loAutoEmbeddedGoto (reserved). Defaults enable loAutoGoto and loAutoOpenURI only; loAutoLaunch and loAutoEmbeddedGoto stay off so a stray click cannot run an arbitrary program. OnAnnotationLinkClick and OnWebLinkClick fire before any automatic action and let the application mark the event Handled or redirect it.
• Form Interaction - Interactive form editing within the viewer, plus the v1.23.0 selection / Undo / Redo helpers
• Visual Styling - PageShadowSize, PageShadowColor, and PageBorderColor paint an optional drop shadow under the page rectangle and a one-pixel border around it; SmoothScroll now animates line/page scrollbar commands in timer-driven segments while thumb tracking remains immediate
• Thumbnail Navigation - TPdfThumbnailView (unit FPdfThumbnail) renders one page thumbnail per row in a scrollable side panel with hover and selection highlighting plus click-to-go navigation. Designed to sit next to a TPdfView. Properties: Pdf, CurrentPageIndex, ThumbnailWidth, ThumbnailHeight, TextColor, HoverColor, SelectionColor, BorderColor; event: OnPageClick.

Compression

• Automatic Compression - When the Compressed property is True (default), all PDF streams are ensured to be FlateDecode compressed when saving
• Post-Processing - The compression engine scans saved PDF data and compresses any uncompressed streams using zlib maximum compression
• Cross-Reference Rebuild - Automatically rebuilds the xref table when stream compression changes byte offsets
• Zero Overhead - If all streams are already compressed, the data passes through without modification

Security

• Password Support - Open password-protected PDF documents
• Permissions - Read document and user permissions; the SecurityAudit demo combines permissions, attachments, document JavaScript, URI / Launch links, signatures, XFA, and V8 availability into a read-only risk surface with TXT / JSON report save and TXT copy actions
• Security Removal - Save documents with security removed (when authorized)

Printing

• Print Modes - Choose between EMF, text-only, PostScript Level 2 / 3, PostScript pass-through, EMF image-mask, and Type 42 print modes through the global SetPdfPrintMode function
• Viewer Preferences - Surface document author intent through PrintCopies, PrintPageRanges (one-based page ranges), PrintScaling, and PrintPaperHandling; SetPdfPrintPaperHandlingDevMode maps the duplex hint into Windows DEVMODE.dmDuplex
• N-up Printing - The Delphi, C++Builder, and Lazarus PrintPreferences demos show N-up sheet composition (1 / 2 / 4 / 9 pages per sheet) with odd / even page filtering, greyscale rendering, optional 1-pixel cell borders, PDF author print preferences, and duplex intent mapping via SetPdfPrintPaperHandlingDevMode

Shipped Demos

The Demo\Delphi, Demo\CBuilder, and Demo\Lazarus trees ship runnable sample projects that exercise the live API surface across all three IDE families. Highlights:

• PDFViewer / MultiPageViewer / SplitView - End-to-end TPdfView usage: load, navigate, zoom, rotate, two-page spread, cover-aware layouts, and Delphi / C++Builder / Lazarus side-by-side PDF comparison with synchronized commands
• ViewerInteractionLab - Delphi, C++Builder, and Lazarus focused TPdfView interaction samples for display modes, fit modes, page colours, rotation, search highlighting, text selection, selected-text preview, clipboard actions, and DeviceToPage coordinate feedback
• SearchAndSelect - Delphi, Lazarus, and C++Builder focused workflow samples for all-page search result listing, previous / next match navigation, double-click result jumping, HighlightSearchText, match-case / whole-word search, AllowUserTextSelection, SelectedText, SelectAll, CopySelectionToClipboard, ClearSelection, and spread display modes
• PreflightReport - Delphi, Lazarus, and C++Builder workflow demos plus a Delphi console companion around reusable FPdfPreflightReport, collecting PDF/A, PDF/UA, PDF/E, PDF/X, PDF/R, and PDF/VT validation results into status, priority, issue category, issue-category counts, next-action summary rows, issue recommendations, text / Markdown / JSON / CSV preview, TXT / HTML / Markdown / JSON / CSV reports, scriptable report generation, batch list and directory processing with report-directory routing, TXT / JSON / HTML aggregate summaries, CSV row manifests, optional report attachment embedding, and CI gating exit codes
• ContentExtractionLab - Delphi, Lazarus, and C++Builder unified content inventory workflow for document metadata, page text, page objects, images, attachments, links, annotations, bookmarks, and font / character metrics with TXT / JSON export, all / none category selection, source-PDF save, and report copy actions
• WatermarkStamp - Delphi, Lazarus, and C++Builder reusable Form XObject workflow for centred watermarks, corner stamps, and page number labels across a multi-page target PDF
• CreatePDF - Build a multi-page PDF from scratch with text, images, paths, and watermark composition
• EuropeanText - Add accented Czech / French / German / Spanish / Portuguese / Polish / Turkish text using system TrueType fonts
• ExtractText / ExtractTextPages / ExtractImages / ContentExtractionLab - Save extracted text or embedded images to disk, split text into one TXT file per page, or generate a multi-category content inventory report in one pass
• FormFill - Read AcroForm field metadata, write values, regenerate /AP appearances, and save either the editable or the flattened result
• FontProperties - Inspect indexed character / font metadata through both TPdf and TPdfView in Delphi, C++Builder, and Lazarus
• MergePDF / SplitPDF - Combine multiple source PDFs or split one PDF into per-page output files
• PDFtoJpg / BatchExport - Delphi, C++Builder, and Lazarus one-shot or batched multi-file PDF to JPG conversion with per-file overall progress, per-page current progress, DPI / quality / password inputs, and a cooperatively-cancellable batch backed by IPdfCancellationToken
• StandardsLab - Delphi, C++Builder, and Lazarus workflow samples for PDF/A, PDF/UA, PDF/E, PDF/X, PDF/R, and PDF/VT validation, issue reporting, and standards-oriented save outputs
• PrintPDF / PrintPreferences - Delphi, C++Builder, and Lazarus standard PDF printing with preview, page ranges, copies, collate, progress, and cancellation (PrintPDF), plus Delphi, C++Builder, and Lazarus N-up sheet composition with odd / even filtering and PDF author print preferences (PrintPreferences)
• SecurityAudit - Delphi, C++Builder, and Lazarus read-only risk-surface samples for permissions, attachments, JavaScript actions, URI / Launch links, web links, signatures, XFA state, V8 / XFA helper availability, and TXT / JSON audit reports
• Attachment - Create PDFs, add / list / extract / delete / save embedded file attachments with MIME subtype display
• ImageToPDF - Delphi, C++Builder, and Lazarus image batch conversion into one PDF, one image per page, with preview and per-image progress

The Delphi, C++Builder, and Lazarus regression suites cover 147 (Pas) / 123 (C++) cases sharing the same fixture PDFs so behaviour stays byte-aligned across all three IDE families.

Platform Support

• Delphi - Delphi XE5 (RAD Studio XE5) through Delphi 13.1 Florence (RAD Studio 13.1)
• C++Builder - C++Builder XE5 (RAD Studio XE5) through C++Builder 13.1 Florence
• Lazarus - Free Pascal / Lazarus support
• Win32 / Win64 - Both 32-bit and 64-bit Windows platforms