Delphi HotPDF Hello World: Your First PDF Program
Write your first PDF in Delphi with HotPDF: a minimal console Hello World that sets a Unicode font, draws text with TextOut, and saves a compressed file
Software Development Blog
HotPDF Delphi Component
HotPDF Delphi Component tutorials, tips, and Delphi code examples for generating and editing PDFs
Reusing a THotPDF Instance Across Documents in Delphi
Why reusing a finished THotPDF throws the load-document error, how the Create, BeginDoc, EndDoc, Free lifecycle works, and when to build a fresh instance
Building AcroForm Fields and Actions with HotPDF in Delphi
Create AcroForm text fields, checkboxes, radio groups, and submit or JavaScript actions in Delphi with HotPDF, and avoid export-value mismatches in form intake
Auto-Calculating PDF Forms in Delphi with HotPDF
Attach Acrobat AF format, validate and calculate scripts to a loaded AcroForm in Delphi with HotPDF, so PDF form fields auto-sum totals and format dates
Add AcroForm Fields to a Loaded PDF in Delphi
Add Text, CheckBox, ComboBox, ListBox, PushButton and Signature fields to an existing PDF in Delphi with HotPDF, and why /NeedAppearances is mandatory
AES-256 PDF Encryption in Delphi: HotPDF Setup and Pitfalls
Set up AES-256 PDF encryption in Delphi with HotPDF: user and owner passwords, permission flags, R5 vs R6 revisions, and the property order that silently fails
Background PDF Rendering Queue in Delphi with HotPDF
Keep Delphi PDF viewers responsive with HotPDF background rendering: queue page renders off the UI thread, cancel pending pages, and cache bitmaps
Generating Scannable Barcodes in PDF with HotPDF in Delphi
Draw linear barcodes into a PDF from Delphi with HotPDF: the symbologies it supports, how module width and quiet zone decide whether a scanner can read it
Add Bookmarks to Existing PDFs in Delphi with HotPDF
Add bookmarks and named destinations to an existing PDF in Delphi with HotPDF: AddLoadedOutline nesting, XYZ destinations, and the /Count semantics trap
Built-In Template-Matching OCR in Delphi with HotPDF
How HotPDF rebuilt its built-in template-matching OCR in Delphi: DIB row order, Otsu binarization, 16x24 glyph templates and case from height clustering
HotPDF Canvas Drawing in Delphi: Vector Paths and Color
Draw vector shapes in a PDF from Delphi with HotPDF: paths with MoveTo and LineTo, stroke and fill, RGB color, line width, in a bottom-left coordinate system
HotPDF Cert Store PDF Signing: CNG vs CAPI Byte Order
Sign PDFs from the Windows certificate store in Delphi and C++Builder using HotPDF: fix the CNG vs CAPI byte order and unresolved CertOpenStore link errors
Drawing Charts in a PDF with HotPDF Primitives
HotPDF has no chart object, so you draw bar, line, and pie charts yourself with Rectangle, LineTo, and Circle in Delphi. Here is the coordinate math and layout
Isolate PDF Image Codecs in Worker Processes with HotPDF
Decode untrusted DCTDecode, JPXDecode and JBIG2Decode images in crash-isolated worker processes with HotPDF, using CodecIsolationMode, timeouts and memory caps
Arabic and RTL Text Shaping in Delphi PDFs with HotPDF
What HotPDF shapes in Delphi PDFs and what it does not: bidi reordering, Arabic joining, coverage from Hebrew to Thai and Devanagari, and how to verify output
HotPDF TextOut in Delphi: Size, Style, Rotation, and Spacing
Go past Hello World with HotPDF TextOut in Delphi: set font size and style, rotate by angle, place coordinates exactly, and tune character and word spacing
CJK Vertical Text in PDF with Delphi and HotPDF
Lay out CJK vertical text in PDF from Delphi with HotPDF: use IsVertical in SetFont, stack glyphs downward, fix U+30FC, and arrange columns right to left
Rewrite PDF Content Streams Safely in Delphi
HotPDF visits every operator in a PDF content stream from Delphi and lets you keep, delete or replace each one, with byte-identical output when nothing changes
PDF Crypt Filters in Delphi: StmF, StrF, EFF Policies
How the HotPDF Delphi PDF component implements ISO 32000 crypt filters: StmF, StrF and EFF policies, per-stream Crypt overrides and object stream keying
HotPDF Custom PDF Viewer in Delphi: the MVC Architecture
How HotPDF splits a Delphi PDF viewer into a headless THPDFViewerModel and a TScrollBox-based view, keeping zoom, search, and navigation logic unit-testable
Hand-Edit a PDF in a Text Editor, Then Repair It
HotPDF writes diagnostic PDFs you can edit in a text editor and repairs them afterward in Delphi, rebuilding lengths, xref and trailer without reserializing
PDF Digital Signatures and PAdES in Delphi with HotPDF
Sign PDFs in Delphi with HotPDF: PFX one-call signing, ByteRange reservation for external signers, PAdES baseline fields, and document timestamps
Processing Large PDFs in Delphi with the HotPDF Direct File API
Process huge PDFs in Delphi without loading them into memory: HotPDF Direct File API handles, encrypted copy, page counts, and incremental updates
DocMDP and FieldMDP: Auditing PDF Revisions in Delphi
Classify every incremental PDF revision after signing with HotPDF AnalyzeLoadedSignatureRevisions and grade the result against DocMDP and FieldMDP in Delphi
Dynamic XFA Form Runtime in Delphi: HotPDF Transactions
Fill dynamic XFA forms in Delphi with HotPDF TXFAWidgetRuntime: atomic commit and rollback, bounded calculate and reflow passes, host neutral threading
ECDSA PDF Signature Verification in Delphi: DER to P1363
Convert CMS DER ECDSA signatures to IEEE P1363 for BCryptVerifySignature in Delphi: strict r and s decoding, curve provider names, and CMS signer matching
Edit Loaded PDF Metadata in Delphi Without Rewriting
Edit Title, Author, XMP, PageMode and bookmarks on an already-loaded PDF with HotPDF in Delphi, then save in place without rebuilding the xref or object graph
Importing EMF and WMF Vectors into Delphi PDFs with HotPDF
The HotPDF EMF and WMF interpreter maps GDI gradient fills to PDF axial shading and hatch brushes to tiling patterns, keeping Delphi vector output real
EN 16931 Schematron Rules Engine in Delphi with HotPDF
HotPDF validates EN 16931 Schematron business rules in Delphi with a native XPath 1.0 engine that skips XPath 2.0 checks and stubs out on Delphi 7
The EndDoc Bug That Silently Disabled Font Subsetting
Font subsetting that ran after the file was already written produced full fonts and no error. See how an EndDoc ordering bug hid in HotPDF and how to catch it
Extract Images From a Loaded PDF in Delphi: HotPDF
Decode images out of a loaded PDF in Delphi with HotPDF ExtractLoadedImage: Flate, LZW, JPEG, JPEG 2000, Indexed, CMYK, CCITT and JBIG2 filters to a TBitmap
Extract Text from a Loaded PDF in Delphi with HotPDF
Extract Unicode text from loaded PDFs in Delphi with HotPDF: ExtractLoadedPageText, layout-preserving extraction, ToUnicode CMaps, and font decode fallbacks
Font Subset Closure: Shaped Glyphs Lost in Delphi PDFs
Shaped Arabic and Indic glyphs render as .notdef when subset closure ignores GSUB output. How HotPDF unions shaping glyph IDs into the Delphi font subset
HotPDF on Free Pascal: Deflate, AES and Codec Limits
What changes when HotPDF compiles under Free Pascal and Lazarus: Pascal deflate and AES backends, stubbed native codecs, and four portability traps
HotPDF on Free Pascal and Lazarus: Win64 Support Limits
HotPDF builds on Free Pascal 3.2.2 and Lazarus 4.6 for Win64: the Delphi mode gate, why native codec objects will not link, and the serial render fallback
Free Pascal Win32: C Symbol Decoration in HotPDF
Free Pascal on Win32 decorates cdecl imports with a leading underscore but exports public names verbatim, and HotPDF bridges both without breaking Delphi
3D Color LUTs in PDF With Type 0 Sampled Functions
PDF Function Type 0 is a multi-dimensional interpolation table. See how HotPDF wraps it for 3D color LUTs and spot-color tint transforms in Delphi
PDF Type 2/3/4 Functions in Delphi: Exponential, PostScript
How HotPDF evaluates PDF Type 2 exponential, Type 3 stitching, and Type 4 PostScript calculator functions in Delphi, including the roll and rounding pitfalls
Rowspan Grids and Repeated Table Headers in HotPDF
HotPDF renders HTML tables with occupancy grids for rowspan, measured row heights and repeated headers across page breaks, with two documented refusals
HTML to PDF in Delphi: The HTML5 Paged-Media Path
HotPDF converts HTML5 to PDF in Delphi with a real CSS cascade, tables and page breaks, refusing network fetches and metering parser and layout budgets
Loading Hybrid-Reference PDFs From Word and Excel in Delphi
Word and Excel export hybrid-reference PDFs that load fine yet fail on resave. See how HotPDF reads the /XRefStm table and resolves them safely in Delphi
HotPDF Delphi Hyperlinks: PrintHyperlink Annotation Tips
HotPDF Delphi hyperlinks: PrintHyperlink URI links, AddURILink hotspots, AddGoToLink internal page navigation, multi-line workarounds, and PDF/UA notes
HotPDF Image Downsampling Kernels and Print Dithering
HotPDF adds separable bicubic and Lanczos3 kernels for image downsampling plus Floyd-Steinberg render dithering, and each one trades speed for quality
Indexed PDF Palettes in Delphi: Base Spaces and Cycles
How HotPDF normalizes Indexed PDF palettes from Gray, CMYK, Lab and ICCBased bases in Delphi, and guards against indirect reference cycles with a depth cap
Invariant PDF Number Formatting in Delphi with HotPDF
Why a decimal comma locale breaks PDF content streams in Delphi, and how HotPDF pins invariant number formatting across Type 1 fonts, SVG and FPC builds
Native JBIG2 Bilevel Image Compression in Delphi PDFs
JBIG2 gives scanned black-and-white pages the smallest PDF size. See how HotPDF writes JBIG2Decode streams and plugs in encoder backends in Delphi
Sharing JBIG2 Symbol Dictionaries Across Pages in Delphi
HotPDF merges JBIG2 symbol dictionaries across pages into one /JBIG2Globals stream in Delphi PDFs, cutting repeat glyph storage on multi-page scans
Adding JPEG 2000 Images to PDFs in Delphi with HotPDF
JPEG 2000 brings high bit-depth and wavelet compression to PDF images. See how HotPDF decodes JPXDecode streams and embeds JP2 and J2K pictures in Delphi
Declarative PDF Layout in Delphi with Tagged Output
HotPDF builds paginated PDF documents from a declarative layout tree in Delphi and emits the PDF/UA structure tree automatically across page breaks
Linearized PDF Output in Delphi: HotPDF Hint Tables
How HotPDF writes linearized PDF output for Fast Web View in Delphi: page partitioning, hint tables, layout convergence and the 4 GiB offset limit
PAdES LTV Evidence and Seed Values in HotPDF
Upgrade a freshly signed PDF from B-B to B-LT with one HotPDF call, complete the chain over AIA caIssuers, and enforce the seed values a field declares
PDF Predictor and LZWDecode Decoding in Delphi with HotPDF
How HotPDF decodes PDF DecodeParms in Delphi: PNG predictor row tags 10 to 15, TIFF Predictor 2 sample differencing, and LZW EarlyChange code widths
Post-Quantum and EdDSA PDF Signing with HotPDF in Delphi
How HotPDF verifies ML-DSA, Ed25519 and Ed448 CMS signatures in Delphi and signs through callback, remote or PKCS#11 providers that hold the private key
NChannel Spot Ink Consistency in Delphi with HotPDF
Write ISO 32000-2 NChannel color spaces in Delphi with HotPDF: DeviceN five-element form, per-spot Separation tints, and PDF/X-6n colorant table checks
PDF Decode Bombs in Delphi: HotPDF Filter Chain Budgets
Why per-filter limits miss nested PDF decode bombs, and how the HotPDF DecodeBudgetBytes ceiling bounds every stage of one filter chain in Delphi
Pure Pascal NIST Curve Arithmetic for PDF Signing
How HotPDF implements P-256, P-384, P-521, X25519 and X448 in pure Pascal, and how one borrow comparison in the Montgomery reduction hid a bug for a month
Non-Destructive PDF Highlight in Delphi: HotPDF Review Layer
HotPDF adds a highlight review layer in Delphi that keeps marker rectangles in memory, never rewrites the PDF, and stays aligned through zoom and rotation
Find PDF Memory Hogs: HotPDF Object Dependency Graphs
Attribute loaded PDF memory to the objects that retain it using HotPDF dependency graphs, dominator retained bytes, parser arena and string intern counters
Object Streams and Incremental Updates in Delphi with HotPDF
Cut Delphi PDF size with object streams and xref streams, then append changes as incremental updates with HotPDF while keeping earlier revisions intact
OpenType GSUB Stylistic Alternates in Pure Delphi
Stylistic sets and alternates live in a font's GSUB table. See how HotPDF resolves salt and ss01 to ss20 substitutions without HarfBuzz, in pure Delphi
CMYK Overprint Proofing and Render Devices in HotPDF
HotPDF renders a loaded PDF page to a bitmap, a printer HDC or a metafile through one device abstraction, and simulates CMYK overprint for press proofing
Export PDF Pages to SVG in Delphi with HotPDF
HotPDF converts any loaded PDF page into standalone SVG from Delphi, preserving text matrices, page rotation, image flips, dash patterns and hairline strokes
Parallel PDF Page Rendering in Delphi Without OOM
HotPDF renders PDF pages across worker threads in Delphi with ordered delivery, output backpressure and a memory budget that caps peak bitmap footprint
PDF Parser Hangs in Delphi: The Cursor That Never Moves
A parser branch that consumes no bytes turns a 40-byte malformed PDF into an endless loop. How HotPDF found four such stalls in Delphi and proved the fixes
PDF MAC Revision Chain Validation in Delphi (ISO 32004)
How HotPDF validates an ISO/TS 32004 PDF MAC revision chain in Delphi: per-revision prefix streams, signature ordering and authenticated permission bits
PDF 2.0, PDF/A-4 and PDF/UA-2 Output with HotPDF in Delphi
Write native PDF 2.0 from Delphi with HotPDF: PDF/A-4 profiles, PDF/UA-2 structure namespaces, associated files and the EndDoc checks that catch a broken tree
PDF/A, PDF/X, and PDF/UA Output in Delphi: a HotPDF Guide
Generate PDF/A, PDF/X, and PDF/UA compliant files from Delphi with HotPDF: output intents, tagged structure, ICC profiles, and veraPDF verification steps
Caching Font Subsets on Disk with HotPDF in Delphi
HotPDF reuses TrueType and OpenType subsets from a persistent disk cache across runs, with content-addressed keys, LRU eviction and readable statistics
Hardening a Delphi PDF Signer Against Malicious PKCS#12
A certificate parser is attack surface. See two real flaws in PKCS#12 and ASN.1 handling, an integer wraparound and a PBKDF2 denial of service, fixed in HotPDF
Automating PDF Preflight Checks in Delphi with HotPDF
Build an automated PDF preflight gate in Delphi: generate standards-clean files with HotPDF, then verify them with veraPDF and Acrobat before release
Print a Loaded PDF in Delphi with HotPDF and TPrinter
Print a loaded PDF from Delphi with HotPDF: drive TPrinter through PrintLoadedDocument, render pages into any HDC, and copy vector EMF pages to the clipboard
Stream Remote PDFs in Delphi: HotPDF Range Coalescing
Load PDFs over HTTP or slow shares with HotPDF THPDFCoalescingRandomAccessSource: block caching, adaptive read-ahead, cancellable reads and range statistics
PDF Redaction and N-up Stitch in Delphi with HotPDF
Cover regions and build N-up layouts on loaded PDFs in Delphi with HotPDF content-stream operators, plus the redaction security boundary you must respect
Reed-Solomon Bugs in Four Delphi 2D Barcode Encoders
How HotPDF fixed a reversed Reed-Solomon generator polynomial in four Delphi 2D barcode encoders, and why the QR, Data Matrix and PDF417 tests missed it
Rendering PDF Gradients in Delphi: Axial and Radial
HotPDF renders PDF axial and radial shadings via the sh operator in Delphi, discretizing each gradient into color bands evaluated by its function engine
Rendering Embedded PDF Fonts in Delphi with HotPDF
How HotPDF renders embedded PDF fonts in Delphi without installing them: TrueType glyf outlines, CFF Type 2 charstrings, Type 3 glyphs, and encoding maps
Render PDF Pages to Bitmap in Delphi with HotPDF
Render loaded PDF pages to TBitmap in Delphi with HotPDF: RenderLoadedPageToBitmap API, embedded TrueType/CFF glyph outlines, Type3 fonts, and page caching
Rendering Separation and DeviceN Spot Colors in Delphi
Render PDF Separation and DeviceN spot colors in Delphi with HotPDF: tint transform functions, Type 4 calculator evaluation, Lab white point adaptation
PDF Renderer Draws Nothing: Four Silent Delphi Bugs
Four silent HotPDF renderer bugs in Delphi: slash prefixed name operands, reversed cm concatenation, and a token index that zeroed twelve operators
Delphi PDF Reports with HotPDF: TextOut, Fonts, and Images
Practical HotPDF guide to Delphi PDF reports: TextOut coordinates, Unicode font embedding, JPEG and PNG image placement, and drawing primitives that scale
Decode Rotated QR Codes in PDF Pages with HotPDF
HotPDF decodes rotated QR symbols in loaded PDF pages by normalizing all eight D4 orientations inside the decoder rather than rotating the scan mask
Search and Replace Text in an Existing PDF with Delphi
Search and replace text in existing PDF files from Delphi using HotPDF: glyph-level search, reverse font encoding, and the real limits of subset fonts
Compare Two PDF Files in Delphi: Structure and Pixels
HotPDF compares two PDF files in Delphi by walking the object graph from the catalog and by diffing rendered pages, with budgets bounding both passes
Structure-Order PDF Text Extraction in Delphi With HotPDF
How HotPDF reads tagged PDF text in authoring order by walking the structure tree and reassembling glyphs by MCID, with a safe fallback for untagged pages
Import SVG into PDF as Reusable Form XObjects
HotPDF imports SVG artwork into PDF as a reusable Form XObject in Delphi, keeping vector gradients, clipping and links while refusing scripts and external refs
Flatten PDF Annotations That Have No /AP Stream in Delphi
HotPDF v2.743.0 bakes PDF annotations with no /AP stream in Delphi, synthesizing widget and markup appearances so NeedAppearances form values survive
Render a Data Table to PDF in Delphi with HotPDF
Draw dataset rows as a real PDF table in Delphi: compute column widths, align cell text, draw grid lines, and repeat the header when the table spans pages
Full Justification for PDF Text in Delphi with HotPDF
Justified PDF text needs script-aware spacing and fast width measurement. See how HotPDF justifies Latin and CJK lines and cuts GDI round-trips in Delphi
PDF Tiling Pattern Rendering in Delphi with HotPDF
How HotPDF renders PDF tiling patterns in Delphi: pattern state across q and Q, clipped fill and stroke paths, visible tile ranges, and hard tile budgets
Typed PDF Table Extraction in Delphi Across Page Breaks
How HotPDF ExtractLoadedTypedTables rebuilds tables from a loaded PDF in Delphi: column tolerance merging, conservative cross-page continuation, typed values
Detecting Missing PDF Glyphs at Draw Time in Delphi
HotPDF can record every code point that would render as tofu while the page is being drawn, then route the gap through per-script font fallback chains
Variable Fonts in PDF: Static Instancing in Delphi
HotPDF turns OpenType variable fonts into static PDF-embeddable instances in Delphi, baking axis values into outlines, metrics and rebuilt sfnt tables
Verify PDF Digital Signatures in Delphi with HotPDF
Verify PDF digital signatures in Delphi with HotPDF: read signer details, re-hash ByteRange bytes, check CMS/RSA signatures, and see what svValid guarantees
WebP to PDF in Delphi: Inside the HotPDF VP8L Decoder
HotPDF decodes WebP lossless VP8L in pure Object Pascal so AddImageFromFile accepts .webp with no DLL, plus the RFC 9649 bit traps that broke it
XFA to AcroForm Flattening in Delphi Using HotPDF
Convert dynamic XFA forms to native AcroForm in Delphi with HotPDF FlattenLoadedXFA, review flatten warnings, and handle archival and PDF/A limits
Flattening XFA Rich-Text Hyperlinks to PDF Links in Delphi
XFA forms store rich text as an HTML subset. See how HotPDF flattens exData runs and turns their a-href links into native PDF Link annotations in Delphi
Import and Export PDF Annotations as XFDF in Delphi
Export and import PDF annotations as XFDF in Delphi with HotPDF: ISO 19444-1 round-trip for lines, polygons, ink, interior color and rich text comments
XPS and OpenXPS to PDF in Delphi: Coordinates and Brushes
How HotPDF converts XPS and OpenXPS to PDF in Delphi: the 0.75 fixed-page matrix, VisualBrush Form XObjects, ImageBrush tiling patterns and elliptical shading
ZUGFeRD and Factur-X E-Invoices in Delphi with HotPDF
Generate, detect, and validate ZUGFeRD and Factur-X e-invoices in Delphi with HotPDF: PDF/A-3 embedding, EN 16931 Schematron rules, and honest engine limits
PDF Annotations in Delphi with HotPDF: Types and Rects
Add PDF annotations in Delphi with HotPDF: text notes, free text, squares, and stamps. How a rect places each one and how they differ from AcroForm fields
RtLTextOut in HotPDF: Right-to-Left PDF Text in Delphi
HotPDF RtLTextOut reference for Delphi: signature, parameters, charset 178/177 setup, RegisterUnicodeTTF, a working example, and common RTL errors fixed