Poppler.Net 0.8.0

Poppler.Net 26.07

Poppler.Net is an in-progress, source-level managed C# port of Poppler 26.07.0. It contains no C++/CLI, P/Invoke, native shared library, external process invocation, or native NuGet dependency.

This 0.8.0 compatibility release is not a complete replacement for libpoppler. It implements the PDF object/xref layer, document and page discovery, common stream filters, metadata, embedded files, structured font/text extraction, a backend-neutral vector display list and an SVG vector preview and a managed RGBA page rasterizer. It can open Standard Security Handler revisions 2–6 with user or owner passwords and decode common simple, composite, CID and vertical text paths. The graphics slice interprets paths, clipping, Form/Image XObjects, tiling patterns and axial/radial shadings. The image slice decodes common raw and compressed Image XObjects, converts calibrated and special color spaces to sRGB, exposes pixels, writes PNG and embeds decoded images in SVG. The raster slice paints paths, images, patterns, gradients and text in exact content-stream order. Managed outline readers cover embedded TrueType, CFF1/CFF2 Type 2 and Type 1 programs; Type 3 CharProcs, text paint/clip modes, inline images and file-based Base-14 substitution are also integrated. Alpha 2 uses Poppler's canonical Base-14 widths when /Widths is omitted and fits substituted outlines to the PDF advance so proportional text does not become monospaced or overlap. Alpha 3 adds filter-aware inline-image boundaries, soft-mask transfer functions and Poppler-compatible page-box normalization/fallback. Beta 1 adds external file-based CMaps with inheritance, initial CFF2/default-instance execution, targeted OpenType vertical/ligature substitution and multi-candidate Narrow/Condensed font matching. Beta 2 adds all four triangle/patch mesh shading families, uncolored tiling patterns, calculator transfer functions, advanced transparency-group surfaces and process-CMYK overprint preview. The stable release preserves the RC 1 public API freeze, makes shared-document read paths concurrency safe, snapshots caller-owned option collections and makes external font/CMap discovery deterministic. See docs/COMPATIBILITY.md before adopting it.

Build

Requirements: .NET SDK 8.0.423. global.json pins the selected feature band.

dotnet build Poppler.Net.sln
dotnet run --project tests/Poppler.Net.Tests -- --noresult

./build.sh performs restore, Release build, NUnitLite regression tests and NuGet packaging. It also rejects native or mixed-mode binaries anywhere in the restored NuGet graph. The production library uses three audited managed runtime packages for JPEG, JPEG 2000 and JBIG2. NUnit and its in-process NUnitLite runner are approved test-only managed dependencies. See VERIFICATION.md for the checks completed in the creation environment.

RC4, MD5, SHA-2 and AES are reached only through managed C# or the .NET cryptography API. The solution does not ship OpenSSL, a platform crypto library or any native cryptography asset.

CI and NuGet publishing

The GitHub Actions workflow builds, tests, verifies and packs the solution on Ubuntu, Windows and macOS for pushes to master and pull requests. It also stores the generated .nupkg as a workflow artifact.

Publishing a GitHub Release runs the same gates and then publishes the package to NuGet.org through OIDC Trusted Publishing. Configure a nuget.org trusted publishing policy for repository owner MiLattanzio, repository Poppler.Net, workflow ci.yml and environment nuget.org. Add a NUGET_USER secret containing the nuget.org profile username (not the email address) to the protected nuget.org GitHub environment. No long-lived NuGet API key is required. Ordinary pushes, pull requests and manual workflow runs never execute the deploy job.

Package author and project metadata identify Mi Lattanzio and https://github.com/MiLattanzio/Poppler.Net.

CLI

dotnet run --project src/Poppler.Net.Cli -- info input.pdf
dotnet run --project src/Poppler.Net.Cli -- text input.pdf --page 1
dotnet run --project src/Poppler.Net.Cli -- fonts input.pdf
dotnet run --project src/Poppler.Net.Cli -- graphics input.pdf --page 1
dotnet run --project src/Poppler.Net.Cli -- images input.pdf output-images
dotnet run --project src/Poppler.Net.Cli -- render input.pdf page.png --page 1 --dpi 144
dotnet run --project src/Poppler.Net.Cli -- render input.pdf page.png --font-dir fonts
dotnet run --project src/Poppler.Net.Cli -- render input.pdf page.png --cmap-dir cmaps
dotnet run --project src/Poppler.Net.Cli -- attachments input.pdf output-dir
dotnet run --project src/Poppler.Net.Cli -- svg input.pdf page.svg --page 1

Encrypted input accepts --user-password VALUE or --owner-password VALUE. Command-line values may be visible to other local processes; applications should normally pass secrets through the Document API instead.

API

using Poppler;
using Poppler.Rendering;

using var document = Document.LoadFromFile("input.pdf");
Console.WriteLine($"{document.Pages} pages, PDF {document.PdfVersion}");

Page page = document.CreatePage(0);
Console.WriteLine(page.Text());
foreach (TextBox word in page.TextList())
    Console.WriteLine($"{word.Text} at {word.BoundingBox}");
foreach (FontInfo font in page.Fonts)
    Console.WriteLine($"{font.Name}: {font.Type}, {font.EmbeddedFormat}");
foreach (PdfGraphicsElement element in page.Graphics)
    Console.WriteLine($"{element.GetType().Name}: {element.State.Transform}");
foreach (PdfImage image in page.Images)
{
    Console.WriteLine($"{image.ResourceName}: {image.Width}x{image.Height}, stride {image.BytesPerRow}");
    image.SavePng($"{image.ResourceName}.png");
}
page.SavePng("page.png", new RasterRenderOptions
{
    Dpi = 144,
    Antialiasing = 4
});

All page indices in the API are zero-based. CLI page numbers are one-based.

Encrypted files can be opened directly:

using var document = Document.LoadFromFile(
    "protected.pdf",
    userPassword: "secret");

Console.WriteLine(document.EncryptionInfo?.Revision);
Console.WriteLine(document.Permissions);

If no correct password is supplied, the returned document remains locked. Unlock(ownerPassword, userPassword) retries from the original bytes and, matching Poppler's C++ API, returns the document's new locking status (false means unlocked).

Design

• Core/ is the managed counterpart of Poppler's Object, Lexer, Parser, XRef, Stream and filter layers.
• DocumentModel/ corresponds to PDFDoc, Catalog, Page, Outline, FileSpec and page labels.
• Text/ corresponds to the first managed slice of TextOutputDev, font encodings, GfxFont, CID metrics and ToUnicode/encoding CMaps.
• Graphics/ is the first managed slice of Gfx, GfxState, Function, patterns and Form XObjects and produces a backend-neutral display list.
• Color/ ports calibrated, ICC matrix/shaper and special color conversion.
• Images/ decodes Image XObjects, masks and common PDF image codecs into tightly packed managed pixel buffers.
• Rendering/ consumes that display list in managed SVG and RGBA/PNG backends; its raster core maps the initial Splash path, image, antialiasing, blend and transparency-group responsibilities.

The implementation uses bounded allocations, recursion limits and decoded stream limits because PDFs are untrusted input. Defaults can be changed with PdfReadOptions.

The 0.2 foundation additionally supports header-relative offsets after a leading transport prefix, validates object generations and compressed-object indices, and reconstructs xref/object streams during damaged-xref recovery. See docs/FOUNDATION.md.

The 0.3 slice ports SecurityHandler/Decrypt: legacy password padding, RC4 object keys, AES-128/256, revision 6 hardened hashing, crypt filters, metadata exclusion and PDF permission flags. See docs/SECURITY.md.

The 0.4 slice separates code-to-CID and code-to-Unicode maps, reads horizontal and vertical CID metrics, recognizes embedded Type 1/CFF/TrueType/ OpenType programs and adds an sfnt cmap fallback, Type 3 metrics, vertical advancement and improved reading order. See docs/FONTS_AND_TEXT.md.

The 0.5 slice interprets vector paths and painting state, clipping, device colors, common ExtGState entries, Form/Image XObjects, colored tiling patterns and type 2/3 shadings. See docs/GRAPHICS.md.

The 0.6 slice decodes raw/predictor, JPEG, JPEG 2000, JBIG2 and CCITT images, applies image masks and soft masks, evaluates sampled/exponential/stitching functions, converts CalGray/CalRGB/Lab/ICCBased/Indexed/Separation/DeviceN, and adds Page.Images, managed PNG export and SVG image embedding. See docs/IMAGES_AND_COLOR.md.

The 0.7 slice adds managed page rasterization, supersampled coverage, straight-alpha PDF compositing, common separable and nonseparable blend modes, Form transparency groups, Alpha/Luminosity soft masks, page rotation and embedded TrueType outline painting. Alpha 2 additionally retains original PDF character codes/CIDs for glyph selection, reads TrueType cmap format 0 subsets and preserves DeviceGray/DeviceRGB/DeviceCMYK text colors. See docs/RENDERING.md.

The 0.8 slice moves text into the graphics display list, preserves exact text/vector/image ordering, executes text inside Forms, implements all Tr fill/stroke/clip modes and decodes raw inline images. It adds managed CFF1 Type 2 and Type 1 charstring outline readers, Type 3 CharProc execution and optional managed font-file substitution for Base-14/non-embedded fonts. Alpha 2 ports the canonical Base-14 width tables and reconciles replacement outline geometry with PDF text advances. Alpha 3 adds filter-aware inline image recovery, soft-mask transfer functions and damaged page-tree geometry fallback. Beta 1 adds bounded external CMap discovery and inheritance, a managed CFF2 default-instance path, non-contextual vert/vrt2 and liga/rlig GSUB substitution, and improved Narrow/Condensed font-file matching. Beta 2 adds shading types 4–7, PaintType 2 patterns, bounded calculator functions, isolated/non-isolated/knockout group surfaces and process-CMYK overprint-mode-1 preview. The stable release preserves the RC 1 public API freeze and hardens concurrent read-only use, option ownership and deterministic resource discovery. Full variable-font interpolation, complex shaping, ICC proofing and spot-color overprint remain outside this release.

License and provenance

Poppler is GPL, not LGPL. This port is distributed under GPL-2.0-or-later and retains Poppler provenance. See LICENSE, NOTICE.md, and docs/PORTING.md. Applications distributing a derivative of this code must comply with the GPL.