Graphite

Read, mark up, and edit PDFs — a fast, native Windows app.

Graphite is a WPF (.NET 8) PDF viewer and editor with an original liquid-glass design: a floating command bar, a pill-shaped page bar, and translucent panels over the Windows 11 Mica backdrop. No Electron, no browser engine — PDFium rendering and a pure managed core keep it quick and small.

Download

Grab the latest Graphite-vX.Y.Z-win-x64.zip from Releases, unzip, and run Graphite.exe. It's a single self-contained executable — no installer, no .NET runtime needed.

Graphite updates itself: it checks for new releases at startup (quietly — it only speaks up when there's something new) and from File → Check for updates…. Accepting an update downloads the package, swaps the files, and restarts the app.

Features

Viewing — PDFium-based rendering (fast, high-fidelity), eased smooth scrolling, smooth zoom (buttons, Ctrl+wheel, fit-width, click the zoom % to reset to 100%), continuous / single-page / two-page spread layouts, page thumbnails, outline navigation, full-text search with per-page highlights, and multi-tab support — each tab remembers its scroll position.

Reading — fullscreen mode (F11, Esc to leave), dark pages (inverted page colors for night reading, moon button in the page bar), and reading history: Alt+Left / Alt+Right walks back and forward through your jumps.

Pen & markup — highlight, underline and strikethrough that snap to words, a freehand marker, and a pressure-friendly pen tuned for styluses: full-rate pen sampling (no coalesced points thrown away) with a jitter filter and an overshoot-free curve fit, so handwriting follows the pen instead of lagging and snapping. Plus rectangles, ellipses, arrows, text boxes (click and type right on the page; double-click later for font, size and colors), sticky notes, and an eraser that splits strokes exactly where you drag.

Signature — draw your signature once and stamp it onto any page; it's kept between sessions. Click the signature tool again (or right-click it) to redraw.

Comments — every annotation carries a comment with threaded replies. The Markup panel lists everything in the document; click a card to jump to it. Annotations are written as standard PDF annotations, so they open in any other viewer. Undo/redo (Ctrl+Z / Ctrl+Y) covers annotations and page operations alike.

Page editing — insert (blank or from another PDF), delete, reorder, rotate and extract pages; merge PDFs; split into single-page files. Right-click a thumbnail for per-page operations. Annotations travel with their pages through every operation.

Content editing — an Edit Text tool (drag over a region, type the replacement — the region is covered and re-typeset, how most PDF editors work under the hood since PDF has no reflowable text) and an Insert Image tool; images can also be pasted straight from the clipboard (Ctrl+V).

Command palette — Ctrl+K opens a searchable palette with every command in the app; type a few letters, Enter runs it.

Conversion — export to Word (.docx, reconstructed paragraphs), Excel (.xlsx, one sheet per page with inferred columns), PowerPoint (.pptx, one slide per page) and PNG/JPEG/WebP images. Opening a Word/Excel/PowerPoint file converts it to a PDF saved next to the original and opens that (uses the installed Microsoft Office via COM; requires Office).

OCR — Tesseract-based recognition for scanned pages. Recognized pages become searchable and selectable immediately, and an invisible text layer is baked into the PDF so it stays searchable after saving, in any viewer.

Security & info — password-protected PDFs open with a prompt and stay protected when you save; any document can be saved as an encrypted copy. A properties dialog shows title, author, dates, producer, PDF version, page size and file size.

Platform — dark/light themes (persisted), Windows 11 Mica backdrop, per-monitor DPI awareness, drag-and-drop, recent files, OneDrive quick-open, printing at 300 dpi with annotations included, and a script to register the .pdf file association.

Building

Requirements: Windows 10/11 and the .NET 8 SDK (or Visual Studio 2022 with the ".NET desktop development" workload).

dotnet build Graphite.sln -c Release
dotnet run --project src/Graphite.App

Or open Graphite.sln in Visual Studio and press F5. NuGet restores everything (PDFtoImage/PDFium, PdfSharp, PdfPig, DocumentFormat.OpenXml, ClosedXML, Tesseract, CommunityToolkit.Mvvm).

Tests

dotnet test src/Graphite.Tests

Unit tests cover the Core engine: page-range parsing, text layout reconstruction, annotation codec round-trips (through real PDFs), color/geometry helpers, search word mapping, and encryption round-trips. CI builds and tests on every push and PR; tagging v* publishes a release zip automatically.

Optional setup

• OCR data — powershell -File tools\get-tessdata.ps1 downloads eng.traineddata into src/Graphite.App/tessdata (copied next to the exe on build). Pass -Languages eng,deu,... for more languages.
• File association — after building: powershell -File tools\register-file-association.ps1 -ExePath <path>\Graphite.exe, then choose Graphite for .pdf in Settings → Default apps (Windows requires that final choice to be made by the user).
• App icon — python tools\gen_icon.py regenerates Assets\Graphite.ico / Graphite-256.png (the pencil-and-"G" artwork is generated, not a stock asset).

Architecture

Graphite.sln
├─ src/Graphite.Core     ── UI-independent engine (net8.0)
│   ├─ Rendering/        PDFium rasterizer (PDFtoImage), thread-safe
│   ├─ Text/             PdfPig text index: word geometry, search, outline, selection
│   ├─ Pdf/              PdfSharp page surgery: merge, split, extract, rotate, reorder
│   ├─ Annotations/      model + codec that reads/writes real PDF annotations
│   ├─ Editing/          cover-and-replace text edits, image placement
│   ├─ Ocr/              Tesseract engine + invisible-text-layer writer
│   └─ Export/           docx / xlsx / pptx / image exporters, Office→PDF via COM
└─ src/Graphite.App      ── WPF shell (net8.0-windows)
    ├─ Themes/           light/dark palettes, styles, original icon geometry
    ├─ ViewModels/       Main / Document / Page / Annotation (CommunityToolkit.Mvvm)
    ├─ Controls/         AnnotationLayer (per-page overlay) + StrokeSmoothing (pen input)
    ├─ Services/         theme/settings, signature store, printing, self-updater
    ├─ Views/            MainWindow + dialogs (input, edit-text, password, signature, properties)
    └─ Interop/          Mica backdrop + dark title bar (DWM)

src/Graphite.Tests       ── xUnit tests for the Core engine

Design decisions worth knowing:

• Operations are pure (bytes in → bytes out). Before any structural operation the current annotations are baked into the PDF and re-read afterwards — so they stay glued to their pages through deletes, moves and merges.
• Rendering is decoupled from layout. Pages lay out at size × zoom immediately; bitmaps re-render ~1.5× oversampled in the background (debounced on zoom), so zooming feels instant.
• The viewer virtualizes. Pages render lazily as they scroll into view; thumbnails likewise.
• Pen input keeps every sample. Stylus hardware reports faster than the UI dispatches; Graphite drains the coalesced point queue instead of dropping it, then fits a midpoint-quadratic curve that can't overshoot into loops.

Design language

Graphite pairs its warm-gray monochrome identity with a liquid-glass treatment that sits naturally on Windows 11: a floating glass command bar and a pill-shaped page bar hover over the document, side panels are translucent gradient glass with a luminous top edge and soft radii, and tabs are pills. Buttons animate on hover and compress on press. The system accent color appears sparingly — checked tools, focus rings, the unsaved-changes dot — while functional color stays reserved for the document itself. Icons are original 1.3px hairline stroke geometry (no icon font), drawn to read clearly at 16px; the app icon is a generated artwork: a pencil resting on the "G" stroke it just drew.

Known limitations

• Text editing is cover-and-replace (see above) — original fonts are not re-embedded.
• Word/Excel export reconstructs layout heuristically from text geometry; complex layouts and tables degrade gracefully but imperfectly.
• Creating PDFs from Office files requires Microsoft Office to be installed.
• Annotations on pages rotated via /Rotate metadata (rather than upright content) can be offset; upright documents — the overwhelming majority — behave correctly.
• Graphite writes annotations without appearance streams; virtually all viewers (Acrobat, browsers, SumatraPDF) regenerate them automatically.
• The self-updater needs write access to the install folder; if it can't swap the files it falls back to opening the release page.