ClearPDF

Simple local PDF reader for Windows 10+. WPF · .NET 8 · no ribbons, AI, or cloud.

UI mocks (locked look): docs/mocks/ — empty/open, reader, password modal.

Download (Windows)

Grab the latest installer from Releases (current: v1.2.0):

1. Download ClearPDF-Setup.exe
2. Run it (SmartScreen may show Unknown publisher once — More info → Run anyway; the build is unsigned)
3. Optional: check “Set ClearPDF as default for .pdf”

Self-contained ~166 MB on disk after install. No .NET install required.

Engine choice

Docnet.Core (NuGet) — managed PDFium bindings. Chosen over PdfiumViewer because it targets modern .NET, restores cleanly with net8.0-windows, and keeps the app on a thin WPF shell instead of WinForms hosts.

Piece	License
ClearPDF app code	MIT (see LICENSE)
Docnet.Core	Apache-2.0
PDFium (native)	Apache-2.0 / BSD-style (Google PDFium)

Passwords are used for view unlock only and are never stored.

Requirements (Win10 build machine)

• Windows 10 or 11
• .NET 8 SDK (includes Windows Desktop / WPF)
• Optional: Visual Studio 2022 with “.NET desktop development”

This repo was scaffolded on a Linux box. WPF does not run there. Build and run on Windows.

Build & run

cd ClearPDF
dotnet restore
dotnet build
dotnet run --project src\ClearPDF\ClearPDF.csproj

Tests (Core helpers — runs on Linux / any OS with .NET 8 SDK):

dotnet test
# equivalent: dotnet test tests/ClearPDF.Tests/ClearPDF.Tests.csproj

On non-Windows, the WPF project is a no-op stub so solution-level dotnet test only exercises ClearPDF.Core.

Open from Explorer / command line

ClearPDF opens the first existing .pdf argument after the exe (spaces/quoted paths OK). No-arg launch still shows the empty Open screen.

ClearPDF.exe "C:\path\to\file.pdf"

Code QA smoke: associate or “Open with” ClearPDF → double-click a PDF → document renders (not the empty Open screen). Drag-drop a PDF onto the window also works. Helper: CommandLinePdfArgs in Core (covered by CommandLinePdfArgsTests).

PDFium native notes

Docnet.Core needs pdfium.dll (and related natives) at runtime on Windows.

1. dotnet restore / dotnet build pulls Docnet.Core. Depending on package version, natives may arrive via runtime assets or a companion package.
2. If the app starts but shows the stub page banner (“PDFium natives not loaded”), copy pdfium.dll next to ClearPDF.exe (usually src\ClearPDF\bin\Debug\net8.0-windows\).
3. Official / community native builds: bblanchon/pdfium-binaries (pick the Windows x64 build matching your RID).
4. On non-Windows scaffold machines, the factory probes for natives and falls back to StubPdfDocument so the UI shell still opens. Real render/find/print quality needs Win10 + natives.

Factory entry point: DocnetPdfDocumentFactory in src/ClearPDF/Services/DocnetPdfDocument.cs.

Logging

Local file logs only (%LocalAppData%\ClearPDF\logs\clearpdf-yyyyMMdd.log): open failures, password errors, unhandled exceptions — no network/Sentry/telemetry.

Render performance

Image-heavy PDFs (brochures, full-bleed photos) used to hitch because GetImage ran on the UI thread and every zoom rebuilt every page via fixed PageDimensions(2.0) + TransformedBitmap.

Current architecture:

Piece	Behavior
Target DPI	RenderPage opens a short-lived Docnet reader at PdfRenderScale.CapPixelsPerPoint(zoom, pageW, pageH) — no TransformedBitmap thrash
Caps	Longest edge ≤ 4096px, ≤ ~8M pixels/page
Cache	PageRasterCache / PageBitmapCache keyed by (pageIndex, quantizedZoom), capped at 24 page rasters; thumbs are a separate map
Threads	Background raster → Dispatcher swaps Image.Source; last frame stays visible
Zoom	Debounced settle (120ms); pan/scroll does not re-Docnet or rebuild thumbs
Scroll	Chrome updates immediately; sharp window is debounced (80ms) and does not cancel in-flight neighbors
Virtualize	Sharp bitmaps for current ±2 pages; far pages keep low-res preview
Thumbnails	Sequential low-res fill at open (separate cache); scroll/zoom only update selection chrome
Password	Unlock once into memory bytes for re-raster; password never retained/stored
Page size	Still PDF points via baseline reader (PdfPageSize)

Helpers: PdfRenderScale, PageRenderPlanner, PageRasterCache<T> in Core (unit-tested). Details: docs/render-perf.md.

Runnable tests without WPF

UI-free logic lives in src/ClearPDF.Core/ (net8.0): ZoomHelper, FindHelper, RecentFilesService, PdfPageSize, RecentFileEntry, CommandLinePdfArgs, PageRenderPlanner, ScrollPagePicker, PageRasterCache<T>, PrintPageRange, PdfUnlockPolicy, PageSelection, PdfPageExtract. ClearPDF.Tests references Core only, so dotnet test runs on Linux. The WPF app (net8.0-windows) references Core and still requires Windows to build/run the shell.

v1 scope

In

• Open PDF (file dialog + recent list + command-line / Explorer “Open with” + window drag-drop)
• Render pages (page hero + left thumbnails)
• Scroll / PageUp·PageDown / Home·End
• Zoom in/out, fit width, fit page
• Find next/prev (extracted text)
• Print, Save As (copy file)
• v1.2 page-selection (ship version 1.2.0): multi-select thumbs (click / Ctrl-toggle / Shift-range; #5A7FA6 border + check beside the gray page number); Save pages as... (toolbar, overflow, tiny 2-line thumb menu) writes a new PDF via Docnet Split; Print Selection is the current page when size is 1, the selected set when multi; Save As with a multi-select shows a quiet in-window card (Selected pages (n) | Entire document) — no title-bar modal. Steal: docs/mocks/v12-STEAL.md
• Password prompt for encrypted PDFs (unlock for viewing only)
• Error banner UI
• Bookmarks/outline when the engine exposes them (stubbed TODO if Docnet has no outline API)

Out

• Forms, annotations, DRM/IRM beyond open-password
• JavaScript, OCR, sync/cloud accounts
• Ribbons / AI features

v2 (ideas)

• Proper outline/bookmarks panel
• Text selection / copy
• Continuous vs single-page modes polish
• Tile / progressive decode for very large pages
• Optional dark canvas

Layout map

Screen	Mock	Code
Empty + Recent	docs/mocks/chrome-arc-empty.png (v1.1) / 01-empty-open.png	EmptyView in MainWindow.xaml
Reader	docs/mocks/chrome-arc-reader.png (v1.1) / 02-reader.png	ReaderView + one icon toolbar + status bar
v1.2 thumbs / extract chrome	docs/mocks/v12-01-multiselect.png, v12-02-context-menu.png, v12-03-save-as-choice.png	Thumbnail multi-select, 2-line thumb menu, Save As one-liner
Password	docs/mocks/03-password.png	Views/PasswordDialog.xaml

Accent: #5A7FA6 (one muted blue — Open CTA pill, selected thumb, find hit). Canvas: #F1F2F7 (sampled from chrome-arc-reader.png so the white page pops). Toolbar: one ~36px icon strip (Segoe MDL2), labels on hover. No ribbons.

Deferred (later 1.1.x): first-open Welcome card (docs/mocks/chrome-arc-intro.png) is not in this polish pass. Empty-state stays Open + Recent.

Graphics/Steve empty-state gate: docs/qa.md.

Project tree

ClearPDF/
  ClearPDF.sln
  LICENSE
  README.md
  .gitignore
  docs/mocks/
  docs/qa.md             # Graphics/Steve standing QA gates
  docs/test-output.txt   # captured `dotnet test` on Linux
  src/ClearPDF.Core/     # net8.0 — ZoomHelper, FindHelper, RecentFiles, PdfPageSize, PdfRenderScale, CommandLinePdfArgs, PageRenderPlanner, PrintPageRange, PdfUnlockPolicy, PageSelection, PdfPageExtract
  src/ClearPDF/          # net8.0-windows WPF shell (refs Core)
    ClearPDF.csproj
    App.xaml
    MainWindow.xaml
    Models/              BookmarkItem
    Services/            Docnet + stub, AppLog (local file logs)
    Views/               PasswordDialog
  tests/ClearPDF.Tests/  # net8.0 → Core only